@@ -57,14 +57,15 @@ qcom_alloc_bam_transaction(struct qcom_nand_controller *nandc)
bam_txn_buf += sizeof(*bam_txn);
bam_txn->bam_ce = bam_txn_buf;
- bam_txn_buf +=
- sizeof(*bam_txn->bam_ce) * QPIC_PER_CW_CMD_ELEMENTS * num_cw;
+ bam_txn->bam_ce_nitems = QPIC_PER_CW_CMD_ELEMENTS * num_cw;
+ bam_txn_buf += sizeof(*bam_txn->bam_ce) * bam_txn->bam_ce_nitems;
bam_txn->cmd_sgl = bam_txn_buf;
- bam_txn_buf +=
- sizeof(*bam_txn->cmd_sgl) * QPIC_PER_CW_CMD_SGL * num_cw;
+ bam_txn->cmd_sgl_nitems = QPIC_PER_CW_CMD_SGL * num_cw;
+ bam_txn_buf += sizeof(*bam_txn->cmd_sgl) * bam_txn->cmd_sgl_nitems;
bam_txn->data_sgl = bam_txn_buf;
+ bam_txn->data_sgl_nitems = QPIC_PER_CW_DATA_SGL * num_cw;
init_completion(&bam_txn->txn_done);
@@ -237,6 +238,11 @@ int qcom_prep_bam_dma_desc_cmd(struct qcom_nand_controller *nandc, bool read,
struct bam_cmd_element *bam_ce_buffer;
struct bam_transaction *bam_txn = nandc->bam_txn;
+ if (bam_txn->bam_ce_pos + size > bam_txn->bam_ce_nitems) {
+ dev_err(nandc->dev, "BAM %s array is full\n", "CE");
+ return -EINVAL;
+ }
+
bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_pos];
/* fill the command desc */
@@ -258,6 +264,12 @@ int qcom_prep_bam_dma_desc_cmd(struct qcom_nand_controller *nandc, bool read,
/* use the separate sgl after this command */
if (flags & NAND_BAM_NEXT_SGL) {
+ if (bam_txn->cmd_sgl_pos >= bam_txn->cmd_sgl_nitems) {
+ dev_err(nandc->dev, "BAM %s array is full\n",
+ "CMD sgl");
+ return -EINVAL;
+ }
+
bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_start];
bam_ce_size = (bam_txn->bam_ce_pos -
bam_txn->bam_ce_start) *
@@ -297,10 +309,20 @@ int qcom_prep_bam_dma_desc_data(struct qcom_nand_controller *nandc, bool read,
struct bam_transaction *bam_txn = nandc->bam_txn;
if (read) {
+ if (bam_txn->rx_sgl_pos >= bam_txn->data_sgl_nitems) {
+ dev_err(nandc->dev, "BAM %s array is full\n", "RX sgl");
+ return -EINVAL;
+ }
+
sg_set_buf(&bam_txn->data_sgl[bam_txn->rx_sgl_pos],
vaddr, size);
bam_txn->rx_sgl_pos++;
} else {
+ if (bam_txn->tx_sgl_pos >= bam_txn->data_sgl_nitems) {
+ dev_err(nandc->dev, "BAM %s array is full\n", "TX sgl");
+ return -EINVAL;
+ }
+
sg_set_buf(&bam_txn->data_sgl[bam_txn->tx_sgl_pos],
vaddr, size);
bam_txn->tx_sgl_pos++;
@@ -240,6 +240,9 @@
* @last_data_desc - last DMA desc in data channel (tx/rx).
* @last_cmd_desc - last DMA desc in command channel.
* @txn_done - completion for NAND transfer.
+ * @bam_ce_nitems - the number of elements in the @bam_ce array
+ * @cmd_sgl_nitems - the number of elements in the @cmd_sgl array
+ * @data_sgl_nitems - the number of elements in the @data_sgl array
* @bam_ce_pos - the index in bam_ce which is available for next sgl
* @bam_ce_start - the index in bam_ce which marks the start position ce
* for current sgl. It will be used for size calculation
@@ -258,6 +261,11 @@ struct bam_transaction {
struct dma_async_tx_descriptor *last_data_desc;
struct dma_async_tx_descriptor *last_cmd_desc;
struct completion txn_done;
+
+ unsigned int bam_ce_nitems;
+ unsigned int cmd_sgl_nitems;
+ unsigned int data_sgl_nitems;
+
struct_group(bam_positions,
u32 bam_ce_pos;
u32 bam_ce_start;
The common QPIC code does not do any boundary checking when it handles the command elements and scatter gater list arrays of a BAM transaction, thus it allows to access out of bounds elements in those. Although it is the responsibility of the given driver to allocate enough space for all possible BAM transaction variations, however there can be mistakes in the driver code which can lead to hidden memory corruption issues which are hard to debug. This kind of problem has been observed during testing the 'spi-qpic-snand' driver. Although the driver has been fixed with a preceding patch, but it still makes sense to reduce the chance of having such errors again later. In order to prevent such errors, change the qcom_alloc_bam_transaction() function to store the number of elements of the arrays in the 'bam_transaction' strucutre during allocation. Also, add sanity checks to the qcom_prep_bam_dma_desc_{cmd,data}() functions to avoid using out of bounds indices for the arrays. Tested-by: Lakshmi Sowjanya D <quic_laksd@quicinc.com> # on SDX75 Signed-off-by: Gabor Juhos <j4g8y7@gmail.com> --- Changes in v2: - remove the inline qcom_err_bam_array_full() function and print the error messages directly from the respective functions instead - add 'Tested-by' tag from Lakshmi Sowjanya D, and remove the "Tested with the 'spi-qpic-snand' driver only." line from the commit message as SDX75 uses the qcom_nandc driver - move the note about of the preferred merging order into the cover letter --- drivers/mtd/nand/qpic_common.c | 30 ++++++++++++++++++++++++++---- include/linux/mtd/nand-qpic-common.h | 8 ++++++++ 2 files changed, 34 insertions(+), 4 deletions(-)