[IPV6] ROUTE: Fix looking up a route on subtree.

Even on RTN_ROOT node, we need to process its subtree first.
Fix NULL pointer dereference in fib6_locate().

Based on MIPL2 kernel patch.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Ville Nuorvala <vnuorval@tcs.hut.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 24 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 35b91ff95db2..5408b64f3b5f 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -850,33 +850,26 @@ static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
                 break;
         }
 
-        while ((fn->fn_flags & RTN_ROOT) == 0) {
-#ifdef CONFIG_IPV6_SUBTREES
-                if (fn->subtree) {
-                        struct fib6_node *st;
-                        struct lookup_args *narg;
-
-                        narg = args + 1;
-
-                        if (narg->addr) {
-                                st = fib6_lookup_1(fn->subtree, narg);
-
-                                if (st && !(st->fn_flags & RTN_ROOT))
-                                        return st;
-                        }
-                }
-#endif
-
-                if (fn->fn_flags & RTN_RTINFO) {
+        while(fn) {
+                if (SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
                         struct rt6key *key;
 
                         key = (struct rt6key *) ((u8 *) fn->leaf +
                                                  args->offset);
 
-                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen))
-                                return fn;
+                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
+#ifdef CONFIG_IPV6_SUBTREES
+                                if (fn->subtree)
+                                        fn = fib6_lookup_1(fn->subtree, args + 1);
+#endif
+                                if (!fn || fn->fn_flags & RTN_RTINFO)
+                                        return fn;
+                        }
                 }
 
+                if (fn->fn_flags & RTN_ROOT)
+                        break;
+
                 fn = fn->parent;
         }
 
@@ -953,10 +946,8 @@ struct fib6_node * fib6_locate(struct fib6_node *root,
 #ifdef CONFIG_IPV6_SUBTREES
         if (src_len) {
                 BUG_TRAP(saddr!=NULL);
-                if (fn == NULL)
-                        fn = fn->subtree;
-                if (fn)
-                        fn = fib6_locate_1(fn, saddr, src_len,
+                if (fn && fn->subtree)
+                        fn = fib6_locate_1(fn->subtree, saddr, src_len,
                                            offsetof(struct rt6_info, rt6i_src));
         }
 #endif