--- /dev/null
+commit 5596732fa8c14139018ecda8356eabbfb599d830
+Author: Steffen Klassert <steffen.klassert@secunet.com>
+Date: Mon Apr 7 08:08:52 2014 +0200
+
+ xfrm: Fix crash with ipv6 IPsec tunnel and NAT.
+
+ The ipv6 xfrm output path is not aware that packets can be
+ rerouted by NAT to not use IPsec. We crash in this case
+ because we expect to have a xfrm state at the dst_entry.
+ This crash happens if the ipv6 layer does IPsec and NAT
+ or if we have an interfamily IPsec tunnel with ipv4 NAT.
+
+ We fix this by checking for a NAT rerouted packet in each
+ address family and dst_output() to the new destination
+ in this case.
+
+ Reported-by: Martin Pelikan <martin.pelikan@gmail.com>
+ Tested-by: Martin Pelikan <martin.pelikan@gmail.com>
+ Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
+
+--- a/net/ipv4/xfrm4_output.c
++++ b/net/ipv4/xfrm4_output.c
+@@ -62,10 +62,7 @@ int xfrm4_prepare_output(struct xfrm_sta
+ if (err)
+ return err;
+
+- memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+- IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;
+-
+- skb->protocol = htons(ETH_P_IP);
++ IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
+
+ return x->outer_mode->output2(x, skb);
+ }
+@@ -73,27 +70,34 @@ EXPORT_SYMBOL(xfrm4_prepare_output);
+
+ int xfrm4_output_finish(struct sk_buff *skb)
+ {
++ memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
++ skb->protocol = htons(ETH_P_IP);
++
++#ifdef CONFIG_NETFILTER
++ IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
++#endif
++
++ return xfrm_output(skb);
++}
++
++static int __xfrm4_output(struct sk_buff *skb)
++{
++ struct xfrm_state *x = skb_dst(skb)->xfrm;
++
+ #ifdef CONFIG_NETFILTER
+- if (!skb_dst(skb)->xfrm) {
++ if (!x) {
+ IPCB(skb)->flags |= IPSKB_REROUTED;
+ return dst_output(skb);
+ }
+-
+- IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+ #endif
+
+- skb->protocol = htons(ETH_P_IP);
+- return xfrm_output(skb);
++ return x->outer_mode->afinfo->output_finish(skb);
+ }
+
+ int xfrm4_output(struct sk_buff *skb)
+ {
+- struct dst_entry *dst = skb_dst(skb);
+- struct xfrm_state *x = dst->xfrm;
+-
+ return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
+- NULL, dst->dev,
+- x->outer_mode->afinfo->output_finish,
++ NULL, skb_dst(skb)->dev, __xfrm4_output,
+ !(IPCB(skb)->flags & IPSKB_REROUTED));
+ }
+
+--- a/net/ipv6/xfrm6_output.c
++++ b/net/ipv6/xfrm6_output.c
+@@ -114,12 +114,6 @@ int xfrm6_prepare_output(struct xfrm_sta
+ if (err)
+ return err;
+
+- memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
+-#ifdef CONFIG_NETFILTER
+- IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
+-#endif
+-
+- skb->protocol = htons(ETH_P_IPV6);
+ skb->local_df = 1;
+
+ return x->outer_mode->output2(x, skb);
+@@ -128,11 +122,13 @@ EXPORT_SYMBOL(xfrm6_prepare_output);
+
+ int xfrm6_output_finish(struct sk_buff *skb)
+ {
++ memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
++ skb->protocol = htons(ETH_P_IPV6);
++
+ #ifdef CONFIG_NETFILTER
+ IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
+ #endif
+
+- skb->protocol = htons(ETH_P_IPV6);
+ return xfrm_output(skb);
+ }
+
+@@ -142,6 +138,13 @@ static int __xfrm6_output(struct sk_buff
+ struct xfrm_state *x = dst->xfrm;
+ int mtu;
+
++#ifdef CONFIG_NETFILTER
++ if (!x) {
++ IP6CB(skb)->flags |= IP6SKB_REROUTED;
++ return dst_output(skb);
++ }
++#endif
++
+ if (skb->protocol == htons(ETH_P_IPV6))
+ mtu = ip6_skb_dst_mtu(skb);
+ else
+@@ -165,6 +168,7 @@ static int __xfrm6_output(struct sk_buff
+
+ int xfrm6_output(struct sk_buff *skb)
+ {
+- return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
+- skb_dst(skb)->dev, __xfrm6_output);
++ return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb,
++ NULL, skb_dst(skb)->dev, __xfrm6_output,
++ !(IP6CB(skb)->flags & IP6SKB_REROUTED));
+ }