l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6 (94d7ee0b) · Commits · 戴 / test

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: ("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>

net/l2tp/l2tp_ip.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -178,9 +178,10 @@ pass_up:

		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);

net/l2tp/l2tp_ip6.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -191,9 +191,10 @@ pass_up:

		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);

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