[v2,63/67] crypto: xcbc - Use API partial block handling

diff --git a/crypto/xcbc.c b/crypto/xcbc.c
index fc785667b134..970ff581dc58 100644
--- a/crypto/xcbc.c
+++ b/crypto/xcbc.c
@@ -8,9 +8,12 @@ 
 
 #include <crypto/internal/cipher.h>
 #include <crypto/internal/hash.h>
+#include <crypto/utils.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
 
 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
 			   0x02020202, 0x02020202, 0x02020202, 0x02020202,
@@ -30,22 +33,6 @@  struct xcbc_tfm_ctx {
 	u8 consts[];
 };
 
-/*
- * +------------------------
- * | <shash desc>
- * +------------------------
- * | xcbc_desc_ctx
- * +------------------------
- * | odds (block size)
- * +------------------------
- * | prev (block size)
- * +------------------------
- */
-struct xcbc_desc_ctx {
-	unsigned int len;
-	u8 odds[];
-};
-
 #define XCBC_BLOCKSIZE	16
 
 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
@@ -70,13 +57,10 @@  static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
 
 static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
 {
-	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	int bs = crypto_shash_blocksize(pdesc->tfm);
-	u8 *prev = &ctx->odds[bs];
+	u8 *prev = shash_desc_ctx(pdesc);
 
-	ctx->len = 0;
 	memset(prev, 0, bs);
-
 	return 0;
 }
 
@@ -85,77 +69,36 @@  static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
 {
 	struct crypto_shash *parent = pdesc->tfm;
 	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
-	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	struct crypto_cipher *tfm = tctx->child;
 	int bs = crypto_shash_blocksize(parent);
-	u8 *odds = ctx->odds;
-	u8 *prev = odds + bs;
+	u8 *prev = shash_desc_ctx(pdesc);
 
-	/* checking the data can fill the block */
-	if ((ctx->len + len) <= bs) {
-		memcpy(odds + ctx->len, p, len);
-		ctx->len += len;
-		return 0;
-	}
-
-	/* filling odds with new data and encrypting it */
-	memcpy(odds + ctx->len, p, bs - ctx->len);
-	len -= bs - ctx->len;
-	p += bs - ctx->len;
-
-	crypto_xor(prev, odds, bs);
-	crypto_cipher_encrypt_one(tfm, prev, prev);
-
-	/* clearing the length */
-	ctx->len = 0;
-
-	/* encrypting the rest of data */
-	while (len > bs) {
+	do {
 		crypto_xor(prev, p, bs);
 		crypto_cipher_encrypt_one(tfm, prev, prev);
 		p += bs;
 		len -= bs;
-	}
-
-	/* keeping the surplus of blocksize */
-	if (len) {
-		memcpy(odds, p, len);
-		ctx->len = len;
-	}
-
-	return 0;
+	} while (len >= bs);
+	return len;
 }
 
-static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
+static int crypto_xcbc_digest_finup(struct shash_desc *pdesc, const u8 *src,
+				    unsigned int len, u8 *out)
 {
 	struct crypto_shash *parent = pdesc->tfm;
 	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
-	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	struct crypto_cipher *tfm = tctx->child;
 	int bs = crypto_shash_blocksize(parent);
-	u8 *odds = ctx->odds;
-	u8 *prev = odds + bs;
+	u8 *prev = shash_desc_ctx(pdesc);
 	unsigned int offset = 0;
 
-	if (ctx->len != bs) {
-		unsigned int rlen;
-		u8 *p = odds + ctx->len;
-
-		*p = 0x80;
-		p++;
-
-		rlen = bs - ctx->len -1;
-		if (rlen)
-			memset(p, 0, rlen);
-
+	crypto_xor(prev, src, len);
+	if (len != bs) {
+		prev[len] ^= 0x80;
 		offset += bs;
 	}
-
-	crypto_xor(prev, odds, bs);
 	crypto_xor(prev, &tctx->consts[offset], bs);
-
 	crypto_cipher_encrypt_one(tfm, out, prev);
-
 	return 0;
 }
 
@@ -216,17 +159,18 @@  static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 	inst->alg.base.cra_blocksize = alg->cra_blocksize;
 	inst->alg.base.cra_ctxsize = sizeof(struct xcbc_tfm_ctx) +
 				     alg->cra_blocksize * 2;
+	inst->alg.base.cra_flags = CRYPTO_AHASH_ALG_BLOCK_ONLY |
+				   CRYPTO_AHASH_ALG_FINAL_NONZERO;
 
 	inst->alg.digestsize = alg->cra_blocksize;
-	inst->alg.descsize = sizeof(struct xcbc_desc_ctx) +
-			     alg->cra_blocksize * 2;
+	inst->alg.descsize = alg->cra_blocksize;
 
 	inst->alg.base.cra_init = xcbc_init_tfm;
 	inst->alg.base.cra_exit = xcbc_exit_tfm;
 
 	inst->alg.init = crypto_xcbc_digest_init;
 	inst->alg.update = crypto_xcbc_digest_update;
-	inst->alg.final = crypto_xcbc_digest_final;
+	inst->alg.finup = crypto_xcbc_digest_finup;
 	inst->alg.setkey = crypto_xcbc_digest_setkey;
 
 	inst->free = shash_free_singlespawn_instance;