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 <redacted>
---
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 1f57094..4d1c942 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -183,14 +183,15 @@ static int l2tp_ip_recv(struct sk_buff *skb)
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 af9abff..e3fc778 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -198,14 +198,15 @@ static int l2tp_ip6_recv(struct sk_buff *skb)
read_lock_bh(&l2tp_ip6_lock);
sk = __l2tp_ip6_bind_lookup(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;
--
2.10.2