diff --git a/include/avb/avb_ab_flow.h b/include/avb/avb_ab_flow.h
new file mode 100644
index 0000000..07db2d5
--- /dev/null
+++ b/include/avb/avb_ab_flow.h
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_AB_H) && !defined(AVB_COMPILATION)
+#error \
+    "Never include this file directly, include libavb_ab/libavb_ab.h instead."
+#endif
+
+#ifndef AVB_AB_FLOW_H_
+#define AVB_AB_FLOW_H_
+
+#include "avb/avb_ab_ops.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Magic for the A/B struct when serialized. */
+#define AVB_AB_MAGIC "\0AB0"
+#define AVB_AB_MAGIC_LEN 4
+
+/* Versioning for the on-disk A/B metadata - keep in sync with avbtool. */
+#define AVB_AB_MAJOR_VERSION 1
+#define AVB_AB_MINOR_VERSION 0
+
+/* Size of AvbABData struct. */
+#define AVB_AB_DATA_SIZE 32
+
+/* Maximum values for slot data */
+#define AVB_AB_MAX_PRIORITY 15
+#define AVB_AB_MAX_TRIES_REMAINING 7
+
+/* Struct used for recording per-slot metadata.
+ *
+ * When serialized, data is stored in network byte-order.
+ */
+typedef struct AvbABSlotData {
+  /* Slot priority. Valid values range from 0 to AVB_AB_MAX_PRIORITY,
+   * both inclusive with 1 being the lowest and AVB_AB_MAX_PRIORITY
+   * being the highest. The special value 0 is used to indicate the
+   * slot is unbootable.
+   */
+  uint8_t priority;
+
+  /* Number of times left attempting to boot this slot ranging from 0
+   * to AVB_AB_MAX_TRIES_REMAINING.
+   */
+  uint8_t tries_remaining;
+
+  /* Non-zero if this slot has booted successfully, 0 otherwise. */
+  uint8_t successful_boot;
+
+  /* Reserved for future use. */
+  uint8_t reserved[1];
+} AVB_ATTR_PACKED AvbABSlotData;
+
+/* Struct used for recording A/B metadata.
+ *
+ * When serialized, data is stored in network byte-order.
+ */
+typedef struct AvbABData {
+  /* Magic number used for identification - see AVB_AB_MAGIC. */
+  uint8_t magic[AVB_AB_MAGIC_LEN];
+
+  /* Version of on-disk struct - see AVB_AB_{MAJOR,MINOR}_VERSION. */
+  uint8_t version_major;
+  uint8_t version_minor;
+
+  /* Padding to ensure |slots| field start eight bytes in. */
+  uint8_t reserved1[2];
+
+  /* Per-slot metadata. */
+  AvbABSlotData slots[2];
+
+  /* Reserved for future use. */
+  uint8_t reserved2[12];
+
+  /* CRC32 of all 28 bytes preceding this field. */
+  uint32_t crc32;
+} AVB_ATTR_PACKED AvbABData;
+
+/* Copies |src| to |dest|, byte-swapping fields in the
+ * process. Returns false if the data is invalid (e.g. wrong magic,
+ * wrong CRC32 etc.), true otherwise.
+ */
+bool avb_ab_data_verify_and_byteswap(const AvbABData* src, AvbABData* dest);
+
+/* Copies |src| to |dest|, byte-swapping fields in the process. Also
+ * updates the |crc32| field in |dest|.
+ */
+void avb_ab_data_update_crc_and_byteswap(const AvbABData* src, AvbABData* dest);
+
+/* Initializes |data| such that it has two slots and both slots have
+ * maximum tries remaining. The CRC is not set.
+ */
+void avb_ab_data_init(AvbABData* data);
+
+/* Reads A/B metadata from the 'misc' partition using |ops|. Returned
+ * data is properly byteswapped. Returns AVB_IO_RESULT_OK on
+ * success, error code otherwise.
+ *
+ * If the data read from disk is invalid (e.g. wrong magic or CRC
+ * checksum failure), the metadata will be reset using
+ * avb_ab_data_init() and then written to disk.
+ */
+AvbIOResult avb_ab_data_read(AvbABOps* ab_ops, AvbABData* data);
+
+/* Writes A/B metadata to the 'misc' partition using |ops|. This will
+ * byteswap and update the CRC as needed. Returns AVB_IO_RESULT_OK on
+ * success, error code otherwise.
+ */
+AvbIOResult avb_ab_data_write(AvbABOps* ab_ops, const AvbABData* data);
+
+/* Return codes used in avb_ab_flow(), see that function for
+ * documentation of each value.
+ */
+typedef enum {
+  AVB_AB_FLOW_RESULT_OK,
+  AVB_AB_FLOW_RESULT_OK_WITH_VERIFICATION_ERROR,
+  AVB_AB_FLOW_RESULT_ERROR_OOM,
+  AVB_AB_FLOW_RESULT_ERROR_IO,
+  AVB_AB_FLOW_RESULT_ERROR_NO_BOOTABLE_SLOTS
+} AvbABFlowResult;
+
+/* Get a textual representation of |result|. */
+const char* avb_ab_flow_result_to_string(AvbABFlowResult result);
+
+/* High-level function to select a slot to boot. The following
+ * algorithm is used:
+ *
+ * 1. A/B metadata is loaded and validated using the
+ * read_ab_metadata() operation. Typically this means it's read from
+ * the 'misc' partition and if it's invalid then it's reset using
+ * avb_ab_data_init() and this reset metadata is returned.
+ *
+ * 2. All bootable slots listed in the A/B metadata are verified using
+ * avb_slot_verify(). If a slot is invalid or if it fails verification
+ * (and |allow_verification_error| is false, see below), it will be
+ * marked as unbootable in the A/B metadata and the metadata will be
+ * saved to disk before returning.
+ *
+ * 3. If there are no bootable slots, the value
+ * AVB_AB_FLOW_RESULT_ERROR_NO_BOOTABLE_SLOTS is returned.
+ *
+ * 4. For each bootable slot, the Stored Rollback Indexes are updated
+ * such that for each rollback index location, the Stored Rollback
+ * Index is the largest number smaller than or equal to the Rollback
+ * Index of each slot.
+ *
+ * 5. The bootable slot with the highest priority is selected and
+ * returned in |out_data|. If this slot is already marked as
+ * successful, the A/B metadata is not modified. However, if the slot
+ * is not marked as bootable its |tries_remaining| count is
+ * decremented and the A/B metadata is saved to disk before returning.
+ * In either case the value AVB_AB_FLOW_RESULT_OK is returning.
+ *
+ * The partitions to load is given in |requested_partitions| as a
+ * NULL-terminated array of NUL-terminated strings. Typically the
+ * |requested_partitions| array only contains a single item for the
+ * boot partition, 'boot'.
+ *
+ * If the device is unlocked (and _only_ if it's unlocked), true
+ * should be passed in the |allow_verification_error| parameter. This
+ * will allow considering slots as verified even when
+ * avb_slot_verify() returns
+ * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
+ * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or
+ * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX for the slot in
+ * question.
+ *
+ * Note that androidboot.slot_suffix is not set in the |cmdline| field
+ * in |AvbSlotVerifyData| - you will have to pass this command-line
+ * option yourself.
+ *
+ * If a slot was selected and it verified then AVB_AB_FLOW_RESULT_OK
+ * is returned.
+ *
+ * If a slot was selected but it didn't verify then
+ * AVB_AB_FLOW_RESULT_OK_WITH_VERIFICATION_ERROR is returned. This can
+ * only happen when |allow_verification_error| is true.
+ *
+ * If an I/O operation - such as loading/saving metadata or checking
+ * rollback indexes - fail, the value AVB_AB_FLOW_RESULT_ERROR_IO is
+ * returned.
+ *
+ * If memory allocation fails, AVB_AB_FLOW_RESULT_ERROR_OOM is
+ * returned.
+ *
+ * Reasonable behavior for handling AVB_AB_FLOW_RESULT_ERROR_NO_BOOTABLE_SLOTS
+ * is to initiate device repair (which is device-dependent).
+ */
+AvbABFlowResult avb_ab_flow(AvbABOps* ab_ops,
+                            const char* const* requested_partitions,
+                            bool allow_verification_error,
+                            AvbSlotVerifyData** out_data);
+
+/* Marks the slot with the given slot number as active. Returns
+ * AVB_IO_RESULT_OK on success, error code otherwise.
+ *
+ * This function is typically used by the OS updater when completing
+ * an update. It can also used by the firmware for implementing the
+ * "set_active" command.
+ */
+AvbIOResult avb_ab_mark_slot_active(AvbABOps* ab_ops, unsigned int slot_number);
+
+/* Marks the slot with the given slot number as unbootable. Returns
+ * AVB_IO_RESULT_OK on success, error code otherwise.
+ *
+ * This function is typically used by the OS updater before writing to
+ * a slot.
+ */
+AvbIOResult avb_ab_mark_slot_unbootable(AvbABOps* ab_ops,
+                                        unsigned int slot_number);
+
+/* Marks the slot with the given slot number as having booted
+ * successfully. Returns AVB_IO_RESULT_OK on success, error code
+ * otherwise.
+ *
+ * Calling this on an unbootable slot is an error - AVB_IO_RESULT_OK
+ * will be returned yet the function will have no side-effects.
+ *
+ * This function is typically used by the OS updater after having
+ * confirmed that the slot works as intended.
+ */
+AvbIOResult avb_ab_mark_slot_successful(AvbABOps* ab_ops,
+                                        unsigned int slot_number);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_AB_FLOW_H_ */
diff --git a/include/avb/avb_ab_ops.h b/include/avb/avb_ab_ops.h
new file mode 100644
index 0000000..2e0055c
--- /dev/null
+++ b/include/avb/avb_ab_ops.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_AB_H) && !defined(AVB_COMPILATION)
+#error \
+    "Never include this file directly, include libavb_ab/libavb_ab.h instead."
+#endif
+
+#ifndef AVB_AB_OPS_H_
+#define AVB_AB_OPS_H_
+
+#include <avb/libavb.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct AvbABOps;
+typedef struct AvbABOps AvbABOps;
+
+struct AvbABData;
+
+/* High-level operations/functions/methods for A/B that are platform
+ * dependent.
+ */
+struct AvbABOps {
+  /* Operations from libavb. */
+  AvbOps* ops;
+
+  /* Reads A/B metadata from persistent storage. Returned data is
+   * properly byteswapped. Returns AVB_IO_RESULT_OK on success, error
+   * code otherwise.
+   *
+   * If the data read is invalid (e.g. wrong magic or CRC checksum
+   * failure), the metadata shoule be reset using avb_ab_data_init()
+   * and then written to persistent storage.
+   *
+   * Implementations will typically want to use avb_ab_data_read()
+   * here to use the 'misc' partition for persistent storage.
+   */
+  AvbIOResult (*read_ab_metadata)(AvbABOps* ab_ops, struct AvbABData* data);
+
+  /* Writes A/B metadata to persistent storage. This will byteswap and
+   * update the CRC as needed. Returns AVB_IO_RESULT_OK on success,
+   * error code otherwise.
+   *
+   * Implementations will typically want to use avb_ab_data_write()
+   * here to use the 'misc' partition for persistent storage.
+   */
+  AvbIOResult (*write_ab_metadata)(AvbABOps* ab_ops,
+                                   const struct AvbABData* data);
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_AB_OPS_H_ */
diff --git a/include/avb/avb_chain_partition_descriptor.h b/include/avb/avb_chain_partition_descriptor.h
new file mode 100644
index 0000000..a841828
--- /dev/null
+++ b/include/avb/avb_chain_partition_descriptor.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_CHAIN_PARTITION_DESCRIPTOR_H_
+#define AVB_CHAIN_PARTITION_DESCRIPTOR_H_
+
+#include "avb_descriptor.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A descriptor containing a pointer to signed integrity data stored
+ * on another partition. The descriptor contains the partition name in
+ * question (without the A/B suffix), the public key used to sign the
+ * integrity data, and rollback index location to use for rollback
+ * protection.
+ *
+ * Following this struct are |partition_name_len| bytes of the
+ * partition name (UTF-8 encoded) and |public_key_len| bytes of the
+ * public key.
+ *
+ * The |reserved| field is for future expansion and must be set to NUL
+ * bytes.
+ */
+typedef struct AvbChainPartitionDescriptor {
+  AvbDescriptor parent_descriptor;
+  uint32_t rollback_index_location;
+  uint32_t partition_name_len;
+  uint32_t public_key_len;
+  uint8_t reserved[64];
+} AVB_ATTR_PACKED AvbChainPartitionDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_chain_partition_descriptor_validate_and_byteswap(
+    const AvbChainPartitionDescriptor* src,
+    AvbChainPartitionDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_CHAIN_PARTITION_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_crypto.h b/include/avb/avb_crypto.h
new file mode 100644
index 0000000..dbc7498
--- /dev/null
+++ b/include/avb/avb_crypto.h
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_CRYPTO_H_
+#define AVB_CRYPTO_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Size of a RSA-2048 signature. */
+#define AVB_RSA2048_NUM_BYTES 256
+
+/* Size of a RSA-4096 signature. */
+#define AVB_RSA4096_NUM_BYTES 512
+
+/* Size of a RSA-8192 signature. */
+#define AVB_RSA8192_NUM_BYTES 1024
+
+/* Size in bytes of a SHA-256 digest. */
+#define AVB_SHA256_DIGEST_SIZE 32
+
+/* Size in bytes of a SHA-512 digest. */
+#define AVB_SHA512_DIGEST_SIZE 64
+
+/* Algorithms that can be used in the vbmeta image for
+ * verification. An algorithm consists of a hash type and a signature
+ * type.
+ *
+ * The data used to calculate the hash is the three blocks mentioned
+ * in the documentation for |AvbVBMetaImageHeader| except for the data
+ * in the "Authentication data" block.
+ *
+ * For signatures with RSA keys, PKCS v1.5 padding is used. The public
+ * key data is stored in the auxiliary data block, see
+ * |AvbRSAPublicKeyHeader| for the serialization format.
+ *
+ * Each algorithm type is described below:
+ *
+ * AVB_ALGORITHM_TYPE_NONE: There is no hash, no signature of the
+ * data, and no public key. The data cannot be verified. The fields
+ * |hash_size|, |signature_size|, and |public_key_size| must be zero.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA2048: The hash function used is
+ * SHA-256, resulting in 32 bytes of hash digest data. This hash is
+ * signed with a 2048-bit RSA key. The field |hash_size| must be 32,
+ * |signature_size| must be 256, and the public key data must have
+ * |key_num_bits| set to 2048.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA4096: Like above, but only with
+ * a 4096-bit RSA key and |signature_size| set to 512.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA8192: Like above, but only with
+ * a 8192-bit RSA key and |signature_size| set to 1024.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA2048: The hash function used is
+ * SHA-512, resulting in 64 bytes of hash digest data. This hash is
+ * signed with a 2048-bit RSA key. The field |hash_size| must be 64,
+ * |signature_size| must be 256, and the public key data must have
+ * |key_num_bits| set to 2048.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA4096: Like above, but only with
+ * a 4096-bit RSA key and |signature_size| set to 512.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA8192: Like above, but only with
+ * a 8192-bit RSA key and |signature_size| set to 1024.
+ */
+typedef enum {
+  AVB_ALGORITHM_TYPE_NONE,
+  AVB_ALGORITHM_TYPE_SHA256_RSA2048,
+  AVB_ALGORITHM_TYPE_SHA256_RSA4096,
+  AVB_ALGORITHM_TYPE_SHA256_RSA8192,
+  AVB_ALGORITHM_TYPE_SHA512_RSA2048,
+  AVB_ALGORITHM_TYPE_SHA512_RSA4096,
+  AVB_ALGORITHM_TYPE_SHA512_RSA8192,
+  _AVB_ALGORITHM_NUM_TYPES
+} AvbAlgorithmType;
+
+/* Holds algorithm-specific data. The |padding| is needed by avb_rsa_verify. */
+typedef struct {
+  const uint8_t* padding;
+  size_t padding_len;
+  size_t hash_len;
+} AvbAlgorithmData;
+
+/* Provides algorithm-specific data for a given |algorithm|. Returns NULL if
+ * |algorithm| is invalid.
+ */
+const AvbAlgorithmData* avb_get_algorithm_data(AvbAlgorithmType algorithm)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* The header for a serialized RSA public key.
+ *
+ * The size of the key is given by |key_num_bits|, for example 2048
+ * for a RSA-2048 key. By definition, a RSA public key is the pair (n,
+ * e) where |n| is the modulus (which can be represented in
+ * |key_num_bits| bits) and |e| is the public exponent. The exponent
+ * is not stored since it's assumed to always be 65537.
+ *
+ * To optimize verification, the key block includes two precomputed
+ * values, |n0inv| (fits in 32 bits) and |rr| and can always be
+ * represented in |key_num_bits|.
+
+ * The value |n0inv| is the value -1/n[0] (mod 2^32). The value |rr|
+ * is (2^key_num_bits)^2 (mod n).
+ *
+ * Following this header is |key_num_bits| bits of |n|, then
+ * |key_num_bits| bits of |rr|. Both values are stored with most
+ * significant bit first. Each serialized number takes up
+ * |key_num_bits|/8 bytes.
+ *
+ * All fields in this struct are stored in network byte order when
+ * serialized.  To generate a copy with fields swapped to native byte
+ * order, use the function avb_rsa_public_key_header_validate_and_byteswap().
+ *
+ * The avb_rsa_verify() function expects a key in this serialized
+ * format.
+ *
+ * The 'avbtool extract_public_key' command can be used to generate a
+ * serialized RSA public key.
+ */
+typedef struct AvbRSAPublicKeyHeader {
+  uint32_t key_num_bits;
+  uint32_t n0inv;
+} AVB_ATTR_PACKED AvbRSAPublicKeyHeader;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ */
+bool avb_rsa_public_key_header_validate_and_byteswap(
+    const AvbRSAPublicKeyHeader* src,
+    AvbRSAPublicKeyHeader* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_CRYPTO_H_ */
diff --git a/include/avb/avb_descriptor.h b/include/avb/avb_descriptor.h
new file mode 100644
index 0000000..13a3efd
--- /dev/null
+++ b/include/avb/avb_descriptor.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_DESCRIPTOR_H_
+#define AVB_DESCRIPTOR_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Well-known descriptor tags.
+ *
+ * AVB_DESCRIPTOR_TAG_PROPERTY: see |AvbPropertyDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_HASHTREE: see |AvbHashtreeDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_HASH: see |AvbHashDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: see |AvbKernelCmdlineDescriptor| struct.
+ * AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: see |AvbChainPartitionDescriptor| struct.
+ */
+typedef enum {
+  AVB_DESCRIPTOR_TAG_PROPERTY,
+  AVB_DESCRIPTOR_TAG_HASHTREE,
+  AVB_DESCRIPTOR_TAG_HASH,
+  AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE,
+  AVB_DESCRIPTOR_TAG_CHAIN_PARTITION,
+} AvbDescriptorTag;
+
+/* The header for a serialized descriptor.
+ *
+ * A descriptor always have two fields, a |tag| (denoting its type,
+ * see the |AvbDescriptorTag| enumeration) and the size of the bytes
+ * following, |num_bytes_following|.
+ *
+ * For padding, |num_bytes_following| is always a multiple of 8.
+ */
+typedef struct AvbDescriptor {
+  uint64_t tag;
+  uint64_t num_bytes_following;
+} AVB_ATTR_PACKED AvbDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_descriptor_validate_and_byteswap(
+    const AvbDescriptor* src, AvbDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Signature for callback function used in avb_descriptor_foreach().
+ * The passed in descriptor is given by |descriptor| and the
+ * |user_data| passed to avb_descriptor_foreach() function is in
+ * |user_data|. Return true to continue iterating, false to stop
+ * iterating.
+ *
+ * Note that |descriptor| points into the image passed to
+ * avb_descriptor_foreach() - all fields need to be byteswapped!
+ */
+typedef bool AvbDescriptorForeachFunc(const AvbDescriptor* descriptor,
+                                      void* user_data);
+
+/* Convenience function to iterate over all descriptors in an vbmeta
+ * image.
+ *
+ * The function given by |foreach_func| will be called for each
+ * descriptor. The given function should return true to continue
+ * iterating, false to stop.
+ *
+ * The |user_data| parameter will be passed to |foreach_func|.
+ *
+ * Returns false if the iteration was short-circuited, that is if
+ * an invocation of |foreach_func| returned false.
+ *
+ * Before using this function, you MUST verify |image_data| with
+ * avb_vbmeta_image_verify() and reject it unless it's signed by a known
+ * good public key. Additionally, |image_data| must be word-aligned.
+ */
+bool avb_descriptor_foreach(const uint8_t* image_data,
+                            size_t image_size,
+                            AvbDescriptorForeachFunc foreach_func,
+                            void* user_data);
+
+/* Gets all descriptors in a vbmeta image.
+ *
+ * The return value is a NULL-pointer terminated array of
+ * AvbDescriptor pointers. Free with avb_free() when you are done with
+ * it. If |out_num_descriptors| is non-NULL, the number of descriptors
+ * will be returned there.
+ *
+ * Note that each AvbDescriptor pointer in the array points into
+ * |image_data| - all fields need to be byteswapped!
+ *
+ * Before using this function, you MUST verify |image_data| with
+ * avb_vbmeta_image_verify() and reject it unless it's signed by a known
+ * good public key. Additionally, |image_data| must be word-aligned.
+ */
+const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
+                                             size_t image_size,
+                                             size_t* out_num_descriptors)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_footer.h b/include/avb/avb_footer.h
new file mode 100644
index 0000000..975136a
--- /dev/null
+++ b/include/avb/avb_footer.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_FOOTER_H_
+#define AVB_FOOTER_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Magic for the footer. */
+#define AVB_FOOTER_MAGIC "AVBf"
+#define AVB_FOOTER_MAGIC_LEN 4
+
+/* Size of the footer. */
+#define AVB_FOOTER_SIZE 64
+
+/* The current footer version used - keep in sync with avbtool. */
+#define AVB_FOOTER_VERSION_MAJOR 1
+#define AVB_FOOTER_VERSION_MINOR 0
+
+/* The struct used as a footer used on partitions, used to find the
+ * AvbVBMetaImageHeader struct. This struct is always stored at the
+ * end of a partition.
+ */
+typedef struct AvbFooter {
+  /*   0: Four bytes equal to "AVBf" (AVB_FOOTER_MAGIC). */
+  uint8_t magic[AVB_FOOTER_MAGIC_LEN];
+  /*   4: The major version of the footer struct. */
+  uint32_t version_major;
+  /*   8: The minor version of the footer struct. */
+  uint32_t version_minor;
+
+  /*  12: The original size of the image on the partition. */
+  uint64_t original_image_size;
+
+  /*  20: The offset of the |AvbVBMetaImageHeader| struct. */
+  uint64_t vbmeta_offset;
+
+  /*  28: The size of the vbmeta block (header + auth + aux blocks). */
+  uint64_t vbmeta_size;
+
+  /*  36: Padding to ensure struct is size AVB_FOOTER_SIZE bytes. This
+   * must be set to zeroes.
+   */
+  uint8_t reserved[28];
+} AVB_ATTR_PACKED AvbFooter;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ */
+bool avb_footer_validate_and_byteswap(const AvbFooter* src, AvbFooter* dest)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_FOOTER_H_ */
diff --git a/include/avb/avb_hash_descriptor.h b/include/avb/avb_hash_descriptor.h
new file mode 100644
index 0000000..1e4f81c
--- /dev/null
+++ b/include/avb/avb_hash_descriptor.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_HASH_DESCRIPTOR_H_
+#define AVB_HASH_DESCRIPTOR_H_
+
+#include "avb_descriptor.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A descriptor containing information about hash for an image.
+ *
+ * This descriptor is typically used for boot partitions to verify the
+ * entire kernel+initramfs image before executing it.
+ *
+ * Following this struct are |partition_name_len| bytes of the
+ * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
+ * |digest_len| bytes of the digest.
+ *
+ * The |reserved| field is for future expansion and must be set to NUL
+ * bytes.
+ */
+typedef struct AvbHashDescriptor {
+  AvbDescriptor parent_descriptor;
+  uint64_t image_size;
+  uint8_t hash_algorithm[32];
+  uint32_t partition_name_len;
+  uint32_t salt_len;
+  uint32_t digest_len;
+  uint8_t reserved[64];
+} AVB_ATTR_PACKED AvbHashDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_hash_descriptor_validate_and_byteswap(const AvbHashDescriptor* src,
+                                               AvbHashDescriptor* dest)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_HASH_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_hashtree_descriptor.h b/include/avb/avb_hashtree_descriptor.h
new file mode 100644
index 0000000..3325115
--- /dev/null
+++ b/include/avb/avb_hashtree_descriptor.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_HASHTREE_DESCRIPTOR_H_
+#define AVB_HASHTREE_DESCRIPTOR_H_
+
+#include "avb_descriptor.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A descriptor containing information about a dm-verity hashtree.
+ *
+ * Hash-trees are used to verify large partitions typically containing
+ * file systems. See
+ * https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity for more
+ * information about dm-verity.
+ *
+ * Following this struct are |partition_name_len| bytes of the
+ * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
+ * |root_digest_len| bytes of the root digest.
+ *
+ * The |reserved| field is for future expansion and must be set to NUL
+ * bytes.
+ */
+typedef struct AvbHashtreeDescriptor {
+  AvbDescriptor parent_descriptor;
+  uint32_t dm_verity_version;
+  uint64_t image_size;
+  uint64_t tree_offset;
+  uint64_t tree_size;
+  uint32_t data_block_size;
+  uint32_t hash_block_size;
+  uint32_t fec_num_roots;
+  uint64_t fec_offset;
+  uint64_t fec_size;
+  uint8_t hash_algorithm[32];
+  uint32_t partition_name_len;
+  uint32_t salt_len;
+  uint32_t root_digest_len;
+  uint8_t reserved[64];
+} AVB_ATTR_PACKED AvbHashtreeDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_hashtree_descriptor_validate_and_byteswap(
+    const AvbHashtreeDescriptor* src,
+    AvbHashtreeDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_HASHTREE_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_kernel_cmdline_descriptor.h b/include/avb/avb_kernel_cmdline_descriptor.h
new file mode 100644
index 0000000..655918d
--- /dev/null
+++ b/include/avb/avb_kernel_cmdline_descriptor.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_KERNEL_CMDLINE_DESCRIPTOR_H_
+#define AVB_KERNEL_CMDLINE_DESCRIPTOR_H_
+
+#include "avb_descriptor.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Flags for kernel command-line descriptors.
+ *
+ * AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_NOT_DISABLED: The
+ * cmdline will only be applied if hashtree verification is not
+ * disabled (cf. AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED).
+ *
+ * AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_DISABLED: The cmdline
+ * will only be applied if hashtree verification is disabled
+ * (cf. AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED).
