[PATCH] crypto: mxs-dcp: Ensure payload is zero when using key slot

[David Gstir]

We could leak stack memory through the payload field when running
AES with a key from one of the hardware's key slots. Fix this by
ensuring the payload field is set to 0 in such cases.

This does not affect the common use case when the key is supplied
from main memory via the descriptor payload.

Signed-off-by: David Gstir <david at sigma-star.at>
Reported-by: kernel test robot <lkp at intel.com>
Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
Closes: https://lore.kernel.org/r/202405270146.Y9tPoil8-lkp@intel.com/
Fixes: 3d16af0b4cfa ("crypto: mxs-dcp: Add support for hardware-bound keys")
---
 drivers/crypto/mxs-dcp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index 057d73c370b7..c82775dbb557 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -225,7 +225,8 @@ static int mxs_dcp_start_dma(struct dcp_async_ctx *actx)
 static int mxs_dcp_run_aes(struct dcp_async_ctx *actx,
 			   struct skcipher_request *req, int init)
 {
-	dma_addr_t key_phys, src_phys, dst_phys;
+	dma_addr_t key_phys = 0;
+	dma_addr_t src_phys, dst_phys;
 	struct dcp *sdcp = global_sdcp;
 	struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
 	struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req);
-- 
2.35.3