From ba5c1a589629f7873fffef9d16ea9ac7614e49e9 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Fri, 1 Mar 2013 05:02:02 +0000 Subject: [PATCH] l2tp: Restore socket refcount when sendmsg succeeds [ Upstream commit 8b82547e33e85fc24d4d172a93c796de1fefa81a ] The sendmsg() syscall handler for PPPoL2TP doesn't decrease the socket reference counter after successful transmissions. Any successful sendmsg() call from userspace will then increase the reference counter forever, thus preventing the kernel's session and tunnel data from being freed later on. The problem only happens when writing directly on L2TP sockets. PPP sockets attached to L2TP are unaffected as the PPP subsystem uses pppol2tp_xmit() which symmetrically increase/decrease reference counters. This patch adds the missing call to sock_put() before returning from pppol2tp_sendmsg(). Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_ppp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index b1bd16f142bd..6f601756bac8 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -360,6 +360,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh l2tp_xmit_skb(session, skb, session->hdr_len); sock_put(ps->tunnel_sock); + sock_put(sk); return error; -- 2.39.2