From 7f5f07509a5b119829f65701458204f0273f05fc Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 24 Mar 2019 20:12:15 -0700
Subject: [PATCH] ircd::net::dns: Add utils to properly check for empty records
 in JSON.

---
 include/ircd/net/dns.h |  2 ++
 ircd/net.cc            | 16 ++++++++++++++++
 ircd/server.cc         |  2 +-
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/ircd/net/dns.h b/include/ircd/net/dns.h
index 5b337cbcb..4835e7ec4 100644
--- a/include/ircd/net/dns.h
+++ b/include/ircd/net/dns.h
@@ -33,6 +33,8 @@ namespace ircd::net::dns
 	// Utilities
 	bool is_error(const json::object &rr);
 	bool is_error(const json::array &rr);
+	bool is_empty(const json::object &rr);
+	bool is_empty(const json::array &rr);
 	time_t get_ttl(const json::object &rr);
 	bool expired(const json::object &rr, const time_t &rr_ts, const time_t &min_ttl);
 	bool expired(const json::object &rr, const time_t &rr_ts);
diff --git a/ircd/net.cc b/ircd/net.cc
index d9b315287..3db105b75 100644
--- a/ircd/net.cc
+++ b/ircd/net.cc
@@ -3456,6 +3456,22 @@ ircd::net::dns::get_ttl(const json::object &rr)
 	return rr.get<time_t>("ttl", 0L);
 }
 
+bool
+ircd::net::dns::is_empty(const json::array &rrs)
+{
+	return std::all_of(begin(rrs), end(rrs), []
+	(const json::object &rr)
+	{
+		return is_empty(rr);
+	});
+}
+
+bool
+ircd::net::dns::is_empty(const json::object &rr)
+{
+	return empty(rr) || (rr.has("ttl") && size(rr) == 1);
+}
+
 bool
 ircd::net::dns::is_error(const json::array &rrs)
 {
diff --git a/ircd/server.cc b/ircd/server.cc
index ea597a34c..c2493abe0 100644
--- a/ircd/server.cc
+++ b/ircd/server.cc
@@ -1080,7 +1080,7 @@ try
 	if(op_fini)
 		return;
 
-	if(empty(rrs))
+	if(net::dns::is_empty(rrs))
 	{
 		err_set(make_exception_ptr<unavailable>("Host has no address record."));
 		assert(this->e && this->e->eptr);