netdev - Re: [PATCH net] net/ipv6: Fix route leaking between VRFs

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Date:   Fri, 30 Mar 2018 14:24:38 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     dsahern@...il.com
Cc:     netdev@...r.kernel.org, sharpd@...ulusnetworks.com
Subject: Re: [PATCH net] net/ipv6: Fix route leaking between VRFs

From: David Ahern <dsahern@...il.com>
Date: Thu, 29 Mar 2018 17:44:57 -0700

> Donald reported that IPv6 route leaking between VRFs is not working.
> The root cause is the strict argument in the call to rt6_lookup when
> validating the nexthop spec.
> 
> ip6_route_check_nh validates the gateway and device (if given) of a
> route spec. It in turn could call rt6_lookup (e.g., lookup in a given
> table did not succeed so it falls back to a full lookup) and if so
> sets the strict argument to 1. That means if the egress device is given,
> the route lookup needs to return a result with the same device. This
> strict requirement does not work with VRFs (IPv4 or IPv6) because the
> oif in the flow struct is overridden with the index of the VRF device
> to trigger a match on the l3mdev rule and force the lookup to its table.
> 
> The right long term solution is to add an l3mdev index to the flow
> struct such that the oif is not overridden. That solution will not
> backport well, so this patch aims for a simpler solution to relax the
> strict argument if the route spec device is an l3mdev slave. As done
> in other places, use the FLOWI_FLAG_SKIP_NH_OIF to know that the
> RT6_LOOKUP_F_IFACE flag needs to be removed.
> 
> Reported-by: Donald Sharp <sharpd@...ulusnetworks.com>
> Signed-off-by: David Ahern <dsahern@...il.com>

Applied, with fixes tag added, and queued up for -stable.

Thanks.