ip_vti/ip6_vti: Preserve skb->mark after rcv_cb call

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@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

2 files changed, 14 insertions, 4 deletions

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 4c318e1c13c8..0c152087ca15 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 104de4da3ff3..ff3bd863fa03 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)));