diff options
| -rw-r--r-- | Doc/library/zipfile.rst | 17 | ||||
| -rw-r--r-- | Lib/test/test_zipfile.py | 86 | ||||
| -rw-r--r-- | Lib/zipfile.py | 27 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
4 files changed, 108 insertions, 25 deletions
diff --git a/Doc/library/zipfile.rst b/Doc/library/zipfile.rst index 9f6e077..54f9b4b 100644 --- a/Doc/library/zipfile.rst +++ b/Doc/library/zipfile.rst @@ -242,6 +242,16 @@ ZipFile Objects to extract to. *member* can be a filename or a :class:`ZipInfo` object. *pwd* is the password used for encrypted files. + .. note:: + + If a member filename is an absolute path, a drive/UNC sharepoint and + leading (back)slashes will be stripped, e.g.: ``///foo/bar`` becomes + ``foo/bar`` on Unix, and ``ะก:\foo\bar`` becomes ``foo\bar`` on Windows. + And all ``".."`` components in a member filename will be removed, e.g.: + ``../../foo../../ba..r`` becomes ``foo../ba..r``. On Windows illegal + characters (``:``, ``<``, ``>``, ``|``, ``"``, ``?``, and ``*``) + replaced by underscore (``_``). + .. method:: ZipFile.extractall(path=None, members=None, pwd=None) @@ -250,12 +260,9 @@ ZipFile Objects be a subset of the list returned by :meth:`namelist`. *pwd* is the password used for encrypted files. - .. warning:: + .. note:: - Never extract archives from untrusted sources without prior inspection. - It is possible that files are created outside of *path*, e.g. members - that have absolute filenames starting with ``"/"`` or filenames with two - dots ``".."``. + See :meth:`extract` note. .. method:: ZipFile.printdir() diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py index b0c529f..81e3036 100644 --- a/Lib/test/test_zipfile.py +++ b/Lib/test/test_zipfile.py @@ -24,7 +24,7 @@ DATAFILES_DIR = 'zipfile_datafiles' SMALL_TEST_DATA = [('_ziptest1', '1q2w3e4r5t'), ('ziptest2dir/_ziptest2', 'qawsedrftg'), - ('/ziptest2dir/ziptest3dir/_ziptest3', 'azsxdcfvgb'), + ('ziptest2dir/ziptest3dir/_ziptest3', 'azsxdcfvgb'), ('ziptest2dir/ziptest3dir/ziptest4dir/_ziptest3', '6y7u8i9o0p')] @@ -501,10 +501,7 @@ class TestsWithSourceFile(unittest.TestCase): writtenfile = zipfp.extract(fpath) # make sure it was written to the right place - if os.path.isabs(fpath): - correctfile = os.path.join(os.getcwd(), fpath[1:]) - else: - correctfile = os.path.join(os.getcwd(), fpath) + correctfile = os.path.join(os.getcwd(), fpath) correctfile = os.path.normpath(correctfile) self.assertEqual(writtenfile, correctfile) @@ -526,10 +523,7 @@ class TestsWithSourceFile(unittest.TestCase): with zipfile.ZipFile(TESTFN2, "r") as zipfp: zipfp.extractall() for fpath, fdata in SMALL_TEST_DATA: - if os.path.isabs(fpath): - outfile = os.path.join(os.getcwd(), fpath[1:]) - else: - outfile = os.path.join(os.getcwd(), fpath) + outfile = os.path.join(os.getcwd(), fpath) with open(outfile, "rb") as f: self.assertEqual(fdata.encode(), f.read()) @@ -539,6 +533,80 @@ class TestsWithSourceFile(unittest.TestCase): # remove the test file subdirectories shutil.rmtree(os.path.join(os.getcwd(), 'ziptest2dir')) + def check_file(self, filename, content): + self.assertTrue(os.path.isfile(filename)) + with open(filename, 'rb') as f: + self.assertEqual(f.read(), content) + + def test_extract_hackers_arcnames(self): + hacknames = [ + ('../foo/bar', 'foo/bar'), + ('foo/../bar', 'foo/bar'), + ('foo/../../bar', 'foo/bar'), + ('foo/bar/..', 'foo/bar'), + ('./../foo/bar', 'foo/bar'), + ('/foo/bar', 'foo/bar'), + ('/foo/../bar', 'foo/bar'), + ('/foo/../../bar', 'foo/bar'), + ('//foo/bar', 'foo/bar'), + ('../../foo../../ba..r', 'foo../ba..r'), + ] + if os.path.sep == '\\': # Windows. + hacknames.extend([ + (r'..\foo\bar', 'foo/bar'), + (r'..\/foo\/bar', 'foo/bar'), + (r'foo/\..