This Linux kernel change "ipv4: Return error for RTA_VIA attribute" is included in the Linux 5.0 release. This change is authored by David Ahern <dsahern [at] gmail.com> on Tue Feb 26 09:00:02 2019 -0800. The commit for this change in Linux stable tree is b6e9e5d (patch).
ipv4: Return error for RTA_VIA attribute 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 <[email protected]> Signed-off-by: David S. Miller <[email protected]>
There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
net/ipv4/fib_frontend.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index fe4f6a6..ed14ec2 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -710,6 +710,10 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, 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;