selinux/nlmsg: add a build time check for rtnl/xfrm cmds

When a new rtnl or xfrm command is added, this part of the code is frequently
missing. Let's help the developer with a build time test.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

security/selinux/nlmsgtab.c

@@ -153,6 +153,8 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
 
 	switch (sclass) {
 	case SECCLASS_NETLINK_ROUTE_SOCKET:
+		/* RTM_MAX always point to RTM_SETxxxx, ie RTM_NEWxxx + 3 */
+		BUILD_BUG_ON(RTM_MAX != (RTM_NEWNSID + 3));
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
 				 sizeof(nlmsg_route_perms));
 		break;
@@ -163,6 +165,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
 		break;
 
 	case SECCLASS_NETLINK_XFRM_SOCKET:
+		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MAPPING);
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
 				 sizeof(nlmsg_xfrm_perms));
 		break;