4.4-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit a3c18422a4b4e108bcf6a2328f48867e1003fd95 ]
Socket must be held while under the protection of the l2tp lock; there
is no guarantee that sk remains valid after the read_unlock_bh() call.
Same issue for l2tp_ip and l2tp_ip6.
Signed-off-by: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/l2tp/l2tp_ip.c | 11 ++++++-----
net/l2tp/l2tp_ip6.c | 11 ++++++-----
2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 48ab93842322..c7e6098c924e 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -184,14 +184,15 @@ pass_up:
read_lock_bh(&l2tp_ip_lock);
sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
+ if (!sk) {
+ read_unlock_bh(&l2tp_ip_lock);
+ goto discard;
+ }
+
+ sock_hold(sk);
read_unlock_bh(&l2tp_ip_lock);
}
- if (sk == NULL)
- goto discard;
-
- sock_hold(sk);
-
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_put;
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index bcdab1cba773..5fe0a6f6af3d 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -196,14 +196,15 @@ pass_up:
read_lock_bh(&l2tp_ip6_lock);
sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
0, tunnel_id);
+ if (!sk) {
+ read_unlock_bh(&l2tp_ip6_lock);
+ goto discard;
+ }
+
+ sock_hold(sk);
read_unlock_bh(&l2tp_ip6_lock);
}
- if (sk == NULL)
- goto discard;
-
- sock_hold(sk);
-
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_put;
--
2.17.1
