From: Chengming Zhou <zhouchengming@bytedance.com>

The req->dst buffer size should be checked before copying from the
scomp_scratch->dst to avoid req->dst buffer overflow problem.

Fixes: 1ab53a77b772 ("crypto: acomp - add driver-side scomp interface")
Reported-by: syzbot+3eff5e51bf1db122a16e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/0000000000000b05cd060d6b5511@google.com/
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
v2:
 - change error code to ENOSPC.
---
 crypto/scompress.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crypto/scompress.c b/crypto/scompress.c
index 442a82c9de7d..b108a30a7600 100644
--- a/crypto/scompress.c
+++ b/crypto/scompress.c
@@ -117,6 +117,7 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 	struct crypto_scomp *scomp = *tfm_ctx;
 	void **ctx = acomp_request_ctx(req);
 	struct scomp_scratch *scratch;
+	unsigned int dlen;
 	int ret;
 
 	if (!req->src || !req->slen || req->slen > SCOMP_SCRATCH_SIZE)
@@ -128,6 +129,8 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 	if (!req->dlen || req->dlen > SCOMP_SCRATCH_SIZE)
 		req->dlen = SCOMP_SCRATCH_SIZE;
 
+	dlen = req->dlen;
+
 	scratch = raw_cpu_ptr(&scomp_scratch);
 	spin_lock(&scratch->lock);
 
@@ -145,6 +148,9 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
 				ret = -ENOMEM;
 				goto out;
 			}
+		} else if (req->dlen > dlen) {
+			ret = -ENOSPC;
+			goto out;
 		}
 		scatterwalk_map_and_copy(scratch->dst, req->dst, 0, req->dlen,
 					 1);
-- 
2.40.1

On Wed, Dec 27, 2023 at 09:35:23AM +0000, chengming.zhou@linux.dev wrote:
> From: Chengming Zhou <zhouchengming@bytedance.com>
> 
> The req->dst buffer size should be checked before copying from the
> scomp_scratch->dst to avoid req->dst buffer overflow problem.
> 
> Fixes: 1ab53a77b772 ("crypto: acomp - add driver-side scomp interface")
> Reported-by: syzbot+3eff5e51bf1db122a16e@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/0000000000000b05cd060d6b5511@google.com/
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
> v2:
>  - change error code to ENOSPC.
> ---
>  crypto/scompress.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

On Wed, Dec 27, 2023 at 5:35 PM <chengming.zhou@linux.dev> wrote:
>
> From: Chengming Zhou <zhouchengming@bytedance.com>
>
> The req->dst buffer size should be checked before copying from the
> scomp_scratch->dst to avoid req->dst buffer overflow problem.
>
> Fixes: 1ab53a77b772 ("crypto: acomp - add driver-side scomp interface")
> Reported-by: syzbot+3eff5e51bf1db122a16e@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/0000000000000b05cd060d6b5511@google.com/
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
> v2:
>  - change error code to ENOSPC.

Reviewed-by: Barry Song <v-songbaohua@oppo.com>


> ---
>  crypto/scompress.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/crypto/scompress.c b/crypto/scompress.c
> index 442a82c9de7d..b108a30a7600 100644
> --- a/crypto/scompress.c
> +++ b/crypto/scompress.c
> @@ -117,6 +117,7 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
>         struct crypto_scomp *scomp = *tfm_ctx;
>         void **ctx = acomp_request_ctx(req);
>         struct scomp_scratch *scratch;
> +       unsigned int dlen;
>         int ret;
>
>         if (!req->src || !req->slen || req->slen > SCOMP_SCRATCH_SIZE)
> @@ -128,6 +129,8 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
>         if (!req->dlen || req->dlen > SCOMP_SCRATCH_SIZE)
>                 req->dlen = SCOMP_SCRATCH_SIZE;
>
> +       dlen = req->dlen;
> +
>         scratch = raw_cpu_ptr(&scomp_scratch);
>         spin_lock(&scratch->lock);
>
> @@ -145,6 +148,9 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
>                                 ret = -ENOMEM;
>                                 goto out;
>                         }
> +               } else if (req->dlen > dlen) {
> +                       ret = -ENOSPC;
> +                       goto out;
>                 }
>                 scatterwalk_map_and_copy(scratch->dst, req->dst, 0, req->dlen,
>                                          1);
> --
> 2.40.1
>