diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2016-09-02 10:22:54 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-10 10:26:31 +0200 |
| commit | 35a017009751dc18b365fe9ec8886a2632f42c18 (patch) | |
| tree | d10b928d13c01ae8e350308de88a13433336d504 /net | |
| parent | 0c17b22c8c5aa1f71a30974066fea2d4b2511980 (diff) | |
l2tp: fix use-after-free during module unload
commit 2f86953e7436c9b9a4690909c5e2db24799e173b upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to '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 2b8b5c57c7f0..8cbccddc0b1e 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1953,6 +1953,9 @@ static __net_exit void l2tp_exit_net(struct net *net) l2tp_tunnel_delete(tunnel); } rcu_read_unlock_bh(); + + flush_workqueue(l2tp_wq); + rcu_barrier(); } static struct pernet_operations l2tp_net_ops = { |