[3.16.y-ckt stable] Patch "netfilter: ipt_rpfilter: remove the nh_scope test in rpfilter_lookup_reverse" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    netfilter: ipt_rpfilter: remove the nh_scope test in rpfilter_lookup_reverse

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 626dcb656bdcaa4012e81fcb751775b2dbebab00 Mon Sep 17 00:00:00 2001
From: lucien <lucien.xin at gmail.com>
Date: Tue, 6 Oct 2015 21:03:07 +0800
Subject: netfilter: ipt_rpfilter: remove the nh_scope test in
 rpfilter_lookup_reverse

commit cc4998febd567d1c671684abce5595344bd4e8b2 upstream.

--accept-local  option works for res.type == RTN_LOCAL, which should be
from the local table, but there, the fib_info's nh->nh_scope =
RT_SCOPE_NOWHERE ( > RT_SCOPE_HOST). in fib_create_info().

	if (cfg->fc_scope == RT_SCOPE_HOST) {
		struct fib_nh *nh = fi->fib_nh;

		/* Local address is added. */
		if (nhs != 1 || nh->nh_gw)
			goto err_inval;
		nh->nh_scope = RT_SCOPE_NOWHERE;   <===
		nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
		err = -ENODEV;
		if (!nh->nh_dev)
			goto failure;

but in our rpfilter_lookup_reverse():

	if (dev_match || flags & XT_RPFILTER_LOOSE)
		return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;

if nh->nh_scope > RT_SCOPE_HOST, it will fail. --accept-local option
will never be passed.

it seems the test is bogus and can be removed to fix this issue.

	if (dev_match || flags & XT_RPFILTER_LOOSE)
		return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;

ipv6 does not have this issue.

Signed-off-by: Xin Long <lucien.xin at gmail.com>
Acked-by: Florian Westphal <fw at strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/netfilter/ipt_rpfilter.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c
index 4bfaedf9b34e..60f27b1e46f6 100644
--- a/net/ipv4/netfilter/ipt_rpfilter.c
+++ b/net/ipv4/netfilter/ipt_rpfilter.c
@@ -61,9 +61,7 @@ static bool rpfilter_lookup_reverse(struct flowi4 *fl4,
 	if (FIB_RES_DEV(res) == dev)
 		dev_match = true;
 #endif
-	if (dev_match || flags & XT_RPFILTER_LOOSE)
-		return FIB_RES_NH(res).nh_scope <= RT_SCOPE_HOST;
-	return dev_match;
+	return dev_match || flags & XT_RPFILTER_LOOSE;
 }

 static bool rpfilter_is_local(const struct sk_buff *skb)