From a3c18422a4b4e108bcf6a2328f48867e1003fd95 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Tue, 29 Nov 2016 13:09:45 +0100 Subject: l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv() 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 Signed-off-by: David S. Miller --- net/l2tp/l2tp_ip.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'net/l2tp/l2tp_ip.c') diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 1f57094d3111..4d1c942cc91b 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -183,14 +183,15 @@ 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; -- cgit v1.2.3-70-g09d2