diff options
| author | Alexander Couzens <lynxis@fe80.eu> | 2015-09-28 11:32:42 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-27 09:45:53 +0900 |
| commit | 91f536c1fa37c84e4771d28b1aee198cd08a41c5 (patch) | |
| tree | 9a9e41ad33f154351ae5dc1ab850ec39c4089188 | |
| parent | 67e128d68505fa37da2b9ae6b532f11db1624a2f (diff) | |
l2tp: protect tunnel->del_work by ref_count
[ Upstream commit 06a15f51cf3618e32a73871ee6a547ef7fd902b5 ]
There is a small chance that tunnel_free() is called before tunnel->del_work scheduled
resulting in a zero pointer dereference.
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/l2tp/l2tp_core.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 85d9d94c0a3c..3679bd6000d7 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1435,7 +1435,7 @@ static void l2tp_tunnel_del_work(struct work_struct *work) tunnel = container_of(work, struct l2tp_tunnel, del_work); sk = l2tp_tunnel_sock_lookup(tunnel); if (!sk) - return; + goto out; sock = sk->sk_socket; @@ -1456,6 +1456,8 @@ static void l2tp_tunnel_del_work(struct work_struct *work) } l2tp_tunnel_sock_put(sk); +out: + l2tp_tunnel_dec_refcount(tunnel); } /* Create a socket for the tunnel, if one isn't set up by @@ -1785,8 +1787,13 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create); */ int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) { + l2tp_tunnel_inc_refcount(tunnel); l2tp_tunnel_closeall(tunnel); - return (false == queue_work(l2tp_wq, &tunnel->del_work)); + if (false == queue_work(l2tp_wq, &tunnel->del_work)) { + l2tp_tunnel_dec_refcount(tunnel); + return 1; + } + return 0; } EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); |