https://github.com/python/cpython/commit/1daad8a1630c9ee011f6ff3796c4e7aef243463b commit: 1daad8a1630c9ee011f6ff3796c4e7aef243463b branch: main author: adang1345 <[email protected]> committer: serhiy-storchaka <[email protected]> date: 2026-05-22T10:20:08+03:00 summary:
gh-133998: Fix gzip file creation when time is out of range (GH-134278) Co-authored-by: Serhiy Storchaka <[email protected]> files: A Misc/NEWS.d/next/Library/2025-05-19-20-29-35.gh-issue-133998.KmElUw.rst M Doc/library/gzip.rst M Lib/gzip.py M Lib/test/test_gzip.py diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst index ed9fdaf1d727b0..2c667ddc522399 100644 --- a/Doc/library/gzip.rst +++ b/Doc/library/gzip.rst @@ -108,9 +108,13 @@ The module defines the following items: is no compression. The default is ``9``. The optional *mtime* argument is the timestamp requested by gzip. The time - is in Unix format, i.e., seconds since 00:00:00 UTC, January 1, 1970. - If *mtime* is omitted or ``None``, the current time is used. Use *mtime* = 0 - to generate a compressed stream that does not depend on creation time. + is in Unix format, i.e., seconds since 00:00:00 UTC, January 1, 1970. Set + *mtime* to ``0`` to generate a compressed stream that does not depend on + creation time. If *mtime* is omitted or ``None``, the current time is used; + however, if the current time is outside the range 00:00:00 UTC, January 1, + 1970 through 06:28:15 UTC, February 7, 2106, or explicitly passed *mtime* + argument is outside the range ``0`` to ``2**32-1``, then the value ``0`` + is used instead. See below for the :attr:`mtime` attribute that is set when decompressing. diff --git a/Lib/gzip.py b/Lib/gzip.py index 1e05f43c0c9e24..8720acc4db9976 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -188,8 +188,10 @@ def __init__(self, filename=None, mode=None, The optional mtime argument is the timestamp requested by gzip. The time is in Unix format, i.e., seconds since 00:00:00 UTC, January 1, 1970. - If mtime is omitted or None, the current time is used. Use mtime = 0 - to generate a compressed stream that does not depend on creation time. + Set mtime to 0 to generate a compressed stream that does not depend on + creation time. If mtime is omitted or None, the current time is used. + If the resulting mtime is outside the range 0 to 2**32-1, then the + value 0 is used instead. """ @@ -295,6 +297,8 @@ def _write_gzip_header(self, compresslevel): mtime = self._write_mtime if mtime is None: mtime = time.time() + if not 0 <= mtime < 2**32: + mtime = 0 write32u(self.fileobj, int(mtime)) if compresslevel == _COMPRESS_LEVEL_BEST: xfl = b'\002' @@ -663,6 +667,8 @@ def compress(data, compresslevel=_COMPRESS_LEVEL_TRADEOFF, *, mtime=0): gzip_data = zlib.compress(data, level=compresslevel, wbits=31) if mtime is None: mtime = time.time() + if not 0 <= mtime < 2**32: + mtime = 0 # Reuse gzip header created by zlib, replace mtime and OS byte for # consistency. header = struct.pack("<4sLBB", gzip_data, int(mtime), gzip_data[8], 255) diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py index b3b7c8f87e4f9f..cafac9d3c8be6e 100644 --- a/Lib/test/test_gzip.py +++ b/Lib/test/test_gzip.py @@ -10,6 +10,7 @@ import sys import unittest from subprocess import PIPE, Popen +from unittest import mock from test.support import catch_unraisable_exception from test.support import force_not_colorized_test_class, import_helper from test.support import os_helper @@ -350,6 +351,26 @@ def test_mtime(self): self.assertEqual(dataRead, data1) self.assertEqual(fRead.mtime, mtime) + def test_mtime_out_of_range(self): + for mtime in (-1, 2**32): + with gzip.GzipFile(self.filename, 'w', mtime=mtime) as fWrite: + fWrite.write(data1) + with gzip.GzipFile(self.filename) as fRead: + fRead.read(1) + self.assertEqual(fRead.mtime, 0) + datac = gzip.compress(data1, mtime=mtime) + with gzip.GzipFile(fileobj=io.BytesIO(datac)) as fRead: + fRead.read(1) + self.assertEqual(fRead.mtime, 0) + + for mtime in (-1, 2**32): + with mock.patch('time.time', return_value=float(mtime)): + with gzip.GzipFile(self.filename, 'w') as fWrite: + fWrite.write(data1) + with gzip.GzipFile(self.filename) as fRead: + fRead.read(1) + self.assertEqual(fRead.mtime, 0) + def test_metadata(self): mtime = 123456789 diff --git a/Misc/NEWS.d/next/Library/2025-05-19-20-29-35.gh-issue-133998.KmElUw.rst b/Misc/NEWS.d/next/Library/2025-05-19-20-29-35.gh-issue-133998.KmElUw.rst new file mode 100644 index 00000000000000..77d92628beefac --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-05-19-20-29-35.gh-issue-133998.KmElUw.rst @@ -0,0 +1,5 @@ +Fix :exc:`struct.error` exception when creating a file with +:class:`gzip.GzipFile` or compressing data with :func:`gzip.compress` +if the system time is outside the range 00:00:00 UTC, January 1, 1970 +through 06:28:15 UTC, February 7, 2106, or explicitly passed *mtime* +argument is outside the range ``0`` to ``2**32-1``. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
