ValueError in zipfile.ZipFile

[jvoisin]

BPO	39064
Nosy	@serhiy-storchaka, @iritkatriel, @dignissimus
PRs	bpo-39064: make ZipFile raise BadZipFile instead of ValueError when reading a corrupt file #30863 gh-83245: Raise BadZipFile instead of ValueError when reading a corrupt file #32291
Files	crash-4da08e9ababa495ac51ecad588fd61081a66b5bb6e7a0e791f44907fa274ec62

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-12-16.12:58:42.379>
labels = ['type-bug', 'library', '3.9']
title = 'ValueError in zipfile.ZipFile'
updated_at = <Date 2022-04-03.18:36:35.140>
user = 'https://bugs.python.org/jvoisin'

bugs.python.org fields:

activity = <Date 2022-04-03.18:36:35.140>
actor = 'sam_ezeh'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2019-12-16.12:58:42.379>
creator = 'jvoisin'
dependencies = []
files = ['48782']
hgrepos = []
issue_num = 39064
keywords = ['patch']
message_count = 8.0
messages = ['358484', '410707', '410760', '411523', '416632', '416634', '416635', '416636']
nosy_count = 4.0
nosy_names = ['serhiy.storchaka', 'jvoisin', 'iritkatriel', 'sam_ezeh']
pr_nums = ['30863', '32291']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39064'
versions = ['Python 3.9']

[jvoisin]

The attached file produces the following stacktrace when opened via zipfile.ZipFile, on Python 3.7.5rc1:

$ cat ziprepro.py 
import zipfile
import sys

zipfile.ZipFile(sys.argv[1])

$ python3 ziprepro.py crash-4da08e9ababa495ac51ecad588fd61081a66b5bb6e7a0e791f44907fa274ec62
Traceback (most recent call last):
  File "ziprepro.py", line 4, in <module>
    zipfile.ZipFile(sys.argv[1])
  File "/usr/lib/python3.7/zipfile.py", line 1225, in __init__
    self._RealGetContents()
  File "/usr/lib/python3.7/zipfile.py", line 1310, in _RealGetContents
    fp.seek(self.start_dir, 0)
ValueError: cannot fit 'int' into an offset-sized integer

The ValueError exception isn't documented as a possible exception when using zipfile.ZipFile ( https://docs.python.org/3/library/tarfile.html ).

[iritkatriel]

It's unlikely that anyone will download a binary from bpo and open it. Can you help us reproduce the issue without that?

First question is whether you can reproduce this on a version of python that is still in maintenance - 3.9 or higher?

[jvoisin]

Yes, I can reproduce it:

$ python3 --version
Python 3.9.9

$ python3.9 ziprepo.py ./crash-4da08e9ababa495ac51ecad588fd61081a66b5bb6e7a0e791f44907fa274ec62 
Traceback (most recent call last):
  File "/home/jvoisin/Downloads/ziprepo.py", line 4, in <module>
    zipfile.ZipFile(sys.argv[1])
  File "/usr/lib/python3.9/zipfile.py", line 1257, in __init__
    self._RealGetContents()
  File "/usr/lib/python3.9/zipfile.py", line 1342, in _RealGetContents
    fp.seek(self.start_dir, 0)
ValueError: cannot fit 'int' into an offset-sized integer
$

It's unlikely that anyone will download a binary from bpo and open it. Can you help us reproduce the issue without that?

The binary is a corrupted zip file to open with zipfile.ZipFile(), it can't be executed on its own.

[iritkatriel]

It's easy enough to convert the exception type (see patch), but I don't know how to write a unit test for this.

[serhiy-storchaka]

Try to create a normal ZIP file (it can be empty), then try to set some byte to FF (or a pair of bytes to FFFF, or 4 consequent bytes to FFFFFFFF, until you get the exactly same error). Then you can just add the binary dump of that file in tests.