On Wed, 2018-01-24 at 08:29 -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 <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;
> + }
Note that since you have to take a branch, you can move the
err = -ENETDOWN inside the branch.
The trick of setting err before doing :
if (cond)
goto xxxx;
Is only relevant if the goto is naked.
By looking at your patch without more context, it is not clear that the
"err = -ENETDOWN" has no side effect.
