net/ipv6: Handle reject routes with onlink flag

Verification of nexthops with onlink flag need to handle unreachable
routes. The lookup is only intended to validate the gateway address
is not a local address and if the gateway resolves the egress device
must match the given device. Hence, hitting any default reject route
is ok.

Fixes: fc1e64e1092f ("net/ipv6: Add support for onlink flag")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index fb2d251c0500..69c43d289c69 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2488,7 +2488,8 @@ static int ip6_route_check_nh_onlink(struct net *net,
         err = 0;
         grt = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0);
         if (grt) {
-                if (grt->rt6i_flags & flags || dev != grt->dst.dev) {
+                if (!grt->dst.error &&
+                    (grt->rt6i_flags & flags || dev != grt->dst.dev)) {
                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
                         err = -EINVAL;
                 }