From 744e1885922a9943458954cfea917b31064b4131 Mon Sep 17 00:00:00 2001
From: Chengming Zhou <zhouchengming@bytedance.com>
Date: Wed, 27 Dec 2023 09:35:23 +0000
Subject: [PATCH] crypto: scomp - fix req->dst buffer overflow
Git-commit: 744e1885922a9943458954cfea917b31064b4131
Patch-mainline: v6.8-rc1
References: git-fixes CVE-2023-52612 bsc#1221616

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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);
-- 
2.35.3