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Description
Bug report
Bug description:
When creating a zip file which contains a file large enough to push additional files beyond the ZIP64_LIMIT, the extract version is correctly incremented to 4.5 in the Central Header, but not in the Local Header. This mismatch is usually ignored, but more picky implementations fail when validating the zip file.
When the Local Header is being generated, the extract version that is used does not account for the fact that if the header is located farther than the ZIP64_LIMIT, the ZIP64_VERSION is needed since to reference the header offset the Central Header needs to store the offset in the Extra Bits.
Repro
Create a directory with a file over the ZIP64_LIMIT and a file after it, then zip the directory:
>tree source_dir/ -hsource_dir/├── [4.7G] 5_gig_file.dat└── [ 229] t# Zip the test directoryout_file="outputs/test.zip"source_dir="source_dir"withzipfile.ZipFile(out_file,"w")aszipf:forroot,_dirs,filesinos.walk(source_dir):forfileinfiles:file_path=os.path.join(root,file)arc_path=pathlib.Path(file_path).relative_to(source_dir)zipf.write(file_path,arcname=arc_path)print(f"generated{out_file}")
Using zipdetails we can see the extract_version in the local header does not match the central header:
> zipdetails outputs/test.zip...12A05F240 LOCAL HEADER #2 04034B5012A05F244 Extract Zip Spec 14 '2.0'12A05F245 Extract OS 00 'MS-DOS'12A05F246 General Purpose Flag 000012A05F248 Compression Method 0000 'Stored'12A05F24A Last Mod Time 58DCB5CE 'Fri Jun 28 22:46:28 2024'12A05F24E CRC BB63C17212A05F252 Compressed Length 000000E512A05F256 Uncompressed Length 000000E512A05F25A Filename Length 000812A05F25C Extra Length 000012A05F25E Filename 'test.TXT'...12A05F39B CENTRAL HEADER #2 02014B5012A05F39F Created Zip Spec 2D '4.5'12A05F3A0 Created OS 00 'MS-DOS'12A05F3A1 Extract Zip Spec 2D '4.5'12A05F3A2 Extract OS 00 'MS-DOS'12A05F3A3 General Purpose Flag 000012A05F3A5 Compression Method 0000 'Stored'12A05F3A7 Last Mod Time 58DCB5CE 'Fri Jun 28 22:46:28 2024'12A05F3AB CRC BB63C17212A05F3AF Compressed Length 000000E512A05F3B3 Uncompressed Length 000000E512A05F3B7 Filename Length 000812A05F3B9 Extra Length 000C12A05F3BB Comment Length 000012A05F3BD Disk Start 000012A05F3BF Int File Attributes 0000 [Bit 0] 0 'Binary Data'12A05F3C1 Ext File Attributes 81B6000012A05F3C5 Local Header Offset FFFFFFFF12A05F3C9 Filename 'test.TXT'12A05F3D1 Extra ID #0001 0001 'ZIP64'12A05F3D3 Length 000812A05F3D5 Offset to Central 000000012A05F240 Dir12A05F3DD ZIP64 END CENTRAL DIR 06064B50 RECORD12A05F3E1 Size of record 000000000000002C12A05F3E9 Created Zip Spec 2D '4.5'12A05F3EA Created OS 00 'MS-DOS'12A05F3EB Extract Zip Spec 2D '4.5'12A05F3EC Extract OS 00 'MS-DOS'12A05F3ED Number of this disk 0000000012A05F3F1 Central Dir Disk no 0000000012A05F3F5 Entries in this disk 000000000000000212A05F3FD Total Entries 000000000000000212A05F405 Size of Central Dir 000000000000009212A05F40D Offset to Central dir 000000012A05F34B12A05F415 ZIP64 END CENTRAL DIR 07064B50 LOCATOR12A05F419 Central Dir Disk no 0000000012A05F41D Offset to Central dir 000000012A05F3DD12A05F425 Total no of Disks 0000000112A05F429 END CENTRAL HEADER 06054B5012A05F42D Number of this disk 000012A05F42F Central Dir Disk no 000012A05F431 Entries in this disk 000212A05F433 Total Entries 000212A05F435 Size of Central Dir 0000009212A05F439 Offset to Central Dir FFFFFFFF12A05F43D Comment Length 0000The zip -F command also warns about the mismatch:
zip --versionCopyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license.This is Zip 3.0 (July 5th 2008), by Info-ZIP....> zip -F outputs/test.zip --out out2.zipFix archive (-F) - assume mostly intact archiveZip entry offsets do not need adjusting copying: 5_gig_file.dat copying: test.TXT zip warning: Local Version Needed To Extract does not match CD: test.TXTCPython versions tested on:
3.10, CPython main branch
Operating systems tested on:
Linux, Windows
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