This is a note to let you know that I've just added the patch titled
l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
l2tp-hold-tunnel-socket-when-handling-control-frames-in-l2tp_ip-and-l2tp_ip6.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 94d7ee0baa8b764cf64ad91ed69464c1a6a0066b Mon Sep 17 00:00:00 2001
From: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Date: Wed, 29 Mar 2017 08:44:59 +0200
Subject: l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6
From: Guillaume Nault <g.nault@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/l2tp/l2tp_ip.c | 5 +++--
net/l2tp/l2tp_ip6.c | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -177,9 +177,10 @@ 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);
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -188,9 +188,10 @@ 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 ipv6hdr *iph = ipv6_hdr(skb);
read_lock_bh(&l2tp_ip6_lock);
Patches currently in stable-queue which might be from g.nault@xxxxxxxxxxxx are
queue-4.4/l2tp-hold-socket-before-dropping-lock-in-l2tp_ip-6-_.patch
queue-4.4/l2tp-hold-tunnel-socket-when-handling-control-frames-in-l2tp_ip-and-l2tp_ip6.patch
