l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6

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: a3c18422a4 ("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>
This commit is contained in:
Guillaume Nault 2017-03-29 08:44:59 +02:00 committed by David S. Miller
parent b768b16de5
commit 94d7ee0baa
2 changed files with 6 additions and 4 deletions

View File

@ -178,9 +178,10 @@ static int l2tp_ip_recv(struct sk_buff *skb)
tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
tunnel = l2tp_tunnel_find(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);

View File

@ -191,9 +191,10 @@ static int l2tp_ip6_recv(struct sk_buff *skb)
tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
tunnel = l2tp_tunnel_find(net, tunnel_id);
if (tunnel != NULL)
if (tunnel) {
sk = tunnel->sock;
else {
sock_hold(sk);
} else {
struct ipv6hdr *iph = ipv6_hdr(skb);
read_lock_bh(&l2tp_ip6_lock);