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l2tp: Fix locking in l2tp_core.c 

l2tp_xmit_skb() must take the socket lock.  It makes use of ip_queue_xmit()
which expects to execute in a socket atomic context.

Since we execute this function in software interrupts, we cannot use the
usual lock_sock()/release_sock() sequence, instead we have to use
bh_lock_sock() and see if a user has the socket locked, and if so drop
the packet.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2011-05-08 13:45:20 -07:00
parent 2f16270f41
commit 6af88da14e
1 changed files with 8 additions and 0 deletions
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8
net/l2tp/l2tp_core.c
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@ -1060,6 +1060,12 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
IPSKB_REROUTED);
nf_reset(skb);
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
dev_kfree_skb(skb);
goto out_unlock;
}
/* Get routing info from the tunnel socket */
skb_dst_drop(skb);
skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
@ -1106,6 +1112,8 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
l2tp_skb_set_owner_w(skb, sk);
l2tp_xmit_core(session, skb, data_len);
out_unlock:
bh_unlock_sock(sk);
abort:
return 0;