[XFRM]: Fix ordering issue in xfrm_dst_hash_transfer().

Keep ordering of policy entries with same selector in
xfrm_dst_hash_transfer().

Issue should not appear in usual cases because multiple policy entries
with same selector are basically not allowed so far.  Bug was pointed
out by Sebastien Decugis <sdecugis@hongo.wide.ad.jp>.

We could convert bydst from hlist to list and use list_add_tail()
instead.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Sebastien Decugis <sdecugis@hongo.wide.ad.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 47219f98053f86217027245dc81b42fbdf4d57e5..9fc4c315f6cd9702a223b5758d3f61e26c89808b 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -331,15 +331,31 @@ static void xfrm_dst_hash_transfer(struct hlist_head *list,
                                   struct hlist_head *ndsttable,
                                   unsigned int nhashmask)
 {
-       struct hlist_node *entry, *tmp;
+       struct hlist_node *entry, *tmp, *entry0 = NULL;
        struct xfrm_policy *pol;
+       unsigned int h0 = 0;
 
+redo:
        hlist_for_each_entry_safe(pol, entry, tmp, list, bydst) {
                unsigned int h;
 
                h = __addr_hash(&pol->selector.daddr, &pol->selector.saddr,
                                pol->family, nhashmask);
-               hlist_add_head(&pol->bydst, ndsttable+h);
+               if (!entry0) {
+                       hlist_del(entry);
+                       hlist_add_head(&pol->bydst, ndsttable+h);
+                       h0 = h;
+               } else {
+                       if (h != h0)
+                               continue;
+                       hlist_del(entry);
+                       hlist_add_after(entry0, &pol->bydst);
+               }
+               entry0 = entry;
+       }
+       if (!hlist_empty(list)) {
+               entry0 = NULL;
+               goto redo;
        }
 }