[PATCH v2 net-next 1/2] ipv6: do not set routes if disable_ipv6 has been enabled

[Lorenzo Bianconi]

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.bianc...@redhat.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