validate add_torrent_params::save_path at run-time

Author: arvidn

ChangeLog

@@ -1,6 +1,7 @@
 
 2.0.11 released
 
+	* validate add_torrent_params::save_path at run-time
 	* use stricter rules for what filenames are valid on Android
 	* fix applying IP filter to DHT traffic (HanabishiRecca)
 	* fix race condition when cancelling requests after becoming a seed

include/libtorrent/error_code.hpp

@@ -389,6 +389,8 @@ namespace errors {
 		// specifying the flag to only save when there's anything new to save
 		// (torrent_handle::only_if_modified) and there wasn't anything changed.
 		resume_data_not_modified,
+		// the save_path in add_torrent_params is not valid
+		invalid_save_path,
 
 
 		// The HTTP header was not correctly formatted

include/libtorrent/session_handle.hpp

@@ -264,6 +264,12 @@ namespace libtorrent {
 		// immediately, without waiting for the torrent to add. Notification of
 		// the torrent being added is sent as add_torrent_alert.
 		//
+		// The ``save_path`` field in add_torrent_params must be set to a valid
+		// path where the files for the torrent will be saved. Even when using a
+		// custom storage, this needs to be set to something. If the save_path
+		// is empty, the call to add_torrent() will throw a system_error
+		// exception.
+		//
 		// The overload that does not take an error_code throws an exception on
 		// error and is not available when building without exception support.
 		// The torrent_handle returned by add_torrent() can be used to retrieve

src/error_code.cpp

@@ -206,7 +206,7 @@ namespace libtorrent {
 			"invalid piece index in slot list",
 			"pieces needs to be reordered",
 			"fastresume not modified since last save",
-			"",
+			"invalid save_path",
 			"",
 			"",
 			"",

src/session_handle.cpp

@@ -405,7 +405,12 @@ namespace {
 #ifndef BOOST_NO_EXCEPTIONS
 	torrent_handle session_handle::add_torrent(add_torrent_params&& params)
 	{
+#ifndef BOOST_NO_EXCEPTIONS
+		if (params.save_path.empty())
+			aux::throw_ex<system_error>(error_code(errors::invalid_save_path));
+#else
 		TORRENT_ASSERT_PRECOND(!params.save_path.empty());
+#endif
 
 #if TORRENT_ABI_VERSION < 3
 		if (!params.info_hashes.has_v1() && !params.info_hashes.has_v2() && !params.ti)
@@ -435,7 +440,11 @@ namespace {
 
 	torrent_handle session_handle::add_torrent(add_torrent_params&& params, error_code& ec)
 	{
-		TORRENT_ASSERT_PRECOND(!params.save_path.empty());
+		if (params.save_path.empty())
+		{
+			ec = error_code(errors::invalid_save_path);
+			return {};
+		}
 
 #if TORRENT_ABI_VERSION < 3
 		if (!params.info_hashes.has_v1() && !params.info_hashes.has_v2() && !params.ti)
@@ -467,7 +476,12 @@ namespace {
 
 	void session_handle::async_add_torrent(add_torrent_params&& params)
 	{
+#ifndef BOOST_NO_EXCEPTIONS
+		if (params.save_path.empty())
+			aux::throw_ex<system_error>(error_code(errors::invalid_save_path));
+#else
 		TORRENT_ASSERT_PRECOND(!params.save_path.empty());
+#endif
 
 #if TORRENT_ABI_VERSION < 3
 		if (!params.info_hashes.has_v1() && !params.info_hashes.has_v2() && !params.ti)
@@ -528,7 +542,12 @@ namespace {
 		, bool const add_paused
 		, client_data_t userdata)
 	{
+#ifndef BOOST_NO_EXCEPTIONS
+		if (save_path.empty())
+			aux::throw_ex<system_error>(error_code(errors::invalid_save_path));
+#else
 		TORRENT_ASSERT_PRECOND(!save_path.empty());
+#endif
 
 		add_torrent_params p;
 		p.trackers.push_back(tracker_url);

test/test_session.cpp

@@ -126,6 +126,23 @@ TORRENT_TEST(async_add_torrent_deprecated_magnet)
 }
 #endif
 
+TORRENT_TEST(async_add_torrent_no_save_path)
+{
+	settings_pack p = settings();
+	p.set_int(settings_pack::alert_mask, ~0);
+	lt::session ses(p);
+
+	add_torrent_params atp;
+	atp.info_hashes.v1.assign("abababababababababab");
+	atp.save_path = "";
+	TEST_THROW(ses.add_torrent(atp));
+	TEST_THROW(ses.async_add_torrent(atp));
+
+	lt::error_code ec;
+	ses.add_torrent(atp, ec);
+	TORRENT_ASSERT(ec == error_code(lt::errors::invalid_save_path));
+}
+
 TORRENT_TEST(async_add_torrent_duplicate_error)
 {
 	settings_pack p = settings();