+ */
+typedef enum {
+  AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_NOT_DISABLED = (1 << 0),
+  AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_DISABLED = (1 << 1)
+} AvbKernelCmdlineFlags;
+
+/* A descriptor containing information to be appended to the kernel
+ * command-line.
+ *
+ * The |flags| field contains flags from the AvbKernelCmdlineFlags
+ * enumeration.
+ *
+ * Following this struct are |kernel_cmdline_len| bytes with the
+ * kernel command-line (UTF-8 encoded).
+ */
+typedef struct AvbKernelCmdlineDescriptor {
+  AvbDescriptor parent_descriptor;
+  uint32_t flags;
+  uint32_t kernel_cmdline_length;
+} AVB_ATTR_PACKED AvbKernelCmdlineDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_kernel_cmdline_descriptor_validate_and_byteswap(
+    const AvbKernelCmdlineDescriptor* src,
+    AvbKernelCmdlineDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_KERNEL_CMDLINE_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_ops.h b/include/avb/avb_ops.h
new file mode 100644
index 0000000..27a55b0
--- /dev/null
+++ b/include/avb/avb_ops.h
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_OPS_H_
+#define AVB_OPS_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Return codes used for I/O operations.
+ *
+ * AVB_IO_RESULT_OK is returned if the requested operation was
+ * successful.
+ *
+ * AVB_IO_RESULT_ERROR_IO is returned if the underlying hardware (disk
+ * or other subsystem) encountered an I/O error.
+ *
+ * AVB_IO_RESULT_ERROR_OOM is returned if unable to allocate memory.
+ *
+ * AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION is returned if the requested
+ * partition does not exist.
+ *
+ * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION is returned if the
+ * range of bytes requested to be read or written is outside the range
+ * of the partition.
+ */
+typedef enum {
+  AVB_IO_RESULT_OK,
+  AVB_IO_RESULT_ERROR_OOM,
+  AVB_IO_RESULT_ERROR_IO,
+  AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION,
+  AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION
+} AvbIOResult;
+
+struct AvbOps;
+typedef struct AvbOps AvbOps;
+
+/* Forward-declaration of operations in libavb_ab. */
+struct AvbABOps;
+
+/* Forward-declaration of operations in libavb_atx. */
+struct AvbAtxOps;
+
+/* High-level operations/functions/methods that are platform
+ * dependent.
+ */
+struct AvbOps {
+  /* This pointer can be used by the application/bootloader using
+   * libavb and is typically used in each operation to get a pointer
+   * to platform-specific resources. It cannot be used by libraries.
+   */
+  void* user_data;
+
+  /* If libavb_ab is used, this should point to the
+   * AvbABOps. Otherwise it must be set to NULL.
+   */
+  struct AvbABOps* ab_ops;
+
+  /* If libavb_atx is used, this should point to the
+   * AvbAtxOps. Otherwise it must be set to NULL.
+   */
+  struct AvbAtxOps* atx_ops;
+
+  /* Reads |num_bytes| from offset |offset| from partition with name
+   * |partition| (NUL-terminated UTF-8 string). If |offset| is
+   * negative, its absolute value should be interpreted as the number
+   * of bytes from the end of the partition.
+   *
+   * This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
+   * there is no partition with the given name,
+   * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
+   * |offset| is outside the partition, and AVB_IO_RESULT_ERROR_IO if
+   * there was an I/O error from the underlying I/O subsystem.  If the
+   * operation succeeds as requested AVB_IO_RESULT_OK is returned and
+   * the data is available in |buffer|.
+   *
+   * The only time partial I/O may occur is if reading beyond the end
+   * of the partition. In this case the value returned in
+   * |out_num_read| may be smaller than |num_bytes|.
+   */
+  AvbIOResult (*read_from_partition)(AvbOps* ops,
+                                     const char* partition,
+                                     int64_t offset,
+                                     size_t num_bytes,
+                                     void* buffer,
+                                     size_t* out_num_read);
+
+  /* Writes |num_bytes| from |bffer| at offset |offset| to partition
+   * with name |partition| (NUL-terminated UTF-8 string). If |offset|
+   * is negative, its absolute value should be interpreted as the
+   * number of bytes from the end of the partition.
+   *
+   * This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
+   * there is no partition with the given name,
+   * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
+   * byterange goes outside the partition, and AVB_IO_RESULT_ERROR_IO
+   * if there was an I/O error from the underlying I/O subsystem.  If
+   * the operation succeeds as requested AVB_IO_RESULT_OK is
+   * returned.
+   *
+   * This function never does any partial I/O, it either transfers all
+   * of the requested bytes or returns an error.
+   */
+  AvbIOResult (*write_to_partition)(AvbOps* ops,
+                                    const char* partition,
+                                    int64_t offset,
+                                    size_t num_bytes,
+                                    const void* buffer);
+
+  /* Checks if the given public key used to sign the 'vbmeta'
+   * partition is trusted. Boot loaders typically compare this with
+   * embedded key material generated with 'avbtool
+   * extract_public_key'.
+   *
+   * The public key is in the array pointed to by |public_key_data|
+   * and is of |public_key_length| bytes.
+   *
+   * If there is no public key metadata (set with the avbtool option
+   * --public_key_metadata) then |public_key_metadata| will be set to
+   * NULL. Otherwise this field points to the data which is
+   * |public_key_metadata_length| bytes long.
+   *
+   * If AVB_IO_RESULT_OK is returned then |out_is_trusted| is set -
+   * true if trusted or false if untrusted.
+   */
+  AvbIOResult (*validate_vbmeta_public_key)(AvbOps* ops,
+                                            const uint8_t* public_key_data,
+                                            size_t public_key_length,
+                                            const uint8_t* public_key_metadata,
+                                            size_t public_key_metadata_length,
+                                            bool* out_is_trusted);
+
+  /* Gets the rollback index corresponding to the location given by
+   * |rollback_index_location|. The value is returned in
+   * |out_rollback_index|. Returns AVB_IO_RESULT_OK if the rollback
+   * index was retrieved, otherwise an error code.
+   *
+   * A device may have a limited amount of rollback index locations (say,
+   * one or four) so may error out if |rollback_index_location| exceeds
+   * this number.
+   */
+  AvbIOResult (*read_rollback_index)(AvbOps* ops,
+                                     size_t rollback_index_location,
+                                     uint64_t* out_rollback_index);
+
+  /* Sets the rollback index corresponding to the location given by
+   * |rollback_index_location| to |rollback_index|. Returns
+   * AVB_IO_RESULT_OK if the rollback index was set, otherwise an
+   * error code.
+   *
+   * A device may have a limited amount of rollback index locations (say,
+   * one or four) so may error out if |rollback_index_location| exceeds
+   * this number.
+   */
+  AvbIOResult (*write_rollback_index)(AvbOps* ops,
+                                      size_t rollback_index_location,
+                                      uint64_t rollback_index);
+
+  /* Gets whether the device is unlocked. The value is returned in
+   * |out_is_unlocked| (true if unlocked, false otherwise). Returns
+   * AVB_IO_RESULT_OK if the state was retrieved, otherwise an error
+   * code.
+   */
+  AvbIOResult (*read_is_device_unlocked)(AvbOps* ops, bool* out_is_unlocked);
+
+  /* Gets the unique partition GUID for a partition with name in
+   * |partition| (NUL-terminated UTF-8 string). The GUID is copied as
+   * a string into |guid_buf| of size |guid_buf_size| and will be NUL
+   * terminated. The string must be lower-case and properly
+   * hyphenated. For example:
+   *
+   *  527c1c6d-6361-4593-8842-3c78fcd39219
+   *
+   * Returns AVB_IO_RESULT_OK on success, otherwise an error code.
+   */
+  AvbIOResult (*get_unique_guid_for_partition)(AvbOps* ops,
+                                               const char* partition,
+                                               char* guid_buf,
+                                               size_t guid_buf_size);
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_OPS_H_ */
diff --git a/include/avb/avb_property_descriptor.h b/include/avb/avb_property_descriptor.h
new file mode 100644
index 0000000..2a70896
--- /dev/null
+++ b/include/avb/avb_property_descriptor.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_PROPERTY_DESCRIPTOR_H_
+#define AVB_PROPERTY_DESCRIPTOR_H_
+
+#include "avb_descriptor.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A descriptor for properties (free-form key/value pairs).
+ *
+ * Following this struct are |key_num_bytes| bytes of key data,
+ * followed by a NUL byte, then |value_num_bytes| bytes of value data,
+ * followed by a NUL byte and then enough padding to make the combined
+ * size a multiple of 8.
+ */
+typedef struct AvbPropertyDescriptor {
+  AvbDescriptor parent_descriptor;
+  uint64_t key_num_bytes;
+  uint64_t value_num_bytes;
+} AVB_ATTR_PACKED AvbPropertyDescriptor;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ *
+ * Data following the struct is not validated nor copied.
+ */
+bool avb_property_descriptor_validate_and_byteswap(
+    const AvbPropertyDescriptor* src,
+    AvbPropertyDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Convenience function for looking up the value for a property with
+ * name |key| in a vbmeta image. If |key_size| is 0, |key| must be
+ * NUL-terminated.
+ *
+ * The |image_data| parameter must be a pointer to a vbmeta image of
+ * size |image_size|.
+ *
+ * This function returns a pointer to the value inside the passed-in
+ * image or NULL if not found. Note that the value is always
+ * guaranteed to be followed by a NUL byte.
+ *
+ * If the value was found and |out_value_size| is not NULL, the size
+ * of the value is returned there.
+ *
+ * This function is O(n) in number of descriptors so if you need to
+ * look up a lot of values, you may want to build a more efficient
+ * lookup-table by manually walking all descriptors using
+ * avb_descriptor_foreach().
+ *
+ * Before using this function, you MUST verify |image_data| with
+ * avb_vbmeta_image_verify() and reject it unless it's signed by a
+ * known good public key.
+ */
+const char* avb_property_lookup(const uint8_t* image_data,
+                                size_t image_size,
+                                const char* key,
+                                size_t key_size,
+                                size_t* out_value_size)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Like avb_property_lookup() but parses the intial portions of the
+ * value as an unsigned 64-bit integer. Both decimal and hexadecimal
+ * representations (e.g. "0x2a") are supported. Returns false on
+ * failure and true on success. On success, the parsed value is
+ * returned in |out_value|.
+ */
+bool avb_property_lookup_uint64(const uint8_t* image_data,
+                                size_t image_size,
+                                const char* key,
+                                size_t key_size,
+                                uint64_t* out_value)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_PROPERTY_DESCRIPTOR_H_ */
diff --git a/include/avb/avb_rsa.h b/include/avb/avb_rsa.h
new file mode 100644
index 0000000..8f648a2
--- /dev/null
+++ b/include/avb/avb_rsa.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifdef AVB_INSIDE_LIBAVB_H
+#error "You can't include avb_rsa.h in the public header libavb.h."
+#endif
+
+#ifndef AVB_COMPILATION
+#error "Never include this file, it may only be used from internal avb code."
+#endif
+
+#ifndef AVB_RSA_H_
+#define AVB_RSA_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "avb_crypto.h"
+#include "avb_sysdeps.h"
+
+/* Using the key given by |key|, verify a RSA signature |sig| of
+ * length |sig_num_bytes| against an expected |hash| of length
+ * |hash_num_bytes|. The padding to expect must be passed in using
+ * |padding| of length |padding_num_bytes|.
+ *
+ * The data in |key| must match the format defined in
+ * |AvbRSAPublicKeyHeader|, including the two large numbers
+ * following. The |key_num_bytes| must be the size of the entire
+ * serialized key.
+ *
+ * Returns false if verification fails, true otherwise.
+ */
+bool avb_rsa_verify(const uint8_t* key,
+                    size_t key_num_bytes,
+                    const uint8_t* sig,
+                    size_t sig_num_bytes,
+                    const uint8_t* hash,
+                    size_t hash_num_bytes,
+                    const uint8_t* padding,
+                    size_t padding_num_bytes) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_RSA_H_ */
diff --git a/include/avb/avb_sha.h b/include/avb/avb_sha.h
new file mode 100644
index 0000000..f1d5f5a
--- /dev/null
+++ b/include/avb/avb_sha.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#ifdef AVB_INSIDE_LIBAVB_H
+#error "You can't include avb_sha.h in the public header libavb.h."
+#endif
+
+#ifndef AVB_COMPILATION
+#error "Never include this file, it may only be used from internal avb code."
+#endif
+
+#ifndef AVB_SHA_H_
+#define AVB_SHA_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "avb_crypto.h"
+#include "avb_sysdeps.h"
+
+/* Block size in bytes of a SHA-256 digest. */
+#define AVB_SHA256_BLOCK_SIZE 64
+
+
+/* Block size in bytes of a SHA-512 digest. */
+#define AVB_SHA512_BLOCK_SIZE 128
+
+/* Data structure used for SHA-256. */
+typedef struct {
+  uint32_t h[8];
+  uint32_t tot_len;
+  uint32_t len;
+  uint8_t block[2 * AVB_SHA256_BLOCK_SIZE];
+  uint8_t buf[AVB_SHA256_DIGEST_SIZE]; /* Used for storing the final digest. */
+} AvbSHA256Ctx;
+
+/* Data structure used for SHA-512. */
+typedef struct {
+  uint64_t h[8];
+  uint32_t tot_len;
+  uint32_t len;
+  uint8_t block[2 * AVB_SHA512_BLOCK_SIZE];
+  uint8_t buf[AVB_SHA512_DIGEST_SIZE]; /* Used for storing the final digest. */
+} AvbSHA512Ctx;
+
+/* Initializes the SHA-256 context. */
+void avb_sha256_init(AvbSHA256Ctx* ctx);
+
+/* Updates the SHA-256 context with |len| bytes from |data|. */
+void avb_sha256_update(AvbSHA256Ctx* ctx, const uint8_t* data, uint32_t len);
+
+/* Returns the SHA-256 digest. */
+uint8_t* avb_sha256_final(AvbSHA256Ctx* ctx) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Initializes the SHA-512 context. */
+void avb_sha512_init(AvbSHA512Ctx* ctx);
+
+/* Updates the SHA-512 context with |len| bytes from |data|. */
+void avb_sha512_update(AvbSHA512Ctx* ctx, const uint8_t* data, uint32_t len);
+
+/* Returns the SHA-512 digest. */
+uint8_t* avb_sha512_final(AvbSHA512Ctx* ctx) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_SHA_H_ */
diff --git a/include/avb/avb_slot_verify.h b/include/avb/avb_slot_verify.h
new file mode 100644
index 0000000..b40a5b9
--- /dev/null
+++ b/include/avb/avb_slot_verify.h
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_SLOT_VERIFY_H_
+#define AVB_SLOT_VERIFY_H_
+
+#include "avb_ops.h"
+#include "avb_vbmeta_image.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Return codes used in avb_slot_verify(), see that function for
+ * documentation for each field.
+ *
+ * Use avb_slot_verify_result_to_string() to get a textual
+ * representation usable for error/debug output.
+ */
+typedef enum {
+  AVB_SLOT_VERIFY_RESULT_OK,
+  AVB_SLOT_VERIFY_RESULT_ERROR_OOM,
+  AVB_SLOT_VERIFY_RESULT_ERROR_IO,
+  AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION,
+  AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX,
+  AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
+  AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA,
+  AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION
+} AvbSlotVerifyResult;
+
+/* Get a textual representation of |result|. */
+const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result);
+
+/* Maximum number of rollback index locations supported. */
+#define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32
+
+/* AvbPartitionData contains data loaded from partitions when using
+ * avb_slot_verify(). The |partition_name| field contains the name of
+ * the partition (without A/B suffix), |data| points to the loaded
+ * data which is |data_size| bytes long.
+ *
+ * Note that this is strictly less than the partition size - it's only
+ * the image stored there, not the entire partition nor any of the
+ * metadata.
+ */
+typedef struct {
+  char* partition_name;
+  uint8_t* data;
+  size_t data_size;
+} AvbPartitionData;
+
+/* AvbVBMetaData contains a vbmeta struct loaded from a partition when
+ * using avb_slot_verify(). The |partition_name| field contains the
+ * name of the partition (without A/B suffix), |vbmeta_data| points to
+ * the loaded data which is |vbmeta_size| bytes long.
+ *
+ * The |verify_result| field contains the result of
+ * avb_vbmeta_image_verify() on the data. This is guaranteed to be
+ * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if
+ * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK.
+ *
+ * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and
+ * avb_vbmeta_image_header_to_host_byte_order() with this data.
+ */
+typedef struct {
+  char* partition_name;
+  uint8_t* vbmeta_data;
+  size_t vbmeta_size;
+  AvbVBMetaVerifyResult verify_result;
+} AvbVBMetaData;
+
+/* AvbSlotVerifyData contains data needed to boot a particular slot
+ * and is returned by avb_slot_verify() if partitions in a slot are
+ * successfully verified.
+ *
+ * All data pointed to by this struct - including data in each item in
+ * the |partitions| array - will be freed when the
+ * avb_slot_verify_data_free() function is called.
+ *
+ * The |ab_suffix| field is the copy of the of |ab_suffix| field
+ * passed to avb_slot_verify(). It is the A/B suffix of the slot.
+ *
+ * The VBMeta images that were checked are available in the
+ * |vbmeta_images| field. The field |num_vbmeta_images| contains the
+ * number of elements in this array. The first element -
+ * vbmeta_images[0] - is guaranteed to be from the partition with the
+ * top-level vbmeta struct. This is usually the "vbmeta" partition in
+ * the requested slot but if there is no "vbmeta" partition it can
+ * also be the "boot" partition.
+ *
+ * The partitions loaded and verified from from the slot are
+ * accessible in the |loaded_partitions| array. The field
+ * |num_loaded_partitions| contains the number of elements in this
+ * array. The order of partitions in this array may not necessarily be
+ * the same order as in the passed-in |requested_partitions| array.
+ *
+ * Rollback indexes for the verified slot are stored in the
+ * |rollback_indexes| field. Note that avb_slot_verify() will NEVER
+ * modify stored_rollback_index[n] locations e.g. it will never use
+ * the write_rollback_index() AvbOps operation. Instead it is the job
+ * of the caller of avb_slot_verify() to do this based on e.g. A/B
+ * policy and other factors. See libavb_ab/avb_ab_flow.c for an
+ * example of how to do this.
+ *
+ * The |cmdline| field is a NUL-terminated string in UTF-8 resulting
+ * from concatenating all |AvbKernelCmdlineDescriptor| and then
+ * performing proper substitution of the variables
+ * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and
+ * $(ANDROID_VBMETA_PARTUUID) using the
+ * get_unique_guid_for_partition() operation in |AvbOps|.
+ *
+ * Additionally, the |cmdline| field will have the following kernel
+ * command-line options set:
+ *
+ *   androidboot.vbmeta.device_state: set to "locked" or "unlocked"
+ *   depending on the result of the result of AvbOps's
+ *   read_is_unlocked() function.
+ *
+ *   androidboot.vbmeta.{hash_alg, size, digest}: Will be set to
+ *   the digest of all images in |vbmeta_images|.
+ *
+ *   androidboot.vbmeta.device: This is set to the value
+ *   PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it
+ *   will end up pointing to the vbmeta partition for the verified
+ *   slot. If there is no vbmeta partition it will point to the boot
+ *   partition of the verified slot.
+ *
+ *   androidboot.vbmeta.avb_version: This is set to the decimal value
+ *   of AVB_VERSION_MAJOR followed by a dot followed by the decimal
+ *   value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This
+ *   version number represents the vbmeta file format version
+ *   supported by libavb copy used in the boot loader. This is not
+ *   necessarily the same version number of the on-disk metadata for
+ *   the slot that was verified.
+ *
+ * Note that androidboot.slot_suffix is not set in |cmdline| - you
+ * will have to pass this command-line option yourself.
+ *
+ * This struct may grow in the future without it being considered an
+ * ABI break.
+ */
+typedef struct {
+  char* ab_suffix;
+  AvbVBMetaData* vbmeta_images;
+  size_t num_vbmeta_images;
+  AvbPartitionData* loaded_partitions;
+  size_t num_loaded_partitions;
+  char* cmdline;
+  uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS];
+} AvbSlotVerifyData;
+
+/* Frees a |AvbSlotVerifyData| including all data it points to. */
+void avb_slot_verify_data_free(AvbSlotVerifyData* data);
+
+/* Performs a full verification of the slot identified by |ab_suffix|
+ * and load the contents of the partitions whose name is in the
+ * NULL-terminated string array |requested_partitions| (each partition
+ * must use hash verification). If not using A/B, pass an empty string
+ * (e.g. "", not NULL) for |ab_suffix|.
+ *
+ * Typically the |requested_partitions| array only contains a single
+ * item for the boot partition, 'boot'.
+ *
+ * Verification includes loading data from the 'vbmeta', all hash
+ * partitions, and possibly other partitions (with |ab_suffix|
+ * appended), inspecting rollback indexes, and checking if the public
+ * key used to sign the data is acceptable. The functions in |ops|
+ * will be used to do this.
+ *
+ * If |out_data| is not NULL, it will be set to a newly allocated
+ * |AvbSlotVerifyData| struct containing all the data needed to
+ * actually boot the slot. This data structure should be freed with
+ * avb_slot_verify_data_free() when you are done with it. See below
+ * for when this is returned.
+ *
+ * If |allow_verification_error| is false this function will bail out
+ * as soon as an error is encountered and |out_data| is set only if
+ * AVB_SLOT_VERIFY_RESULT_OK is returned.
+ *
+ * Otherwise if |allow_verification_error| is true the function will
+ * continue verification efforts and |out_data| is also set if
+ * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
+ * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or
+ * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is
+ * undefined which error is returned if more than one distinct error
+ * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is
+ * returned if, and only if, there are no errors. This mode is needed
+ * to boot valid but unverified slots when the device is unlocked.
+ *
+ * Also note that |out_data| is never set if
+ * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO,
+ * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned.
+ *
+ * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified
+ * correctly and all public keys are accepted.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if
+ * everything is verified correctly out but one or more public keys
+ * are not accepted. This includes the case where integrity data is
+ * not signed.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to
+ * allocate memory.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error
+ * occurred while trying to load data or get a rollback index.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data
+ * did not verify, e.g. the digest didn't match or signature checks
+ * failed.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a
+ * rollback index was less than its stored value.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some
+ * of the metadata is invalid or inconsistent.
+ *
+ * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if
+ * some of the metadata requires a newer version of libavb than what
+ * is in use.
+ */
+AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
+                                    const char* const* requested_partitions,
+                                    const char* ab_suffix,
+                                    bool allow_verification_error,
+                                    AvbSlotVerifyData** out_data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_SLOT_VERIFY_H_ */
diff --git a/include/avb/avb_sysdeps.h b/include/avb/avb_sysdeps.h
new file mode 100644
index 0000000..27c6651
--- /dev/null
+++ b/include/avb/avb_sysdeps.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_SYSDEPS_H_
+#define AVB_SYSDEPS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Change these includes to match your platform to bring in the
+ * equivalent types available in a normal C runtime. At least things
+ * like uint8_t, uint64_t, and bool (with |false|, |true| keywords)
+ * must be present.
+ */
+#include "common.h"
+
+/* If you don't have gcc or clang, these attribute macros may need to
+ * be adjusted.
+ */
+#define AVB_ATTR_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+#define AVB_ATTR_PACKED __attribute__((packed))
+#define AVB_ATTR_NO_RETURN __attribute__((noreturn))
+#define AVB_ATTR_SENTINEL __attribute__((__sentinel__))
+
+/* Size in bytes used for alignment. */
+#ifdef __LP64__
+#define AVB_ALIGNMENT_SIZE 8
+#else
+#define AVB_ALIGNMENT_SIZE 4
+#endif
+
+/* Compare |n| bytes in |src1| and |src2|.
+ *
+ * Returns an integer less than, equal to, or greater than zero if the
+ * first |n| bytes of |src1| is found, respectively, to be less than,
+ * to match, or be greater than the first |n| bytes of |src2|. */
+int avb_memcmp(const void* src1,
+               const void* src2,
+               size_t n) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Compare two strings.
+ *
+ * Return an integer less than, equal to, or greater than zero if |s1|
+ * is found, respectively, to be less than, to match, or be greater
+ * than |s2|.
+ */
+int avb_strcmp(const char* s1, const char* s2);
+
+/* Copy |n| bytes from |src| to |dest|. */
+void* avb_memcpy(void* dest, const void* src, size_t n);
+
+/* Set |n| bytes starting at |s| to |c|.  Returns |dest|. */
+void* avb_memset(void* dest, const int c, size_t n);
+
+/* Prints out a message. The string passed must be a NUL-terminated
+ * UTF-8 string.
+ */
+void avb_print(const char* message);
+
+/* Prints out a vector of strings. Each argument must point to a
+ * NUL-terminated UTF-8 string and NULL should be the last argument.
+ */
+void avb_printv(const char* message, ...) AVB_ATTR_SENTINEL;
+
+/* Aborts the program or reboots the device. */
+void avb_abort(void) AVB_ATTR_NO_RETURN;
+
+/* Allocates |size| bytes. Returns NULL if no memory is available,
+ * otherwise a pointer to the allocated memory.
+ *
+ * The memory is not initialized.
+ *
+ * The pointer returned is guaranteed to be word-aligned.
+ *
+ * The memory should be freed with avb_free() when you are done with it.
+ */
+void* avb_malloc_(size_t size) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Frees memory previously allocated with avb_malloc(). */
+void avb_free(void* ptr);
+
+/* Returns the lenght of |str|, excluding the terminating NUL-byte. */
+size_t avb_strlen(const char* str) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_SYSDEPS_H_ */
diff --git a/include/avb/avb_util.h b/include/avb/avb_util.h
new file mode 100644
index 0000000..98b8918
--- /dev/null
+++ b/include/avb/avb_util.h
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_UTIL_H_
+#define AVB_UTIL_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define AVB_STRINGIFY(x) #x
+#define AVB_TO_STRING(x) AVB_STRINGIFY(x)
+
+#ifdef AVB_ENABLE_DEBUG
+/* Aborts the program if |expr| is false.
+ *
+ * This has no effect unless AVB_ENABLE_DEBUG is defined.
+ */
+#define avb_assert(expr)                     \
+  do {                                       \
+    if (!(expr)) {                           \
+      avb_fatal("assert fail: " #expr "\n"); \
+    }                                        \
+  } while (0)
+#else
+#define avb_assert(expr)
+#endif
+
+/* Aborts the program if reached.
+ *
+ * This has no effect unless AVB_ENABLE_DEBUG is defined.
+ */
+#ifdef AVB_ENABLE_DEBUG
+#define avb_assert_not_reached()         \
+  do {                                   \
+    avb_fatal("assert_not_reached()\n"); \
+  } while (0)
+#else
+#define avb_assert_not_reached()
+#endif
+
+/* Aborts the program if |addr| is not word-aligned.
