From 071d93931a75dc1f82f0baa9959613af81c5a032 Mon Sep 17 00:00:00 2001 From: Krzysztof Mazur Date: Sat, 10 Nov 2012 23:33:19 +0100 Subject: [PATCH] pppoatm: drop frames to not-ready vcc The vcc_destroy_socket() closes vcc before the protocol is detached from vcc by calling vcc->push() with NULL skb. This leaves some time window, where the protocol may call vcc->send() on closed vcc and crash. Now pppoatm_send(), like vcc_sendmsg(), checks for vcc flags that indicate that vcc is not ready. If the vcc is not ready we just drop frame. Queueing frames is much more complicated because we don't have callbacks that inform us about vcc flags changes. Signed-off-by: Krzysztof Mazur Signed-off-by: David Woodhouse --- net/atm/pppoatm.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c index c4a57bca77bf..aeb726cffc8c 100644 --- a/net/atm/pppoatm.c +++ b/net/atm/pppoatm.c @@ -284,6 +284,13 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) bh_lock_sock(sk_atm(vcc)); if (sock_owned_by_user(sk_atm(vcc))) goto nospace; + if (test_bit(ATM_VF_RELEASED, &vcc->flags) || + test_bit(ATM_VF_CLOSE, &vcc->flags) || + !test_bit(ATM_VF_READY, &vcc->flags)) { + bh_unlock_sock(sk_atm(vcc)); + kfree_skb(skb); + return DROP_PACKET; + } switch (pvcc->encaps) { /* LLC encapsulation needed */ case e_llc: -- 2.20.1