changeset: 81874:4d1948689ee1 branch: 2.7 parent: 81865:6074530b526f user: Gregory P. Smith date: Fri Feb 01 11:40:18 2013 -0800 files: Doc/library/zipfile.rst Lib/test/test_zipfile.py Lib/zipfile.py Misc/NEWS description: Fixes Issue #6972: The zipfile module no longer overwrites files outside of its destination path when extracting malicious zip files. diff -r 6074530b526f -r 4d1948689ee1 Doc/library/zipfile.rst --- a/Doc/library/zipfile.rst Fri Feb 01 13:13:32 2013 +0200 +++ b/Doc/library/zipfile.rst Fri Feb 01 11:40:18 2013 -0800 @@ -242,6 +242,16 @@ .. versionadded:: 2.6 + .. 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.read(name[, pwd]) diff -r 6074530b526f -r 4d1948689ee1 Lib/test/test_zipfile.py --- a/Lib/test/test_zipfile.py Fri Feb 01 13:13:32 2013 +0200 +++ b/Lib/test/test_zipfile.py Fri Feb 01 11:40:18 2013 -0800 @@ -26,7 +26,7 @@ SMALL_TEST_DATA = [('_ziptest1', '1q2w3e4r5t'), ('ziptest2dir/_ziptest2', 'qawsedrftg'), - ('/ziptest2dir/ziptest3dir/_ziptest3', 'azsxdcfvgb'), + ('ziptest2dir/ziptest3dir/_ziptest3', 'azsxdcfvgb'), ('ziptest2dir/ziptest3dir/ziptest4dir/_ziptest3', '6y7u8i9o0p')] @@ -391,10 +391,7 @@ 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) @@ -414,10 +411,7 @@ 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) self.assertEqual(fdata, open(outfile, "rb").read()) os.remove(outfile) @@ -425,6 +419,80 @@ # 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 == '\\': + 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\ce|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(self): zipfp = zipfile.ZipFile(TESTFN2, "w") zipfp.writestr("a.txt", "hello world", compress_type=zipfile.ZIP_STORED) diff -r 6074530b526f -r 4d1948689ee1 Lib/zipfile.py --- a/Lib/zipfile.py Fri Feb 01 13:13:32 2013 +0200 +++ b/Lib/zipfile.py Fri Feb 01 11:40:18 2013 -0800 @@ -1040,17 +1040,22 @@ """ # 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] + arcname = member.filename.replace('/', os.path.sep) - # 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) + 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. diff -r 6074530b526f -r 4d1948689ee1 Misc/NEWS --- a/Misc/NEWS Fri Feb 01 13:13:32 2013 +0200 +++ b/Misc/NEWS Fri Feb 01 11:40:18 2013 -0800 @@ -202,6 +202,9 @@ Library ------- +- Issue #6972: The zipfile module no longer overwrites files outside of + its destination path when extracting malicious zip files. + - Issue #17049: Localized calendar methods now return unicode if a locale includes an encoding and the result string contains month or weekday (was regression from Python 2.6).