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

BugLink: http://bugs.launchpad.net/bugs/1780499
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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 5231f421ad0006663e14b28cf47b577ad0443c83..ef2064d560a6a78ac89f38ca81234445f0e567fe 100644 (file)
--- 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;