Patch "fib_trie: leaf_walk_rcu should not compute key if key is less than pn->key" has been added to the 4.2-stable tree

Patch "fib_trie: leaf_walk_rcu should not compute key if key is less than pn->key" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fib_trie: leaf_walk_rcu should not compute key if key is less than pn->key

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fib_trie-leaf_walk_rcu-should-not-compute-key-if-key-is-less-than-pn-key.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Tue Nov 17 14:34:38 PST 2015
From: Alexander Duyck <aduyck@mirantis.com>
Date: Tue, 27 Oct 2015 15:06:45 -0700
Subject: fib_trie: leaf_walk_rcu should not compute key if key is less than pn->key

From: Alexander Duyck <aduyck@mirantis.com>

[ Upstream commit c2229fe1430d4e1c70e36520229dd64a87802b20 ]

We were computing the child index in cases where the key value we were
looking for was actually less than the base key of the tnode.  As a result
we were getting incorrect index values that would cause us to skip over
some children.

To fix this I have added a test that will force us to use child index 0 if
the key we are looking for is less than the key of the current tnode.

Fixes: 8be33e955cb9 ("fib_trie: Fib walk rcu should take a tnode and key instead of a trie and a leaf")
Reported-by: Brian Rak <brak@gameservers.com>
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/fib_trie.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1561,7 +1561,7 @@ static struct key_vector *leaf_walk_rcu(
 	do {
 		/* record parent and next child index */
 		pn = n;
-		cindex = key ? get_index(key, pn) : 0;
+		cindex = (key > pn->key) ? get_index(key, pn) : 0;
 
 		if (cindex >> pn->bits)
 			break;


Patches currently in stable-queue which might be from aduyck@mirantis.com are

queue-4.2/fib_trie-leaf_walk_rcu-should-not-compute-key-if-key-is-less-than-pn-key.patch