[PATCH 3.12 73/86] sctp: listen on the sock only when it's state is listening or closed

[Jiri Slaby]

From: Xin Long <lucien.xin@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

[ Upstream commit 34b2789f1d9bf8dcca9b5cb553d076ca2cd898ee ]

Now sctp doesn't check sock's state before listening on it. It could
even cause changing a sock with any state to become a listening sock
when doing sctp_listen.

This patch is to fix it by checking sock's state in sctp_listen, so
that it will listen on the sock with right state.

Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
 net/sctp/socket.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0059ce3fb747..16f03f76ff8f 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6169,6 +6169,9 @@ int sctp_inet_listen(struct socket *sock, int backlog)
 	if (sock->state != SS_UNCONNECTED)
 		goto out;
 
+	if (!sctp_sstate(sk, LISTENING) && !sctp_sstate(sk, CLOSED))
+		goto out;
+
 	/* If backlog is zero, disable listening. */
 	if (!backlog) {
 		if (sctp_sstate(sk, CLOSED))
-- 
2.12.2