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

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 <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Stephan Mueller <smueller@chronox.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index c49766b03165..7846c0c20cfe 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -158,16 +158,16 @@ 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) + addr_len - sizeof(*sa) - 1] = 0;