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authorSabrina Dubroca <sd@queasysnail.net>2016-09-02 10:22:54 +0200
committerDavid S. Miller <davem@davemloft.net>2016-09-02 11:44:44 -0700
commit2f86953e7436c9b9a4690909c5e2db24799e173b (patch)
tree52019189807bf0a51f0c45638403dbbabd1e7328 /net/l2tp
parentab34380162cbc9b5172afdadf5136643c687bb73 (diff)
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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>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_core.c3
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 = {