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

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

[David Ahern]

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@gmail.com>
---
 net/ipv6/route.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f85da2f1e729..689670713744 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2734,6 +2734,11 @@ 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");
+		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

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

[Roopa Prabhu]

On Tue, Jan 23, 2018 at 7:13 PM, David Ahern <dsahern@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 <dsahern@gmail.com>
> ---
>  net/ipv6/route.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index f85da2f1e729..689670713744 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -2734,6 +2734,11 @@ 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");
> +               goto out;
> +       }

looks like it will need a -ENETDOWN too ?



> +
>         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
>

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

[Ido Schimmel]

On Tue, Jan 23, 2018 at 07:13:43PM -0800, David Ahern 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@gmail.com>

I figured people might complain if I change that, but I obviously prefer
to have it like IPv4. Agree with Roopa about the error code.

Thanks