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>

diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index d5f6bd9a210ab93ed27177ecffc9499259dbe999..dab73813cb9208dafaae1277e281c2255601a771 100644 (file)
--- 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 ca3f29b98ae5d76b7e69c38f617362a90fd9fd04..010f8bd2d577f9767d7d44182b246e62f4a118f6 100644 (file)
--- 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;