3.2.97-rc1 review patch. If anyone has any objections, please let me know.
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From: Guillaume Nault g.nault@alphalink.fr
commit 94d7ee0baa8b764cf64ad91ed69464c1a6a0066b upstream.
The code following l2tp_tunnel_find() expects that a new reference is held on sk. Either sk_receive_skb() or the discard_put error path will drop a reference from the tunnel's socket.
This issue exists in both l2tp_ip and l2tp_ip6.
Fixes: a3c18422a4b4 ("l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()") Signed-off-by: Guillaume Nault g.nault@alphalink.fr Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 3.2: - Drop changes to l2tp_ip6.c - Adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -190,9 +190,10 @@ pass_up:
tunnel_id = ntohl(*(__be32 *) &skb->data[4]); tunnel = l2tp_tunnel_find(&init_net, tunnel_id); - if (tunnel != NULL) + if (tunnel) { sk = tunnel->sock; - else { + sock_hold(sk); + } else { struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
read_lock_bh(&l2tp_ip_lock);