From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guillaume Nault , "David S . Miller" , Sasha Levin Subject: [PATCH AUTOSEL 4.4 45/65] l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv() Date: Thu, 25 Oct 2018 10:16:45 -0400 Message-Id: <20181025141705.213937-45-sashal@kernel.org> In-Reply-To: <20181025141705.213937-1-sashal@kernel.org> References: <20181025141705.213937-1-sashal@kernel.org> List-ID: From: Guillaume Nault [ 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- 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 @@ 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 bcdab1cba773..5fe0a6f6af3d 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -196,14 +196,15 @@ static int l2tp_ip6_recv(struct sk_buff *skb) 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