netdev - Re: [PATCH v3 net-next] net/ipv6: Do not allow route add with a device that is down

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Date:   Thu, 25 Jan 2018 07:53:43 -0800
From:   Roopa Prabhu <roopa@...ulusnetworks.com>
To:     David Ahern <dsahern@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH v3 net-next] net/ipv6: Do not allow route add with a
 device that is down

On Wed, Jan 24, 2018 at 7:45 PM, David Ahern <dsahern@...il.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 <dsahern@...il.com>

Reviewed-by: Roopa Prabhu <roopa@...ulusnetworks.com>

> ---
> v3
> - moved err=-ENETDOWN under the if check per Eric's request
> - left the up check using dev->flags for consistency with IPv4
>   and that it is used more often in ipv4 and ivp6 code than
>   netif_running
>
> 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..aa4411c81e7e 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;
>
> +       if (!(dev->flags & IFF_UP)) {
> +               NL_SET_ERR_MSG(extack, "Nexthop device is not up");
> +               err = -ENETDOWN;
> +               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");
> --
> 2.11.0
>