diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2016-09-02 10:22:54 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-02 11:44:44 -0700 |
| commit | 2f86953e7436c9b9a4690909c5e2db24799e173b (patch) | |
| tree | 52019189807bf0a51f0c45638403dbbabd1e7328 | |
| parent | ab34380162cbc9b5172afdadf5136643c687bb73 (diff) | |
l2tp: fix use-after-free during module unload
Tunnel deletion is delayed by both a workqueue (l2tp_tunnel_delete -> wq
-> l2tp_tunnel_del_work) and RCU (sk_destruct -> RCU ->
l2tp_tunnel_destruct).
By the time l2tp_tunnel_destruct() runs to destroy the tunnel and finish
destroying the socket, the private data reserved via the net_generic
mechanism has already been freed, but l2tp_tunnel_destruct() actually
uses this data.
Make sure tunnel deletion for the netns has completed before returning
from l2tp_exit_net() by first flushing the tunnel removal workqueue, and
then waiting for RCU callbacks to complete.
Fixes: 167eb17e0b17 ("l2tp: create tunnel sockets in the right namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/l2tp/l2tp_core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 1e40dacaa137..a2ed3bda4ddc 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1855,6 +1855,9 @@ static __net_exit void l2tp_exit_net(struct net *net) (void)l2tp_tunnel_delete(tunnel); } rcu_read_unlock_bh(); + + flush_workqueue(l2tp_wq); + rcu_barrier(); } static struct pernet_operations l2tp_net_ops = { |