[PATCH 3.16 118/366] crypto: af_alg - fix possible uninit-value in alg_bind()

Ben Hutchings
2018-10-14T23:16:45Z

From: Eric Dumazet <edumazet@google.com>

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>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
crypto/af_alg.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -157,16 +157,16 @@ static int alg_bind(struct socket *sock,
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;