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authorGuillaume Nault <g.nault@alphalink.fr>2017-09-22 15:39:23 +0200
committerDavid S. Miller <davem@davemloft.net>2017-09-25 14:44:41 -0700
commitcdd10c9627496ad25c87ce6394e29752253c69d3 (patch)
tree98e157d68334d1e93dd530a9167526952b6b779f /net/l2tp
parent5c346525d3591cb032eca86d0f904cc01f1069ff (diff)
downloadlinux-cdd10c9627496ad25c87ce6394e29752253c69d3.tar.bz2
l2tp: ensure sessions are freed after their PPPOL2TP socket
If l2tp_tunnel_delete() or l2tp_tunnel_closeall() deletes a session right after pppol2tp_release() orphaned its socket, then the 'sock' variable of the pppol2tp_session_close() callback is NULL. Yet the session is still used by pppol2tp_release(). Therefore we need to take an extra reference in any case, to prevent l2tp_tunnel_delete() or l2tp_tunnel_closeall() from freeing the session. Since the pppol2tp_session_close() callback is only set if the session is associated to a PPPOL2TP socket and that both l2tp_tunnel_delete() and l2tp_tunnel_closeall() hold the PPPOL2TP socket before calling pppol2tp_session_close(), we're sure that pppol2tp_session_close() and pppol2tp_session_destruct() are paired and called in the right order. So the reference taken by the former will be released by the later. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_ppp.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 50e3ee9a9d61..bc6e8bfc5be4 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -437,11 +437,11 @@ static void pppol2tp_session_close(struct l2tp_session *session)
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
- if (sock) {
+ if (sock)
inet_shutdown(sock, SEND_SHUTDOWN);
- /* Don't let the session go away before our socket does */
- l2tp_session_inc_refcount(session);
- }
+
+ /* Don't let the session go away before our socket does */
+ l2tp_session_inc_refcount(session);
}
/* Really kill the session socket. (Called from sock_put() if