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* [PATCH net] sctp: change sk state only when it has assocs in sctp_shutdown
@ 2016-11-13 13:44 ` Xin Long
  0 siblings, 0 replies; 8+ messages in thread
From: Xin Long @ 2016-11-13 13:44 UTC (permalink / raw)
  To: network dev, linux-sctp
  Cc: davem, Marcelo Ricardo Leitner, Neil Horman, Vlad Yasevich, andreyknvl

Now when users shutdown a sock with SEND_SHUTDOWN in sctp, even if
this sock has no connection (assoc), sk state would be changed to
SCTP_SS_CLOSING, which is not as we expect.

Besides, after that if users try to listen on this sock, kernel
could even panic when it dereference sctp_sk(sk)->bind_hash in
sctp_inet_listen, as bind_hash is null when sock has no assoc.

This patch is to move sk state change after checking sk assocs
is not empty, and also merge these two if() conditions and reduce
indent level.

Fixes: d46e416c11c8 ("sctp: sctp should change socket state when shutdown is received")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/socket.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index faa48ff..f23ad91 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4285,19 +4285,18 @@ static void sctp_shutdown(struct sock *sk, int how)
 {
 	struct net *net = sock_net(sk);
 	struct sctp_endpoint *ep;
-	struct sctp_association *asoc;
 
 	if (!sctp_style(sk, TCP))
 		return;
 
-	if (how & SEND_SHUTDOWN) {
+	ep = sctp_sk(sk)->ep;
+	if (how & SEND_SHUTDOWN && !list_empty(&ep->asocs)) {
+		struct sctp_association *asoc;
+
 		sk->sk_state = SCTP_SS_CLOSING;
-		ep = sctp_sk(sk)->ep;
-		if (!list_empty(&ep->asocs)) {
-			asoc = list_entry(ep->asocs.next,
-					  struct sctp_association, asocs);
-			sctp_primitive_SHUTDOWN(net, asoc, NULL);
-		}
+		asoc = list_entry(ep->asocs.next,
+				  struct sctp_association, asocs);
+		sctp_primitive_SHUTDOWN(net, asoc, NULL);
 	}
 }
 
-- 
2.1.0

^ permalink raw reply related	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2016-11-14 21:23 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-11-13 13:44 [PATCH net] sctp: change sk state only when it has assocs in sctp_shutdown Xin Long
2016-11-13 13:44 ` Xin Long
2016-11-14 10:32 ` Marcelo Ricardo Leitner
2016-11-14 10:32   ` Marcelo Ricardo Leitner
2016-11-14 15:52 ` Neil Horman
2016-11-14 15:52   ` Neil Horman
2016-11-14 21:23 ` David Miller
2016-11-14 21:23   ` David Miller

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