[XFRM]: Fix crash introduced by struct dst_entry reordering

XFRM expects xfrm_dst->u.next to be same pointer as dst->next, which
was broken by the dst_entry reordering in commit 1e19e02c~, causing
an oops in xfrm_bundle_ok when walking the bundle upwards.

Kill xfrm_dst->u.next and change the only user to use dst->next instead.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 1 insertions, 2 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index ae959e950174..a5f80bfbaaa4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -585,7 +585,6 @@ static inline int xfrm_sec_ctx_match(struct xfrm_sec_ctx *s1, struct xfrm_sec_ct
 struct xfrm_dst
 {
         union {
-                struct xfrm_dst         *next;
                 struct dst_entry        dst;
                 struct rtable           rt;
                 struct rt6_info         rt6;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 157bfbd250ba..b48f06fc9fd9 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2141,7 +2141,7 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
                 if (last == first)
                         break;
 
-                last = last->u.next;
+                last = (struct xfrm_dst *)last->u.dst.next;
                 last->child_mtu_cached = mtu;
         }