ipsec: Fix dst leak in xfrm_bundle_create().

[David Miller]

If we cannot find a suitable inner_mode value, we will leak
the currently allocated 'xdst'.

The fix is to make sure it is linked into the chain before
erroring out.

Signed-off-by: David S. Miller <da...@davemloft.net>
---

Steffen, I found this via visual inspection.  Please double check my
work before applying this :-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index f06253969972..2746b62a8944 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1573,6 +1573,14 @@ static struct dst_entry *xfrm_bundle_create(struct 
xfrm_policy *policy,
                        goto put_states;
                }
 
+               if (!dst_prev)
+                       dst0 = dst1;
+               else
+                       /* Ref count is taken during xfrm_alloc_dst()
+                        * No need to do dst_clone() on dst1
+                        */
+                       dst_prev->child = dst1;
+
                if (xfrm[i]->sel.family == AF_UNSPEC) {
                        inner_mode = xfrm_ip2inner_mode(xfrm[i],
                                                        xfrm_af2proto(family));
@@ -1584,14 +1592,6 @@ static struct dst_entry *xfrm_bundle_create(struct 
xfrm_policy *policy,
                } else
                        inner_mode = xfrm[i]->inner_mode;
 
-               if (!dst_prev)
-                       dst0 = dst1;
-               else
-                       /* Ref count is taken during xfrm_alloc_dst()
-                        * No need to do dst_clone() on dst1
-                        */
-                       dst_prev->child = dst1;
-
                xdst->route = dst;
                dst_copy_metrics(dst1, dst);