Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751881AbdFHCZT (ORCPT ); Wed, 7 Jun 2017 22:25:19 -0400 Received: from slow1-d.mail.gandi.net ([217.70.178.86]:36019 "EHLO slow1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751203AbdFHCZR (ORCPT ); Wed, 7 Jun 2017 22:25:17 -0400 X-Originating-IP: 74.125.82.52 MIME-Version: 1.0 In-Reply-To: <1496883476-17445-1-git-send-email-yanhaishuang@cmss.chinamobile.com> References: <1496883476-17445-1-git-send-email-yanhaishuang@cmss.chinamobile.com> From: Pravin Shelar Date: Wed, 7 Jun 2017 19:13:42 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv To: Haishuang Yan Cc: "=David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , Linux Kernel Network Developers , linux-kernel@vger.kernel.org, Pravin B Shelar , Haishuang Yan Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1506 Lines: 45 On Wed, Jun 7, 2017 at 5:57 PM, Haishuang Yan wrote: > When ip_tunnel_rcv fails, the tun_dst won't be freed, so move > skb_dst_set to begin and tun_dst would be freed by kfree_skb. > > CC: Pravin B Shelar > Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.") > Signed-off-by: Haishuang Yan > --- > net/ipv4/ip_tunnel.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c > index b878ecb..27fc20f 100644 > --- a/net/ipv4/ip_tunnel.c > +++ b/net/ipv4/ip_tunnel.c > @@ -386,6 +386,9 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb, > const struct iphdr *iph = ip_hdr(skb); > int err; > > + if (tun_dst) > + skb_dst_set(skb, (struct dst_entry *)tun_dst); > + If dst is set so early, skb_scrub_packet() would remove the tunnel dst reference. It is better to call skb_dst_drop() from error code path. > #ifdef CONFIG_NET_IPGRE_BROADCAST > if (ipv4_is_multicast(iph->daddr)) { > tunnel->dev->stats.multicast++; > @@ -439,9 +442,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb, > skb->dev = tunnel->dev; > } > > - if (tun_dst) > - skb_dst_set(skb, (struct dst_entry *)tun_dst); > - > gro_cells_receive(&tunnel->gro_cells, skb); > return 0; > > -- > 1.8.3.1 > > >