\/bar', 'foo/bar'), + (r'foo\/../\bar', 'foo/bar'), + (r'C:foo/bar', 'foo/bar'), + (r'C:/foo/bar', 'foo/bar'), + (r'C://foo/bar', 'foo/bar'), + (r'C:\foo\bar', 'foo/bar'), + (r'//conky/mountpoint/foo/bar', 'foo/bar'), + (r'\\conky\mountpoint\foo\bar', 'foo/bar'), + (r'///conky/mountpoint/foo/bar', 'conky/mountpoint/foo/bar'), + (r'\\\conky\mountpoint\foo\bar', 'conky/mountpoint/foo/bar'), + (r'//conky//mountpoint/foo/bar', 'conky/mountpoint/foo/bar'), + (r'\\conky\\mountpoint\foo\bar', 'conky/mountpoint/foo/bar'), + (r'//?/C:/foo/bar', 'foo/bar'), + (r'\\?\C:\foo\bar', 'foo/bar'), + (r'C:/../C:/foo/bar', 'C_/foo/bar'), + (r'a:b\c<d>e|f"g?h*i', 'b/c_d_e_f_g_h_i'), + ]) + + for arcname, fixedname in hacknames: + content = b'foobar' + arcname.encode() + with zipfile.ZipFile(TESTFN2, 'w', zipfile.ZIP_STORED) as zipfp: + zipfp.writestr(arcname, content) + + targetpath = os.path.join('target', 'subdir', 'subsub') + correctfile = os.path.join(targetpath, *fixedname.split('/')) + + with zipfile.ZipFile(TESTFN2, 'r') as zipfp: + writtenfile = zipfp.extract(arcname, targetpath) + self.assertEqual(writtenfile, correctfile) + self.check_file(correctfile, content) + shutil.rmtree('target') + + with zipfile.ZipFile(TESTFN2, 'r') as zipfp: + zipfp.extractall(targetpath) + self.check_file(correctfile, content) + shutil.rmtree('target') + + correctfile = os.path.join(os.getcwd(), *fixedname.split('/')) + + with zipfile.ZipFile(TESTFN2, 'r') as zipfp: + writtenfile = zipfp.extract(arcname) + self.assertEqual(writtenfile, correctfile) + self.check_file(correctfile, content) + shutil.rmtree(fixedname.split('/')[0]) + + with zipfile.ZipFile(TESTFN2, 'r') as zipfp: + zipfp.extractall() + self.check_file(correctfile, content) + shutil.rmtree(fixedname.split('/')[0]) + + os.remove(TESTFN2) + def test_writestr_compression_stored(self): zipfp = zipfile.ZipFile(TESTFN2, "w") zipfp.writestr("a.txt", "hello world", compress_type=zipfile.ZIP_STORED) diff --git a/Lib/zipfile.py b/Lib/zipfile.py index 235b811..f5c3f17 100644 --- a/Lib/zipfile.py +++ b/Lib/zipfile.py @@ -1229,17 +1229,22 @@ class ZipFile: """ # build the destination pathname, replacing # forward slashes to platform specific separators. - # Strip trailing path separator, unless it represents the root. - if (targetpath[-1:] in (os.path.sep, os.path.altsep) - and len(os.path.splitdrive(targetpath)[1]) > 1): - targetpath = targetpath[:-1] - - # don't include leading "/" from file name if present - if member.filename[0] == '/': - targetpath = os.path.join(targetpath, member.filename[1:]) - else: - targetpath = os.path.join(targetpath, member.filename) - + arcname = member.filename.replace('/', os.path.sep) + + if os.path.altsep: + arcname = arcname.replace(os.path.altsep, os.path.sep) + # interpret absolute pathname as relative, remove drive letter or + # UNC path, redundant separators, "." and ".." components. + arcname = os.path.splitdrive(arcname)[1] + arcname = os.path.sep.join(x for x in arcname.split(os.path.sep) + if x not in ('', os.path.curdir, os.path.pardir)) + # filter illegal characters on Windows + if os.path.sep == '\\': + illegal = ':<>|"?*' + table = str.maketrans(illegal, '_' * len(illegal)) + arcname = arcname.translate(table) + + targetpath = os.path.join(targetpath, arcname) targetpath = os.path.normpath(targetpath) # Create all upper directories if necessary. @@ -167,6 +167,9 @@ Core and Builtins Library ------- +- Issue #6972: The zipfile module no longer overwrites files outside of + its destination path when extracting malicious zip files. + - Issue #4844: ZipFile now raises BadZipFile when opens a ZIP file with an incomplete "End of Central Directory" record. Original patch by Guilherme Polo and Alan McIntyre. |