crypto: scomp - fix req->dst buffer overflow

[ Upstream commit 744e1885922a9943458954cfea917b31064b4131 ]

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>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/crypto/scompress.c b/crypto/scompress.c
index 738f4f8f0f41ac356de42004784ec680593d1153..4d6366a4440077d9810b89bc2632d6754188b0f4 100644 (file)
--- a/crypto/scompress.c
+++ b/crypto/scompress.c
@@ -124,6 +124,7 @@ 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)
@@ -135,6 +136,8 @@ 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);
 
@@ -152,6 +155,9 @@ 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);