Revert "af_unix: dont send SCM_CREDENTIAL when dest socket is NULL"

This reverts commit 14134f6584212d585b310ce95428014b653dfaf6.

The problem that the above patch was meant to address is that af_unix
messages are not being coallesced because we are sending unnecesarry
credentials.  Not sending credentials in maybe_add_creds totally
breaks unconnected unix domain sockets that wish to send credentails
to other sockets.

In practice this break some versions of udev because they receive a
message and the sending uid is bogus so they drop the message.

Reported-by: Sven Joachim <svenjoac@gmx.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 971282b6f6a3..f153a8d6e339 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1412,8 +1412,8 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
         if (UNIXCB(skb).cred)
                 return;
         if (test_bit(SOCK_PASSCRED, &sock->flags) ||
-            (other->sk_socket &&
-            test_bit(SOCK_PASSCRED, &other->sk_socket->flags))) {
+            !other->sk_socket ||
+            test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
                 UNIXCB(skb).pid  = get_pid(task_tgid(current));
                 UNIXCB(skb).cred = get_current_cred();
         }