2022-02-17 23:22:29

by Gilad Ben-Yossef

Subject: [PATCH] crypto: ccree: don't attempt 0 len DMA mappings

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 <[email protected]>
Reported-by: Corentin Labbe <[email protected]>
Fixes: ce0fc6db38de ("crypto: ccree - protect against empty or NULL
scatterlists")
---
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;
--
2.25.1

2022-02-20 20:27:10

by Corentin Labbe

Subject: Re: [PATCH] crypto: ccree: don't attempt 0 len DMA mappings

Le Thu, Feb 17, 2022 at 09:27:26PM +0200, Gilad Ben-Yossef a ?crit :
> 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 <[email protected]>
> Reported-by: Corentin Labbe <[email protected]>
> Fixes: ce0fc6db38de ("crypto: ccree - protect against empty or NULL
> scatterlists")
> ---
> 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;
> --
> 2.25.1
>

Hello

With this patch, the stacktrace I reported is not present anymore.

Tested-by: Corentin Labbe <[email protected]>
Tested-on: r8a7795-salvator-x

Regards