fix piece size check when loading torrents

ChangeLog

@@ -1,3 +1,4 @@
+	* fix piece size check when loading torrents
 	* back-port fix last_upload and last_download resume data fields to use posix time
 	* back-port treat CGNAT address range as local IPs
 

include/libtorrent/piece_picker.hpp

@@ -97,9 +97,9 @@ namespace libtorrent {
 			// priority factor
 			prio_factor = 3,
 			// max blocks per piece
-			// there are counters in downloading_piece that only have 15 bits to
+			// there are counters in downloading_piece that only have 14 bits to
 			// count blocks per piece, that's restricting this
-			max_blocks_per_piece = (1 << 15) - 1
+			max_blocks_per_piece = (1 << 14) - 1
 		};
 
 		struct block_info

src/torrent_info.cpp

@@ -53,6 +53,8 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/announce_entry.hpp"
 #include "libtorrent/hex.hpp" // to_hex
 #include "libtorrent/aux_/numeric_cast.hpp"
+#include "libtorrent/piece_picker.hpp"
+#include "libtorrent/disk_interface.hpp" // for default_block_size
 
 #if TORRENT_ABI_VERSION == 1
 #include "libtorrent/lazy_entry.hpp"
@@ -1027,11 +1029,16 @@ namespace {
 
 		// extract piece length
 		std::int64_t piece_length = info.dict_find_int_value("piece length", -1);
-		if (piece_length <= 0 || piece_length > std::numeric_limits<int>::max())
+		if (piece_length <= 0)
 		{
 			ec = errors::torrent_missing_piece_length;
 			return false;
 		}
+		if (piece_length > piece_picker::max_blocks_per_piece * default_block_size)
+		{
+			ec = errors::invalid_piece_size;
+			return false;
+		}
 		file_storage files;
 		files.set_piece_length(static_cast<int>(piece_length));
 

test/test_torrent.cpp

@@ -167,7 +167,7 @@ void test_running_torrent(std::shared_ptr<torrent_info> info, std::int64_t file_
 	TEST_CHECK(h.get_file_priorities() == prio);
 }
 
-void test_large_piece_size(int const size)
+void test_large_piece_size(std::int64_t const size)
 {
 	entry torrent;
 	entry& info = torrent["info"];
@@ -179,7 +179,15 @@ void test_large_piece_size(int const size)
 	std::vector<char> buf;
 	bencode(std::back_inserter(buf), torrent);
 	add_torrent_params atp;
-	atp.ti = std::make_shared<torrent_info>(buf, from_span);
+	try
+	{
+		atp.ti = std::make_shared<torrent_info>(buf, from_span);
+	}
+	catch (lt::system_error const& e)
+	{
+		TEST_CHECK(e.code() == error_code(lt::errors::invalid_piece_size));
+		return;
+	}
 	atp.save_path = ".";
 
 	lt::session ses;
@@ -212,9 +220,12 @@ TORRENT_TEST(long_names)
 
 TORRENT_TEST(large_piece_size)
 {
-	test_large_piece_size(32768 * 16 * 1024);
-	test_large_piece_size(65536 * 16 * 1024);
-	test_large_piece_size(65537 * 16 * 1024);
+	test_large_piece_size(0xfffc000 + 0x4000);
+	test_large_piece_size(0x10000000);
+	test_large_piece_size(0x20000000);
+	test_large_piece_size(0x40000000);
+	test_large_piece_size(0x80000000);
+	test_large_piece_size(0x100000000);
 }
 
 TORRENT_TEST(total_wanted)