netlink: Check for NULL return from npt_alloc()

Reviewed by: glebius, pouria
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D57171

sys/netlink/netlink_message_parser.c

@@ -122,6 +122,8 @@ nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val)
 {
 	struct nlattr *nla = npt_alloc(npt, sizeof(*nla) + sizeof(uint32_t));
 
+	if (nla == NULL)
+		return;
 	nla->nla_type = NLMSGERR_ATTR_COOKIE;
 	nla->nla_len = sizeof(*nla) + sizeof(uint32_t);
 	memcpy(nla + 1, &val, sizeof(uint32_t));

sys/netlink/route/iface_drivers.c

@@ -155,6 +155,9 @@ _nl_store_ifp_cookie(struct nl_pstate *npt, struct ifnet *ifp)
 		sizeof(ifindex) + NL_ITEM_ALIGN(ifname_len + 1);
 	struct nlattr *nla_cookie = npt_alloc(npt, nla_len);
 
+	if (nla_cookie == NULL)
+		return;
+
 	/* Nested TLV */
 	nla_cookie->nla_len = nla_len;
 	nla_cookie->nla_type = NLMSGERR_ATTR_COOKIE;

sys/netlink/route/rt.c

@@ -896,6 +896,10 @@ create_nexthop_from_attrs(struct nl_parsed_route *attrs,
 		int num_nhops = attrs->rta_multipath->num_nhops;
 		struct weightened_nhop *wn = npt_alloc(npt, sizeof(*wn) * num_nhops);
 
+		if (wn == NULL) {
+			*perror = ENOMEM;
+			return (NULL);
+		}
 		for (int i = 0; i < num_nhops; i++) {
 			struct rta_mpath_nh *mpnh = &attrs->rta_multipath->nhops[i];