[PATCH 4.17 066/101] crypto: af_alg - Initialize sg_num_bytes in error code path

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stephan Mueller <smueller@xxxxxxxxxx>

commit 2546da99212f22034aecf279da9c47cbfac6c981 upstream.

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@xxxxxxxxxx>
Reported-by: syzbot+9c251bdd09f83b92ba95@xxxxxxxxxxxxxxxxxxxxxxxxx
#syz test: https://github.com/google/kmsan.git master
CC: <stable@xxxxxxxxxxxxxxx> #4.14
Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management")
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 crypto/af_alg.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1156,8 +1156,10 @@ int af_alg_get_rsgl(struct sock *sk, str
 
 		/* 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)