[ 11/46] ipv6: dont stop backtracking in fib6_lookup_1 if subtree does not match

From: Greg Kroah-Hartman
Date: Thu Sep 12 2013 - 14:27:06 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 3e3be275851bc6fc90bfdcd732cd95563acd982b ]

In case a subtree did not match we currently stop backtracking and return
NULL (root table from fib_lookup). This could yield in invalid routing
table lookups when using subtrees.

Instead continue to backtrack until a valid subtree or node is found
and return this match.

Also remove unneeded NULL check.

Reported-by: Teco Boot <teco@xxxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Cc: David Lamparter <equinox@xxxxxxxxxx>
Cc: <boutier@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_fib.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -993,14 +993,22 @@ static struct fib6_node * fib6_lookup_1(

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);
+ if (fn->subtree) {
+ struct fib6_node *sfn;
+ sfn = fib6_lookup_1(fn->subtree,
+ args + 1);
+ if (!sfn)
+ goto backtrack;
+ fn = sfn;
+ }
#endif
- if (!fn || fn->fn_flags & RTN_RTINFO)
+ if (fn->fn_flags & RTN_RTINFO)
return fn;
}
}
-
+#ifdef CONFIG_IPV6_SUBTREES
+backtrack:
+#endif
if (fn->fn_flags & RTN_ROOT)
break;



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