On 1/24/18 10:09 AM, Stephen Hemminger wrote:
> On Wed, 24 Jan 2018 08:29:24 -0800
> David Ahern <dsah...@gmail.com> wrote:
>
>> IPv6 allows routes to be installed when the device is not up (admin up).
>> Worse, it does not mark it as LINKDOWN. IPv4 does not allow it and really
>> there is no reason for IPv6 to allow it, so check the flags and deny if
>> device is admin down.
>>
>> Signed-off-by: David Ahern <dsah...@gmail.com>
>> ---
>> v2
>> - missed setting err to -ENETDOWN (thanks for catching that Roopa)
>>
>> net/ipv6/route.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>> index f85da2f1e729..4e8fab766018 100644
>> --- a/net/ipv6/route.c
>> +++ b/net/ipv6/route.c
>> @@ -2734,6 +2734,12 @@ static struct rt6_info *ip6_route_info_create(struct
>> fib6_config *cfg,
>> if (!dev)
>> goto out;
>>
>> + err = -ENETDOWN;
>> + if (!(dev->flags & IFF_UP)) {
>> + NL_SET_ERR_MSG(extack, "Nexthop device is not up");
>> + goto out;
>> + }
>> +
>> if (!ipv6_addr_any(&cfg->fc_prefsrc)) {
>> if (!ipv6_chk_addr(net, &cfg->fc_prefsrc, dev, 0)) {
>> NL_SET_ERR_MSG(extack, "Invalid source address");
>
> This looks like a good idea.
>
> There are two equal ways to check for admin up. Either the dev flags or
> look at link state via netif_running(). Maybe the latter would
> be better.
>
I used dev->flags for consistency with IPv4. Looking at use of
netif_running vs dev->flags in IPv4 and IPv6 code the flag is much more
prevalent.
