netdev - [PATCH v2 net-next 1/2] ipv6: do not set routes if disable

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Date:   Thu, 29 Mar 2018 11:02:24 +0200
From:   Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: [PATCH v2 net-next 1/2] ipv6: do not set routes if disable_ipv6 has been enabled

Do not allow setting ipv6 routes from userspace if disable_ipv6 has been
enabled. The issue can be triggered using the following reproducer:

- sysctl net.ipv6.conf.all.disable_ipv6=1
- ip -6 route add a:b:c:d::/64 dev em1
- ip -6 route show
  a:b:c:d::/64 dev em1 metric 1024 pref medium

Fix it checking disable_ipv6 value in ip6_route_info_create routine

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
---
 net/ipv6/route.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ba8d5df50ebe..e461ef1158b6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2917,6 +2917,12 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
 	if (!dev)
 		goto out;
 
+	if (idev->cnf.disable_ipv6) {
+		NL_SET_ERR_MSG(extack, "IPv6 is disabled on nexthop device");
+		err = -EACCES;
+		goto out;
+	}
+
 	if (!(dev->flags & IFF_UP)) {
 		NL_SET_ERR_MSG(extack, "Nexthop device is not up");
 		err = -ENETDOWN;
-- 
2.14.3