[PATCH 6.18 120/198] crypto: algif_aead - Fix minimum RX size check for decryption

Greg Kroah-Hartman
2026-04-20T16:02:21Z

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit 3d14bd48e3a77091cbce637a12c2ae31b4a1687c ]

The check for the minimum receive buffer size did not take the
tag size into account during decryption. Fix this by adding the
required extra length.

Reported-by: syzbot+aa11561819dc42ebbc7c@syzkaller.appspotmail.com
Reported-by: Daniel Pouzzner <douzzer@mega.nu>
Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
crypto/algif_aead.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index dda15bb05e892..f8bd45f7dc839 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -144,7 +144,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
if (usedpages < outlen) {
size_t less = outlen - usedpages;

- if (used < less) {
+ if (used < less + (ctx->enc ? 0 : as)) {
err = -EINVAL;
goto free;
}
--
2.53.0