merge tracker exchange patch from RC_0_16

ChangeLog

@@ -20,6 +20,7 @@
 	* fix uTP edge case where udp socket buffer fills up
 	* fix nagle implementation in uTP
 
+	* prevent tracker exchange for magnet links before metadata is received
 	* fix crash in make_magnet_uri when generating links longer than 1024 characters
 	* fix hanging issue when closing files on windows (completing a download)
 	* fix piece picking edge case that could cause torrents to get stuck at hash failure

src/lt_trackers.cpp

@@ -245,7 +245,7 @@ namespace libtorrent { namespace
 
 			if (m_full_list)
 			{
-				send_full_tex_list();
+				if (send_full_tex_list())
 					m_full_list = false;
 			}
 			else
@@ -261,6 +261,9 @@ namespace libtorrent { namespace
 			// if there's no change in out tracker set, don't send anything
 			if (m_tp.num_updates() == 0) return;
 
+			if (!m_torrent.valid_metadata() || m_torrent.torrent_file().priv())
+				return;
+
 			std::vector<char> const& tex_msg = m_tp.get_lt_tex_msg();
 
 			char msg[6];
@@ -274,9 +277,12 @@ namespace libtorrent { namespace
 			m_pc.setup_send();
 		}
 
-		void send_full_tex_list() const
+		bool send_full_tex_list() const
 		{
-			if (m_tp.trackers().empty()) return;
+			if (m_tp.trackers().empty()) return false;
+
+			if (!m_torrent.valid_metadata() || m_torrent.torrent_file().priv())
+				return false;
 
 #ifdef TORRENT_VERBOSE_LOGGING
 			std::stringstream log_line;
@@ -311,6 +317,8 @@ namespace libtorrent { namespace
 			m_pc.send_buffer(msg, sizeof(msg));
 			m_pc.send_buffer(&tex_msg[0], tex_msg.size());
 			m_pc.setup_send();
+
+			return true;
 		}
 
 		// this is the message index the remote peer uses
@@ -331,6 +339,9 @@ namespace libtorrent { namespace
 		if (pc->type() != peer_connection::bittorrent_connection)
 			return boost::shared_ptr<peer_plugin>();
 
+		if (m_torrent.valid_metadata() && m_torrent.torrent_file().priv())
+			return boost::shared_ptr<peer_plugin>();
+
 		bt_peer_connection* c = static_cast<bt_peer_connection*>(pc);
 		return boost::shared_ptr<peer_plugin>(new lt_tracker_peer_plugin(m_torrent, *c, *this));
 	}

test/test_trackers_extension.cpp

@@ -40,6 +40,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/extensions/metadata_transfer.hpp"
 #include "libtorrent/extensions/ut_metadata.hpp"
 #include "libtorrent/extensions/lt_trackers.hpp"
+#include "libtorrent/bencode.hpp"
 
 using boost::tuples::ignore;
 
@@ -61,7 +62,48 @@ int test_main()
 	torrent_handle tor2 = ses2.add_torrent(atp, ec);
 	tor2.connect_peer(tcp::endpoint(address_v4::from_string("127.0.0.1"), ses1.listen_port()));
 
-	for (int i = 0; i < 130; ++i)
+	// trackers are NOT supposed to be exchanged for torrents that we
+	// don't have metadata for, since they might be private
+	for (int i = 0; i < 10; ++i)
+	{
+		// make sure this function can be called on
+		// torrents without metadata
+		print_alerts(ses1, "ses1", false, true);
+		print_alerts(ses2, "ses2", false, true);
+
+		if (tor1.trackers().size() != 0) break;
+		test_sleep(1000);
+	}
+
+	TEST_CHECK(tor1.trackers().size() == 0);
+
+	entry info;
+	info["pieces"] = "aaaaaaaaaaaaaaaaaaaa";
+	info["name"] = "slightly shorter name, it's kind of sad that people started the trend of incorrectly encoding the regular name field and then adding another one with correct encoding";
+	info["name.utf-8"] = "this is a long ass name in order to try to make make_magnet_uri overflow and hopefully crash. Although, by the time you read this that particular bug should have been fixed";
+	info["piece length"] = 16 * 1024;
+	info["length"] = 3245;
+	entry torrent;
+	torrent["info"] = info;
+
+	std::vector<char> buf;
+	bencode(std::back_inserter(buf), torrent);
+	boost::intrusive_ptr<torrent_info> ti(new torrent_info(&buf[0], buf.size(), ec));
+	TEST_CHECK(!ec);
+
+	atp.ti = ti;
+	atp.info_hash.clear();
+	atp.save_path = "./";
+	atp.trackers.clear();
+
+	tor1 = ses1.add_torrent(atp, ec);
+	atp.trackers.push_back("http://test.non-existent.com/announce");
+	tor2 = ses2.add_torrent(atp, ec);
+	tor2.connect_peer(tcp::endpoint(address_v4::from_string("127.0.0.1"), ses1.listen_port()));
+
+	TEST_CHECK(tor1.trackers().size() == 0);
+
+	for (int i = 0; i < 60; ++i)
 	{
 		// make sure this function can be called on
 		// torrents without metadata
@@ -73,6 +115,7 @@ int test_main()
 	}
 
 	TEST_CHECK(tor1.trackers().size() == 1);
+
 	return 0;
 }