commit 14134f6584212d585b310ce95428014b653dfaf6
author dingtianhong <dingtianhong@huawei.com> Mon Mar 25 17:02:04 2013 +0000
committer David S. Miller <davem@davemloft.net> Tue Mar 26 12:33:55 2013 -0400
tree dfaa64172441eecd90557d1f1bedba1695fa4cd6
parent 465c0a165938992455357982d7f15ac105528b4a

af_unix: dont send SCM_CREDENTIAL when dest socket is NULL

SCM_SCREDENTIALS should apply to write() syscalls only either source or destination
socket asserted SOCK_PASSCRED. The original implememtation in maybe_add_creds is wrong,
and breaks several LSB testcases ( i.e. /tset/LSB.os/netowkr/recvfrom/T.recvfrom).

Origionally-authored-by: Karel Srot <ksrot@redhat.com>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/unix/af_unix.c

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f153a8d..971282b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1412,8 +1412,8 @@
 	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();
 	}