Writing a small file into a ZipFile while forcing zip64 extensions results in an incorrect zip file

[pR0Ps]

Bug report

When forcing a small file to be added to a zipfile.Zipfile object with zip64 extensions when it doesn't need it, a Zip64 extra record is added to the resulting file, but the minimum version and filesize information are not updated to reflect this.

An example of this issue in the wild: pR0Ps/zipstream-ng#13

To reproduce:

Create the file:

import zipfile

with zipfile.ZipFile("out.zip", mode="w", allowZip64=True) as zf:
    with zf.open("text.txt", mode="w", force_zip64=True) as zi:
        zi.write(b"some data")

Using zipdetails to parse information from the resulting file (red lines are incorrect):

 0000 LOCAL HEADER #1       04034B50
-0004 Extract Zip Spec      14 '2.0'
 0005 Extract OS            00 'MS-DOS'
 0006 General Purpose Flag  0000
 0008 Compression Method    0000 'Stored'
 000A Last Mod Time         00210000 'Mon Dec 31 19:00:00 1979'
 000E CRC                   D9C2E91E
-0012 Compressed Length     00000009
-0016 Uncompressed Length   00000009
 001A Filename Length       0008
 001C Extra Length          0014
 001E Filename              'text.txt'
 0026 Extra ID #0001        0001 'ZIP64'
 0028   Length              0010
 002A   Uncompressed Size   0000000000000009
 0032   Compressed Size     0000000000000009
 003A PAYLOAD               some data
 
 0043 CENTRAL HEADER #1     02014B50
-0047 Created Zip Spec      14 '2.0'
 0048 Created OS            03 'Unix'
-0049 Extract Zip Spec      14 '2.0'
 004A Extract OS            00 'MS-DOS'
 004B General Purpose Flag  0000
 004D Compression Method    0000 'Stored'
 004F Last Mod Time         00210000 'Mon Dec 31 19:00:00 1979'
 0053 CRC                   D9C2E91E
 0057 Compressed Length     00000009
 005B Uncompressed Length   00000009
 005F Filename Length       0008
 0061 Extra Length          0000
 0063 Comment Length        0000
 0065 Disk Start            0000
 0067 Int File Attributes   0000
      [Bit 0]               0 'Binary Data'
 0069 Ext File Attributes   01800000
 006D Local Header Offset   00000000
 0071 Filename              'text.txt'
 
 0079 END CENTRAL HEADER    06054B50
 007D Number of this disk   0000
 007F Central Dir Disk no   0000
 0081 Entries in this disk  0001
 0083 Total Entries         0001
 0085 Size of Central Dir   00000036
 0089 Offset to Central Dir 00000043
 008D Comment Length        0000

In this case, the Extract Zip Spec should be 0x2D (zipfile.ZIP64_VERSION) and the Compressed/Uncompressed Lengths should both be 0xFFFFFFFF in order to defer to the lengths in the Zip64 record.

Your environment

• CPython versions tested on: 3.12.0
• Operating system and architecture: macOS Mojave (x86)

Linked PRs

• gh-103861: Fix Zip64 extensions not being properly applied in some cases #103863
• [3.11] gh-103861: Fix Zip64 extensions not being properly applied in some cases (GH-103863) #104534