From 044a832a7779c0638bea2d0fea901c055b995f4a Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Mon, 12 Jan 2015 13:38:49 +0100
Subject: [PATCH] xfrm: Fix local error reporting crash with interfamily
 tunnels

We set the outer mode protocol too early. As a result, the
local error handler might dispatch to the wrong address family
and report the error to a wrong socket type. We fix this by
setting the outer protocol to the skb after we accessed the
inner mode for the last time, right before we do the atcual
encapsulation where we switch finally to the outer mode.

Reported-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Tested-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/xfrm4_output.c | 2 +-
 net/ipv6/xfrm6_output.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index d5f6bd9a210a..dab73813cb92 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -63,6 +63,7 @@ int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 		return err;
 
 	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
+	skb->protocol = htons(ETH_P_IP);
 
 	return x->outer_mode->output2(x, skb);
 }
@@ -71,7 +72,6 @@ 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;
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index ca3f29b98ae5..010f8bd2d577 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -114,6 +114,7 @@ int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 		return err;
 
 	skb->ignore_df = 1;
+	skb->protocol = htons(ETH_P_IPV6);
 
 	return x->outer_mode->output2(x, skb);
 }
@@ -122,7 +123,6 @@ 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;
-- 
2.34.1