On Wed, Dec 27, 2023 at 5:35 PM <chengming.zhou@xxxxxxxxx> wrote:
>
> From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://lore.kernel.org/all/0000000000000b05cd060d6b5511@xxxxxxxxxx/
> Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
> ---
> v2:
> - change error code to ENOSPC.
Reviewed-by: Barry Song <v-songbaohua@xxxxxxxx>
> ---
> 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
>