+ *
+ * This has no effect unless AVB_ENABLE_DEBUG is defined.
+ */
+#define avb_assert_aligned(addr) \
+  avb_assert((((uintptr_t)addr) & (AVB_ALIGNMENT_SIZE - 1)) == 0)
+
+#ifdef AVB_ENABLE_DEBUG
+/* Print functions, used for diagnostics.
+ *
+ * These have no effect unless AVB_ENABLE_DEBUG is defined.
+ */
+#define avb_debug(message)              \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": DEBUG: ",             \
+               message,                 \
+               NULL);                   \
+  } while (0)
+#define avb_debugv(message, ...)        \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": DEBUG: ",             \
+               message,                 \
+               ##__VA_ARGS__);          \
+  } while (0)
+#else
+#define avb_debug(message)
+#define avb_debugv(message, ...)
+#endif
+
+/* Prints out a message. This is typically used if a runtime-error
+ * occurs.
+ */
+#define avb_error(message)              \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": ERROR: ",             \
+               message,                 \
+               NULL);                   \
+  } while (0)
+#define avb_errorv(message, ...)        \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": ERROR: ",             \
+               message,                 \
+               ##__VA_ARGS__);          \
+  } while (0)
+
+/* Prints out a message and calls avb_abort().
+ */
+#define avb_fatal(message)              \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": FATAL: ",             \
+               message,                 \
+               NULL);                   \
+    avb_abort();                        \
+  } while (0)
+#define avb_fatalv(message, ...)        \
+  do {                                  \
+    avb_printv(avb_basename(__FILE__),  \
+               ":",                     \
+               AVB_TO_STRING(__LINE__), \
+               ": FATAL: ",             \
+               message,                 \
+               ##__VA_ARGS__);          \
+    avb_abort();                        \
+  } while (0)
+
+/* Converts a 32-bit unsigned integer from big-endian to host byte order. */
+uint32_t avb_be32toh(uint32_t in) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Converts a 64-bit unsigned integer from big-endian to host byte order. */
+uint64_t avb_be64toh(uint64_t in) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Converts a 32-bit unsigned integer from host to big-endian byte order. */
+uint32_t avb_htobe32(uint32_t in) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Converts a 64-bit unsigned integer from host to big-endian byte order. */
+uint64_t avb_htobe64(uint64_t in) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Compare |n| bytes starting at |s1| with |s2| and return 0 if they
+ * match, 1 if they don't.  Returns 0 if |n|==0, since no bytes
+ * mismatched.
+ *
+ * Time taken to perform the comparison is only dependent on |n| and
+ * not on the relationship of the match between |s1| and |s2|.
+ *
+ * Note that unlike avb_memcmp(), this only indicates inequality, not
+ * whether |s1| is less than or greater than |s2|.
+ */
+int avb_safe_memcmp(const void* s1,
+                    const void* s2,
+                    size_t n) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Adds |value_to_add| to |value| with overflow protection.
+ *
+ * Returns false if the addition overflows, true otherwise. In either
+ * case, |value| is always modified.
+ */
+bool avb_safe_add_to(uint64_t* value,
+                     uint64_t value_to_add) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Adds |a| and |b| with overflow protection, returning the value in
+ * |out_result|.
+ *
+ * It's permissible to pass NULL for |out_result| if you just want to
+ * check that the addition would not overflow.
+ *
+ * Returns false if the addition overflows, true otherwise.
+ */
+bool avb_safe_add(uint64_t* out_result,
+                  uint64_t a,
+                  uint64_t b) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Checks if |num_bytes| data at |data| is a valid UTF-8
+ * string. Returns true if valid UTF-8, false otherwise.
+ */
+bool avb_validate_utf8(const uint8_t* data,
+                       size_t num_bytes) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Concatenates |str1| (of |str1_len| bytes) and |str2| (of |str2_len|
+ * bytes) and puts the result in |buf| which holds |buf_size|
+ * bytes. The result is also guaranteed to be NUL terminated. Fail if
+ * there is not enough room in |buf| for the resulting string plus
+ * terminating NUL byte.
+ *
+ * Returns true if the operation succeeds, false otherwise.
+ */
+bool avb_str_concat(char* buf,
+                    size_t buf_size,
+                    const char* str1,
+                    size_t str1_len,
+                    const char* str2,
+                    size_t str2_len);
+
+/* Like avb_malloc_() but prints a error using avb_error() if memory
+ * allocation fails.
+ */
+void* avb_malloc(size_t size) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Like avb_malloc() but sets the memory with zeroes. */
+void* avb_calloc(size_t size) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Duplicates a NUL-terminated string. Returns NULL on OOM. */
+char* avb_strdup(const char* str) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Duplicates a NULL-terminated array of NUL-terminated strings by
+ * concatenating them. The returned string will be
+ * NUL-terminated. Returns NULL on OOM.
+ */
+char* avb_strdupv(const char* str,
+                  ...) AVB_ATTR_WARN_UNUSED_RESULT AVB_ATTR_SENTINEL;
+
+/* Finds the first occurrence of |needle| in the string |haystack|
+ * where both strings are NUL-terminated strings. The terminating NUL
+ * bytes are not compared.
+ *
+ * Returns NULL if not found, otherwise points into |haystack| for the
+ * first occurrence of |needle|.
+ */
+const char* avb_strstr(const char* haystack,
+                       const char* needle) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Finds the first occurrence of |str| in the NULL-terminated string
+ * array |strings|. Each element in |strings| must be
+ * NUL-terminated. The string given by |str| need not be
+ * NUL-terminated but its size must be given in |str_size|.
+ *
+ * Returns NULL if not found, otherwise points into |strings| for the
+ * first occurrence of |str|.
+ */
+const char* avb_strv_find_str(const char* const* strings,
+                              const char* str,
+                              size_t str_size);
+
+/* Replaces all occurrences of |search| with |replace| in |str|.
+ *
+ * Returns a newly allocated string or NULL if out of memory.
+ */
+char* avb_replace(const char* str,
+                  const char* search,
+                  const char* replace) AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* Calculates the CRC-32 for data in |buf| of size |buf_size|. */
+uint32_t avb_crc32(const uint8_t* buf, size_t buf_size);
+
+/* Returns the basename of |str|. This is defined as the last path
+ * component, assuming the normal POSIX separator '/'. If there are no
+ * separators, returns |str|.
+ */
+const char* avb_basename(const char* str);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_UTIL_H_ */
diff --git a/include/avb/avb_vbmeta_image.h b/include/avb/avb_vbmeta_image.h
new file mode 100644
index 0000000..abff6e1
--- /dev/null
+++ b/include/avb/avb_vbmeta_image.h
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_VBMETA_IMAGE_H_
+#define AVB_VBMETA_IMAGE_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "avb_crypto.h"
+#include "avb_descriptor.h"
+
+/* Size of the vbmeta image header. */
+#define AVB_VBMETA_IMAGE_HEADER_SIZE 256
+
+/* Magic for the vbmeta image header. */
+#define AVB_MAGIC "AVB0"
+#define AVB_MAGIC_LEN 4
+
+/* Maximum size of the release string including the terminating NUL byte. */
+#define AVB_RELEASE_STRING_SIZE 48
+
+/* Flags for the vbmeta image.
+ *
+ * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED: If this flag is set,
+ * hashtree image verification will be disabled.
+ */
+typedef enum {
+  AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED = (1 << 0)
+} AvbVBMetaImageFlags;
+
+/* Binary format for header of the vbmeta image.
+ *
+ * The vbmeta image consists of three blocks:
+ *
+ *  +-----------------------------------------+
+ *  | Header data - fixed size                |
+ *  +-----------------------------------------+
+ *  | Authentication data - variable size     |
+ *  +-----------------------------------------+
+ *  | Auxiliary data - variable size          |
+ *  +-----------------------------------------+
+ *
+ * The "Header data" block is described by this struct and is always
+ * |AVB_VBMETA_IMAGE_HEADER_SIZE| bytes long.
+ *
+ * The "Authentication data" block is |authentication_data_block_size|
+ * bytes long and contains the hash and signature used to authenticate
+ * the vbmeta image. The type of the hash and signature is defined by
+ * the |algorithm_type| field.
+ *
+ * The "Auxiliary data" is |auxiliary_data_block_size| bytes long and
+ * contains the auxiliary data including the public key used to make
+ * the signature and descriptors.
+ *
+ * The public key is at offset |public_key_offset| with size
+ * |public_key_size| in this block. The size of the public key data is
+ * defined by the |algorithm_type| field. The format of the public key
+ * data is described in the |AvbRSAPublicKeyHeader| struct.
+ *
+ * The descriptors starts at |descriptors_offset| from the beginning
+ * of the "Auxiliary Data" block and take up |descriptors_size|
+ * bytes. Each descriptor is stored as a |AvbDescriptor| with tag and
+ * number of bytes following. The number of descriptors can be
+ * determined by walking this data until |descriptors_size| is
+ * exhausted.
+ *
+ * The size of each of the "Authentication data" and "Auxiliary data"
+ * blocks must be divisible by 64. This is to ensure proper alignment.
+ *
+ * Descriptors are free-form blocks stored in a part of the vbmeta
+ * image subject to the same integrity checks as the rest of the
+ * image. See the documentation for |AvbDescriptor| for well-known
+ * descriptors. See avb_descriptor_foreach() for a convenience
+ * function to iterate over descriptors.
+ *
+ * This struct is versioned, see the |required_libavb_version_major|
+ * and |required_libavb_version_minor| fields. This represents the
+ * minimum version of libavb required to verify the header and depends
+ * on the features (e.g. algorithms, descriptors) used. Note that this
+ * may be 1.0 even if generated by an avbtool from 1.4 but where no
+ * features introduced after 1.0 has been used. See the "Versioning
+ * and compatibility" section in the README.md file for more details.
+ *
+ * All fields are stored in network byte order when serialized. To
+ * generate a copy with fields swapped to native byte order, use the
+ * function avb_vbmeta_image_header_to_host_byte_order().
+ *
+ * Before reading and/or using any of this data, you MUST verify it
+ * using avb_vbmeta_image_verify() and reject it unless it's signed by
+ * a known good public key.
+ */
+typedef struct AvbVBMetaImageHeader {
+  /*   0: Four bytes equal to "AVB0" (AVB_MAGIC). */
+  uint8_t magic[AVB_MAGIC_LEN];
+
+  /*   4: The major version of libavb required for this header. */
+  uint32_t required_libavb_version_major;
+  /*   8: The minor version of libavb required for this header. */
+  uint32_t required_libavb_version_minor;
+
+  /*  12: The size of the signature block. */
+  uint64_t authentication_data_block_size;
+  /*  20: The size of the auxiliary data block. */
+  uint64_t auxiliary_data_block_size;
+
+  /*  28: The verification algorithm used, see |AvbAlgorithmType| enum. */
+  uint32_t algorithm_type;
+
+  /*  32: Offset into the "Authentication data" block of hash data. */
+  uint64_t hash_offset;
+  /*  40: Length of the hash data. */
+  uint64_t hash_size;
+
+  /*  48: Offset into the "Authentication data" block of signature data. */
+  uint64_t signature_offset;
+  /*  56: Length of the signature data. */
+  uint64_t signature_size;
+
+  /*  64: Offset into the "Auxiliary data" block of public key data. */
+  uint64_t public_key_offset;
+  /*  72: Length of the public key data. */
+  uint64_t public_key_size;
+
+  /*  80: Offset into the "Auxiliary data" block of public key metadata. */
+  uint64_t public_key_metadata_offset;
+  /*  88: Length of the public key metadata. Must be set to zero if there
+   *  is no public key metadata.
+   */
+  uint64_t public_key_metadata_size;
+
+  /*  96: Offset into the "Auxiliary data" block of descriptor data. */
+  uint64_t descriptors_offset;
+  /* 104: Length of descriptor data. */
+  uint64_t descriptors_size;
+
+  /* 112: The rollback index which can be used to prevent rollback to
+   *  older versions.
+   */
+  uint64_t rollback_index;
+
+  /* 120: Flags from the AvbVBMetaImageFlags enumeration. This must be
+   * set to zero if the vbmeta image is not a top-level image.
+   */
+  uint32_t flags;
+
+  /* 124: Reserved to ensure |release_string| start on a 16-byte
+   * boundary. Must be set to zeroes.
+   */
+  uint8_t reserved0[4];
+
+  /* 128: The release string from avbtool, e.g. "avbtool 1.0.0" or
+   * "avbtool 1.0.0 xyz_board Git-234abde89". Is guaranteed to be NUL
+   * terminated. Applications must not make assumptions about how this
+   * string is formatted.
+   */
+  uint8_t release_string[AVB_RELEASE_STRING_SIZE];
+
+  /* 176: Padding to ensure struct is size AVB_VBMETA_IMAGE_HEADER_SIZE
+   * bytes. This must be set to zeroes.
+   */
+  uint8_t reserved[80];
+} AVB_ATTR_PACKED AvbVBMetaImageHeader;
+
+/* Copies |src| to |dest|, byte-swapping fields in the process.
+ *
+ * Make sure you've verified |src| using avb_vbmeta_image_verify()
+ * before accessing the data and/or using this function.
+ */
+void avb_vbmeta_image_header_to_host_byte_order(const AvbVBMetaImageHeader* src,
+                                                AvbVBMetaImageHeader* dest);
+
+/* Return codes used in avb_vbmeta_image_verify().
+ *
+ * AVB_VBMETA_VERIFY_RESULT_OK is returned if the vbmeta image header
+ * is valid, the hash is correct and the signature is correct. Keep in
+ * mind that you still need to check that you know the public key used
+ * to sign the image, see avb_vbmeta_image_verify() for details.
+ *
+ * AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED is returned if the vbmeta
+ * image header is valid but there is no signature or hash.
+ *
+ * AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER is returned if the
+ * header of the vbmeta image is invalid, for example, invalid magic
+ * or inconsistent data.
+ *
+ * AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION is returned if a) the
+ * vbmeta image requires a minimum version of libavb which exceeds the
+ * version of libavb used; or b) the vbmeta image major version
+ * differs from the major version of libavb in use.
+ *
+ * AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH is returned if the hash
+ * stored in the "Authentication data" block does not match the
+ * calculated hash.
+ *
+ * AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH is returned if the
+ * signature stored in the "Authentication data" block is invalid or
+ * doesn't match the public key stored in the vbmeta image.
+ */
+typedef enum {
+  AVB_VBMETA_VERIFY_RESULT_OK,
+  AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED,
+  AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER,
+  AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION,
+  AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH,
+  AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH,
+} AvbVBMetaVerifyResult;
+
+/* Get a textual representation of |result|. */
+const char* avb_vbmeta_verify_result_to_string(AvbVBMetaVerifyResult result);
+
+/* Checks that vbmeta image at |data| of size |length| is a valid
+ * vbmeta image. The complete contents of the vbmeta image must be
+ * passed in. It's fine if |length| is bigger than the actual image,
+ * typically callers of this function will load the entire contents of
+ * the 'vbmeta_a' or 'vbmeta_b' partition and pass in its length (for
+ * example, 1 MiB).
+ *
+ * See the |AvbVBMetaImageHeader| struct for information about the
+ * three blocks (header, authentication, auxiliary) that make up a
+ * vbmeta image.
+ *
+ * If the function returns |AVB_VBMETA_VERIFY_RESULT_OK| and
+ * |out_public_key_data| is non-NULL, it will be set to point inside
+ * |data| for where the serialized public key data is stored and
+ * |out_public_key_length|, if non-NULL, will be set to the length of
+ * the public key data. If there is no public key in the metadata then
+ * |out_public_key_data| is set to NULL.
+ *
+ * See the |AvbVBMetaVerifyResult| enum for possible return values.
+ *
+ * VERY IMPORTANT:
+ *
+ *   1. Even if |AVB_VBMETA_VERIFY_RESULT_OK| is returned, you still
+ *      need to check that the public key embedded in the image
+ *      matches a known key! You can use 'avbtool extract_public_key'
+ *      to extract the key (at build time, then store it along your
+ *      code) and compare it to what is returned in
+ *      |out_public_key_data|.
+ *
+ *   2. You need to check the |rollback_index| field against a stored
+ *      value in NVRAM and reject the vbmeta image if the value in
+ *      NVRAM is bigger than |rollback_index|. You must also update
+ *      the value stored in NVRAM to the smallest value of
+ *      |rollback_index| field from boot images in all bootable and
+ *      authentic slots marked as GOOD.
+ *
+ * This is a low-level function to only verify the vbmeta data - you
+ * are likely looking for avb_slot_verify() instead for verifying
+ * integrity data for a whole set of partitions.
+ */
+AvbVBMetaVerifyResult avb_vbmeta_image_verify(
+    const uint8_t* data,
+    size_t length,
+    const uint8_t** out_public_key_data,
+    size_t* out_public_key_length) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_VBMETA_IMAGE_H_ */
diff --git a/include/avb/avb_version.h b/include/avb/avb_version.h
new file mode 100644
index 0000000..4a636d0
--- /dev/null
+++ b/include/avb/avb_version.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_VERSION_H_
+#define AVB_VERSION_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The version number of AVB - keep in sync with avbtool. */
+#define AVB_VERSION_MAJOR 1
+#define AVB_VERSION_MINOR 0
+#define AVB_VERSION_SUB 0
+
+/* Returns a NUL-terminated string for the libavb version in use.  The
+ * returned string usually looks like "%d.%d.%d". Applications must
+ * not make assumptions about the content of this string.
+ *
+ * Boot loaders should display this string in debug/diagnostics output
+ * to aid with debugging.
+ *
+ * This is similar to the string put in the |release_string| string
+ * field in the VBMeta struct by avbtool.
+ */
+const char* avb_version_string(void);
+
+/* TODO: remove when there are no more users of AVB_{MAJOR,MINOR}_VERSION. */
+#define AVB_MAJOR_VERSION AVB_VERSION_MAJOR
+#define AVB_MINOR_VERSION AVB_VERSION_MINOR
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_VERSION_H_ */
diff --git a/include/avb/libavb.h b/include/avb/libavb.h
new file mode 100644
index 0000000..dab17ce
--- /dev/null
+++ b/include/avb/libavb.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#ifndef LIBAVB_H_
+#define LIBAVB_H_
+
+/* The AVB_INSIDE_LIBAVB_H preprocessor symbol is used to enforce
+ * library users to include only this file. All public interfaces, and
+ * only public interfaces, must be included here.
+ */
+
+#define AVB_INSIDE_LIBAVB_H
+#include "avb_chain_partition_descriptor.h"
+#include "avb_crypto.h"
+#include "avb_descriptor.h"
+#include "avb_footer.h"
+#include "avb_hash_descriptor.h"
+#include "avb_hashtree_descriptor.h"
+#include "avb_kernel_cmdline_descriptor.h"
+#include "avb_ops.h"
+#include "avb_property_descriptor.h"
+#include "avb_slot_verify.h"
+#include "avb_sysdeps.h"
+#include "avb_util.h"
+#include "avb_vbmeta_image.h"
+#include "avb_version.h"
+#undef AVB_INSIDE_LIBAVB_H
+
+#endif /* LIBAVB_H_ */
diff --git a/include/avb/libavb_ab.h b/include/avb/libavb_ab.h
new file mode 100644
index 0000000..bdbee26
--- /dev/null
+++ b/include/avb/libavb_ab.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#ifndef LIBAVB_AB_H_
+#define LIBAVB_AB_H_
+
+#include <avb/libavb.h>
+
+/* The AVB_INSIDE_LIBAVB_AB_H preprocessor symbol is used to enforce
+ * library users to include only this file. All public interfaces, and
+ * only public interfaces, must be included here.
+ */
+
+#define AVB_INSIDE_LIBAVB_AB_H
+#include "avb_ab_flow.h"
+#include "avb_ab_ops.h"
+#undef AVB_INSIDE_LIBAVB_AB_H
+
+#endif /* LIBAVB_AB_H_ */
diff --git a/lib/libavb/avb_chain_partition_descriptor.c b/lib/libavb/avb_chain_partition_descriptor.c
new file mode 100644
index 0000000..05ac954
--- /dev/null
+++ b/lib/libavb/avb_chain_partition_descriptor.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_chain_partition_descriptor.h"
+#include "avb/avb_util.h"
+
+bool avb_chain_partition_descriptor_validate_and_byteswap(
+    const AvbChainPartitionDescriptor* src, AvbChainPartitionDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbChainPartitionDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_CHAIN_PARTITION) {
+    avb_error("Invalid tag for chain partition descriptor.\n");
+    return false;
+  }
+
+  dest->rollback_index_location = avb_be32toh(dest->rollback_index_location);
+  dest->partition_name_len = avb_be32toh(dest->partition_name_len);
+  dest->public_key_len = avb_be32toh(dest->public_key_len);
+
+  if (dest->rollback_index_location < 1) {
+    avb_error("Invalid rollback index location value.\n");
+    return false;
+  }
+
+  /* Check that partition_name and public_key are fully contained. */
+  expected_size = sizeof(AvbChainPartitionDescriptor) - sizeof(AvbDescriptor);
+  if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
+      !avb_safe_add_to(&expected_size, dest->public_key_len)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+  return true;
+}
diff --git a/lib/libavb/avb_crypto.c b/lib/libavb/avb_crypto.c
new file mode 100644
index 0000000..ec3ec91
--- /dev/null
+++ b/lib/libavb/avb_crypto.c
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_crypto.h"
+#include "avb/avb_rsa.h"
+#include "avb/avb_sha.h"
+#include "avb/avb_util.h"
+
+/* NOTE: The PKC1-v1.5 padding is a blob of binary DER of ASN.1 and is
+ * obtained from section 5.2.2 of RFC 4880.
+ */
+
+static const uint8_t
+    padding_RSA2048_SHA256[AVB_RSA2048_NUM_BYTES - AVB_SHA256_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0x00, 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65,
+        0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20};
+
+static const uint8_t
+    padding_RSA4096_SHA256[AVB_RSA4096_NUM_BYTES - AVB_SHA256_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
+        0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20};
+
+static const uint8_t
+    padding_RSA8192_SHA256[AVB_RSA8192_NUM_BYTES - AVB_SHA256_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0x00, 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65,
+        0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20};
+
+static const uint8_t
+    padding_RSA2048_SHA512[AVB_RSA2048_NUM_BYTES - AVB_SHA512_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60,
+        0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40};
+
+static const uint8_t
+    padding_RSA4096_SHA512[AVB_RSA4096_NUM_BYTES - AVB_SHA512_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x51, 0x30,
+        0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
+        0x05, 0x00, 0x04, 0x40};
+
+static const uint8_t
+    padding_RSA8192_SHA512[AVB_RSA8192_NUM_BYTES - AVB_SHA512_DIGEST_SIZE] = {
+        0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60,
+        0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40};
+
+static AvbAlgorithmData algorithm_data[_AVB_ALGORITHM_NUM_TYPES] = {
+    /* AVB_ALGORITHM_TYPE_NONE */
+    {.padding = NULL, .padding_len = 0, .hash_len = 0},
+    /* AVB_ALGORITHM_TYPE_SHA256_RSA2048 */
+    {.padding = padding_RSA2048_SHA256,
+     .padding_len = sizeof(padding_RSA2048_SHA256),
+     .hash_len = AVB_SHA256_DIGEST_SIZE},
+    /* AVB_ALGORITHM_TYPE_SHA256_RSA4096 */
+    {.padding = padding_RSA4096_SHA256,
+     .padding_len = sizeof(padding_RSA4096_SHA256),
+     .hash_len = AVB_SHA256_DIGEST_SIZE},
+    /* AVB_ALGORITHM_TYPE_SHA256_RSA8192 */
+    {.padding = padding_RSA8192_SHA256,
+     .padding_len = sizeof(padding_RSA8192_SHA256),
+     .hash_len = AVB_SHA256_DIGEST_SIZE},
+    /* AVB_ALGORITHM_TYPE_SHA512_RSA2048 */
+    {.padding = padding_RSA2048_SHA512,
+     .padding_len = sizeof(padding_RSA2048_SHA512),
+     .hash_len = AVB_SHA512_DIGEST_SIZE},
+    /* AVB_ALGORITHM_TYPE_SHA512_RSA4096 */
+    {.padding = padding_RSA4096_SHA512,
+     .padding_len = sizeof(padding_RSA4096_SHA512),
+     .hash_len = AVB_SHA512_DIGEST_SIZE},
+    /* AVB_ALGORITHM_TYPE_SHA512_RSA8192 */
+    {.padding = padding_RSA8192_SHA512,
+     .padding_len = sizeof(padding_RSA8192_SHA512),
+     .hash_len = AVB_SHA512_DIGEST_SIZE},
+};
+
+const AvbAlgorithmData* avb_get_algorithm_data(AvbAlgorithmType algorithm) {
+  if (algorithm >= AVB_ALGORITHM_TYPE_NONE &&
+      algorithm < _AVB_ALGORITHM_NUM_TYPES) {
+    return &algorithm_data[algorithm];
+  }
+  return NULL;
+}
+
+bool avb_rsa_public_key_header_validate_and_byteswap(
+    const AvbRSAPublicKeyHeader* src, AvbRSAPublicKeyHeader* dest) {
+  avb_memcpy(dest, src, sizeof(AvbRSAPublicKeyHeader));
+
+  dest->key_num_bits = avb_be32toh(dest->key_num_bits);
+  dest->n0inv = avb_be32toh(dest->n0inv);
+
+  return true;
+}
diff --git a/lib/libavb/avb_descriptor.c b/lib/libavb/avb_descriptor.c
new file mode 100644
index 0000000..a3d5c0b
--- /dev/null
+++ b/lib/libavb/avb_descriptor.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_descriptor.h"
+#include "avb/avb_util.h"
+#include "avb/avb_vbmeta_image.h"
+
+bool avb_descriptor_validate_and_byteswap(const AvbDescriptor* src,
+                                          AvbDescriptor* dest) {
+  dest->tag = avb_be64toh(src->tag);
+  dest->num_bytes_following = avb_be64toh(src->num_bytes_following);
+
+  if ((dest->num_bytes_following & 0x07) != 0) {
+    avb_error("Descriptor size is not divisible by 8.\n");
+    return false;
+  }
+  return true;
+}
+
+bool avb_descriptor_foreach(const uint8_t* image_data,
+                            size_t image_size,
+                            AvbDescriptorForeachFunc foreach_func,
+                            void* user_data) {
+  const AvbVBMetaImageHeader* header = NULL;
+  bool ret = false;
+  const uint8_t* image_end;
+  const uint8_t* desc_start;
+  const uint8_t* desc_end;
+  const uint8_t* p;
+
+  if (image_data == NULL) {
+    avb_error("image_data is NULL\n.");
+    goto out;
+  }
+
+  if (foreach_func == NULL) {
+    avb_error("foreach_func is NULL\n.");
+    goto out;
+  }
+
+  if (image_size < sizeof(AvbVBMetaImageHeader)) {
+    avb_error("Length is smaller than header.\n");
+    goto out;
+  }
+
+  /* Ensure magic is correct. */
+  if (avb_memcmp(image_data, AVB_MAGIC, AVB_MAGIC_LEN) != 0) {
+    avb_error("Magic is incorrect.\n");
+    goto out;
+  }
+
+  /* Careful, not byteswapped - also ensure it's aligned properly. */
+  avb_assert_aligned(image_data);
+  header = (const AvbVBMetaImageHeader*)image_data;
+  image_end = image_data + image_size;
+
+  desc_start = image_data + sizeof(AvbVBMetaImageHeader) +
+               avb_be64toh(header->authentication_data_block_size) +
+               avb_be64toh(header->descriptors_offset);
+
+  desc_end = desc_start + avb_be64toh(header->descriptors_size);
+
+  if (desc_start < image_data || desc_start > image_end ||
+      desc_end < image_data || desc_end > image_end || desc_end < desc_start) {
+    avb_error("Descriptors not inside passed-in data.\n");
+    goto out;
+  }
+
+  for (p = desc_start; p < desc_end;) {
+    const AvbDescriptor* dh = (const AvbDescriptor*)p;
+    avb_assert_aligned(dh);
+    uint64_t nb_following = avb_be64toh(dh->num_bytes_following);
+    uint64_t nb_total = sizeof(AvbDescriptor) + nb_following;
+
+    if ((nb_total & 7) != 0) {
+      avb_error("Invalid descriptor length.\n");
+      goto out;
+    }
+
+    if (nb_total + p < desc_start || nb_total + p > desc_end) {
+      avb_error("Invalid data in descriptors array.\n");
+      goto out;
+    }
+
+    if (foreach_func(dh, user_data) == 0) {
+      goto out;
+    }
+
+    p += nb_total;
+  }
+
+  ret = true;
+
+out:
+  return ret;
+}
+
+static bool count_descriptors(const AvbDescriptor* descriptor,
+                              void* user_data) {
+  size_t* num_descriptors = user_data;
+  *num_descriptors += 1;
+  return true;
+}
+
+typedef struct {
+  size_t descriptor_number;
+  const AvbDescriptor** descriptors;
+} SetDescriptorData;
+
+static bool set_descriptors(const AvbDescriptor* descriptor, void* user_data) {
+  SetDescriptorData* data = user_data;
+  data->descriptors[data->descriptor_number++] = descriptor;
+  return true;
+}
+
+const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
+                                             size_t image_size,
+                                             size_t* out_num_descriptors) {
+  size_t num_descriptors = 0;
+  SetDescriptorData data;
+
+  avb_descriptor_foreach(
+      image_data, image_size, count_descriptors, &num_descriptors);
+
+  data.descriptor_number = 0;
+  data.descriptors =
+      avb_calloc(sizeof(const AvbDescriptor*) * (num_descriptors + 1));
+  if (data.descriptors == NULL) {
+    return NULL;
+  }
+  avb_descriptor_foreach(image_data, image_size, set_descriptors, &data);
+  avb_assert(data.descriptor_number == num_descriptors);
+
+  if (out_num_descriptors != NULL) {
+    *out_num_descriptors = num_descriptors;
+  }
+
+  return data.descriptors;
+}
diff --git a/lib/libavb/avb_footer.c b/lib/libavb/avb_footer.c
new file mode 100644
index 0000000..ad8ca28
--- /dev/null
+++ b/lib/libavb/avb_footer.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_footer.h"
+#include "avb/avb_util.h"
+
+bool avb_footer_validate_and_byteswap(const AvbFooter* src, AvbFooter* dest) {
+  avb_memcpy(dest, src, sizeof(AvbFooter));
+
+  dest->version_major = avb_be32toh(dest->version_major);
+  dest->version_minor = avb_be32toh(dest->version_minor);
+
+  dest->original_image_size = avb_be64toh(dest->original_image_size);
+  dest->vbmeta_offset = avb_be64toh(dest->vbmeta_offset);
+  dest->vbmeta_size = avb_be64toh(dest->vbmeta_size);
+
+  /* Check that magic is correct. */
+  if (avb_safe_memcmp(dest->magic, AVB_FOOTER_MAGIC, AVB_FOOTER_MAGIC_LEN) !=
+      0) {
+    avb_error("Footer magic is incorrect.\n");
+    return false;
+  }
+
+  /* Ensure we don't attempt to access any fields if the footer major
+   * version is not supported.
