[PATCH 31/33] scsi: qla2xxx: Zero SFP DMA buffer in FRU/I2C bsg handlers

The FRU and I2C bsg handlers stage their transfer in a DMA_POOL_SIZE
(256-byte) bounce buffer obtained from dma_pool_alloc(), which does not
zero the allocation. They initialize only a few leading bytes before
handing the buffer to qla2x00_write_sfp().

qla2x00_write_sfp() can override the transfer length with a user-supplied
value:

	if (len == 1)
		opt |= BIT_0;
	if (opt & BIT_0)
		len = *sfp;

*sfp is the first byte of the (user-controlled) payload, so len can grow
up to 255. The device then DMA-reads len bytes from the 256-byte pool
buffer. Since only a small prefix was written
(e.g. MAX_FRU_SIZE == 36 bytes for a FRU version, one byte for a FRU
status register), the hardware reads past the initialized region and
writes up to ~219 bytes of stale DMA-pool heap memory to the device
flash.

Allocate the buffer with dma_pool_zalloc() in all five FRU/I2C handlers
so any bytes beyond the initialized data are zero rather than stale heap
contents.

Fixes: 697a4bc69159 ("[SCSI] qla2xxx: Provide method for updating I2C attached VPD.")
Fixes: 9ebb5d9c69f1 ("[SCSI] qla2xxx: Add I2C BSG interface.")
Cc: [email protected]
Reported-by: Sashiko <[email protected]>
Signed-off-by: Nilesh Javali <[email protected]>
---
 drivers/scsi/qla2xxx/qla_bsg.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_bsg.c b/drivers/scsi/qla2xxx/qla_bsg.c
index 7fe7480fdc1b..59fcc726b682 100644
--- a/drivers/scsi/qla2xxx/qla_bsg.c
+++ b/drivers/scsi/qla2xxx/qla_bsg.c
@@ -2008,7 +2008,7 @@ qla2x00_update_fru_versions(struct bsg_job *bsg_job)
 	struct qla_image_version *image;
 	uint32_t count;
 	dma_addr_t sfp_dma;
-	void *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
+	void *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
 
 	if (!sfp) {
 		bsg_reply->reply_data.vendor_reply.vendor_rsp[0] =
@@ -2066,7 +2066,7 @@ qla2x00_read_fru_status(struct bsg_job *bsg_job)
 	uint8_t bsg[DMA_POOL_SIZE] = {};
 	struct qla_status_reg *sr = (void *)bsg;
 	dma_addr_t sfp_dma;
-	uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
+	uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
 
 	if (!sfp) {
 		bsg_reply->reply_data.vendor_reply.vendor_rsp[0] =
@@ -2117,7 +2117,7 @@ qla2x00_write_fru_status(struct bsg_job *bsg_job)
 	uint8_t bsg[DMA_POOL_SIZE] = {};
 	struct qla_status_reg *sr = (void *)bsg;
 	dma_addr_t sfp_dma;
-	uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
+	uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
 
 	if (!sfp) {
 		bsg_reply->reply_data.vendor_reply.vendor_rsp[0] =
@@ -2164,7 +2164,7 @@ qla2x00_write_i2c(struct bsg_job *bsg_job)
 	uint8_t bsg[DMA_POOL_SIZE] = {};
 	struct qla_i2c_access *i2c = (void *)bsg;
 	dma_addr_t sfp_dma;
-	uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
+	uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
 
 	if (!sfp) {
 		bsg_reply->reply_data.vendor_reply.vendor_rsp[0] =
@@ -2210,7 +2210,7 @@ qla2x00_read_i2c(struct bsg_job *bsg_job)
 	uint8_t bsg[DMA_POOL_SIZE] = {};
 	struct qla_i2c_access *i2c = (void *)bsg;
 	dma_addr_t sfp_dma;
-	uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
+	uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma);
 
 	if (!sfp) {
 		bsg_reply->reply_data.vendor_reply.vendor_rsp[0] =
-- 
2.47.3