4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Ahern <dsahern@xxxxxxxxx> [ Upstream commit b6e9e5df4ecf100f6a10ab2ade8e46d47a4b9779 ] IPv4 currently does not support nexthops outside of the AF_INET family. Specifically, it does not handle RTA_VIA attribute. If it is passed in a route add request, the actual route added only uses the device which is clearly not what the user intended: $ ip ro add 172.16.1.0/24 via inet6 2001:db8:1::1 dev eth0 $ ip ro ls ... 172.16.1.0/24 dev eth0 Catch this and fail the route add: $ ip ro add 172.16.1.0/24 via inet6 2001:db8:1::1 dev eth0 Error: IPv4 does not support RTA_VIA attribute. Fixes: 03c0566542f4c ("mpls: Netlink commands to add, remove, and dump routes") Signed-off-by: David Ahern <dsahern@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/fib_frontend.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -700,6 +700,10 @@ static int rtm_to_fib_config(struct net case RTA_GATEWAY: cfg->fc_gw = nla_get_be32(attr); break; + case RTA_VIA: + NL_SET_ERR_MSG(extack, "IPv4 does not support RTA_VIA attribute"); + err = -EINVAL; + goto errout; case RTA_PRIORITY: cfg->fc_priority = nla_get_u32(attr); break;