net: mpls: route: perform strict checks also for doit handlers

Make RTM_GETROUTE'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>

1 files changed, 59 insertions, 2 deletions

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 7d55d4c04088..733c86db551b 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -2236,6 +2236,64 @@ errout:
                 rtnl_set_sk_err(net, RTNLGRP_MPLS_ROUTE, err);
 }
 
+static int mpls_valid_getroute_req(struct sk_buff *skb,
+                                   const struct nlmsghdr *nlh,
+                                   struct nlattr **tb,
+                                   struct netlink_ext_ack *extack)
+{
+        struct rtmsg *rtm;
+        int i, err;
+
+        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
+                NL_SET_ERR_MSG_MOD(extack,
+                                   "Invalid header for get route request");
+                return -EINVAL;
+        }
+
+        if (!netlink_strict_get_check(skb))
+                return nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX,
+                                   rtm_mpls_policy, extack);
+
+        rtm = nlmsg_data(nlh);
+        if ((rtm->rtm_dst_len && rtm->rtm_dst_len != 20) ||
+            rtm->rtm_src_len || rtm->rtm_tos || rtm->rtm_table ||
+            rtm->rtm_protocol || rtm->rtm_scope || rtm->rtm_type) {
+                NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get route request");
+                return -EINVAL;
+        }
+        if (rtm->rtm_flags & ~RTM_F_FIB_MATCH) {
+                NL_SET_ERR_MSG_MOD(extack,
+                                   "Invalid flags for get route request");
+                return -EINVAL;
+        }
+
+        err = nlmsg_parse_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
+                                 rtm_mpls_policy, extack);
+        if (err)
+                return err;
+
+        if ((tb[RTA_DST] || tb[RTA_NEWDST]) && !rtm->rtm_dst_len) {
+                NL_SET_ERR_MSG_MOD(extack, "rtm_dst_len must be 20 for MPLS");
+                return -EINVAL;
+        }
+
+        for (i = 0; i <= RTA_MAX; i++) {
+                if (!tb[i])
+                        continue;
+
+                switch (i) {
+                case RTA_DST:
+                case RTA_NEWDST:
+                        break;
+                default:
+                        NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get route request");
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
 static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
                          struct netlink_ext_ack *extack)
 {
@@ -2255,8 +2313,7 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
         u8 n_labels;
         int err;
 
-        err = nlmsg_parse(in_nlh, sizeof(*rtm), tb, RTA_MAX,
-                          rtm_mpls_policy, extack);
+        err = mpls_valid_getroute_req(in_skb, in_nlh, tb, extack);
         if (err < 0)
                 goto errout;