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authorAlexander Couzens <lynxis@fe80.eu>2015-09-28 12:32:42 +0300
committerDavid S. Miller <davem@davemloft.net>2015-09-29 08:39:10 +0300
commit06a15f51cf3618e32a73871ee6a547ef7fd902b5 (patch)
tree5d7f25db11b5b985c7366d8bf954aeca976f2b2b /net/l2tp
parent661dfc65f7981481ba2e31aaa702371e82336e56 (diff)
downloadlinux-06a15f51cf3618e32a73871ee6a547ef7fd902b5.tar.xz
l2tp: protect tunnel->del_work by ref_count
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>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_core.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index f6b090df3930..afca2eb4dfa7 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1319,7 +1319,7 @@ 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;
@@ -1341,6 +1341,8 @@ 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
@@ -1636,8 +1638,13 @@ 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);