+   */
+  if (dest->version_major > AVB_FOOTER_VERSION_MAJOR) {
+    avb_error("No support for footer version.\n");
+    return false;
+  }
+
+  return true;
+}
diff --git a/lib/libavb/avb_hash_descriptor.c b/lib/libavb/avb_hash_descriptor.c
new file mode 100644
index 0000000..02547c2
--- /dev/null
+++ b/lib/libavb/avb_hash_descriptor.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_hash_descriptor.h"
+#include "avb/avb_util.h"
+
+bool avb_hash_descriptor_validate_and_byteswap(const AvbHashDescriptor* src,
+                                               AvbHashDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbHashDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_HASH) {
+    avb_error("Invalid tag for hash descriptor.\n");
+    return false;
+  }
+
+  dest->image_size = avb_be64toh(dest->image_size);
+  dest->partition_name_len = avb_be32toh(dest->partition_name_len);
+  dest->salt_len = avb_be32toh(dest->salt_len);
+  dest->digest_len = avb_be32toh(dest->digest_len);
+
+  /* Check that partition_name, salt, and digest are fully contained. */
+  expected_size = sizeof(AvbHashDescriptor) - sizeof(AvbDescriptor);
+  if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
+      !avb_safe_add_to(&expected_size, dest->salt_len) ||
+      !avb_safe_add_to(&expected_size, dest->digest_len)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+  return true;
+}
diff --git a/lib/libavb/avb_hashtree_descriptor.c b/lib/libavb/avb_hashtree_descriptor.c
new file mode 100644
index 0000000..bac5157
--- /dev/null
+++ b/lib/libavb/avb_hashtree_descriptor.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_hashtree_descriptor.h"
+#include "avb/avb_util.h"
+
+bool avb_hashtree_descriptor_validate_and_byteswap(
+    const AvbHashtreeDescriptor* src, AvbHashtreeDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbHashtreeDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_HASHTREE) {
+    avb_error("Invalid tag for hashtree descriptor.\n");
+    return false;
+  }
+
+  dest->dm_verity_version = avb_be32toh(dest->dm_verity_version);
+  dest->image_size = avb_be64toh(dest->image_size);
+  dest->tree_offset = avb_be64toh(dest->tree_offset);
+  dest->tree_size = avb_be64toh(dest->tree_size);
+  dest->data_block_size = avb_be32toh(dest->data_block_size);
+  dest->hash_block_size = avb_be32toh(dest->hash_block_size);
+  dest->fec_num_roots = avb_be32toh(dest->fec_num_roots);
+  dest->fec_offset = avb_be64toh(dest->fec_offset);
+  dest->fec_size = avb_be64toh(dest->fec_size);
+  dest->partition_name_len = avb_be32toh(dest->partition_name_len);
+  dest->salt_len = avb_be32toh(dest->salt_len);
+  dest->root_digest_len = avb_be32toh(dest->root_digest_len);
+
+  /* Check that partition_name, salt, and root_digest are fully contained. */
+  expected_size = sizeof(AvbHashtreeDescriptor) - sizeof(AvbDescriptor);
+  if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
+      !avb_safe_add_to(&expected_size, dest->salt_len) ||
+      !avb_safe_add_to(&expected_size, dest->root_digest_len)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+  return true;
+}
diff --git a/lib/libavb/avb_kernel_cmdline_descriptor.c b/lib/libavb/avb_kernel_cmdline_descriptor.c
new file mode 100644
index 0000000..0ee6994
--- /dev/null
+++ b/lib/libavb/avb_kernel_cmdline_descriptor.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_kernel_cmdline_descriptor.h"
+#include "avb/avb_util.h"
+
+bool avb_kernel_cmdline_descriptor_validate_and_byteswap(
+    const AvbKernelCmdlineDescriptor* src, AvbKernelCmdlineDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbKernelCmdlineDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE) {
+    avb_error("Invalid tag for kernel cmdline descriptor.\n");
+    return false;
+  }
+
+  dest->flags = avb_be32toh(dest->flags);
+  dest->kernel_cmdline_length = avb_be32toh(dest->kernel_cmdline_length);
+
+  /* Check that kernel_cmdline is fully contained. */
+  expected_size = sizeof(AvbKernelCmdlineDescriptor) - sizeof(AvbDescriptor);
+  if (!avb_safe_add_to(&expected_size, dest->kernel_cmdline_length)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+
+  return true;
+}
diff --git a/lib/libavb/avb_property_descriptor.c b/lib/libavb/avb_property_descriptor.c
new file mode 100644
index 0000000..c1af02f
--- /dev/null
+++ b/lib/libavb/avb_property_descriptor.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_property_descriptor.h"
+#include "avb/avb_util.h"
+
+bool avb_property_descriptor_validate_and_byteswap(
+    const AvbPropertyDescriptor* src, AvbPropertyDescriptor* dest) {
+  uint64_t expected_size;
+
+  avb_memcpy(dest, src, sizeof(AvbPropertyDescriptor));
+
+  if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
+                                            (AvbDescriptor*)dest))
+    return false;
+
+  if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
+    avb_error("Invalid tag for property descriptor.\n");
+    return false;
+  }
+
+  dest->key_num_bytes = avb_be64toh(dest->key_num_bytes);
+  dest->value_num_bytes = avb_be64toh(dest->value_num_bytes);
+
+  /* Check that key and value are fully contained. */
+  expected_size = sizeof(AvbPropertyDescriptor) - sizeof(AvbDescriptor) + 2;
+  if (!avb_safe_add_to(&expected_size, dest->key_num_bytes) ||
+      !avb_safe_add_to(&expected_size, dest->value_num_bytes)) {
+    avb_error("Overflow while adding up sizes.\n");
+    return false;
+  }
+  if (expected_size > dest->parent_descriptor.num_bytes_following) {
+    avb_error("Descriptor payload size overflow.\n");
+    return false;
+  }
+
+  return true;
+}
+
+typedef struct {
+  const char* key;
+  size_t key_size;
+  const char* ret_value;
+  size_t ret_value_size;
+} PropertyIteratorData;
+
+static bool property_lookup_desc_foreach(const AvbDescriptor* header,
+                                         void* user_data) {
+  PropertyIteratorData* data = (PropertyIteratorData*)user_data;
+  AvbPropertyDescriptor prop_desc;
+  const uint8_t* p;
+  bool ret = true;
+
+  if (header->tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
+    goto out;
+  }
+
+  if (!avb_property_descriptor_validate_and_byteswap(
+          (const AvbPropertyDescriptor*)header, &prop_desc)) {
+    goto out;
+  }
+
+  p = (const uint8_t*)header;
+  if (p[sizeof(AvbPropertyDescriptor) + prop_desc.key_num_bytes] != 0) {
+    avb_error("No terminating NUL byte in key.\n");
+    goto out;
+  }
+
+  if (data->key_size == prop_desc.key_num_bytes) {
+    if (avb_memcmp(p + sizeof(AvbPropertyDescriptor),
+                   data->key,
+                   data->key_size) == 0) {
+      data->ret_value = (const char*)(p + sizeof(AvbPropertyDescriptor) +
+                                      prop_desc.key_num_bytes + 1);
+      data->ret_value_size = prop_desc.value_num_bytes;
+      /* Stop iterating. */
+      ret = false;
+      goto out;
+    }
+  }
+
+out:
+  return ret;
+}
+
+const char* avb_property_lookup(const uint8_t* image_data,
+                                size_t image_size,
+                                const char* key,
+                                size_t key_size,
+                                size_t* out_value_size) {
+  PropertyIteratorData data;
+
+  if (key_size == 0) {
+    key_size = avb_strlen(key);
+  }
+
+  data.key = key;
+  data.key_size = key_size;
+
+  if (avb_descriptor_foreach(
+          image_data, image_size, property_lookup_desc_foreach, &data) == 0) {
+    if (out_value_size != NULL) {
+      *out_value_size = data.ret_value_size;
+    }
+    return data.ret_value;
+  }
+
+  if (out_value_size != NULL) {
+    *out_value_size = 0;
+  }
+  return NULL;
+}
+
+bool avb_property_lookup_uint64(const uint8_t* image_data,
+                                size_t image_size,
+                                const char* key,
+                                size_t key_size,
+                                uint64_t* out_value) {
+  const char* value;
+  bool ret = false;
+  uint64_t parsed_val;
+  int base;
+  int n;
+
+  value = avb_property_lookup(image_data, image_size, key, key_size, NULL);
+  if (value == NULL) {
+    goto out;
+  }
+
+  base = 10;
+  if (avb_memcmp(value, "0x", 2) == 0) {
+    base = 16;
+    value += 2;
+  }
+
+  parsed_val = 0;
+  for (n = 0; value[n] != '\0'; n++) {
+    int c = value[n];
+    int digit;
+
+    parsed_val *= base;
+
+    if (c >= '0' && c <= '9') {
+      digit = c - '0';
+    } else if (base == 16 && c >= 'a' && c <= 'f') {
+      digit = c - 'a' + 10;
+    } else if (base == 16 && c >= 'A' && c <= 'F') {
+      digit = c - 'A' + 10;
+    } else {
+      avb_error("Invalid digit.\n");
+      goto out;
+    }
+
+    parsed_val += digit;
+  }
+
+  ret = true;
+  if (out_value != NULL) {
+    *out_value = parsed_val;
+  }
+
+out:
+  return ret;
+}
diff --git a/lib/libavb/avb_rsa.c b/lib/libavb/avb_rsa.c
new file mode 100644
index 0000000..6bb3866
--- /dev/null
+++ b/lib/libavb/avb_rsa.c
@@ -0,0 +1,277 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ * Copyright (c) 2011 The Chromium OS Authors.
+ *
+ * SPDX-License-Identifier:	(BSD-3-Clause or MIT)
+ */
+
+/* Implementation of RSA signature verification which uses a pre-processed
+ * key for computation. The code extends libmincrypt RSA verification code to
+ * support multiple RSA key lengths and hash digest algorithms.
+ */
+
+#include "avb/avb_rsa.h"
+#include "avb/avb_sha.h"
+#include "avb/avb_util.h"
+#include "avb/avb_vbmeta_image.h"
+
+typedef struct Key {
+  unsigned int len; /* Length of n[] in number of uint32_t */
+  uint32_t n0inv;   /* -1 / n[0] mod 2^32 */
+  uint32_t* n;      /* modulus as array (host-byte order) */
+  uint32_t* rr;     /* R^2 as array (host-byte order) */
+} Key;
+
+Key* parse_key_data(const uint8_t* data, size_t length) {
+  AvbRSAPublicKeyHeader h;
+  Key* key = NULL;
+  size_t expected_length;
+  unsigned int i;
+  const uint8_t* n;
+  const uint8_t* rr;
+
+  if (!avb_rsa_public_key_header_validate_and_byteswap(
+          (const AvbRSAPublicKeyHeader*)data, &h)) {
+    avb_error("Invalid key.\n");
+    goto fail;
+  }
+
+  if (!(h.key_num_bits == 2048 || h.key_num_bits == 4096 ||
+        h.key_num_bits == 8192)) {
+    avb_error("Unexpected key length.\n");
+    goto fail;
+  }
+
+  expected_length = sizeof(AvbRSAPublicKeyHeader) + 2 * h.key_num_bits / 8;
+  if (length != expected_length) {
+    avb_error("Key does not match expected length.\n");
+    goto fail;
+  }
+
+  n = data + sizeof(AvbRSAPublicKeyHeader);
+  rr = data + sizeof(AvbRSAPublicKeyHeader) + h.key_num_bits / 8;
+
+  /* Store n and rr following the key header so we only have to do one
+   * allocation.
+   */
+  key = (Key*)(avb_malloc(sizeof(Key) + 2 * h.key_num_bits / 8));
+  if (key == NULL) {
+    goto fail;
+  }
+
+  key->len = h.key_num_bits / 32;
+  key->n0inv = h.n0inv;
+  key->n = (uint32_t*)(key + 1); /* Skip ahead sizeof(Key) bytes. */
+  key->rr = key->n + key->len;
+
+  /* Crypto-code below (modpowF4() and friends) expects the key in
+   * little-endian format (rather than the format we're storing the
+   * key in), so convert it.
+   */
+  for (i = 0; i < key->len; i++) {
+    key->n[i] = avb_be32toh(((uint32_t*)n)[key->len - i - 1]);
+    key->rr[i] = avb_be32toh(((uint32_t*)rr)[key->len - i - 1]);
+  }
+  return key;
+
+fail:
+  if (key != NULL) {
+    avb_free(key);
+  }
+  return NULL;
+}
+
+void free_parsed_key(Key* key) {
+  avb_free(key);
+}
+
+/* a[] -= mod */
+static void subM(const Key* key, uint32_t* a) {
+  int64_t A = 0;
+  uint32_t i;
+  for (i = 0; i < key->len; ++i) {
+    A += (uint64_t)a[i] - key->n[i];
+    a[i] = (uint32_t)A;
+    A >>= 32;
+  }
+}
+
+/* return a[] >= mod */
+static int geM(const Key* key, uint32_t* a) {
+  uint32_t i;
+  for (i = key->len; i;) {
+    --i;
+    if (a[i] < key->n[i]) {
+      return 0;
+    }
+    if (a[i] > key->n[i]) {
+      return 1;
+    }
+  }
+  return 1; /* equal */
+}
+
+/* montgomery c[] += a * b[] / R % mod */
+static void montMulAdd(const Key* key,
+                       uint32_t* c,
+                       const uint32_t a,
+                       const uint32_t* b) {
+  uint64_t A = (uint64_t)a * b[0] + c[0];
+  uint32_t d0 = (uint32_t)A * key->n0inv;
+  uint64_t B = (uint64_t)d0 * key->n[0] + (uint32_t)A;
+  uint32_t i;
+
+  for (i = 1; i < key->len; ++i) {
+    A = (A >> 32) + (uint64_t)a * b[i] + c[i];
+    B = (B >> 32) + (uint64_t)d0 * key->n[i] + (uint32_t)A;
+    c[i - 1] = (uint32_t)B;
+  }
+
+  A = (A >> 32) + (B >> 32);
+
+  c[i - 1] = (uint32_t)A;
+
+  if (A >> 32) {
+    subM(key, c);
+  }
+}
+
+/* montgomery c[] = a[] * b[] / R % mod */
+static void montMul(const Key* key, uint32_t* c, uint32_t* a, uint32_t* b) {
+  uint32_t i;
+  for (i = 0; i < key->len; ++i) {
+    c[i] = 0;
+  }
+  for (i = 0; i < key->len; ++i) {
+    montMulAdd(key, c, a[i], b);
+  }
+}
+
+/* In-place public exponentiation. (65537}
+ * Input and output big-endian byte array in inout.
+ */
+static void modpowF4(const Key* key, uint8_t* inout) {
+  uint32_t* a = (uint32_t*)avb_malloc(key->len * sizeof(uint32_t));
+  uint32_t* aR = (uint32_t*)avb_malloc(key->len * sizeof(uint32_t));
+  uint32_t* aaR = (uint32_t*)avb_malloc(key->len * sizeof(uint32_t));
+  if (a == NULL || aR == NULL || aaR == NULL) {
+    goto out;
+  }
+
+  uint32_t* aaa = aaR; /* Re-use location. */
+  int i;
+
+  /* Convert from big endian byte array to little endian word array. */
+  for (i = 0; i < (int)key->len; ++i) {
+    uint32_t tmp = (inout[((key->len - 1 - i) * 4) + 0] << 24) |
+                   (inout[((key->len - 1 - i) * 4) + 1] << 16) |
+                   (inout[((key->len - 1 - i) * 4) + 2] << 8) |
+                   (inout[((key->len - 1 - i) * 4) + 3] << 0);
+    a[i] = tmp;
+  }
+
+  montMul(key, aR, a, key->rr); /* aR = a * RR / R mod M   */
+  for (i = 0; i < 16; i += 2) {
+    montMul(key, aaR, aR, aR);  /* aaR = aR * aR / R mod M */
+    montMul(key, aR, aaR, aaR); /* aR = aaR * aaR / R mod M */
+  }
+  montMul(key, aaa, aR, a); /* aaa = aR * a / R mod M */
+
+  /* Make sure aaa < mod; aaa is at most 1x mod too large. */
+  if (geM(key, aaa)) {
+    subM(key, aaa);
+  }
+
+  /* Convert to bigendian byte array */
+  for (i = (int)key->len - 1; i >= 0; --i) {
+    uint32_t tmp = aaa[i];
+    *inout++ = (uint8_t)(tmp >> 24);
+    *inout++ = (uint8_t)(tmp >> 16);
+    *inout++ = (uint8_t)(tmp >> 8);
+    *inout++ = (uint8_t)(tmp >> 0);
+  }
+
+out:
+  if (a != NULL) {
+    avb_free(a);
+  }
+  if (aR != NULL) {
+    avb_free(aR);
+  }
+  if (aaR != NULL) {
+    avb_free(aaR);
+  }
+}
+
+/* Verify a RSA PKCS1.5 signature against an expected hash.
+ * Returns false on failure, true on success.
+ */
+bool avb_rsa_verify(const uint8_t* key,
+                    size_t key_num_bytes,
+                    const uint8_t* sig,
+                    size_t sig_num_bytes,
+                    const uint8_t* hash,
+                    size_t hash_num_bytes,
+                    const uint8_t* padding,
+                    size_t padding_num_bytes) {
+  uint8_t* buf = NULL;
+  Key* parsed_key = NULL;
+  bool success = false;
+
+  if (key == NULL || sig == NULL || hash == NULL || padding == NULL) {
+    avb_error("Invalid input.\n");
+    goto out;
+  }
+
+  parsed_key = parse_key_data(key, key_num_bytes);
+  if (parsed_key == NULL) {
+    avb_error("Error parsing key.\n");
+    goto out;
+  }
+
+  if (sig_num_bytes != (parsed_key->len * sizeof(uint32_t))) {
+    avb_error("Signature length does not match key length.\n");
+    goto out;
+  }
+
+  if (padding_num_bytes != sig_num_bytes - hash_num_bytes) {
+    avb_error("Padding length does not match hash and signature lengths.\n");
+    goto out;
+  }
+
+  buf = (uint8_t*)avb_malloc(sig_num_bytes);
+  if (buf == NULL) {
+    avb_error("Error allocating memory.\n");
+    goto out;
+  }
+  avb_memcpy(buf, sig, sig_num_bytes);
+
+  modpowF4(parsed_key, buf);
+
+  /* Check padding bytes.
+   *
+   * Even though there are probably no timing issues here, we use
+   * avb_safe_memcmp() just to be on the safe side.
+   */
+  if (avb_safe_memcmp(buf, padding, padding_num_bytes)) {
+    avb_error("Padding check failed.\n");
+    goto out;
+  }
+
+  /* Check hash. */
+  if (avb_safe_memcmp(buf + padding_num_bytes, hash, hash_num_bytes)) {
+    avb_error("Hash check failed.\n");
+    goto out;
+  }
+
+  success = true;
+
+out:
+  if (parsed_key != NULL) {
+    free_parsed_key(parsed_key);
+  }
+  if (buf != NULL) {
+    avb_free(buf);
+  }
+  return success;
+}
diff --git a/lib/libavb/avb_sha256.c b/lib/libavb/avb_sha256.c
new file mode 100644
index 0000000..110b512
--- /dev/null
+++ b/lib/libavb/avb_sha256.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) 2005, 2007 Olivier Gay <olivier.gay@a3.epfl.ch>
+ * All rights reserved.
