[IPSEC]: Policy list disorder

The recent hashing introduced an off-by-one bug in policy list insertion.
Instead of adding after the last entry with a lesser or equal priority,
we're adding after the successor of that entry.

This patch fixes this and also adds a warning if we detect a duplicate
entry in the policy list.  This should never happen due to this if clause.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 11 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index bebd40e5a62e..b7e537fe2d75 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -650,19 +650,18 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
         struct xfrm_policy *pol;
         struct xfrm_policy *delpol;
         struct hlist_head *chain;
-        struct hlist_node *entry, *newpos, *last;
+        struct hlist_node *entry, *newpos;
         struct dst_entry *gc_list;
 
         write_lock_bh(&xfrm_policy_lock);
         chain = policy_hash_bysel(&policy->selector, policy->family, dir);
         delpol = NULL;
         newpos = NULL;
-        last = NULL;
         hlist_for_each_entry(pol, entry, chain, bydst) {
-                if (!delpol &&
-                    pol->type == policy->type &&
+                if (pol->type == policy->type &&
                     !selector_cmp(&pol->selector, &policy->selector) &&
-                    xfrm_sec_ctx_match(pol->security, policy->security)) {
+                    xfrm_sec_ctx_match(pol->security, policy->security) &&
+                    !WARN_ON(delpol)) {
                         if (excl) {
                                 write_unlock_bh(&xfrm_policy_lock);
                                 return -EEXIST;
@@ -671,17 +670,12 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
                         if (policy->priority > pol->priority)
                                 continue;
                 } else if (policy->priority >= pol->priority) {
-                        last = &pol->bydst;
+                        newpos = &pol->bydst;
                         continue;
                 }
-                if (!newpos)
-                        newpos = &pol->bydst;
                 if (delpol)
                         break;
-                last = &pol->bydst;
         }
-        if (!newpos)
-                newpos = last;
         if (newpos)
                 hlist_add_after(newpos, &policy->bydst);
         else