From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934836AbcKMLcu (ORCPT ); Sun, 13 Nov 2016 06:32:50 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36382 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934822AbcKML3h (ORCPT ); Sun, 13 Nov 2016 06:29:37 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shmulik Ladkani , Daniel Borkmann , Pravin Shelar , Jiri Pirko , "David S. Miller" Subject: [PATCH 4.8 03/35] net/sched: act_vlan: Push skb->data to mac_header prior calling skb_vlan_*() functions Date: Sun, 13 Nov 2016 12:27:17 +0100 Message-Id: <20161113112420.992984055@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161113112420.863033770@linuxfoundation.org> References: <20161113112420.863033770@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shmulik Ladkani [ Upstream commit f39acc84aad10710e89835c60d3b6694c43a8dd9 ] Generic skb_vlan_push/skb_vlan_pop functions don't properly handle the case where the input skb data pointer does not point at the mac header: - They're doing push/pop, but fail to properly unwind data back to its original location. For example, in the skb_vlan_push case, any subsequent 'skb_push(skb, skb->mac_len)' calls make the skb->data point 4 bytes BEFORE start of frame, leading to bogus frames that may be transmitted. - They update rcsum per the added/removed 4 bytes tag. Alas if data is originally after the vlan/eth headers, then these bytes were already pulled out of the csum. OTOH calling skb_vlan_push/skb_vlan_pop with skb->data at mac_header present no issues. act_vlan is the only caller to skb_vlan_*() that has skb->data pointing at network header (upon ingress). Other calles (ovs, bpf) already adjust skb->data at mac_header. This patch fixes act_vlan to point to the mac_header prior calling skb_vlan_*() functions, as other callers do. Signed-off-by: Shmulik Ladkani Cc: Daniel Borkmann Cc: Pravin Shelar Cc: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/act_vlan.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/net/sched/act_vlan.c +++ b/net/sched/act_vlan.c @@ -36,6 +36,12 @@ static int tcf_vlan(struct sk_buff *skb, bstats_update(&v->tcf_bstats, skb); action = v->tcf_action; + /* Ensure 'data' points at mac_header prior calling vlan manipulating + * functions. + */ + if (skb_at_tc_ingress(skb)) + skb_push_rcsum(skb, skb->mac_len); + switch (v->tcfv_action) { case TCA_VLAN_ACT_POP: err = skb_vlan_pop(skb); @@ -57,6 +63,9 @@ drop: action = TC_ACT_SHOT; v->tcf_qstats.drops++; unlock: + if (skb_at_tc_ingress(skb)) + skb_pull_rcsum(skb, skb->mac_len); + spin_unlock(&v->tcf_lock); return action; }