+ *
+ * FIPS 180-2 SHA-224/256/384/512 implementation
+ * Last update: 02/02/2007
+ * Issue date:  04/30/2005
+ *
+ * SPDX-License-Identifier:	BSD-3-Clause
+ */
+
+#include "avb/avb_sha.h"
+
+#define SHFR(x, n) (x >> n)
+#define ROTR(x, n) ((x >> n) | (x << ((sizeof(x) << 3) - n)))
+#define ROTL(x, n) ((x << n) | (x >> ((sizeof(x) << 3) - n)))
+#define CH(x, y, z) ((x & y) ^ (~x & z))
+#define MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
+
+#define SHA256_F1(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
+#define SHA256_F2(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
+#define SHA256_F3(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHFR(x, 3))
+#define SHA256_F4(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHFR(x, 10))
+
+#define UNPACK32(x, str)                 \
+  {                                      \
+    *((str) + 3) = (uint8_t)((x));       \
+    *((str) + 2) = (uint8_t)((x) >> 8);  \
+    *((str) + 1) = (uint8_t)((x) >> 16); \
+    *((str) + 0) = (uint8_t)((x) >> 24); \
+  }
+
+#define PACK32(str, x)                                                    \
+  {                                                                       \
+    *(x) = ((uint32_t) * ((str) + 3)) | ((uint32_t) * ((str) + 2) << 8) | \
+           ((uint32_t) * ((str) + 1) << 16) |                             \
+           ((uint32_t) * ((str) + 0) << 24);                              \
+  }
+
+/* Macros used for loops unrolling */
+
+#define SHA256_SCR(i) \
+  { w[i] = SHA256_F4(w[i - 2]) + w[i - 7] + SHA256_F3(w[i - 15]) + w[i - 16]; }
+
+#define SHA256_EXP(a, b, c, d, e, f, g, h, j)                               \
+  {                                                                         \
+    t1 = wv[h] + SHA256_F2(wv[e]) + CH(wv[e], wv[f], wv[g]) + sha256_k[j] + \
+         w[j];                                                              \
+    t2 = SHA256_F1(wv[a]) + MAJ(wv[a], wv[b], wv[c]);                       \
+    wv[d] += t1;                                                            \
+    wv[h] = t1 + t2;                                                        \
+  }
+
+static const uint32_t sha256_h0[8] = {0x6a09e667,
+                                      0xbb67ae85,
+                                      0x3c6ef372,
+                                      0xa54ff53a,
+                                      0x510e527f,
+                                      0x9b05688c,
+                                      0x1f83d9ab,
+                                      0x5be0cd19};
+
+static const uint32_t sha256_k[64] = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+    0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+    0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+    0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+    0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+    0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+
+/* SHA-256 implementation */
+void avb_sha256_init(AvbSHA256Ctx* ctx) {
+#ifndef UNROLL_LOOPS
+  int i;
+  for (i = 0; i < 8; i++) {
+    ctx->h[i] = sha256_h0[i];
+  }
+#else
+  ctx->h[0] = sha256_h0[0];
+  ctx->h[1] = sha256_h0[1];
+  ctx->h[2] = sha256_h0[2];
+  ctx->h[3] = sha256_h0[3];
+  ctx->h[4] = sha256_h0[4];
+  ctx->h[5] = sha256_h0[5];
+  ctx->h[6] = sha256_h0[6];
+  ctx->h[7] = sha256_h0[7];
+#endif /* !UNROLL_LOOPS */
+
+  ctx->len = 0;
+  ctx->tot_len = 0;
+}
+
+static void SHA256_transform(AvbSHA256Ctx* ctx,
+                             const uint8_t* message,
+                             unsigned int block_nb) {
+  uint32_t w[64];
+  uint32_t wv[8];
+  uint32_t t1, t2;
+  const unsigned char* sub_block;
+  int i;
+
+#ifndef UNROLL_LOOPS
+  int j;
+#endif
+
+  for (i = 0; i < (int)block_nb; i++) {
+    sub_block = message + (i << 6);
+
+#ifndef UNROLL_LOOPS
+    for (j = 0; j < 16; j++) {
+      PACK32(&sub_block[j << 2], &w[j]);
+    }
+
+    for (j = 16; j < 64; j++) {
+      SHA256_SCR(j);
+    }
+
+    for (j = 0; j < 8; j++) {
+      wv[j] = ctx->h[j];
+    }
+
+    for (j = 0; j < 64; j++) {
+      t1 = wv[7] + SHA256_F2(wv[4]) + CH(wv[4], wv[5], wv[6]) + sha256_k[j] +
+           w[j];
+      t2 = SHA256_F1(wv[0]) + MAJ(wv[0], wv[1], wv[2]);
+      wv[7] = wv[6];
+      wv[6] = wv[5];
+      wv[5] = wv[4];
+      wv[4] = wv[3] + t1;
+      wv[3] = wv[2];
+      wv[2] = wv[1];
+      wv[1] = wv[0];
+      wv[0] = t1 + t2;
+    }
+
+    for (j = 0; j < 8; j++) {
+      ctx->h[j] += wv[j];
+    }
+#else
+    PACK32(&sub_block[0], &w[0]);
+    PACK32(&sub_block[4], &w[1]);
+    PACK32(&sub_block[8], &w[2]);
+    PACK32(&sub_block[12], &w[3]);
+    PACK32(&sub_block[16], &w[4]);
+    PACK32(&sub_block[20], &w[5]);
+    PACK32(&sub_block[24], &w[6]);
+    PACK32(&sub_block[28], &w[7]);
+    PACK32(&sub_block[32], &w[8]);
+    PACK32(&sub_block[36], &w[9]);
+    PACK32(&sub_block[40], &w[10]);
+    PACK32(&sub_block[44], &w[11]);
+    PACK32(&sub_block[48], &w[12]);
+    PACK32(&sub_block[52], &w[13]);
+    PACK32(&sub_block[56], &w[14]);
+    PACK32(&sub_block[60], &w[15]);
+
+    SHA256_SCR(16);
+    SHA256_SCR(17);
+    SHA256_SCR(18);
+    SHA256_SCR(19);
+    SHA256_SCR(20);
+    SHA256_SCR(21);
+    SHA256_SCR(22);
+    SHA256_SCR(23);
+    SHA256_SCR(24);
+    SHA256_SCR(25);
+    SHA256_SCR(26);
+    SHA256_SCR(27);
+    SHA256_SCR(28);
+    SHA256_SCR(29);
+    SHA256_SCR(30);
+    SHA256_SCR(31);
+    SHA256_SCR(32);
+    SHA256_SCR(33);
+    SHA256_SCR(34);
+    SHA256_SCR(35);
+    SHA256_SCR(36);
+    SHA256_SCR(37);
+    SHA256_SCR(38);
+    SHA256_SCR(39);
+    SHA256_SCR(40);
+    SHA256_SCR(41);
+    SHA256_SCR(42);
+    SHA256_SCR(43);
+    SHA256_SCR(44);
+    SHA256_SCR(45);
+    SHA256_SCR(46);
+    SHA256_SCR(47);
+    SHA256_SCR(48);
+    SHA256_SCR(49);
+    SHA256_SCR(50);
+    SHA256_SCR(51);
+    SHA256_SCR(52);
+    SHA256_SCR(53);
+    SHA256_SCR(54);
+    SHA256_SCR(55);
+    SHA256_SCR(56);
+    SHA256_SCR(57);
+    SHA256_SCR(58);
+    SHA256_SCR(59);
+    SHA256_SCR(60);
+    SHA256_SCR(61);
+    SHA256_SCR(62);
+    SHA256_SCR(63);
+
+    wv[0] = ctx->h[0];
+    wv[1] = ctx->h[1];
+    wv[2] = ctx->h[2];
+    wv[3] = ctx->h[3];
+    wv[4] = ctx->h[4];
+    wv[5] = ctx->h[5];
+    wv[6] = ctx->h[6];
+    wv[7] = ctx->h[7];
+
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 0);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 1);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 2);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 3);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 4);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 5);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 6);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 7);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 8);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 9);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 10);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 11);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 12);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 13);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 14);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 15);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 16);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 17);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 18);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 19);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 20);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 21);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 22);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 23);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 24);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 25);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 26);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 27);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 28);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 29);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 30);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 31);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 32);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 33);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 34);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 35);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 36);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 37);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 38);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 39);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 40);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 41);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 42);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 43);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 44);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 45);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 46);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 47);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 48);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 49);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 50);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 51);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 52);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 53);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 54);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 55);
+    SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 56);
+    SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 57);
+    SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 58);
+    SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 59);
+    SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 60);
+    SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 61);
+    SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 62);
+    SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 63);
+
+    ctx->h[0] += wv[0];
+    ctx->h[1] += wv[1];
+    ctx->h[2] += wv[2];
+    ctx->h[3] += wv[3];
+    ctx->h[4] += wv[4];
+    ctx->h[5] += wv[5];
+    ctx->h[6] += wv[6];
+    ctx->h[7] += wv[7];
+#endif /* !UNROLL_LOOPS */
+  }
+}
+
+void avb_sha256_update(AvbSHA256Ctx* ctx, const uint8_t* data, uint32_t len) {
+  unsigned int block_nb;
+  unsigned int new_len, rem_len, tmp_len;
+  const uint8_t* shifted_data;
+
+  tmp_len = AVB_SHA256_BLOCK_SIZE - ctx->len;
+  rem_len = len < tmp_len ? len : tmp_len;
+
+  avb_memcpy(&ctx->block[ctx->len], data, rem_len);
+
+  if (ctx->len + len < AVB_SHA256_BLOCK_SIZE) {
+    ctx->len += len;
+    return;
+  }
+
+  new_len = len - rem_len;
+  block_nb = new_len / AVB_SHA256_BLOCK_SIZE;
+
+  shifted_data = data + rem_len;
+
+  SHA256_transform(ctx, ctx->block, 1);
+  SHA256_transform(ctx, shifted_data, block_nb);
+
+  rem_len = new_len % AVB_SHA256_BLOCK_SIZE;
+
+  avb_memcpy(ctx->block, &shifted_data[block_nb << 6], rem_len);
+
+  ctx->len = rem_len;
+  ctx->tot_len += (block_nb + 1) << 6;
+}
+
+uint8_t* avb_sha256_final(AvbSHA256Ctx* ctx) {
+  unsigned int block_nb;
+  unsigned int pm_len;
+  unsigned int len_b;
+#ifndef UNROLL_LOOPS
+  int i;
+#endif
+
+  block_nb =
+      (1 + ((AVB_SHA256_BLOCK_SIZE - 9) < (ctx->len % AVB_SHA256_BLOCK_SIZE)));
+
+  len_b = (ctx->tot_len + ctx->len) << 3;
+  pm_len = block_nb << 6;
+
+  avb_memset(ctx->block + ctx->len, 0, pm_len - ctx->len);
+  ctx->block[ctx->len] = 0x80;
+  UNPACK32(len_b, ctx->block + pm_len - 4);
+
+  SHA256_transform(ctx, ctx->block, block_nb);
+
+#ifndef UNROLL_LOOPS
+  for (i = 0; i < 8; i++) {
+    UNPACK32(ctx->h[i], &ctx->buf[i << 2]);
+  }
+#else
+  UNPACK32(ctx->h[0], &ctx->buf[0]);
+  UNPACK32(ctx->h[1], &ctx->buf[4]);
+  UNPACK32(ctx->h[2], &ctx->buf[8]);
+  UNPACK32(ctx->h[3], &ctx->buf[12]);
+  UNPACK32(ctx->h[4], &ctx->buf[16]);
+  UNPACK32(ctx->h[5], &ctx->buf[20]);
+  UNPACK32(ctx->h[6], &ctx->buf[24]);
+  UNPACK32(ctx->h[7], &ctx->buf[28]);
+#endif /* !UNROLL_LOOPS */
+
+  return ctx->buf;
+}
diff --git a/lib/libavb/avb_sha512.c b/lib/libavb/avb_sha512.c
new file mode 100644
index 0000000..6a1caa8
--- /dev/null
+++ b/lib/libavb/avb_sha512.c
@@ -0,0 +1,362 @@
+/*
+ * Copyright (C) 2005, 2007 Olivier Gay <olivier.gay@a3.epfl.ch>
+ * All rights reserved.
+ *
+ * FIPS 180-2 SHA-224/256/384/512 implementation
+ * Last update: 02/02/2007
+ * Issue date:  04/30/2005
+ *
+ * SPDX-License-Identifier:	BSD-3-Clause
+ */
+
+#include "avb/avb_sha.h"
+
+#define SHFR(x, n) (x >> n)
+#define ROTR(x, n) ((x >> n) | (x << ((sizeof(x) << 3) - n)))
+#define ROTL(x, n) ((x << n) | (x >> ((sizeof(x) << 3) - n)))
+#define CH(x, y, z) ((x & y) ^ (~x & z))
+#define MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
+
+#define SHA512_F1(x) (ROTR(x, 28) ^ ROTR(x, 34) ^ ROTR(x, 39))
+#define SHA512_F2(x) (ROTR(x, 14) ^ ROTR(x, 18) ^ ROTR(x, 41))
+#define SHA512_F3(x) (ROTR(x, 1) ^ ROTR(x, 8) ^ SHFR(x, 7))
+#define SHA512_F4(x) (ROTR(x, 19) ^ ROTR(x, 61) ^ SHFR(x, 6))
+
+#define UNPACK32(x, str)                 \
+  {                                      \
+    *((str) + 3) = (uint8_t)((x));       \
+    *((str) + 2) = (uint8_t)((x) >> 8);  \
+    *((str) + 1) = (uint8_t)((x) >> 16); \
+    *((str) + 0) = (uint8_t)((x) >> 24); \
+  }
+
+#define UNPACK64(x, str)                         \
+  {                                              \
+    *((str) + 7) = (uint8_t)x;                   \
+    *((str) + 6) = (uint8_t)((uint64_t)x >> 8);  \
+    *((str) + 5) = (uint8_t)((uint64_t)x >> 16); \
+    *((str) + 4) = (uint8_t)((uint64_t)x >> 24); \
+    *((str) + 3) = (uint8_t)((uint64_t)x >> 32); \
+    *((str) + 2) = (uint8_t)((uint64_t)x >> 40); \
+    *((str) + 1) = (uint8_t)((uint64_t)x >> 48); \
+    *((str) + 0) = (uint8_t)((uint64_t)x >> 56); \
+  }
+
+#define PACK64(str, x)                                                        \
+  {                                                                           \
+    *(x) =                                                                    \
+        ((uint64_t) * ((str) + 7)) | ((uint64_t) * ((str) + 6) << 8) |        \
+        ((uint64_t) * ((str) + 5) << 16) | ((uint64_t) * ((str) + 4) << 24) | \
+        ((uint64_t) * ((str) + 3) << 32) | ((uint64_t) * ((str) + 2) << 40) | \
+        ((uint64_t) * ((str) + 1) << 48) | ((uint64_t) * ((str) + 0) << 56);  \
+  }
+
+/* Macros used for loops unrolling */
+
+#define SHA512_SCR(i) \
+  { w[i] = SHA512_F4(w[i - 2]) + w[i - 7] + SHA512_F3(w[i - 15]) + w[i - 16]; }
+
+#define SHA512_EXP(a, b, c, d, e, f, g, h, j)                               \
+  {                                                                         \
+    t1 = wv[h] + SHA512_F2(wv[e]) + CH(wv[e], wv[f], wv[g]) + sha512_k[j] + \
+         w[j];                                                              \
+    t2 = SHA512_F1(wv[a]) + MAJ(wv[a], wv[b], wv[c]);                       \
+    wv[d] += t1;                                                            \
+    wv[h] = t1 + t2;                                                        \
+  }
+
+static const uint64_t sha512_h0[8] = {0x6a09e667f3bcc908ULL,
+                                      0xbb67ae8584caa73bULL,
+                                      0x3c6ef372fe94f82bULL,
+                                      0xa54ff53a5f1d36f1ULL,
+                                      0x510e527fade682d1ULL,
+                                      0x9b05688c2b3e6c1fULL,
+                                      0x1f83d9abfb41bd6bULL,
+                                      0x5be0cd19137e2179ULL};
+
+static const uint64_t sha512_k[80] = {
+    0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL,
+    0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
+    0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL, 0xd807aa98a3030242ULL,
+    0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
+    0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL,
+    0xc19bf174cf692694ULL, 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
+    0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL,
+    0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
+    0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL,
+    0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
+    0x06ca6351e003826fULL, 0x142929670a0e6e70ULL, 0x27b70a8546d22ffcULL,
+    0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
+    0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL,
+    0x92722c851482353bULL, 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
+    0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL,
+    0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
+    0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL,
+    0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
+    0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL, 0x748f82ee5defb2fcULL,
+    0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
+    0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL,
+    0xc67178f2e372532bULL, 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
+    0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL,
+    0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
+    0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL,
+    0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
+    0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL};
+
+/* SHA-512 implementation */
+
+void avb_sha512_init(AvbSHA512Ctx* ctx) {
+#ifdef UNROLL_LOOPS_SHA512
+  ctx->h[0] = sha512_h0[0];
+  ctx->h[1] = sha512_h0[1];
+  ctx->h[2] = sha512_h0[2];
+  ctx->h[3] = sha512_h0[3];
+  ctx->h[4] = sha512_h0[4];
+  ctx->h[5] = sha512_h0[5];
+  ctx->h[6] = sha512_h0[6];
+  ctx->h[7] = sha512_h0[7];
+#else
+  int i;
+
+  for (i = 0; i < 8; i++)
+    ctx->h[i] = sha512_h0[i];
+#endif /* UNROLL_LOOPS_SHA512 */
+
+  ctx->len = 0;
+  ctx->tot_len = 0;
+}
+
+static void SHA512_transform(AvbSHA512Ctx* ctx,
+                             const uint8_t* message,
+                             unsigned int block_nb) {
+  uint64_t w[80];
+  uint64_t wv[8];
+  uint64_t t1, t2;
+  const uint8_t* sub_block;
+  int i, j;
+
+  for (i = 0; i < (int)block_nb; i++) {
+    sub_block = message + (i << 7);
+
+#ifdef UNROLL_LOOPS_SHA512
+    PACK64(&sub_block[0], &w[0]);
+    PACK64(&sub_block[8], &w[1]);
+    PACK64(&sub_block[16], &w[2]);
+    PACK64(&sub_block[24], &w[3]);
+    PACK64(&sub_block[32], &w[4]);
+    PACK64(&sub_block[40], &w[5]);
+    PACK64(&sub_block[48], &w[6]);
+    PACK64(&sub_block[56], &w[7]);
+    PACK64(&sub_block[64], &w[8]);
+    PACK64(&sub_block[72], &w[9]);
+    PACK64(&sub_block[80], &w[10]);
+    PACK64(&sub_block[88], &w[11]);
+    PACK64(&sub_block[96], &w[12]);
+    PACK64(&sub_block[104], &w[13]);
+    PACK64(&sub_block[112], &w[14]);
+    PACK64(&sub_block[120], &w[15]);
+
+    SHA512_SCR(16);
+    SHA512_SCR(17);
+    SHA512_SCR(18);
+    SHA512_SCR(19);
+    SHA512_SCR(20);
+    SHA512_SCR(21);
+    SHA512_SCR(22);
+    SHA512_SCR(23);
+    SHA512_SCR(24);
+    SHA512_SCR(25);
+    SHA512_SCR(26);
+    SHA512_SCR(27);
+    SHA512_SCR(28);
+    SHA512_SCR(29);
+    SHA512_SCR(30);
+    SHA512_SCR(31);
+    SHA512_SCR(32);
+    SHA512_SCR(33);
+    SHA512_SCR(34);
+    SHA512_SCR(35);
+    SHA512_SCR(36);
+    SHA512_SCR(37);
+    SHA512_SCR(38);
+    SHA512_SCR(39);
+    SHA512_SCR(40);
+    SHA512_SCR(41);
+    SHA512_SCR(42);
+    SHA512_SCR(43);
+    SHA512_SCR(44);
+    SHA512_SCR(45);
+    SHA512_SCR(46);
+    SHA512_SCR(47);
+    SHA512_SCR(48);
+    SHA512_SCR(49);
+    SHA512_SCR(50);
+    SHA512_SCR(51);
+    SHA512_SCR(52);
+    SHA512_SCR(53);
+    SHA512_SCR(54);
+    SHA512_SCR(55);
+    SHA512_SCR(56);
+    SHA512_SCR(57);
+    SHA512_SCR(58);
+    SHA512_SCR(59);
+    SHA512_SCR(60);
+    SHA512_SCR(61);
+    SHA512_SCR(62);
+    SHA512_SCR(63);
+    SHA512_SCR(64);
+    SHA512_SCR(65);
+    SHA512_SCR(66);
+    SHA512_SCR(67);
+    SHA512_SCR(68);
+    SHA512_SCR(69);
+    SHA512_SCR(70);
+    SHA512_SCR(71);
+    SHA512_SCR(72);
+    SHA512_SCR(73);
+    SHA512_SCR(74);
+    SHA512_SCR(75);
+    SHA512_SCR(76);
+    SHA512_SCR(77);
+    SHA512_SCR(78);
+    SHA512_SCR(79);
+
+    wv[0] = ctx->h[0];
+    wv[1] = ctx->h[1];
+    wv[2] = ctx->h[2];
+    wv[3] = ctx->h[3];
+    wv[4] = ctx->h[4];
+    wv[5] = ctx->h[5];
+    wv[6] = ctx->h[6];
+    wv[7] = ctx->h[7];
+
+    j = 0;
+
+    do {
+      SHA512_EXP(0, 1, 2, 3, 4, 5, 6, 7, j);
+      j++;
+      SHA512_EXP(7, 0, 1, 2, 3, 4, 5, 6, j);
+      j++;
+      SHA512_EXP(6, 7, 0, 1, 2, 3, 4, 5, j);
+      j++;
+      SHA512_EXP(5, 6, 7, 0, 1, 2, 3, 4, j);
+      j++;
+      SHA512_EXP(4, 5, 6, 7, 0, 1, 2, 3, j);
+      j++;
+      SHA512_EXP(3, 4, 5, 6, 7, 0, 1, 2, j);
+      j++;
+      SHA512_EXP(2, 3, 4, 5, 6, 7, 0, 1, j);
+      j++;
+      SHA512_EXP(1, 2, 3, 4, 5, 6, 7, 0, j);
+      j++;
+    } while (j < 80);
+
+    ctx->h[0] += wv[0];
+    ctx->h[1] += wv[1];
+    ctx->h[2] += wv[2];
+    ctx->h[3] += wv[3];
+    ctx->h[4] += wv[4];
+    ctx->h[5] += wv[5];
+    ctx->h[6] += wv[6];
+    ctx->h[7] += wv[7];
+#else
+    for (j = 0; j < 16; j++) {
+      PACK64(&sub_block[j << 3], &w[j]);
+    }
+
+    for (j = 16; j < 80; j++) {
+      SHA512_SCR(j);
+    }
+
+    for (j = 0; j < 8; j++) {
+      wv[j] = ctx->h[j];
+    }
+
+    for (j = 0; j < 80; j++) {
+      t1 = wv[7] + SHA512_F2(wv[4]) + CH(wv[4], wv[5], wv[6]) + sha512_k[j] +
+           w[j];
+      t2 = SHA512_F1(wv[0]) + MAJ(wv[0], wv[1], wv[2]);
+      wv[7] = wv[6];
+      wv[6] = wv[5];
+      wv[5] = wv[4];
+      wv[4] = wv[3] + t1;
+      wv[3] = wv[2];
+      wv[2] = wv[1];
+      wv[1] = wv[0];
+      wv[0] = t1 + t2;
+    }
+
+    for (j = 0; j < 8; j++)
+      ctx->h[j] += wv[j];
+#endif /* UNROLL_LOOPS_SHA512 */
+  }
+}
+
+void avb_sha512_update(AvbSHA512Ctx* ctx, const uint8_t* data, uint32_t len) {
+  unsigned int block_nb;
+  unsigned int new_len, rem_len, tmp_len;
+  const uint8_t* shifted_data;
+
+  tmp_len = AVB_SHA512_BLOCK_SIZE - ctx->len;
+  rem_len = len < tmp_len ? len : tmp_len;
+
+  avb_memcpy(&ctx->block[ctx->len], data, rem_len);
+
+  if (ctx->len + len < AVB_SHA512_BLOCK_SIZE) {
+    ctx->len += len;
+    return;
+  }
+
+  new_len = len - rem_len;
+  block_nb = new_len / AVB_SHA512_BLOCK_SIZE;
+
+  shifted_data = data + rem_len;
+
+  SHA512_transform(ctx, ctx->block, 1);
+  SHA512_transform(ctx, shifted_data, block_nb);
+
+  rem_len = new_len % AVB_SHA512_BLOCK_SIZE;
+
+  avb_memcpy(ctx->block, &shifted_data[block_nb << 7], rem_len);
+
+  ctx->len = rem_len;
+  ctx->tot_len += (block_nb + 1) << 7;
+}
+
+uint8_t* avb_sha512_final(AvbSHA512Ctx* ctx) {
+  unsigned int block_nb;
+  unsigned int pm_len;
+  unsigned int len_b;
+
+#ifndef UNROLL_LOOPS_SHA512
+  int i;
+#endif
+
+  block_nb =
+      1 + ((AVB_SHA512_BLOCK_SIZE - 17) < (ctx->len % AVB_SHA512_BLOCK_SIZE));
+
+  len_b = (ctx->tot_len + ctx->len) << 3;
+  pm_len = block_nb << 7;
+
+  avb_memset(ctx->block + ctx->len, 0, pm_len - ctx->len);
+  ctx->block[ctx->len] = 0x80;
+  UNPACK32(len_b, ctx->block + pm_len - 4);
+
+  SHA512_transform(ctx, ctx->block, block_nb);
+
+#ifdef UNROLL_LOOPS_SHA512
+  UNPACK64(ctx->h[0], &ctx->buf[0]);
+  UNPACK64(ctx->h[1], &ctx->buf[8]);
+  UNPACK64(ctx->h[2], &ctx->buf[16]);
+  UNPACK64(ctx->h[3], &ctx->buf[24]);
+  UNPACK64(ctx->h[4], &ctx->buf[32]);
+  UNPACK64(ctx->h[5], &ctx->buf[40]);
+  UNPACK64(ctx->h[6], &ctx->buf[48]);
+  UNPACK64(ctx->h[7], &ctx->buf[56]);
+#else
+  for (i = 0; i < 8; i++)
+    UNPACK64(ctx->h[i], &ctx->buf[i << 3]);
+#endif /* UNROLL_LOOPS_SHA512 */
+
+  return ctx->buf;
+}
diff --git a/lib/libavb/avb_slot_verify.c b/lib/libavb/avb_slot_verify.c
new file mode 100644
index 0000000..17e73d6
--- /dev/null
+++ b/lib/libavb/avb_slot_verify.c
@@ -0,0 +1,1169 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_slot_verify.h"
+#include "avb/avb_chain_partition_descriptor.h"
+#include "avb/avb_footer.h"
+#include "avb/avb_hash_descriptor.h"
+#include "avb/avb_kernel_cmdline_descriptor.h"
+#include "avb/avb_sha.h"
+#include "avb/avb_util.h"
+#include "avb/avb_vbmeta_image.h"
+#include "avb/avb_version.h"
+
+/* Maximum allow length (in bytes) of a partition name, including
+ * ab_suffix.
+ */
+#define PART_NAME_MAX_SIZE 32
+
+/* Maximum number of partitions that can be loaded with avb_slot_verify(). */
+#define MAX_NUMBER_OF_LOADED_PARTITIONS 32
+
+/* Maximum number of vbmeta images that can be loaded with avb_slot_verify(). */
+#define MAX_NUMBER_OF_VBMETA_IMAGES 32
+
+/* Maximum size of a vbmeta image - 64 KiB. */
+#define VBMETA_MAX_SIZE (64 * 1024)
+
+/* Helper function to see if we should continue with verification in
+ * allow_verification_error=true mode if something goes wrong. See the
+ * comments for the avb_slot_verify() function for more information.
