net: ipv6: addr: perform strict checks also for doit handlers

Make RTM_GETADDR's doit handler use strict checks when
NETLINK_F_STRICT_CHK is set.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -5179,6 +5179,52 @@ static int inet6_dump_ifacaddr(struct sk_buff *skb, struct netlink_callback *cb)
 	return inet6_dump_addr(skb, cb, type);
 }
 
+static int inet6_rtm_valid_getaddr_req(struct sk_buff *skb,
+				       const struct nlmsghdr *nlh,
+				       struct nlattr **tb,
+				       struct netlink_ext_ack *extack)
+{
+	struct ifaddrmsg *ifm;
+	int i, err;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid header for get address request");
+		return -EINVAL;
+	}
+
+	ifm = nlmsg_data(nlh);
+	if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get address request");
+		return -EINVAL;
+	}
+
+	if (!netlink_strict_get_check(skb))
+		return nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX,
+				   ifa_ipv6_policy, extack);
+
+	err = nlmsg_parse_strict(nlh, sizeof(*ifm), tb, IFA_MAX,
+				 ifa_ipv6_policy, extack);
+	if (err)
+		return err;
+
+	for (i = 0; i <= IFA_MAX; i++) {
+		if (!tb[i])
+			continue;
+
+		switch (i) {
+		case IFA_TARGET_NETNSID:
+		case IFA_ADDRESS:
+		case IFA_LOCAL:
+			break;
+		default:
+			NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get address request");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 			     struct netlink_ext_ack *extack)
 {
@@ -5199,8 +5245,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 	struct sk_buff *skb;
 	int err;
 
-	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy,
-			  extack);
+	err = inet6_rtm_valid_getaddr_req(in_skb, nlh, tb, extack);
 	if (err < 0)
 		return err;