crypto: af_alg - Initialize sg_num_bytes in error code path

The RX SGL in processing is already registered with the RX SGL tracking
list to support proper cleanup. The cleanup code path uses the
sg_num_bytes variable which must therefore be always initialized, even
in the error code path.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Reported-by: syzbot+9c251bdd09f83b92ba95@syzkaller.appspotmail.com
#syz test: https://github.com/google/kmsan.git master
CC: <stable@vger.kernel.org> #4.14
Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 3 insertions, 1 deletions

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 7846c0c20cfe..b52a14fc3bae 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1156,8 +1156,10 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 
                 /* make one iovec available as scatterlist */
                 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
-                if (err < 0)
+                if (err < 0) {
+                        rsgl->sg_num_bytes = 0;
                         return err;
+                }
 
                 /* chain the new scatterlist with previous one */
                 if (areq->last_rsgl)