+ */
+static inline bool result_should_continue(AvbSlotVerifyResult result) {
+  switch (result) {
+    case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
+      return false;
+
+    case AVB_SLOT_VERIFY_RESULT_OK:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
+    case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
+      return true;
+  }
+
+  return false;
+}
+
+static AvbSlotVerifyResult load_and_verify_hash_partition(
+    AvbOps* ops,
+    const char* const* requested_partitions,
+    const char* ab_suffix,
+    bool allow_verification_error,
+    const AvbDescriptor* descriptor,
+    AvbSlotVerifyData* slot_data) {
+  AvbHashDescriptor hash_desc;
+  const uint8_t* desc_partition_name = NULL;
+  const uint8_t* desc_salt;
+  const uint8_t* desc_digest;
+  char part_name[PART_NAME_MAX_SIZE];
+  AvbSlotVerifyResult ret;
+  AvbIOResult io_ret;
+  uint8_t* image_buf = NULL;
+  size_t part_num_read;
+  uint8_t* digest;
+  size_t digest_len;
+  const char* found;
+
+  if (!avb_hash_descriptor_validate_and_byteswap(
+          (const AvbHashDescriptor*)descriptor, &hash_desc)) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  desc_partition_name =
+      ((const uint8_t*)descriptor) + sizeof(AvbHashDescriptor);
+  desc_salt = desc_partition_name + hash_desc.partition_name_len;
+  desc_digest = desc_salt + hash_desc.salt_len;
+
+  if (!avb_validate_utf8(desc_partition_name, hash_desc.partition_name_len)) {
+    avb_error("Partition name is not valid UTF-8.\n");
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  if (!avb_str_concat(part_name,
+                      sizeof part_name,
+                      (const char*)desc_partition_name,
+                      hash_desc.partition_name_len,
+                      ab_suffix,
+                      avb_strlen(ab_suffix))) {
+    avb_error("Partition name and suffix does not fit.\n");
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  image_buf = avb_malloc(hash_desc.image_size);
+  if (image_buf == NULL) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  }
+
+  io_ret = ops->read_from_partition(ops,
+                                    part_name,
+                                    0 /* offset */,
+                                    hash_desc.image_size,
+                                    image_buf,
+                                    &part_num_read);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  } else if (io_ret != AVB_IO_RESULT_OK) {
+    avb_errorv(part_name, ": Error loading data from partition.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+    goto out;
+  }
+  if (part_num_read != hash_desc.image_size) {
+    avb_errorv(part_name, ": Read fewer than requested bytes.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+    goto out;
+  }
+
+  if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha256") == 0) {
+    AvbSHA256Ctx sha256_ctx;
+    avb_sha256_init(&sha256_ctx);
+    avb_sha256_update(&sha256_ctx, desc_salt, hash_desc.salt_len);
+    avb_sha256_update(&sha256_ctx, image_buf, hash_desc.image_size);
+    digest = avb_sha256_final(&sha256_ctx);
+    digest_len = AVB_SHA256_DIGEST_SIZE;
+  } else if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha512") == 0) {
+    AvbSHA512Ctx sha512_ctx;
+    avb_sha512_init(&sha512_ctx);
+    avb_sha512_update(&sha512_ctx, desc_salt, hash_desc.salt_len);
+    avb_sha512_update(&sha512_ctx, image_buf, hash_desc.image_size);
+    digest = avb_sha512_final(&sha512_ctx);
+    digest_len = AVB_SHA512_DIGEST_SIZE;
+  } else {
+    avb_errorv(part_name, ": Unsupported hash algorithm.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  if (digest_len != hash_desc.digest_len) {
+    avb_errorv(
+        part_name, ": Digest in descriptor not of expected size.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  if (avb_safe_memcmp(digest, desc_digest, digest_len) != 0) {
+    avb_errorv(part_name,
+               ": Hash of data does not match digest in descriptor.\n",
+               NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
+    goto out;
+  }
+
+  ret = AVB_SLOT_VERIFY_RESULT_OK;
+
+out:
+
+  if (ret == AVB_SLOT_VERIFY_RESULT_OK || result_should_continue(ret)) {
+    /* If this is the requested partition, copy to slot_data. */
+    found = avb_strv_find_str(requested_partitions,
+                              (const char*)desc_partition_name,
+                              hash_desc.partition_name_len);
+    if (found != NULL) {
+      AvbPartitionData* loaded_partition;
+      if (slot_data->num_loaded_partitions == MAX_NUMBER_OF_LOADED_PARTITIONS) {
+        avb_errorv(part_name, ": Too many loaded partitions.\n", NULL);
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+        goto fail;
+      }
+      loaded_partition =
+          &slot_data->loaded_partitions[slot_data->num_loaded_partitions++];
+      loaded_partition->partition_name = avb_strdup(found);
+      loaded_partition->data_size = hash_desc.image_size;
+      loaded_partition->data = image_buf;
+      image_buf = NULL;
+    }
+  }
+
+fail:
+  if (image_buf != NULL) {
+    avb_free(image_buf);
+  }
+  return ret;
+}
+
+static AvbSlotVerifyResult load_and_verify_vbmeta(
+    AvbOps* ops,
+    const char* const* requested_partitions,
+    const char* ab_suffix,
+    bool allow_verification_error,
+    AvbVBMetaImageFlags toplevel_vbmeta_flags,
+    int rollback_index_location,
+    const char* partition_name,
+    size_t partition_name_len,
+    const uint8_t* expected_public_key,
+    size_t expected_public_key_length,
+    AvbSlotVerifyData* slot_data,
+    AvbAlgorithmType* out_algorithm_type) {
+  char full_partition_name[PART_NAME_MAX_SIZE];
+  AvbSlotVerifyResult ret;
+  AvbIOResult io_ret;
+  size_t vbmeta_offset;
+  size_t vbmeta_size;
+  uint8_t* vbmeta_buf = NULL;
+  size_t vbmeta_num_read;
+  AvbVBMetaVerifyResult vbmeta_ret;
+  const uint8_t* pk_data;
+  size_t pk_len;
+  AvbVBMetaImageHeader vbmeta_header;
+  uint64_t stored_rollback_index;
+  const AvbDescriptor** descriptors = NULL;
+  size_t num_descriptors;
+  size_t n;
+  bool is_main_vbmeta;
+  bool is_vbmeta_partition;
+  AvbVBMetaData* vbmeta_image_data = NULL;
+
+  ret = AVB_SLOT_VERIFY_RESULT_OK;
+
+  avb_assert(slot_data != NULL);
+
+  /* Since we allow top-level vbmeta in 'boot', use
+   * rollback_index_location to determine whether we're the main
+   * vbmeta struct.
+   */
+  is_main_vbmeta = (rollback_index_location == 0);
+  is_vbmeta_partition = (avb_strcmp(partition_name, "vbmeta") == 0);
+
+  if (!avb_validate_utf8((const uint8_t*)partition_name, partition_name_len)) {
+    avb_error("Partition name is not valid UTF-8.\n");
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  /* Construct full partition name. */
+  if (!avb_str_concat(full_partition_name,
+                      sizeof full_partition_name,
+                      partition_name,
+                      partition_name_len,
+                      ab_suffix,
+                      avb_strlen(ab_suffix))) {
+    avb_error("Partition name and suffix does not fit.\n");
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  avb_debugv("Loading vbmeta struct from partition '",
+             full_partition_name,
+             "'.\n",
+             NULL);
+
+  /* If we're loading from the main vbmeta partition, the vbmeta
+   * struct is in the beginning. Otherwise we have to locate it via a
+   * footer.
+   */
+  if (is_vbmeta_partition) {
+    vbmeta_offset = 0;
+    vbmeta_size = VBMETA_MAX_SIZE;
+  } else {
+    uint8_t footer_buf[AVB_FOOTER_SIZE];
+    size_t footer_num_read;
+    AvbFooter footer;
+
+    io_ret = ops->read_from_partition(ops,
+                                      full_partition_name,
+                                      -AVB_FOOTER_SIZE,
+                                      AVB_FOOTER_SIZE,
+                                      footer_buf,
+                                      &footer_num_read);
+    if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto out;
+    } else if (io_ret != AVB_IO_RESULT_OK) {
+      avb_errorv(full_partition_name, ": Error loading footer.\n", NULL);
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+      goto out;
+    }
+    avb_assert(footer_num_read == AVB_FOOTER_SIZE);
+
+    if (!avb_footer_validate_and_byteswap((const AvbFooter*)footer_buf,
+                                          &footer)) {
+      avb_errorv(full_partition_name, ": Error validating footer.\n", NULL);
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+      goto out;
+    }
+
+    /* Basic footer sanity check since the data is untrusted. */
+    if (footer.vbmeta_size > VBMETA_MAX_SIZE) {
+      avb_errorv(
+          full_partition_name, ": Invalid vbmeta size in footer.\n", NULL);
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+      goto out;
+    }
+
+    vbmeta_offset = footer.vbmeta_offset;
+    vbmeta_size = footer.vbmeta_size;
+  }
+
+  vbmeta_buf = avb_malloc(vbmeta_size);
+  if (vbmeta_buf == NULL) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  }
+
+  io_ret = ops->read_from_partition(ops,
+                                    full_partition_name,
+                                    vbmeta_offset,
+                                    vbmeta_size,
+                                    vbmeta_buf,
+                                    &vbmeta_num_read);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  } else if (io_ret != AVB_IO_RESULT_OK) {
+    /* If we're looking for 'vbmeta' but there is no such partition,
+     * go try to get it from the boot partition instead.
+     */
+    if (is_main_vbmeta && io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION &&
+        is_vbmeta_partition) {
+      avb_debugv(full_partition_name,
+                 ": No such partition. Trying 'boot' instead.\n",
+                 NULL);
+      ret = load_and_verify_vbmeta(ops,
+                                   requested_partitions,
+                                   ab_suffix,
+                                   allow_verification_error,
+                                   0 /* toplevel_vbmeta_flags */,
+                                   0 /* rollback_index_location */,
+                                   "boot",
+                                   avb_strlen("boot"),
+                                   NULL /* expected_public_key */,
+                                   0 /* expected_public_key_length */,
+                                   slot_data,
+                                   out_algorithm_type);
+      goto out;
+    } else {
+      avb_errorv(full_partition_name, ": Error loading vbmeta data.\n", NULL);
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+      goto out;
+    }
+  }
+  avb_assert(vbmeta_num_read <= vbmeta_size);
+
+  /* Check if the image is properly signed and get the public key used
+   * to sign the image.
+   */
+  vbmeta_ret =
+      avb_vbmeta_image_verify(vbmeta_buf, vbmeta_num_read, &pk_data, &pk_len);
+  switch (vbmeta_ret) {
+    case AVB_VBMETA_VERIFY_RESULT_OK:
+      avb_assert(pk_data != NULL && pk_len > 0);
+      break;
+
+    case AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED:
+    case AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH:
+    case AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH:
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
+      avb_errorv(full_partition_name,
+                 ": Error verifying vbmeta image: ",
+                 avb_vbmeta_verify_result_to_string(vbmeta_ret),
+                 "\n",
+                 NULL);
+      if (!allow_verification_error) {
+        goto out;
+      }
+      break;
+
+    case AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER:
+      /* No way to continue this case. */
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+      avb_errorv(full_partition_name,
+                 ": Error verifying vbmeta image: invalid vbmeta header\n",
+                 NULL);
+      goto out;
+
+    case AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION:
+      /* No way to continue this case. */
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION;
+      avb_errorv(full_partition_name,
+                 ": Error verifying vbmeta image: unsupported AVB version\n",
+                 NULL);
+      goto out;
+  }
+
+  /* Byteswap the header. */
+  avb_vbmeta_image_header_to_host_byte_order((AvbVBMetaImageHeader*)vbmeta_buf,
+                                             &vbmeta_header);
+
+  /* If we're the toplevel, assign flags so they'll be passed down. */
+  if (is_main_vbmeta) {
+    toplevel_vbmeta_flags = (AvbVBMetaImageFlags)vbmeta_header.flags;
+  } else {
+    if (vbmeta_header.flags != 0) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+      avb_errorv(full_partition_name,
+                 ": chained vbmeta image has non-zero flags\n",
+                 NULL);
+      goto out;
+    }
+  }
+
+  /* Check if key used to make signature matches what is expected. */
+  if (pk_data != NULL) {
+    if (expected_public_key != NULL) {
+      avb_assert(!is_main_vbmeta);
+      if (expected_public_key_length != pk_len ||
+          avb_safe_memcmp(expected_public_key, pk_data, pk_len) != 0) {
+        avb_errorv(full_partition_name,
+                   ": Public key used to sign data does not match key in chain "
+                   "partition descriptor.\n",
+                   NULL);
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
+        if (!allow_verification_error) {
+          goto out;
+        }
+      }
+    } else {
+      bool key_is_trusted = false;
+      const uint8_t* pk_metadata = NULL;
+      size_t pk_metadata_len = 0;
+
+      if (vbmeta_header.public_key_metadata_size > 0) {
+        pk_metadata = vbmeta_buf + sizeof(AvbVBMetaImageHeader) +
+                      vbmeta_header.authentication_data_block_size +
+                      vbmeta_header.public_key_metadata_offset;
+        pk_metadata_len = vbmeta_header.public_key_metadata_size;
+      }
+
+      avb_assert(is_main_vbmeta);
+      io_ret = ops->validate_vbmeta_public_key(
+          ops, pk_data, pk_len, pk_metadata, pk_metadata_len, &key_is_trusted);
+      if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+        goto out;
+      } else if (io_ret != AVB_IO_RESULT_OK) {
+        avb_errorv(full_partition_name,
+                   ": Error while checking public key used to sign data.\n",
+                   NULL);
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+        goto out;
+      }
+      if (!key_is_trusted) {
+        avb_errorv(full_partition_name,
+                   ": Public key used to sign data rejected.\n",
+                   NULL);
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
+        if (!allow_verification_error) {
+          goto out;
+        }
+      }
+    }
+  }
+
+  /* Check rollback index. */
+  io_ret = ops->read_rollback_index(
+      ops, rollback_index_location, &stored_rollback_index);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  } else if (io_ret != AVB_IO_RESULT_OK) {
+    avb_errorv(full_partition_name,
+               ": Error getting rollback index for location.\n",
+               NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+    goto out;
+  }
+  if (vbmeta_header.rollback_index < stored_rollback_index) {
+    avb_errorv(
+        full_partition_name,
+        ": Image rollback index is less than the stored rollback index.\n",
+        NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX;
+    if (!allow_verification_error) {
+      goto out;
+    }
+  }
+
+  /* Copy vbmeta to vbmeta_images before recursing. */
+  if (is_main_vbmeta) {
+    avb_assert(slot_data->num_vbmeta_images == 0);
+  } else {
+    avb_assert(slot_data->num_vbmeta_images > 0);
+  }
+  if (slot_data->num_vbmeta_images == MAX_NUMBER_OF_VBMETA_IMAGES) {
+    avb_errorv(full_partition_name, ": Too many vbmeta images.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto out;
+  }
+  vbmeta_image_data = &slot_data->vbmeta_images[slot_data->num_vbmeta_images++];
+  vbmeta_image_data->partition_name = avb_strdup(partition_name);
+  vbmeta_image_data->vbmeta_data = vbmeta_buf;
+  /* Note that |vbmeta_buf| is actually |vbmeta_num_read| bytes long
+   * and this includes data past the end of the image. Pass the
+   * actual size of the vbmeta image. Also, no need to use
+   * avb_safe_add() since the header has already been verified.
+   */
+  vbmeta_image_data->vbmeta_size =
+      sizeof(AvbVBMetaImageHeader) +
+      vbmeta_header.authentication_data_block_size +
+      vbmeta_header.auxiliary_data_block_size;
+  vbmeta_image_data->verify_result = vbmeta_ret;
+
+  /* Now go through all descriptors and take the appropriate action:
+   *
+   * - hash descriptor: Load data from partition, calculate hash, and
+   *   checks that it matches what's in the hash descriptor.
+   *
+   * - hashtree descriptor: Do nothing since verification happens
+   *   on-the-fly from within the OS.
+   *
+   * - chained partition descriptor: Load the footer, load the vbmeta
+   *   image, verify vbmeta image (includes rollback checks, hash
+   *   checks, bail on chained partitions).
+   */
+  descriptors =
+      avb_descriptor_get_all(vbmeta_buf, vbmeta_num_read, &num_descriptors);
+  for (n = 0; n < num_descriptors; n++) {
+    AvbDescriptor desc;
+
+    if (!avb_descriptor_validate_and_byteswap(descriptors[n], &desc)) {
+      avb_errorv(full_partition_name, ": Descriptor is invalid.\n", NULL);
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+      goto out;
+    }
+
+    switch (desc.tag) {
+      case AVB_DESCRIPTOR_TAG_HASH: {
+        AvbSlotVerifyResult sub_ret;
+        sub_ret = load_and_verify_hash_partition(ops,
+                                                 requested_partitions,
+                                                 ab_suffix,
+                                                 allow_verification_error,
+                                                 descriptors[n],
+                                                 slot_data);
+        if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
+          ret = sub_ret;
+          if (!allow_verification_error || !result_should_continue(ret)) {
+            goto out;
+          }
+        }
+      } break;
+
+      case AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: {
+        AvbSlotVerifyResult sub_ret;
+        AvbChainPartitionDescriptor chain_desc;
+        const uint8_t* chain_partition_name;
+        const uint8_t* chain_public_key;
+
+        /* Only allow CHAIN_PARTITION descriptors in the main vbmeta image. */
+        if (!is_main_vbmeta) {
+          avb_errorv(full_partition_name,
+                     ": Encountered chain descriptor not in main image.\n",
+                     NULL);
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+          goto out;
+        }
+
+        if (!avb_chain_partition_descriptor_validate_and_byteswap(
+                (AvbChainPartitionDescriptor*)descriptors[n], &chain_desc)) {
+          avb_errorv(full_partition_name,
+                     ": Chain partition descriptor is invalid.\n",
+                     NULL);
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+          goto out;
+        }
+
+        if (chain_desc.rollback_index_location == 0) {
+          avb_errorv(full_partition_name,
+                     ": Chain partition has invalid "
+                     "rollback_index_location field.\n",
+                     NULL);
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+          goto out;
+        }
+
+        chain_partition_name = ((const uint8_t*)descriptors[n]) +
+                               sizeof(AvbChainPartitionDescriptor);
+        chain_public_key = chain_partition_name + chain_desc.partition_name_len;
+
+        sub_ret = load_and_verify_vbmeta(ops,
+                                         requested_partitions,
+                                         ab_suffix,
+                                         allow_verification_error,
+                                         toplevel_vbmeta_flags,
+                                         chain_desc.rollback_index_location,
+                                         (const char*)chain_partition_name,
+                                         chain_desc.partition_name_len,
+                                         chain_public_key,
+                                         chain_desc.public_key_len,
+                                         slot_data,
+                                         NULL /* out_algorithm_type */);
+        if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
+          ret = sub_ret;
+          if (!result_should_continue(ret)) {
+            goto out;
+          }
+        }
+      } break;
+
+      case AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: {
+        const uint8_t* kernel_cmdline;
+        AvbKernelCmdlineDescriptor kernel_cmdline_desc;
+        bool apply_cmdline;
+
+        if (!avb_kernel_cmdline_descriptor_validate_and_byteswap(
+                (AvbKernelCmdlineDescriptor*)descriptors[n],
+                &kernel_cmdline_desc)) {
+          avb_errorv(full_partition_name,
+                     ": Kernel cmdline descriptor is invalid.\n",
+                     NULL);
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+          goto out;
+        }
+
+        kernel_cmdline = ((const uint8_t*)descriptors[n]) +
+                         sizeof(AvbKernelCmdlineDescriptor);
+
+        if (!avb_validate_utf8(kernel_cmdline,
+                               kernel_cmdline_desc.kernel_cmdline_length)) {
+          avb_errorv(full_partition_name,
+                     ": Kernel cmdline is not valid UTF-8.\n",
+                     NULL);
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+          goto out;
+        }
+
+        /* Compare the flags for top-level VBMeta struct with flags in
+         * the command-line descriptor so command-line snippets only
+         * intended for a certain mode (dm-verity enabled/disabled)
+         * are skipped if applicable.
+         */
+        apply_cmdline = true;
+        if (toplevel_vbmeta_flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) {
+          if (kernel_cmdline_desc.flags &
+              AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_NOT_DISABLED) {
+            apply_cmdline = false;
+          }
+        } else {
+          if (kernel_cmdline_desc.flags &
+              AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_DISABLED) {
+            apply_cmdline = false;
+          }
+        }
+
+        if (apply_cmdline) {
+          if (slot_data->cmdline == NULL) {
+            slot_data->cmdline =
+                avb_calloc(kernel_cmdline_desc.kernel_cmdline_length + 1);
+            if (slot_data->cmdline == NULL) {
+              ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+              goto out;
+            }
+            avb_memcpy(slot_data->cmdline,
+                       kernel_cmdline,
+                       kernel_cmdline_desc.kernel_cmdline_length);
+          } else {
+            /* new cmdline is: <existing_cmdline> + ' ' + <newcmdline> + '\0' */
+            size_t orig_size = avb_strlen(slot_data->cmdline);
+            size_t new_size =
+                orig_size + 1 + kernel_cmdline_desc.kernel_cmdline_length + 1;
+            char* new_cmdline = avb_calloc(new_size);
+            if (new_cmdline == NULL) {
+              ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+              goto out;
+            }
+            avb_memcpy(new_cmdline, slot_data->cmdline, orig_size);
+            new_cmdline[orig_size] = ' ';
+            avb_memcpy(new_cmdline + orig_size + 1,
+                       kernel_cmdline,
+                       kernel_cmdline_desc.kernel_cmdline_length);
+            avb_free(slot_data->cmdline);
+            slot_data->cmdline = new_cmdline;
+          }
+        }
+      } break;
+
+      /* Explicit fall-through */
+      case AVB_DESCRIPTOR_TAG_PROPERTY:
+      case AVB_DESCRIPTOR_TAG_HASHTREE:
+        /* Do nothing. */
+        break;
+    }
+  }
+
+  if (rollback_index_location >= AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS) {
+    avb_errorv(
+        full_partition_name, ": Invalid rollback_index_location.\n", NULL);
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
+    goto out;
+  }
+
+  slot_data->rollback_indexes[rollback_index_location] =
+      vbmeta_header.rollback_index;
+
+  if (out_algorithm_type != NULL) {
+    *out_algorithm_type = (AvbAlgorithmType)vbmeta_header.algorithm_type;
+  }
+
+out:
+  /* If |vbmeta_image_data| isn't NULL it means that it adopted
+   * |vbmeta_buf| so in that case don't free it here.
+   */
+  if (vbmeta_image_data == NULL) {
+    if (vbmeta_buf != NULL) {
+      avb_free(vbmeta_buf);
+    }
+  }
+  if (descriptors != NULL) {
+    avb_free(descriptors);
+  }
+  return ret;
+}
+
+#define NUM_GUIDS 3
+
+/* Substitutes all variables (e.g. $(ANDROID_SYSTEM_PARTUUID)) with
+ * values. Returns NULL on OOM, otherwise the cmdline with values
+ * replaced.
+ */
+static char* sub_cmdline(AvbOps* ops,
+                         const char* cmdline,
+                         const char* ab_suffix,
+                         bool using_boot_for_vbmeta) {
+  const char* part_name_str[NUM_GUIDS] = {"system", "boot", "vbmeta"};
+  const char* replace_str[NUM_GUIDS] = {"$(ANDROID_SYSTEM_PARTUUID)",
+                                        "$(ANDROID_BOOT_PARTUUID)",
+                                        "$(ANDROID_VBMETA_PARTUUID)"};
+  char* ret = NULL;
+  AvbIOResult io_ret;
+
+  /* Special-case for when the top-level vbmeta struct is in the boot
+   * partition.
+   */
+  if (using_boot_for_vbmeta) {
+    part_name_str[2] = "boot";
+  }
+
+  /* Replace unique partition GUIDs */
+  for (size_t n = 0; n < NUM_GUIDS; n++) {
+    char part_name[PART_NAME_MAX_SIZE];
+    char guid_buf[37];
+
+    if (!avb_str_concat(part_name,
+                        sizeof part_name,
+                        part_name_str[n],
+                        avb_strlen(part_name_str[n]),
+                        ab_suffix,
+                        avb_strlen(ab_suffix))) {
+      avb_error("Partition name and suffix does not fit.\n");
+      goto fail;
+    }
+
+    io_ret = ops->get_unique_guid_for_partition(
+        ops, part_name, guid_buf, sizeof guid_buf);
+    if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+      return NULL;
+    } else if (io_ret != AVB_IO_RESULT_OK) {
+      avb_error("Error getting unique GUID for partition.\n");
+      goto fail;
+    }
+
+    if (ret == NULL) {
+      ret = avb_replace(cmdline, replace_str[n], guid_buf);
+    } else {
+      char* new_ret = avb_replace(ret, replace_str[n], guid_buf);
+      avb_free(ret);
+      ret = new_ret;
+    }
+    if (ret == NULL) {
+      goto fail;
+    }
+  }
+
+  return ret;
+
+fail:
+  if (ret != NULL) {
+    avb_free(ret);
+  }
+  return NULL;
+}
+
+static int cmdline_append_option(AvbSlotVerifyData* slot_data,
+                                 const char* key,
+                                 const char* value) {
+  size_t offset, key_len, value_len;
+  char* new_cmdline;
+
+  key_len = avb_strlen(key);
+  value_len = avb_strlen(value);
+
+  offset = 0;
+  if (slot_data->cmdline != NULL) {
+    offset = avb_strlen(slot_data->cmdline);
+    if (offset > 0) {
+      offset += 1;
+    }
+  }
+
+  new_cmdline = avb_calloc(offset + key_len + value_len + 2);
+  if (new_cmdline == NULL) {
+    return 0;
+  }
+  if (offset > 0) {
+    avb_memcpy(new_cmdline, slot_data->cmdline, offset - 1);
+    new_cmdline[offset - 1] = ' ';
+  }
+  avb_memcpy(new_cmdline + offset, key, key_len);
+  new_cmdline[offset + key_len] = '=';
+  avb_memcpy(new_cmdline + offset + key_len + 1, value, value_len);
+  if (slot_data->cmdline != NULL) {
+    avb_free(slot_data->cmdline);
+  }
+  slot_data->cmdline = new_cmdline;
+
+  return 1;
+}
+
+#define AVB_MAX_DIGITS_UINT64 32
+
+/* Writes |value| to |digits| in base 10 followed by a NUL byte.
+ * Returns number of characters written excluding the NUL byte.
