netdev - [PATCH 7/7] ip_vti/ip6_vti: Preserve skb->mark after rcv

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Message-ID: <1432798090-20657-8-git-send-email-steffen.klassert@secunet.com>
Date:	Thu, 28 May 2015 09:28:10 +0200
From:	Steffen Klassert <steffen.klassert@...unet.com>
To:	David Miller <davem@...emloft.net>
CC:	Herbert Xu <herbert@...dor.apana.org.au>,
	Steffen Klassert <steffen.klassert@...unet.com>,
	<netdev@...r.kernel.org>
Subject: [PATCH 7/7] ip_vti/ip6_vti: Preserve skb->mark after rcv_cb call

From: Alexander Duyck <alexander.h.duyck@...hat.com>

The vti6_rcv_cb and vti_rcv_cb calls were leaving the skb->mark modified
after completing the function.  This resulted in the original skb->mark
value being lost.  Since we only need skb->mark to be set for
xfrm_policy_check we can pull the assignment into the rcv_cb calls and then
just restore the original mark after xfrm_policy_check has been completed.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...hat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/ipv4/ip_vti.c  | 9 +++++++--
 net/ipv6/ip6_vti.c | 9 +++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 4c318e1..0c15208 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -65,7 +65,6 @@ static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
 			goto drop;
 
 		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
-		skb->mark = be32_to_cpu(tunnel->parms.i_key);
 
 		return xfrm_input(skb, nexthdr, spi, encap_type);
 	}
@@ -91,6 +90,8 @@ static int vti_rcv_cb(struct sk_buff *skb, int err)
 	struct pcpu_sw_netstats *tstats;
 	struct xfrm_state *x;
 	struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
+	u32 orig_mark = skb->mark;
+	int ret;
 
 	if (!tunnel)
 		return 1;
@@ -107,7 +108,11 @@ static int vti_rcv_cb(struct sk_buff *skb, int err)
 	x = xfrm_input_state(skb);
 	family = x->inner_mode->afinfo->family;
 
-	if (!xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family))
+	skb->mark = be32_to_cpu(tunnel->parms.i_key);
+	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
+	skb->mark = orig_mark;
+
+	if (!ret)
 		return -EPERM;
 
 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 104de4d..ff3bd86 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -322,7 +322,6 @@ static int vti6_rcv(struct sk_buff *skb)
 		}
 
 		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
-		skb->mark = be32_to_cpu(t->parms.i_key);
 
 		rcu_read_unlock();
 
@@ -342,6 +341,8 @@ static int vti6_rcv_cb(struct sk_buff *skb, int err)
 	struct pcpu_sw_netstats *tstats;
 	struct xfrm_state *x;
 	struct ip6_tnl *t = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6;
+	u32 orig_mark = skb->mark;
+	int ret;
 
 	if (!t)
 		return 1;
@@ -358,7 +359,11 @@ static int vti6_rcv_cb(struct sk_buff *skb, int err)
 	x = xfrm_input_state(skb);
 	family = x->inner_mode->afinfo->family;
 
-	if (!xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family))
+	skb->mark = be32_to_cpu(t->parms.i_key);
+	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
+	skb->mark = orig_mark;
+
+	if (!ret)
 		return -EPERM;
 
 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(skb->dev)));
-- 
1.9.1

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