1 files changed, 122 insertions, 20 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 0113993..5bf653f 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -315,6 +315,32 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb)
 	return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 }
 
+bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
+{
+	bool dev_match = false;
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+	int ret;
+
+	for (ret = 0; ret < fi->fib_nhs; ret++) {
+		struct fib_nh *nh = &fi->fib_nh[ret];
+
+		if (nh->nh_dev == dev) {
+			dev_match = true;
+			break;
+		} else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
+			dev_match = true;
+			break;
+		}
+	}
+#else
+	if (fi->fib_nh[0].nh_dev == dev)
+		dev_match = true;
+#endif
+
+	return dev_match;
+}
+EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
+
 /* Given (packet source, input interface) and optional (dst, oif, tos):
  * - (main) check, that source is valid i.e. not broadcast or our local
  *   address.
@@ -361,24 +387,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	    (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
 		goto e_inval;
 	fib_combine_itag(itag, &res);
-	dev_match = false;
 
-#ifdef CONFIG_IP_ROUTE_MULTIPATH
-	for (ret = 0; ret < res.fi->fib_nhs; ret++) {
-		struct fib_nh *nh = &res.fi->fib_nh[ret];
-
-		if (nh->nh_dev == dev) {
-			dev_match = true;
-			break;
-		} else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
-			dev_match = true;
-			break;
-		}
-	}
-#else
-	if (FIB_RES_DEV(res) == dev)
-		dev_match = true;
-#endif
+	dev_match = fib_info_nh_uses_dev(res.fi, dev);
 	if (dev_match) {
 		ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 		return ret;
@@ -792,19 +802,111 @@ errout:
 	return err;
 }
 
+int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
+			  struct fib_dump_filter *filter,
+			  struct netlink_callback *cb)
+{
+	struct netlink_ext_ack *extack = cb->extack;
+	struct nlattr *tb[RTA_MAX + 1];
+	struct rtmsg *rtm;
+	int err, i;
+
+	ASSERT_RTNL();
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
+		NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
+		return -EINVAL;
+	}
+
+	rtm = nlmsg_data(nlh);
+	if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
+	    rtm->rtm_scope) {
+		NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
+		return -EINVAL;
+	}
+	if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
+		NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
+		return -EINVAL;
+	}
+
+	filter->flags    = rtm->rtm_flags;
+	filter->protocol = rtm->rtm_protocol;
+	filter->rt_type  = rtm->rtm_type;
+	filter->table_id = rtm->rtm_table;
+
+	err = nlmsg_parse_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
+				 rtm_ipv4_policy, extack);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i <= RTA_MAX; ++i) {
+		int ifindex;
+
+		if (!tb[i])
+			continue;
+
+		switch (i) {
+		case RTA_TABLE:
+			filter->table_id = nla_get_u32(tb[i]);
+			break;
+		case RTA_OIF:
+			ifindex = nla_get_u32(tb[i]);
+			filter->dev = __dev_get_by_index(net, ifindex);
+			if (!filter->dev)
+				return -ENODEV;
+			break;
+		default:
+			NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
+			return -EINVAL;
+		}
+	}
+
+	if (filter->flags || filter->protocol || filter->rt_type ||
+	    filter->table_id || filter->dev) {
+		filter->filter_set = 1;
+		cb->answer_flags = NLM_F_DUMP_FILTERED;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
+
 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
+	struct fib_dump_filter filter = {};
 	unsigned int h, s_h;
 	unsigned int e = 0, s_e;
 	struct fib_table *tb;
 	struct hlist_head *head;
 	int dumped = 0, err;
 
-	if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
-	    ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
+	if (cb->strict_check) {
+		err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
+		if (err < 0)
+			return err;
+	} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
+		struct rtmsg *rtm = nlmsg_data(nlh);
+
+		filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
+	}
+
+	/* fib entries are never clones and ipv4 does not use prefix flag */
+	if (filter.flags & (RTM_F_PREFIX | RTM_F_CLONED))
 		return skb->len;
 
+	if (filter.table_id) {
+		tb = fib_get_table(net, filter.table_id);
+		if (!tb) {
+			NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
+			return -ENOENT;
+		}
+
+		err = fib_table_dump(tb, skb, cb, &filter);
+		return skb->len ? : err;
+	}
+
 	s_h = cb->args[0];
 	s_e = cb->args[1];
 
@@ -819,7 +921,7 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 			if (dumped)
 				memset(&cb->args[2], 0, sizeof(cb->args) -
 						 2 * sizeof(cb->args[0]));
-			err = fib_table_dump(tb, skb, cb);
+			err = fib_table_dump(tb, skb, cb, &filter);
 			if (err < 0) {
 				if (likely(skb->len))
 					goto out;