+ */
+static size_t uint64_to_base10(uint64_t value,
+                               char digits[AVB_MAX_DIGITS_UINT64]) {
+  char rev_digits[AVB_MAX_DIGITS_UINT64];
+  size_t n, num_digits;
+
+  for (num_digits = 0; num_digits < AVB_MAX_DIGITS_UINT64 - 1;) {
+    rev_digits[num_digits++] = (value % 10) + '0';
+    value /= 10;
+    if (value == 0) {
+      break;
+    }
+  }
+
+  for (n = 0; n < num_digits; n++) {
+    digits[n] = rev_digits[num_digits - 1 - n];
+  }
+  digits[n] = '\0';
+  return n;
+}
+
+static int cmdline_append_version(AvbSlotVerifyData* slot_data,
+                                  const char* key,
+                                  uint64_t major_version,
+                                  uint64_t minor_version) {
+  char major_digits[AVB_MAX_DIGITS_UINT64];
+  char minor_digits[AVB_MAX_DIGITS_UINT64];
+  char combined[AVB_MAX_DIGITS_UINT64 * 2 + 1];
+  size_t num_major_digits, num_minor_digits;
+
+  num_major_digits = uint64_to_base10(major_version, major_digits);
+  num_minor_digits = uint64_to_base10(minor_version, minor_digits);
+  avb_memcpy(combined, major_digits, num_major_digits);
+  combined[num_major_digits] = '.';
+  avb_memcpy(combined + num_major_digits + 1, minor_digits, num_minor_digits);
+  combined[num_major_digits + 1 + num_minor_digits] = '\0';
+
+  return cmdline_append_option(slot_data, key, combined);
+}
+
+static int cmdline_append_uint64_base10(AvbSlotVerifyData* slot_data,
+                                        const char* key,
+                                        uint64_t value) {
+  char digits[AVB_MAX_DIGITS_UINT64];
+  uint64_to_base10(value, digits);
+  return cmdline_append_option(slot_data, key, digits);
+}
+
+static int cmdline_append_hex(AvbSlotVerifyData* slot_data,
+                              const char* key,
+                              const uint8_t* data,
+                              size_t data_len) {
+  char hex_digits[17] = "0123456789abcdef";
+  char* hex_data;
+  int ret;
+  size_t n;
+
+  hex_data = avb_malloc(data_len * 2 + 1);
+  if (hex_data == NULL) {
+    return 0;
+  }
+
+  for (n = 0; n < data_len; n++) {
+    hex_data[n * 2] = hex_digits[data[n] >> 4];
+    hex_data[n * 2 + 1] = hex_digits[data[n] & 0x0f];
+  }
+  hex_data[n * 2] = '\0';
+
+  ret = cmdline_append_option(slot_data, key, hex_data);
+  avb_free(hex_data);
+  return ret;
+}
+
+AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
+                                    const char* const* requested_partitions,
+                                    const char* ab_suffix,
+                                    bool allow_verification_error,
+                                    AvbSlotVerifyData** out_data) {
+  AvbSlotVerifyResult ret;
+  AvbSlotVerifyData* slot_data = NULL;
+  AvbAlgorithmType algorithm_type = AVB_ALGORITHM_TYPE_NONE;
+  AvbIOResult io_ret;
+  bool using_boot_for_vbmeta = false;
+
+  if (out_data != NULL) {
+    *out_data = NULL;
+  }
+
+  slot_data = avb_calloc(sizeof(AvbSlotVerifyData));
+  if (slot_data == NULL) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto fail;
+  }
+  slot_data->vbmeta_images =
+      avb_calloc(sizeof(AvbVBMetaData) * MAX_NUMBER_OF_VBMETA_IMAGES);
+  if (slot_data->vbmeta_images == NULL) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto fail;
+  }
+  slot_data->loaded_partitions =
+      avb_calloc(sizeof(AvbPartitionData) * MAX_NUMBER_OF_LOADED_PARTITIONS);
+  if (slot_data->loaded_partitions == NULL) {
+    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+    goto fail;
+  }
+
+  ret = load_and_verify_vbmeta(ops,
+                               requested_partitions,
+                               ab_suffix,
+                               allow_verification_error,
+                               0 /* toplevel_vbmeta_flags */,
+                               0 /* rollback_index_location */,
+                               "vbmeta",
+                               avb_strlen("vbmeta"),
+                               NULL /* expected_public_key */,
+                               0 /* expected_public_key_length */,
+                               slot_data,
+                               &algorithm_type);
+  if (!allow_verification_error && ret != AVB_SLOT_VERIFY_RESULT_OK) {
+    goto fail;
+  }
+
+  if (avb_strcmp(slot_data->vbmeta_images[0].partition_name, "vbmeta") != 0) {
+    avb_assert(avb_strcmp(slot_data->vbmeta_images[0].partition_name, "boot") ==
+               0);
+    using_boot_for_vbmeta = true;
+  }
+
+  /* If things check out, mangle the kernel command-line as needed. */
+  if (result_should_continue(ret)) {
+    /* Fill in |ab_suffix| field. */
+    slot_data->ab_suffix = avb_strdup(ab_suffix);
+    if (slot_data->ab_suffix == NULL) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto fail;
+    }
+
+    /* Add androidboot.vbmeta.device option. */
+    if (!cmdline_append_option(slot_data,
+                               "androidboot.vbmeta.device",
+                               "PARTUUID=$(ANDROID_VBMETA_PARTUUID)")) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto fail;
+    }
+
+    /* Add androidboot.vbmeta.avb_version option. */
+    if (!cmdline_append_version(slot_data,
+                                "androidboot.vbmeta.avb_version",
+                                AVB_VERSION_MAJOR,
+                                AVB_VERSION_MINOR)) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto fail;
+    }
+
+    /* Substitute $(ANDROID_SYSTEM_PARTUUID) and friends. */
+    if (slot_data->cmdline != NULL) {
+      char* new_cmdline;
+      new_cmdline = sub_cmdline(
+          ops, slot_data->cmdline, ab_suffix, using_boot_for_vbmeta);
+      if (new_cmdline == NULL) {
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+        goto fail;
+      }
+      avb_free(slot_data->cmdline);
+      slot_data->cmdline = new_cmdline;
+    }
+
+    /* Set androidboot.avb.device_state to "locked" or "unlocked". */
+    bool is_device_unlocked;
+    io_ret = ops->read_is_device_unlocked(ops, &is_device_unlocked);
+    if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto fail;
+    } else if (io_ret != AVB_IO_RESULT_OK) {
+      avb_error("Error getting device state.\n");
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
+      goto fail;
+    }
+    if (!cmdline_append_option(slot_data,
+                               "androidboot.vbmeta.device_state",
+                               is_device_unlocked ? "unlocked" : "locked")) {
+      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+      goto fail;
+    }
+
+    /* Set androidboot.vbmeta.{hash_alg, size, digest} - use same hash
+     * function as is used to sign vbmeta.
+     */
+    switch (algorithm_type) {
+      /* Explicit fallthrough. */
+      case AVB_ALGORITHM_TYPE_NONE:
+      case AVB_ALGORITHM_TYPE_SHA256_RSA2048:
+      case AVB_ALGORITHM_TYPE_SHA256_RSA4096:
+      case AVB_ALGORITHM_TYPE_SHA256_RSA8192: {
+        AvbSHA256Ctx ctx;
+        size_t n, total_size = 0;
+        avb_sha256_init(&ctx);
+        for (n = 0; n < slot_data->num_vbmeta_images; n++) {
+          avb_sha256_update(&ctx,
+                            slot_data->vbmeta_images[n].vbmeta_data,
+                            slot_data->vbmeta_images[n].vbmeta_size);
+          total_size += slot_data->vbmeta_images[n].vbmeta_size;
+        }
+        if (!cmdline_append_option(
+                slot_data, "androidboot.vbmeta.hash_alg", "sha256") ||
+            !cmdline_append_uint64_base10(
+                slot_data, "androidboot.vbmeta.size", total_size) ||
+            !cmdline_append_hex(slot_data,
+                                "androidboot.vbmeta.digest",
+                                avb_sha256_final(&ctx),
+                                AVB_SHA256_DIGEST_SIZE)) {
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+          goto fail;
+        }
+      } break;
+      /* Explicit fallthrough. */
+      case AVB_ALGORITHM_TYPE_SHA512_RSA2048:
+      case AVB_ALGORITHM_TYPE_SHA512_RSA4096:
+      case AVB_ALGORITHM_TYPE_SHA512_RSA8192: {
+        AvbSHA512Ctx ctx;
+        size_t n, total_size = 0;
+        avb_sha512_init(&ctx);
+        for (n = 0; n < slot_data->num_vbmeta_images; n++) {
+          avb_sha512_update(&ctx,
+                            slot_data->vbmeta_images[n].vbmeta_data,
+                            slot_data->vbmeta_images[n].vbmeta_size);
+          total_size += slot_data->vbmeta_images[n].vbmeta_size;
+        }
+        if (!cmdline_append_option(
+                slot_data, "androidboot.vbmeta.hash_alg", "sha512") ||
+            !cmdline_append_uint64_base10(
+                slot_data, "androidboot.vbmeta.size", total_size) ||
+            !cmdline_append_hex(slot_data,
+                                "androidboot.vbmeta.digest",
+                                avb_sha512_final(&ctx),
+                                AVB_SHA512_DIGEST_SIZE)) {
+          ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
+          goto fail;
+        }
+      } break;
+      case _AVB_ALGORITHM_NUM_TYPES:
+        avb_assert_not_reached();
+        break;
+    }
+
+    if (out_data != NULL) {
+      *out_data = slot_data;
+    } else {
+      avb_slot_verify_data_free(slot_data);
+    }
+  }
+
+  if (!allow_verification_error) {
+    avb_assert(ret == AVB_SLOT_VERIFY_RESULT_OK);
+  }
+
+  return ret;
+
+fail:
+  if (slot_data != NULL) {
+    avb_slot_verify_data_free(slot_data);
+  }
+  return ret;
+}
+
+void avb_slot_verify_data_free(AvbSlotVerifyData* data) {
+  if (data->ab_suffix != NULL) {
+    avb_free(data->ab_suffix);
+  }
+  if (data->cmdline != NULL) {
+    avb_free(data->cmdline);
+  }
+  if (data->vbmeta_images != NULL) {
+    size_t n;
+    for (n = 0; n < data->num_vbmeta_images; n++) {
+      AvbVBMetaData* vbmeta_image = &data->vbmeta_images[n];
+      if (vbmeta_image->partition_name != NULL) {
+        avb_free(vbmeta_image->partition_name);
+      }
+      if (vbmeta_image->vbmeta_data != NULL) {
+        avb_free(vbmeta_image->vbmeta_data);
+      }
+    }
+    avb_free(data->vbmeta_images);
+  }
+  if (data->loaded_partitions != NULL) {
+    size_t n;
+    for (n = 0; n < data->num_loaded_partitions; n++) {
+      AvbPartitionData* loaded_partition = &data->loaded_partitions[n];
+      if (loaded_partition->partition_name != NULL) {
+        avb_free(loaded_partition->partition_name);
+      }
+      if (loaded_partition->data != NULL) {
+        avb_free(loaded_partition->data);
+      }
+    }
+    avb_free(data->loaded_partitions);
+  }
+  avb_free(data);
+}
+
+const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result) {
+  const char* ret = NULL;
+
+  switch (result) {
+    case AVB_SLOT_VERIFY_RESULT_OK:
+      ret = "OK";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
+      ret = "ERROR_OOM";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
+      ret = "ERROR_IO";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
+      ret = "ERROR_VERIFICATION";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
+      ret = "ERROR_ROLLBACK_INDEX";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
+      ret = "ERROR_PUBLIC_KEY_REJECTED";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
+      ret = "ERROR_INVALID_METADATA";
+      break;
+    case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
+      ret = "ERROR_UNSUPPORTED_VERSION";
+      break;
+      /* Do not add a 'default:' case here because of -Wswitch. */
+  }
+
+  if (ret == NULL) {
+    avb_error("Unknown AvbSlotVerifyResult value.\n");
+    ret = "(unknown)";
+  }
+
+  return ret;
+}
diff --git a/lib/libavb/avb_sysdeps_posix.c b/lib/libavb/avb_sysdeps_posix.c
new file mode 100644
index 0000000..3ede5c4
--- /dev/null
+++ b/lib/libavb/avb_sysdeps_posix.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include <stdarg.h>
+#include <stdlib.h>
+
+#include "avb/avb_sysdeps.h"
+
+int avb_memcmp(const void* src1, const void* src2, size_t n) {
+  return memcmp(src1, src2, n);
+}
+
+void* avb_memcpy(void* dest, const void* src, size_t n) {
+  return memcpy(dest, src, n);
+}
+
+void* avb_memset(void* dest, const int c, size_t n) {
+  return memset(dest, c, n);
+}
+
+int avb_strcmp(const char* s1, const char* s2) {
+  return strcmp(s1, s2);
+}
+
+size_t avb_strlen(const char* str) {
+  return strlen(str);
+}
+
+void avb_abort(void) {
+  hang();
+}
+
+void avb_print(const char* message) {
+  printf("%s", message);
+}
+
+void avb_printv(const char* message, ...) {
+  va_list ap;
+  const char* m;
+
+  va_start(ap, message);
+  for (m = message; m != NULL; m = va_arg(ap, const char*)) {
+    printf("%s", m);
+  }
+  va_end(ap);
+}
+
+void* avb_malloc_(size_t size) {
+  return malloc(size);
+}
+
+void avb_free(void* ptr) {
+  free(ptr);
+}
diff --git a/lib/libavb/avb_util.c b/lib/libavb/avb_util.c
new file mode 100644
index 0000000..8119ac0
--- /dev/null
+++ b/lib/libavb/avb_util.c
@@ -0,0 +1,385 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_util.h"
+
+#include <stdarg.h>
+
+uint32_t avb_be32toh(uint32_t in) {
+  uint8_t* d = (uint8_t*)&in;
+  uint32_t ret;
+  ret = ((uint32_t)d[0]) << 24;
+  ret |= ((uint32_t)d[1]) << 16;
+  ret |= ((uint32_t)d[2]) << 8;
+  ret |= ((uint32_t)d[3]);
+  return ret;
+}
+
+uint64_t avb_be64toh(uint64_t in) {
+  uint8_t* d = (uint8_t*)&in;
+  uint64_t ret;
+  ret = ((uint64_t)d[0]) << 56;
+  ret |= ((uint64_t)d[1]) << 48;
+  ret |= ((uint64_t)d[2]) << 40;
+  ret |= ((uint64_t)d[3]) << 32;
+  ret |= ((uint64_t)d[4]) << 24;
+  ret |= ((uint64_t)d[5]) << 16;
+  ret |= ((uint64_t)d[6]) << 8;
+  ret |= ((uint64_t)d[7]);
+  return ret;
+}
+
+/* Converts a 32-bit unsigned integer from host to big-endian byte order. */
+uint32_t avb_htobe32(uint32_t in) {
+  union {
+    uint32_t word;
+    uint8_t bytes[4];
+  } ret;
+  ret.bytes[0] = (in >> 24) & 0xff;
+  ret.bytes[1] = (in >> 16) & 0xff;
+  ret.bytes[2] = (in >> 8) & 0xff;
+  ret.bytes[3] = in & 0xff;
+  return ret.word;
+}
+
+/* Converts a 64-bit unsigned integer from host to big-endian byte order. */
+uint64_t avb_htobe64(uint64_t in) {
+  union {
+    uint64_t word;
+    uint8_t bytes[8];
+  } ret;
+  ret.bytes[0] = (in >> 56) & 0xff;
+  ret.bytes[1] = (in >> 48) & 0xff;
+  ret.bytes[2] = (in >> 40) & 0xff;
+  ret.bytes[3] = (in >> 32) & 0xff;
+  ret.bytes[4] = (in >> 24) & 0xff;
+  ret.bytes[5] = (in >> 16) & 0xff;
+  ret.bytes[6] = (in >> 8) & 0xff;
+  ret.bytes[7] = in & 0xff;
+  return ret.word;
+}
+
+int avb_safe_memcmp(const void* s1, const void* s2, size_t n) {
+  const unsigned char* us1 = s1;
+  const unsigned char* us2 = s2;
+  int result = 0;
+
+  if (0 == n) {
+    return 0;
+  }
+
+  /*
+   * Code snippet without data-dependent branch due to Nate Lawson
+   * (nate@root.org) of Root Labs.
+   */
+  while (n--) {
+    result |= *us1++ ^ *us2++;
+  }
+
+  return result != 0;
+}
+
+bool avb_safe_add_to(uint64_t* value, uint64_t value_to_add) {
+  uint64_t original_value;
+
+  avb_assert(value != NULL);
+
+  original_value = *value;
+
+  *value += value_to_add;
+  if (*value < original_value) {
+    avb_error("Overflow when adding values.\n");
+    return false;
+  }
+
+  return true;
+}
+
+bool avb_safe_add(uint64_t* out_result, uint64_t a, uint64_t b) {
+  uint64_t dummy;
+  if (out_result == NULL) {
+    out_result = &dummy;
+  }
+  *out_result = a;
+  return avb_safe_add_to(out_result, b);
+}
+
+bool avb_validate_utf8(const uint8_t* data, size_t num_bytes) {
+  size_t n;
+  unsigned int num_cc;
+
+  for (n = 0, num_cc = 0; n < num_bytes; n++) {
+    uint8_t c = data[n];
+
+    if (num_cc > 0) {
+      if ((c & (0x80 | 0x40)) == 0x80) {
+        /* 10xx xxxx */
+      } else {
+        goto fail;
+      }
+      num_cc--;
+    } else {
+      if (c < 0x80) {
+        num_cc = 0;
+      } else if ((c & (0x80 | 0x40 | 0x20)) == (0x80 | 0x40)) {
+        /* 110x xxxx */
+        num_cc = 1;
+      } else if ((c & (0x80 | 0x40 | 0x20 | 0x10)) == (0x80 | 0x40 | 0x20)) {
+        /* 1110 xxxx */
+        num_cc = 2;
+      } else if ((c & (0x80 | 0x40 | 0x20 | 0x10 | 0x08)) ==
+                 (0x80 | 0x40 | 0x20 | 0x10)) {
+        /* 1111 0xxx */
+        num_cc = 3;
+      } else {
+        goto fail;
+      }
+    }
+  }
+
+  if (num_cc != 0) {
+    goto fail;
+  }
+
+  return true;
+
+fail:
+  return false;
+}
+
+bool avb_str_concat(char* buf,
+                    size_t buf_size,
+                    const char* str1,
+                    size_t str1_len,
+                    const char* str2,
+                    size_t str2_len) {
+  uint64_t combined_len;
+
+  if (!avb_safe_add(&combined_len, str1_len, str2_len)) {
+    avb_error("Overflow when adding string sizes.\n");
+    return false;
+  }
+
+  if (combined_len > buf_size - 1) {
+    avb_error("Insufficient buffer space.\n");
+    return false;
+  }
+
+  avb_memcpy(buf, str1, str1_len);
+  avb_memcpy(buf + str1_len, str2, str2_len);
+  buf[combined_len] = '\0';
+
+  return true;
+}
+
+void* avb_malloc(size_t size) {
+  void* ret = avb_malloc_(size);
+  if (ret == NULL) {
+    avb_error("Failed to allocate memory.\n");
+    return NULL;
+  }
+  return ret;
+}
+
+void* avb_calloc(size_t size) {
+  void* ret = avb_malloc(size);
+  if (ret == NULL) {
+    return NULL;
+  }
+
+  avb_memset(ret, '\0', size);
+  return ret;
+}
+
+char* avb_strdup(const char* str) {
+  size_t len = avb_strlen(str);
+  char* ret = avb_malloc(len + 1);
+  if (ret == NULL) {
+    return NULL;
+  }
+
+  avb_memcpy(ret, str, len);
+  ret[len] = '\0';
+
+  return ret;
+}
+
+const char* avb_strstr(const char* haystack, const char* needle) {
+  size_t n, m;
+
+  /* Look through |haystack| and check if the first character of
+   * |needle| matches. If so, check the rest of |needle|.
+   */
+  for (n = 0; haystack[n] != '\0'; n++) {
+    if (haystack[n] != needle[0]) {
+      continue;
+    }
+
+    for (m = 1;; m++) {
+      if (needle[m] == '\0') {
+        return haystack + n;
+      }
+
+      if (haystack[n + m] != needle[m]) {
+        break;
+      }
+    }
+  }
+
+  return NULL;
+}
+
+const char* avb_strv_find_str(const char* const* strings,
+                              const char* str,
+                              size_t str_size) {
+  size_t n;
+  for (n = 0; strings[n] != NULL; n++) {
+    if (avb_strlen(strings[n]) == str_size &&
+        avb_memcmp(strings[n], str, str_size) == 0) {
+      return strings[n];
+    }
+  }
+  return NULL;
+}
+
+char* avb_replace(const char* str, const char* search, const char* replace) {
+  char* ret = NULL;
+  size_t ret_len = 0;
+  size_t search_len, replace_len;
+  const char* str_after_last_replace;
+
+  search_len = avb_strlen(search);
+  replace_len = avb_strlen(replace);
+
+  str_after_last_replace = str;
+  while (*str != '\0') {
+    const char* s;
+    size_t num_before;
+    size_t num_new;
+
+    s = avb_strstr(str, search);
+    if (s == NULL) {
+      break;
+    }
+
+    num_before = s - str;
+
+    if (ret == NULL) {
+      num_new = num_before + replace_len + 1;
+      ret = avb_malloc(num_new);
+      if (ret == NULL) {
+        goto out;
+      }
+      avb_memcpy(ret, str, num_before);
+      avb_memcpy(ret + num_before, replace, replace_len);
+      ret[num_new - 1] = '\0';
+      ret_len = num_new - 1;
+    } else {
+      char* new_str;
+      num_new = ret_len + num_before + replace_len + 1;
+      new_str = avb_malloc(num_new);
+      if (ret == NULL) {
+        goto out;
+      }
+      avb_memcpy(new_str, ret, ret_len);
+      avb_memcpy(new_str + ret_len, str, num_before);
+      avb_memcpy(new_str + ret_len + num_before, replace, replace_len);
+      new_str[num_new - 1] = '\0';
+      avb_free(ret);
+      ret = new_str;
+      ret_len = num_new - 1;
+    }
+
+    str = s + search_len;
+    str_after_last_replace = str;
+  }
+
+  if (ret == NULL) {
+    ret = avb_strdup(str_after_last_replace);
+    if (ret == NULL) {
+      goto out;
+    }
+  } else {
+    size_t num_remaining = avb_strlen(str_after_last_replace);
+    size_t num_new = ret_len + num_remaining + 1;
+    char* new_str = avb_malloc(num_new);
+    if (ret == NULL) {
+      goto out;
+    }
+    avb_memcpy(new_str, ret, ret_len);
+    avb_memcpy(new_str + ret_len, str_after_last_replace, num_remaining);
+    new_str[num_new - 1] = '\0';
+    avb_free(ret);
+    ret = new_str;
+    ret_len = num_new - 1;
+  }
+
+out:
+  return ret;
+}
+
+/* We only support a limited amount of strings in avb_strdupv(). */
+#define AVB_STRDUPV_MAX_NUM_STRINGS 32
+
+char* avb_strdupv(const char* str, ...) {
+  va_list ap;
+  const char* strings[AVB_STRDUPV_MAX_NUM_STRINGS];
+  size_t lengths[AVB_STRDUPV_MAX_NUM_STRINGS];
+  size_t num_strings, n;
+  uint64_t total_length;
+  char *ret = NULL, *dest;
+
+  num_strings = 0;
+  total_length = 0;
+  va_start(ap, str);
+  do {
+    size_t str_len = avb_strlen(str);
+    strings[num_strings] = str;
+    lengths[num_strings] = str_len;
+    if (!avb_safe_add_to(&total_length, str_len)) {
+      avb_fatal("Overflow while determining total length.\n");
+      break;
+    }
+    num_strings++;
+    if (num_strings == AVB_STRDUPV_MAX_NUM_STRINGS) {
+      avb_fatal("Too many strings passed.\n");
+      break;
+    }
+    str = va_arg(ap, const char*);
+  } while (str != NULL);
+  va_end(ap);
+
+  ret = avb_malloc(total_length + 1);
+  if (ret == NULL) {
+    goto out;
+  }
+
+  dest = ret;
+  for (n = 0; n < num_strings; n++) {
+    avb_memcpy(dest, strings[n], lengths[n]);
+    dest += lengths[n];
+  }
+  *dest = '\0';
+  avb_assert(dest == ret + total_length);
+
+out:
+  return ret;
+}
+
+const char* avb_basename(const char* str) {
+  int64_t n;
+  size_t len;
+
+  len = avb_strlen(str);
+  if (len >= 2) {
+    for (n = len - 2; n >= 0; n--) {
+      if (str[n] == '/') {
+        return str + n + 1;
+      }
+    }
+  }
+  return str;
+}
diff --git a/lib/libavb/avb_vbmeta_image.c b/lib/libavb/avb_vbmeta_image.c
new file mode 100644
index 0000000..12bd3d6
--- /dev/null
+++ b/lib/libavb/avb_vbmeta_image.c
@@ -0,0 +1,290 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_vbmeta_image.h"
+#include "avb/avb_crypto.h"
+#include "avb/avb_rsa.h"
+#include "avb/avb_sha.h"
+#include "avb/avb_util.h"
+#include "avb/avb_version.h"
+
+AvbVBMetaVerifyResult avb_vbmeta_image_verify(
+    const uint8_t* data,
+    size_t length,
+    const uint8_t** out_public_key_data,
+    size_t* out_public_key_length) {
+  AvbVBMetaVerifyResult ret;
+  AvbVBMetaImageHeader h;
+  uint8_t* computed_hash;
+  const AvbAlgorithmData* algorithm;
+  AvbSHA256Ctx sha256_ctx;
+  AvbSHA512Ctx sha512_ctx;
+  const uint8_t* header_block;
+  const uint8_t* authentication_block;
+  const uint8_t* auxiliary_block;
+  int verification_result;
+
+  ret = AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER;
+
+  if (out_public_key_data != NULL) {
+    *out_public_key_data = NULL;
+  }
+  if (out_public_key_length != NULL) {
+    *out_public_key_length = 0;
+  }
+
+  /* Ensure magic is correct. */
+  if (avb_safe_memcmp(data, AVB_MAGIC, AVB_MAGIC_LEN) != 0) {
+    avb_error("Magic is incorrect.\n");
+    goto out;
+  }
+
+  /* Before we byteswap, ensure length is long enough. */
+  if (length < sizeof(AvbVBMetaImageHeader)) {
+    avb_error("Length is smaller than header.\n");
+    goto out;
+  }
+  avb_vbmeta_image_header_to_host_byte_order((const AvbVBMetaImageHeader*)data,
+                                             &h);
+
+  /* Ensure we don't attempt to access any fields if we do not meet
+   * the specified minimum version of libavb.
+   */
+  if ((h.required_libavb_version_major != AVB_VERSION_MAJOR) ||
+      (h.required_libavb_version_minor > AVB_VERSION_MINOR)) {
+    avb_error("Mismatch between image version and libavb version.\n");
+    ret = AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION;
+    goto out;
+  }
+
+  /* Ensure |release_string| ends with a NUL byte. */
+  if (h.release_string[AVB_RELEASE_STRING_SIZE - 1] != '\0') {
+    avb_error("Release string does not end with a NUL byte.\n");
+    goto out;
+  }
+
+  /* Ensure inner block sizes are multiple of 64. */
+  if ((h.authentication_data_block_size & 0x3f) != 0 ||
+      (h.auxiliary_data_block_size & 0x3f) != 0) {
+    avb_error("Block size is not a multiple of 64.\n");
+    goto out;
+  }
+
+  /* Ensure block sizes all add up to at most |length|. */
+  uint64_t block_total = sizeof(AvbVBMetaImageHeader);
+  if (!avb_safe_add_to(&block_total, h.authentication_data_block_size) ||
+      !avb_safe_add_to(&block_total, h.auxiliary_data_block_size)) {
+    avb_error("Overflow while computing size of boot image.\n");
+    goto out;
+  }
+  if (block_total > length) {
+    avb_error("Block sizes add up to more than given length.\n");
+    goto out;
+  }
+
+  uintptr_t data_ptr = (uintptr_t)data;
+  /* Ensure passed in memory doesn't wrap. */
+  if (!avb_safe_add(NULL, (uint64_t)data_ptr, length)) {
+    avb_error("Boot image location and length mismatch.\n");
+    goto out;
+  }
+
+  /* Ensure hash and signature are entirely in the Authentication data block. */
+  uint64_t hash_end;
+  if (!avb_safe_add(&hash_end, h.hash_offset, h.hash_size) ||
+      hash_end > h.authentication_data_block_size) {
+    avb_error("Hash is not entirely in its block.\n");
+    goto out;
+  }
+  uint64_t signature_end;
+  if (!avb_safe_add(&signature_end, h.signature_offset, h.signature_size) ||
+      signature_end > h.authentication_data_block_size) {
+    avb_error("Signature is not entirely in its block.\n");
+    goto out;
+  }
+
+  /* Ensure public key is entirely in the Auxiliary data block. */
+  uint64_t pubkey_end;
+  if (!avb_safe_add(&pubkey_end, h.public_key_offset, h.public_key_size) ||
+      pubkey_end > h.auxiliary_data_block_size) {
+    avb_error("Public key is not entirely in its block.\n");
+    goto out;
+  }
+
+  /* Ensure public key metadata (if set) is entirely in the Auxiliary
+   * data block. */
+  if (h.public_key_metadata_size > 0) {
+    uint64_t pubkey_md_end;
+    if (!avb_safe_add(&pubkey_md_end,
+                      h.public_key_metadata_offset,
+                      h.public_key_metadata_size) ||
+        pubkey_md_end > h.auxiliary_data_block_size) {
+      avb_error("Public key metadata is not entirely in its block.\n");
+      goto out;
+    }
+  }
+
+  /* Bail early if there's no hash or signature. */
+  if (h.algorithm_type == AVB_ALGORITHM_TYPE_NONE) {
+    ret = AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED;
+    goto out;
+  }
+
+  /* Ensure algorithm field is supported. */
+  algorithm = avb_get_algorithm_data(h.algorithm_type);
+  if (!algorithm) {
+    avb_error("Invalid or unknown algorithm.\n");
+    goto out;
+  }
+
+  /* Bail if the embedded hash size doesn't match the chosen algorithm. */
+  if (h.hash_size != algorithm->hash_len) {
+    avb_error("Embedded hash has wrong size.\n");
+    goto out;
+  }
+
+  /* No overflow checks needed from here-on after since all block
+   * sizes and offsets have been verified above.
