crypto: af_alg - fix possible uninit-value in alg_bind()

commit a466856e0b7ab269cdf9461886d007e88ff575b0 upstream.

syzbot reported :

BUG: KMSAN: uninit-value in alg_bind+0xe3/0xd90 crypto/af_alg.c:162

We need to check addr_len before dereferencing sa (or uaddr)

Fixes: bb30b8848c85 ("crypto: af_alg - whitelist mask and type")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Stephan Mueller <[email protected]>
Cc: Herbert Xu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

crypto/af_alg.c

@@ -157,16 +157,16 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	void *private;
 	int err;
 
-	/* If caller uses non-allowed flag, return error. */
-	if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
-		return -EINVAL;
-
 	if (sock->state == SS_CONNECTED)
 		return -EINVAL;
 
 	if (addr_len != sizeof(*sa))
 		return -EINVAL;
 
+	/* If caller uses non-allowed flag, return error. */
+	if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
+		return -EINVAL;
+
 	sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 	sa->salg_name[sizeof(sa->salg_name) - 1] = 0;