[PATCH 5.17 0230/1126] crypto: ccree - dont attempt 0 len DMA mappings

Greg Kroah-Hartman
2022-04-05T07:52:45Z

From: Gilad Ben-Yossef <gilad@benyossef.com>

[ Upstream commit 1fb37b5692c915edcc2448a6b37255738c7c77e0 ]

Refuse to try mapping zero bytes as this may cause a fault
on some configurations / platforms and it seems the prev.
attempt is not enough and we need to be more explicit.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Fixes: ce0fc6db38de ("crypto: ccree - protect against empty or NULL
scatterlists")
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/crypto/ccree/cc_buffer_mgr.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/crypto/ccree/cc_buffer_mgr.c b/drivers/crypto/ccree/cc_buffer_mgr.c
index a5e041d9d2cf..11e0278c8631 100644
--- a/drivers/crypto/ccree/cc_buffer_mgr.c
+++ b/drivers/crypto/ccree/cc_buffer_mgr.c
@@ -258,6 +258,13 @@ static int cc_map_sg(struct device *dev, struct scatterlist *sg,
{
int ret = 0;

+ if (!nbytes) {
+ *mapped_nents = 0;
+ *lbytes = 0;
+ *nents = 0;
+ return 0;
+ }
+
*nents = cc_get_sgl_nents(dev, sg, nbytes, lbytes);
if (*nents > max_sg_nents) {
*nents = 0;
--
2.34.1