af_unix: Avoid socket->sk NULL OOPS in stream connect security hooks.

unix_release() can asynchornously set socket->sk to NULL, and
it does so without holding the unix_state_lock() on "other"
during stream connects.

However, the reverse mapping, sk->sk_socket, is only transitioned
to NULL under the unix_state_lock().

Therefore make the security hooks follow the reverse mapping instead
of the forward mapping.

Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/security/security.c b/security/security.c
index 1b798d3df710..e5fb07a3052d 100644
--- a/security/security.c
+++ b/security/security.c
@@ -977,8 +977,7 @@ EXPORT_SYMBOL(security_inode_getsecctx);
 
 #ifdef CONFIG_SECURITY_NETWORK
 
-int security_unix_stream_connect(struct socket *sock, struct socket *other,
-                                 struct sock *newsk)
+int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk)
 {
         return security_ops->unix_stream_connect(sock, other, newsk);
 }