[ 067/143] ipv6: dont stop backtracking in fib6_lookup_1 if subtree does not

Willy Tarreau
2014-05-12T01:59:00Z

match

From: Hannes Frederic Sowa <hannes@stressinduktion.org>

[ 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@inf-net.nl>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: David Lamparter <equinox@diac24.net>
Cc: <boutier@pps.univ-paris-diderot.fr>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/ipv6/ip6_fib.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 0e93ca5..0a36d8d 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -846,14 +846,22 @@ static struct fib6_node * fib6_lookup_1(struct fib6_node *root,

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;

--
1.7.12.2.21.g234cd45.dirty