[PATCH 4.20 53/76] mpls: Return error for RTA_GATEWAY attribute

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Ahern <dsahern@xxxxxxxxx>

[ Upstream commit be48220edd48ca0d569782992840488a52373a24 ]

MPLS does not support nexthops with an MPLS address family.
Specifically, it does not handle RTA_GATEWAY attribute. Make it
clear by returning an error.

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/mpls/af_mpls.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -1838,6 +1838,9 @@ static int rtm_to_route_config(struct sk
 				goto errout;
 			break;
 		}
+		case RTA_GATEWAY:
+			NL_SET_ERR_MSG(extack, "MPLS does not support RTA_GATEWAY attribute");
+			goto errout;
 		case RTA_VIA:
 		{
 			if (nla_get_via(nla, &cfg->rc_via_alen,