+   */
+
+  header_block = data;
+  authentication_block = header_block + sizeof(AvbVBMetaImageHeader);
+  auxiliary_block = authentication_block + h.authentication_data_block_size;
+
+  switch (h.algorithm_type) {
+    /* Explicit fall-through: */
+    case AVB_ALGORITHM_TYPE_SHA256_RSA2048:
+    case AVB_ALGORITHM_TYPE_SHA256_RSA4096:
+    case AVB_ALGORITHM_TYPE_SHA256_RSA8192:
+      avb_sha256_init(&sha256_ctx);
+      avb_sha256_update(
+          &sha256_ctx, header_block, sizeof(AvbVBMetaImageHeader));
+      avb_sha256_update(
+          &sha256_ctx, auxiliary_block, h.auxiliary_data_block_size);
+      computed_hash = avb_sha256_final(&sha256_ctx);
+      break;
+    /* Explicit fall-through: */
+    case AVB_ALGORITHM_TYPE_SHA512_RSA2048:
+    case AVB_ALGORITHM_TYPE_SHA512_RSA4096:
+    case AVB_ALGORITHM_TYPE_SHA512_RSA8192:
+      avb_sha512_init(&sha512_ctx);
+      avb_sha512_update(
+          &sha512_ctx, header_block, sizeof(AvbVBMetaImageHeader));
+      avb_sha512_update(
+          &sha512_ctx, auxiliary_block, h.auxiliary_data_block_size);
+      computed_hash = avb_sha512_final(&sha512_ctx);
+      break;
+    default:
+      avb_error("Unknown algorithm.\n");
+      goto out;
+  }
+
+  if (avb_safe_memcmp(authentication_block + h.hash_offset,
+                      computed_hash,
+                      h.hash_size) != 0) {
+    avb_error("Hash does not match!\n");
+    ret = AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH;
+    goto out;
+  }
+
+  verification_result =
+      avb_rsa_verify(auxiliary_block + h.public_key_offset,
+                     h.public_key_size,
+                     authentication_block + h.signature_offset,
+                     h.signature_size,
+                     authentication_block + h.hash_offset,
+                     h.hash_size,
+                     algorithm->padding,
+                     algorithm->padding_len);
+
+  if (verification_result == 0) {
+    ret = AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH;
+    goto out;
+  }
+
+  if (h.public_key_size > 0) {
+    if (out_public_key_data != NULL) {
+      *out_public_key_data = auxiliary_block + h.public_key_offset;
+    }
+    if (out_public_key_length != NULL) {
+      *out_public_key_length = h.public_key_size;
+    }
+  }
+
+  ret = AVB_VBMETA_VERIFY_RESULT_OK;
+
+out:
+  return ret;
+}
+
+void avb_vbmeta_image_header_to_host_byte_order(const AvbVBMetaImageHeader* src,
+                                                AvbVBMetaImageHeader* dest) {
+  avb_memcpy(dest, src, sizeof(AvbVBMetaImageHeader));
+
+  dest->required_libavb_version_major =
+      avb_be32toh(dest->required_libavb_version_major);
+  dest->required_libavb_version_minor =
+      avb_be32toh(dest->required_libavb_version_minor);
+
+  dest->authentication_data_block_size =
+      avb_be64toh(dest->authentication_data_block_size);
+  dest->auxiliary_data_block_size =
+      avb_be64toh(dest->auxiliary_data_block_size);
+
+  dest->algorithm_type = avb_be32toh(dest->algorithm_type);
+
+  dest->hash_offset = avb_be64toh(dest->hash_offset);
+  dest->hash_size = avb_be64toh(dest->hash_size);
+
+  dest->signature_offset = avb_be64toh(dest->signature_offset);
+  dest->signature_size = avb_be64toh(dest->signature_size);
+
+  dest->public_key_offset = avb_be64toh(dest->public_key_offset);
+  dest->public_key_size = avb_be64toh(dest->public_key_size);
+
+  dest->public_key_metadata_offset =
+      avb_be64toh(dest->public_key_metadata_offset);
+  dest->public_key_metadata_size = avb_be64toh(dest->public_key_metadata_size);
+
+  dest->descriptors_offset = avb_be64toh(dest->descriptors_offset);
+  dest->descriptors_size = avb_be64toh(dest->descriptors_size);
+
+  dest->rollback_index = avb_be64toh(dest->rollback_index);
+  dest->flags = avb_be32toh(dest->flags);
+}
+
+const char* avb_vbmeta_verify_result_to_string(AvbVBMetaVerifyResult result) {
+  const char* ret = NULL;
+
+  switch (result) {
+    case AVB_VBMETA_VERIFY_RESULT_OK:
+      ret = "OK";
+      break;
+    case AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED:
+      ret = "OK_NOT_SIGNED";
+      break;
+    case AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER:
+      ret = "INVALID_VBMETA_HEADER";
+      break;
+    case AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION:
+      ret = "UNSUPPORTED_VERSION";
+      break;
+    case AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH:
+      ret = "HASH_MISMATCH";
+      break;
+    case AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH:
+      ret = "SIGNATURE_MISMATCH";
+      break;
+      /* Do not add a 'default:' case here because of -Wswitch. */
+  }
+
+  if (ret == NULL) {
+    avb_error("Unknown AvbVBMetaVerifyResult value.\n");
+    ret = "(unknown)";
+  }
+
+  return ret;
+}
diff --git a/lib/libavb/avb_version.c b/lib/libavb/avb_version.c
new file mode 100644
index 0000000..e07e0ed
--- /dev/null
+++ b/lib/libavb/avb_version.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_version.h"
+
+#define AVB_QUOTE(str) #str
+#define AVB_EXPAND_AND_QUOTE(str) AVB_QUOTE(str)
+
+/* Keep in sync with get_release_string() in avbtool. */
+const char* avb_version_string(void) {
+  return AVB_EXPAND_AND_QUOTE(AVB_VERSION_MAJOR) "." AVB_EXPAND_AND_QUOTE(
+      AVB_VERSION_MINOR) "." AVB_EXPAND_AND_QUOTE(AVB_VERSION_SUB);
+}
diff --git a/lib/libavb_ab/avb_ab_flow.c b/lib/libavb_ab/avb_ab_flow.c
new file mode 100644
index 0000000..7517003
--- /dev/null
+++ b/lib/libavb_ab/avb_ab_flow.c
@@ -0,0 +1,502 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#include "avb/avb_ab_flow.h"
+
+uint32_t avb_crc32(const uint8_t* buf, size_t size) {
+  return crc32(0, buf, size);
+}
+
+bool avb_ab_data_verify_and_byteswap(const AvbABData* src, AvbABData* dest) {
+  /* Ensure magic is correct. */
+  if (avb_safe_memcmp(src->magic, AVB_AB_MAGIC, AVB_AB_MAGIC_LEN) != 0) {
+    avb_error("Magic is incorrect.\n");
+    return false;
+  }
+
+  avb_memcpy(dest, src, sizeof(AvbABData));
+  dest->crc32 = avb_be32toh(dest->crc32);
+
+  /* Ensure we don't attempt to access any fields if the major version
+   * is not supported.
+   */
+  if (dest->version_major > AVB_AB_MAJOR_VERSION) {
+    avb_error("No support for given major version.\n");
+    return false;
+  }
+
+  /* Bail if CRC32 doesn't match. */
+  if (dest->crc32 !=
+      avb_crc32((const uint8_t*)dest, sizeof(AvbABData) - sizeof(uint32_t))) {
+    avb_error("CRC32 does not match.\n");
+    return false;
+  }
+
+  return true;
+}
+
+void avb_ab_data_update_crc_and_byteswap(const AvbABData* src,
+                                         AvbABData* dest) {
+  avb_memcpy(dest, src, sizeof(AvbABData));
+  dest->crc32 = avb_htobe32(
+      avb_crc32((const uint8_t*)dest, sizeof(AvbABData) - sizeof(uint32_t)));
+}
+
+void avb_ab_data_init(AvbABData* data) {
+  avb_memset(data, '\0', sizeof(AvbABData));
+  avb_memcpy(data->magic, AVB_AB_MAGIC, AVB_AB_MAGIC_LEN);
+  data->version_major = AVB_AB_MAJOR_VERSION;
+  data->version_minor = AVB_AB_MINOR_VERSION;
+  data->slots[0].priority = AVB_AB_MAX_PRIORITY;
+  data->slots[0].tries_remaining = AVB_AB_MAX_TRIES_REMAINING;
+  data->slots[0].successful_boot = 0;
+  data->slots[1].priority = AVB_AB_MAX_PRIORITY - 1;
+  data->slots[1].tries_remaining = AVB_AB_MAX_TRIES_REMAINING;
+  data->slots[1].successful_boot = 0;
+}
+
+/* The AvbABData struct is stored 2048 bytes into the 'misc' partition
+ * following the 'struct bootloader_message' field. The struct is
+ * compatible with the guidelines in bootable/recovery/bootloader.h -
+ * e.g. it is stored in the |slot_suffix| field, starts with a
+ * NUL-byte, and is 32 bytes long.
+ */
+#define AB_METADATA_MISC_PARTITION_OFFSET 2048
+
+AvbIOResult avb_ab_data_read(AvbABOps* ab_ops, AvbABData* data) {
+  AvbOps* ops = ab_ops->ops;
+  AvbABData serialized;
+  AvbIOResult io_ret;
+  size_t num_bytes_read;
+
+  io_ret = ops->read_from_partition(ops,
+                                    "misc",
+                                    AB_METADATA_MISC_PARTITION_OFFSET,
+                                    sizeof(AvbABData),
+                                    &serialized,
+                                    &num_bytes_read);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    return AVB_IO_RESULT_ERROR_OOM;
+  } else if (io_ret != AVB_IO_RESULT_OK ||
+             num_bytes_read != sizeof(AvbABData)) {
+    avb_error("Error reading A/B metadata.\n");
+    return AVB_IO_RESULT_ERROR_IO;
+  }
+
+  if (!avb_ab_data_verify_and_byteswap(&serialized, data)) {
+    avb_error(
+        "Error validating A/B metadata from disk. "
+        "Resetting and writing new A/B metadata to disk.\n");
+    avb_ab_data_init(data);
+    return avb_ab_data_write(ab_ops, data);
+  }
+
+  return AVB_IO_RESULT_OK;
+}
+
+AvbIOResult avb_ab_data_write(AvbABOps* ab_ops, const AvbABData* data) {
+  AvbOps* ops = ab_ops->ops;
+  AvbABData serialized;
+  AvbIOResult io_ret;
+
+  avb_ab_data_update_crc_and_byteswap(data, &serialized);
+  io_ret = ops->write_to_partition(ops,
+                                   "misc",
+                                   AB_METADATA_MISC_PARTITION_OFFSET,
+                                   sizeof(AvbABData),
+                                   &serialized);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    return AVB_IO_RESULT_ERROR_OOM;
+  } else if (io_ret != AVB_IO_RESULT_OK) {
+    avb_error("Error writing A/B metadata.\n");
+    return AVB_IO_RESULT_ERROR_IO;
+  }
+  return AVB_IO_RESULT_OK;
+}
+
+static bool slot_is_bootable(AvbABSlotData* slot) {
+  return slot->priority > 0 &&
+         (slot->successful_boot || (slot->tries_remaining > 0));
+}
+
+static void slot_set_unbootable(AvbABSlotData* slot) {
+  slot->priority = 0;
+  slot->tries_remaining = 0;
+  slot->successful_boot = 0;
+}
+
+/* Ensure all unbootable and/or illegal states are marked as the
+ * canonical 'unbootable' state, e.g. priority=0, tries_remaining=0,
+ * and successful_boot=0.
+ */
+static void slot_normalize(AvbABSlotData* slot) {
+  if (slot->priority > 0) {
+    if (slot->tries_remaining == 0 && !slot->successful_boot) {
+      /* We've exhausted all tries -> unbootable. */
+      slot_set_unbootable(slot);
+    }
+    if (slot->tries_remaining > 0 && slot->successful_boot) {
+      /* Illegal state - avb_ab_mark_slot_successful() will clear
+       * tries_remaining when setting successful_boot.
+       */
+      slot_set_unbootable(slot);
+    }
+  } else {
+    slot_set_unbootable(slot);
+  }
+}
+
+static const char* slot_suffixes[2] = {"_a", "_b"};
+
+/* Helper function to load metadata - returns AVB_IO_RESULT_OK on
+ * success, error code otherwise.
+ */
+static AvbIOResult load_metadata(AvbABOps* ab_ops,
+                                 AvbABData* ab_data,
+                                 AvbABData* ab_data_orig) {
+  AvbIOResult io_ret;
+
+  io_ret = ab_ops->read_ab_metadata(ab_ops, ab_data);
+  if (io_ret != AVB_IO_RESULT_OK) {
+    avb_error("I/O error while loading A/B metadata.\n");
+    return io_ret;
+  }
+  *ab_data_orig = *ab_data;
+
+  /* Ensure data is normalized, e.g. illegal states will be marked as
+   * unbootable and all unbootable states are represented with
+   * (priority=0, tries_remaining=0, successful_boot=0).
+   */
+  slot_normalize(&ab_data->slots[0]);
+  slot_normalize(&ab_data->slots[1]);
+  return AVB_IO_RESULT_OK;
+}
+
+/* Writes A/B metadata to disk only if it has changed - returns
+ * AVB_IO_RESULT_OK on success, error code otherwise.
+ */
+static AvbIOResult save_metadata_if_changed(AvbABOps* ab_ops,
+                                            AvbABData* ab_data,
+                                            AvbABData* ab_data_orig) {
+  if (avb_safe_memcmp(ab_data, ab_data_orig, sizeof(AvbABData)) != 0) {
+    avb_debug("Writing A/B metadata to disk.\n");
+    return ab_ops->write_ab_metadata(ab_ops, ab_data);
+  }
+  return AVB_IO_RESULT_OK;
+}
+
+AvbABFlowResult avb_ab_flow(AvbABOps* ab_ops,
+                            const char* const* requested_partitions,
+                            bool allow_verification_error,
+                            AvbSlotVerifyData** out_data) {
+  AvbOps* ops = ab_ops->ops;
+  AvbSlotVerifyData* slot_data[2] = {NULL, NULL};
+  AvbSlotVerifyData* data = NULL;
+  AvbABFlowResult ret;
+  AvbABData ab_data, ab_data_orig;
+  size_t slot_index_to_boot, n;
+  AvbIOResult io_ret;
+  bool saw_and_allowed_verification_error = false;
+
+  io_ret = load_metadata(ab_ops, &ab_data, &ab_data_orig);
+  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+    ret = AVB_AB_FLOW_RESULT_ERROR_OOM;
+    goto out;
+  } else if (io_ret != AVB_IO_RESULT_OK) {
+    ret = AVB_AB_FLOW_RESULT_ERROR_IO;
+    goto out;
+  }
+
+  /* Validate all bootable slots. */
+  for (n = 0; n < 2; n++) {
+    if (slot_is_bootable(&ab_data.slots[n])) {
+      AvbSlotVerifyResult verify_result;
+      bool set_slot_unbootable = false;
+
+      verify_result = avb_slot_verify(ops,
+                                      requested_partitions,
+                                      slot_suffixes[n],
+                                      allow_verification_error,
+                                      &slot_data[n]);
+      switch (verify_result) {
+        case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
+          ret = AVB_AB_FLOW_RESULT_ERROR_OOM;
+          goto out;
+
+        case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
+          ret = AVB_AB_FLOW_RESULT_ERROR_IO;
+          goto out;
+
+        case AVB_SLOT_VERIFY_RESULT_OK:
+          break;
+
+        case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
+        case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
+          /* Even with |allow_verification_error| these mean game over. */
+          set_slot_unbootable = true;
+          break;
+
+        /* explicit fallthrough. */
+        case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
+        case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
+        case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
+          if (allow_verification_error) {
+            /* Do nothing since we allow this. */
+            avb_debugv("Allowing slot ",
+                       slot_suffixes[n],
+                       " which verified "
+                       "with result ",
+                       avb_slot_verify_result_to_string(verify_result),
+                       " because |allow_verification_error| is true.\n",
+                       NULL);
+            saw_and_allowed_verification_error = true;
+          } else {
+            set_slot_unbootable = true;
+          }
+          break;
+      }
+
+      if (set_slot_unbootable) {
+        avb_errorv("Error verifying slot ",
+                   slot_suffixes[n],
+                   " with result ",
+                   avb_slot_verify_result_to_string(verify_result),
+                   " - setting unbootable.\n",
+                   NULL);
+        slot_set_unbootable(&ab_data.slots[n]);
+      }
+    }
+  }
+
+  if (slot_is_bootable(&ab_data.slots[0]) &&
+      slot_is_bootable(&ab_data.slots[1])) {
+    if (ab_data.slots[1].priority > ab_data.slots[0].priority) {
+      slot_index_to_boot = 1;
+    } else {
+      slot_index_to_boot = 0;
+    }
+  } else if (slot_is_bootable(&ab_data.slots[0])) {
+    slot_index_to_boot = 0;
+  } else if (slot_is_bootable(&ab_data.slots[1])) {
+    slot_index_to_boot = 1;
+  } else {
+    /* No bootable slots! */
+    avb_error("No bootable slots found.\n");
+    ret = AVB_AB_FLOW_RESULT_ERROR_NO_BOOTABLE_SLOTS;
+    goto out;
+  }
+
+  /* Update stored rollback index such that the stored rollback index
+   * is the largest value supporting all currently bootable slots. Do
+   * this for every rollback index location.
+   */
+  for (n = 0; n < AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS; n++) {
+    uint64_t rollback_index_value = 0;
+
+    if (slot_data[0] != NULL && slot_data[1] != NULL) {
+      uint64_t a_rollback_index = slot_data[0]->rollback_indexes[n];
+      uint64_t b_rollback_index = slot_data[1]->rollback_indexes[n];
+      rollback_index_value =
+          (a_rollback_index < b_rollback_index ? a_rollback_index
+                                               : b_rollback_index);
+    } else if (slot_data[0] != NULL) {
+      rollback_index_value = slot_data[0]->rollback_indexes[n];
+    } else if (slot_data[1] != NULL) {
+      rollback_index_value = slot_data[1]->rollback_indexes[n];
+    }
+
+    if (rollback_index_value != 0) {
+      uint64_t current_rollback_index_value;
+      io_ret = ops->read_rollback_index(ops, n, &current_rollback_index_value);
+      if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+        ret = AVB_AB_FLOW_RESULT_ERROR_OOM;
+        goto out;
+      } else if (io_ret != AVB_IO_RESULT_OK) {
+        avb_error("Error getting rollback index for slot.\n");
+        ret = AVB_AB_FLOW_RESULT_ERROR_IO;
+        goto out;
+      }
+      if (current_rollback_index_value != rollback_index_value) {
+        io_ret = ops->write_rollback_index(ops, n, rollback_index_value);
+        if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+          ret = AVB_AB_FLOW_RESULT_ERROR_OOM;
+          goto out;
+        } else if (io_ret != AVB_IO_RESULT_OK) {
+          avb_error("Error setting stored rollback index.\n");
+          ret = AVB_AB_FLOW_RESULT_ERROR_IO;
+          goto out;
+        }
+      }
+    }
+  }
+
+  /* Finally, select this slot. */
+  avb_assert(slot_data[slot_index_to_boot] != NULL);
+  data = slot_data[slot_index_to_boot];
+  slot_data[slot_index_to_boot] = NULL;
+  if (saw_and_allowed_verification_error) {
+    avb_assert(allow_verification_error);
+    ret = AVB_AB_FLOW_RESULT_OK_WITH_VERIFICATION_ERROR;
+  } else {
+    ret = AVB_AB_FLOW_RESULT_OK;
+  }
+
+  /* ... and decrement tries remaining, if applicable. */
+  if (!ab_data.slots[slot_index_to_boot].successful_boot &&
+      ab_data.slots[slot_index_to_boot].tries_remaining > 0) {
+    ab_data.slots[slot_index_to_boot].tries_remaining -= 1;
+  }
+
+out:
+  io_ret = save_metadata_if_changed(ab_ops, &ab_data, &ab_data_orig);
+  if (io_ret != AVB_IO_RESULT_OK) {
+    if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
+      ret = AVB_AB_FLOW_RESULT_ERROR_OOM;
+    } else {
+      ret = AVB_AB_FLOW_RESULT_ERROR_IO;
+    }
+    if (data != NULL) {
+      avb_slot_verify_data_free(data);
+      data = NULL;
+    }
+  }
+
+  for (n = 0; n < 2; n++) {
+    if (slot_data[n] != NULL) {
+      avb_slot_verify_data_free(slot_data[n]);
+    }
+  }
+
+  if (out_data != NULL) {
+    *out_data = data;
+  } else {
+    if (data != NULL) {
+      avb_slot_verify_data_free(data);
+    }
+  }
+
+  return ret;
+}
+
+AvbIOResult avb_ab_mark_slot_active(AvbABOps* ab_ops,
+                                    unsigned int slot_number) {
+  AvbABData ab_data, ab_data_orig;
+  unsigned int other_slot_number;
+  AvbIOResult ret;
+
+  avb_assert(slot_number < 2);
+
+  ret = load_metadata(ab_ops, &ab_data, &ab_data_orig);
+  if (ret != AVB_IO_RESULT_OK) {
+    goto out;
+  }
+
+  /* Make requested slot top priority, unsuccessful, and with max tries. */
+  ab_data.slots[slot_number].priority = AVB_AB_MAX_PRIORITY;
+  ab_data.slots[slot_number].tries_remaining = AVB_AB_MAX_TRIES_REMAINING;
+  ab_data.slots[slot_number].successful_boot = 0;
+
+  /* Ensure other slot doesn't have as high a priority. */
+  other_slot_number = 1 - slot_number;
+  if (ab_data.slots[other_slot_number].priority == AVB_AB_MAX_PRIORITY) {
+    ab_data.slots[other_slot_number].priority = AVB_AB_MAX_PRIORITY - 1;
+  }
+
+  ret = AVB_IO_RESULT_OK;
+
+out:
+  if (ret == AVB_IO_RESULT_OK) {
+    ret = save_metadata_if_changed(ab_ops, &ab_data, &ab_data_orig);
+  }
+  return ret;
+}
+
+AvbIOResult avb_ab_mark_slot_unbootable(AvbABOps* ab_ops,
+                                        unsigned int slot_number) {
+  AvbABData ab_data, ab_data_orig;
+  AvbIOResult ret;
+
+  avb_assert(slot_number < 2);
+
+  ret = load_metadata(ab_ops, &ab_data, &ab_data_orig);
+  if (ret != AVB_IO_RESULT_OK) {
+    goto out;
+  }
+
+  slot_set_unbootable(&ab_data.slots[slot_number]);
+
+  ret = AVB_IO_RESULT_OK;
+
+out:
+  if (ret == AVB_IO_RESULT_OK) {
+    ret = save_metadata_if_changed(ab_ops, &ab_data, &ab_data_orig);
+  }
+  return ret;
+}
+
+AvbIOResult avb_ab_mark_slot_successful(AvbABOps* ab_ops,
+                                        unsigned int slot_number) {
+  AvbABData ab_data, ab_data_orig;
+  AvbIOResult ret;
+
+  avb_assert(slot_number < 2);
+
+  ret = load_metadata(ab_ops, &ab_data, &ab_data_orig);
+  if (ret != AVB_IO_RESULT_OK) {
+    goto out;
+  }
+
+  if (!slot_is_bootable(&ab_data.slots[slot_number])) {
+    avb_error("Cannot mark unbootable slot as successful.\n");
+    ret = AVB_IO_RESULT_OK;
+    goto out;
+  }
+
+  ab_data.slots[slot_number].tries_remaining = 0;
+  ab_data.slots[slot_number].successful_boot = 1;
+
+  ret = AVB_IO_RESULT_OK;
+
+out:
+  if (ret == AVB_IO_RESULT_OK) {
+    ret = save_metadata_if_changed(ab_ops, &ab_data, &ab_data_orig);
+  }
+  return ret;
+}
+
+const char* avb_ab_flow_result_to_string(AvbABFlowResult result) {
+  const char* ret = NULL;
+
+  switch (result) {
+    case AVB_AB_FLOW_RESULT_OK:
+      ret = "OK";
+      break;
+
+    case AVB_AB_FLOW_RESULT_OK_WITH_VERIFICATION_ERROR:
+      ret = "OK_WITH_VERIFICATION_ERROR";
+      break;
+
+    case AVB_AB_FLOW_RESULT_ERROR_OOM:
+      ret = "ERROR_OOM";
+      break;
+
+    case AVB_AB_FLOW_RESULT_ERROR_IO:
+      ret = "ERROR_IO";
+      break;
+
+    case AVB_AB_FLOW_RESULT_ERROR_NO_BOOTABLE_SLOTS:
+      ret = "ERROR_NO_BOOTABLE_SLOTS";
+      break;
+      /* Do not add a 'default:' case here because of -Wswitch. */
+  }
+
+  if (ret == NULL) {
+    avb_error("Unknown AvbABFlowResult value.\n");
+    ret = "(unknown)";
+  }
+
+  return ret;
+}
