https://github.com/python/cpython/commit/7ccdbaba2c54250a70d7f25632152df7655a5e0a commit: 7ccdbaba2c54250a70d7f25632152df7655a5e0a branch: main author: Petr Viktorin <[email protected]> committer: encukou <[email protected]> date: 2026-06-29T17:41:26+02:00 summary:
gh-151987: Pass filter_function to TarFile._extract_one() during .extract() (GH-151988) Co-authored-by: Seth Michael Larson <[email protected]> files: A Misc/NEWS.d/next/Security/2026-06-23-14-19-30.gh-issue-151987.8mNIMf.rst M Lib/tarfile.py M Lib/test/test_tarfile.py diff --git a/Lib/tarfile.py b/Lib/tarfile.py index fe75b658ebb3f82..385dbb536d8a7dc 100644 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -2534,7 +2534,8 @@ def extract(self, member, path="", set_attrs=True, *, numeric_owner=False, tarinfo, unfiltered = self._get_extract_tarinfo( member, filter_function, path) if tarinfo is not None: - self._extract_one(tarinfo, path, set_attrs, numeric_owner) + self._extract_one(tarinfo, path, set_attrs, numeric_owner, + filter_function=filter_function) def _get_extract_tarinfo(self, member, filter_function, path): """Get (filtered, unfiltered) TarInfos from *member* diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index d657802d344803b..2998a3667b4d17d 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -4539,6 +4539,98 @@ def test_chmod_outside_dir(self): st_mode = cc.outerdir.stat().st_mode self.assertNotEqual(st_mode & 0o777, 0o777) + @symlink_test + @unittest.skipUnless(hasattr(os, 'chown'), "missing os.chown") + @unittest.skipUnless(hasattr(os, 'lchown'), "missing os.lchown") + @unittest.skipUnless(hasattr(os, 'geteuid'), "missing os.geteuid") + @support.subTests('link_type', (tarfile.SYMTYPE, tarfile.LNKTYPE)) + def test_chown_links_on_extract(self, link_type): + with ArchiveMaker() as arc: + arc.add("test.txt", + uid=1337, gid=1337, uname="", gname="", mode='-rwxr-xr-x') + arc.add("link", + type=link_type, + linkname='test.txt', + uid=1337, gid=1337, uname="", gname="", mode='-rwxr-xr-x') + + with ( + os_helper.temp_dir() as tmpdir, + arc.open() as tar, + unittest.mock.patch("os.chown") as mock_chown, + unittest.mock.patch("os.lchown") as mock_lchown, + unittest.mock.patch("os.geteuid") as mock_geteuid, + ): + # Set UID to 0 so chown() is attempted. + mock_geteuid.return_value = 0 + tar.extract("link", path=tmpdir, filter='data') + extract_path = os.path.join(tmpdir, "link") + + if link_type == tarfile.SYMTYPE: + mock_chown.assert_not_called() + mock_lchown.assert_called_once_with(extract_path, -1, -1) + else: + mock_chown.assert_has_calls([ + unittest.mock.call(extract_path, -1, -1), + unittest.mock.call(extract_path, -1, -1) + ]) + mock_lchown.assert_not_called() + + @symlink_test + @unittest.skipUnless(hasattr(os, 'chown'), "missing os.chown") + @unittest.skipUnless(hasattr(os, 'lchown'), "missing os.lchown") + @unittest.skipUnless(hasattr(os, 'geteuid'), "missing os.geteuid") + @support.subTests('link_type', (tarfile.SYMTYPE, tarfile.LNKTYPE)) + def test_chown_links_on_extractall(self, link_type): + with ArchiveMaker() as arc: + arc.add("test.txt", + uid=1337, gid=1337, uname="", gname="", mode='-rwxr-xr-x') + arc.add("link", + type=link_type, + linkname='test.txt', + uid=1337, gid=1337, uname="", gname="", mode='-rwxr-xr-x') + + with ( + os_helper.temp_dir() as tmpdir, + arc.open() as tar, + unittest.mock.patch("os.chown") as mock_chown, + unittest.mock.patch("os.lchown") as mock_lchown, + unittest.mock.patch("os.geteuid") as mock_geteuid, + ): + # Set UID to 0 so chown() is attempted. + mock_geteuid.return_value = 0 + tar.extractall(path=tmpdir, filter='data') + extract_link_path = os.path.join(tmpdir, "link") + extract_file_path = os.path.join(tmpdir, "test.txt") + + if link_type == tarfile.SYMTYPE: + mock_chown.assert_called_once_with(extract_file_path, -1, -1) + mock_lchown.assert_called_once_with(extract_link_path, -1, -1) + else: + mock_chown.assert_has_calls([ + unittest.mock.call(extract_file_path, -1, -1), + unittest.mock.call(extract_link_path, -1, -1) + ]) + mock_lchown.assert_not_called() + + def test_extract_filters_target(self): + # Test that when extract() falls back to extracting (rather than + # linking) a hardlink target, it filters the target. + with ArchiveMaker() as arc: + arc.add("target") + arc.add("link", hardlink_to="target") + def testing_filter(member, path): + if member.name == 'target': + # target: set read-only + return member.replace(mode=stat.S_IRUSR) + # link: don't overwrite the mode + return member.replace(mode=None) + tempdir = pathlib.Path(TEMPDIR) / 'extract' + with os_helper.temp_dir(tempdir), arc.open() as tar: + tar.extract("link", path=tempdir, filter=testing_filter) + path = tempdir / 'link' + if os_helper.can_chmod(): + self.assertFalse(path.stat().st_mode & stat.S_IWUSR) + def test_link_fallback_normalizes(self): # Make sure hardlink fallbacks work for non-normalized paths for all # filters diff --git a/Misc/NEWS.d/next/Security/2026-06-23-14-19-30.gh-issue-151987.8mNIMf.rst b/Misc/NEWS.d/next/Security/2026-06-23-14-19-30.gh-issue-151987.8mNIMf.rst new file mode 100644 index 000000000000000..9eea7b32c4d2b4f --- /dev/null +++ b/Misc/NEWS.d/next/Security/2026-06-23-14-19-30.gh-issue-151987.8mNIMf.rst @@ -0,0 +1,2 @@ +The :meth:`tarfile.TarFile.extract` method now applies the given filter when +it extracts a link target from the archive as a fallback. _______________________________________________ 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]
