4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: David Ahern <dsah...@gmail.com> [ Upstream commit b6cdbc85234b072340b8923e69f49ec293f905dc ] 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. Fixes: ca254490c8df ("net: Add VRF support to IPv6 stack") Reported-by: Donald Sharp <sha...@cumulusnetworks.com> Signed-off-by: David Ahern <dsah...@gmail.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- net/ipv6/route.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -856,6 +856,9 @@ static struct rt6_info *ip6_pol_route_lo struct fib6_node *fn; struct rt6_info *rt; + if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) + flags &= ~RT6_LOOKUP_F_IFACE; + read_lock_bh(&table->tb6_lock); fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr); restart: