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bpo-38270: Check for hash digest algorithms and avoid MD5 (GH-16382) 

Make it easier to run and test Python on systems with restrict crypto policies:

* add requires_hashdigest to test.support to check if a hash digest algorithm is available and working
* avoid MD5 in test_hmac
* replace MD5 with SHA256 in test_tarfile
* mark network tests that require MD5 for MD5-based digest auth or CRAM-MD5


https://bugs.python.org/issue38270
This commit is contained in:
Christian Heimes 2019-09-25 16:30:20 +02:00 committed by Miss Islington (bot)
parent 417089e88b
commit c64a1a61e6
8 changed files with 119 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
Lib/test/support/__init__.py
View File

@ -12,6 +12,7 @@ import fnmatch
import functools
import gc
import glob
import hashlib
import importlib
import importlib.util
import locale
@ -648,6 +649,29 @@ def requires_mac_ver(*min_version):
return decorator
def requires_hashdigest(digestname):
"""Decorator raising SkipTest if a hashing algorithm is not available
The hashing algorithm could be missing or blocked by a strict crypto
policy.
ValueError: [digital envelope routines: EVP_DigestInit_ex] disabled for FIPS
ValueError: unsupported hash type md4
"""
def decorator(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
try:
hashlib.new(digestname)
except ValueError:
raise unittest.SkipTest(
f"hash digest '{digestname}' is not available."
)
return func(*args, **kwargs)
return wrapper
return decorator
HOST = "localhost"
HOSTv4 = "127.0.0.1"
HOSTv6 = "::1"

60
Lib/test/test_hmac.py
View File

@ -6,6 +6,8 @@ import unittest
import unittest.mock
import warnings
from test.support import requires_hashdigest
def ignore_warning(func):
@functools.wraps(func)
@ -19,6 +21,7 @@ def ignore_warning(func):
class TestVectorsTestCase(unittest.TestCase):
@requires_hashdigest('md5')
def test_md5_vectors(self):
# Test the HMAC module against test vectors from the RFC.
@ -76,6 +79,7 @@ class TestVectorsTestCase(unittest.TestCase):
b"and Larger Than One Block-Size Data"),
"6f630fad67cda0ee1fb1f562db3aa53e")
@requires_hashdigest('sha1')
def test_sha_vectors(self):
def shatest(key, data, digest):
h = hmac.HMAC(key, data, digestmod=hashlib.sha1)
@ -268,23 +272,28 @@ class TestVectorsTestCase(unittest.TestCase):
'134676fb6de0446065c97440fa8c6a58',
})
@requires_hashdigest('sha224')
def test_sha224_rfc4231(self):
self._rfc4231_test_cases(hashlib.sha224, 'sha224', 28, 64)
@requires_hashdigest('sha256')
def test_sha256_rfc4231(self):
self._rfc4231_test_cases(hashlib.sha256, 'sha256', 32, 64)
@requires_hashdigest('sha384')
def test_sha384_rfc4231(self):
self._rfc4231_test_cases(hashlib.sha384, 'sha384', 48, 128)
@requires_hashdigest('sha512')
def test_sha512_rfc4231(self):
self._rfc4231_test_cases(hashlib.sha512, 'sha512', 64, 128)
@requires_hashdigest('sha256')
def test_legacy_block_size_warnings(self):
class MockCrazyHash(object):
"""Ain't no block_size attribute here."""
def __init__(self, *args):
self._x = hashlib.sha1(*args)
self._x = hashlib.sha256(*args)
self.digest_size = self._x.digest_size
def update(self, v):
self._x.update(v)
@ -308,65 +317,78 @@ class TestVectorsTestCase(unittest.TestCase):
data = b"Hi There"
hmac.HMAC(key, data, digestmod=None)
class ConstructorTestCase(unittest.TestCase):
expected = (
"6c845b47f52b3b47f6590c502db7825aad757bf4fadc8fa972f7cd2e76a5bdeb"
)
@requires_hashdigest('sha256')
def test_normal(self):
# Standard constructor call.
failed = 0
try:
h = hmac.HMAC(b"key", digestmod='md5')
hmac.HMAC(b"key", digestmod='sha256')
except Exception:
self.fail("Standard constructor call raised exception.")
@requires_hashdigest('sha256')
def test_with_str_key(self):
# Pass a key of type str, which is an error, because it expects a key
# of type bytes
with self.assertRaises(TypeError):
h = hmac.HMAC("key", digestmod='md5')
h = hmac.HMAC("key", digestmod='sha256')
@requires_hashdigest('sha256')
def test_dot_new_with_str_key(self):
# Pass a key of type str, which is an error, because it expects a key
# of type bytes
with self.assertRaises(TypeError):
h = hmac.new("key", digestmod='md5')
h = hmac.new("key", digestmod='sha256')
@requires_hashdigest('sha256')
def test_withtext(self):
# Constructor call with text.
try:
h = hmac.HMAC(b"key", b"hash this!", digestmod='md5')
h = hmac.HMAC(b"key", b"hash this!", digestmod='sha256')
except Exception:
self.fail("Constructor call with text argument raised exception.")
self.assertEqual(h.hexdigest(), '34325b639da4cfd95735b381e28cb864')
self.assertEqual(h.hexdigest(), self.expected)
@requires_hashdigest('sha256')
def test_with_bytearray(self):
try:
h = hmac.HMAC(bytearray(b"key"), bytearray(b"hash this!"),
digestmod="md5")
digestmod="sha256")
except Exception:
self.fail("Constructor call with bytearray arguments raised exception.")
self.assertEqual(h.hexdigest(), '34325b639da4cfd95735b381e28cb864')
self.assertEqual(h.hexdigest(), self.expected)
@requires_hashdigest('sha256')
def test_with_memoryview_msg(self):
try:
h = hmac.HMAC(b"key", memoryview(b"hash this!"), digestmod="md5")
h = hmac.HMAC(b"key", memoryview(b"hash this!"), digestmod="sha256")
except Exception:
self.fail("Constructor call with memoryview msg raised exception.")
self.assertEqual(h.hexdigest(), '34325b639da4cfd95735b381e28cb864')
self.assertEqual(h.hexdigest(), self.expected)
@requires_hashdigest('sha256')
def test_withmodule(self):
# Constructor call with text and digest module.
try:
h = hmac.HMAC(b"key", b"", hashlib.sha1)
h = hmac.HMAC(b"key", b"", hashlib.sha256)
except Exception:
self.fail("Constructor call with hashlib.sha1 raised exception.")
self.fail("Constructor call with hashlib.sha256 raised exception.")
class SanityTestCase(unittest.TestCase):
@requires_hashdigest('sha256')
def test_exercise_all_methods(self):
# Exercising all methods once.
# This must not raise any exceptions
try:
h = hmac.HMAC(b"my secret key", digestmod="md5")
h = hmac.HMAC(b"my secret key", digestmod="sha256")
h.update(b"compute the hash of this text!")
dig = h.digest()
dig = h.hexdigest()
@ -374,11 +396,13 @@ class SanityTestCase(unittest.TestCase):
except Exception:
self.fail("Exception raised during normal usage of HMAC class.")
class CopyTestCase(unittest.TestCase):
@requires_hashdigest('sha256')
def test_attributes(self):
# Testing if attributes are of same type.
h1 = hmac.HMAC(b"key", digestmod="md5")
h1 = hmac.HMAC(b"key", digestmod="sha256")
h2 = h1.copy()
self.assertTrue(h1.digest_cons == h2.digest_cons,
"digest constructors don't match.")
@ -387,9 +411,10 @@ class CopyTestCase(unittest.TestCase):
self.assertEqual(type(h1.outer), type(h2.outer),
"Types of outer don't match.")
@requires_hashdigest('sha256')
def test_realcopy(self):
# Testing if the copy method created a real copy.
h1 = hmac.HMAC(b"key", digestmod="md5")
h1 = hmac.HMAC(b"key", digestmod="sha256")
h2 = h1.copy()
# Using id() in case somebody has overridden __eq__/__ne__.
self.assertTrue(id(h1) != id(h2), "No real copy of the HMAC instance.")
@ -398,9 +423,10 @@ class CopyTestCase(unittest.TestCase):
self.assertTrue(id(h1.outer) != id(h2.outer),
"No real copy of the attribute 'outer'.")
@requires_hashdigest('sha256')
def test_equality(self):
# Testing if the copy has the same digests.
h1 = hmac.HMAC(b"key", digestmod="md5")
h1 = hmac.HMAC(b"key", digestmod="sha256")
h1.update(b"some random text")
h2 = h1.copy()
self.assertEqual(h1.digest(), h2.digest(),

6
Lib/test/test_imaplib.py
View File

@ -10,7 +10,8 @@ import threading
import socket
from test.support import (reap_threads, verbose, transient_internet,
run_with_tz, run_with_locale, cpython_only)
run_with_tz, run_with_locale, cpython_only,
requires_hashdigest)
import unittest
from unittest import mock
from datetime import datetime, timezone, timedelta
@ -370,6 +371,7 @@ class NewIMAPTestsMixin():
self.assertEqual(code, 'OK')
self.assertEqual(server.response, b'ZmFrZQ==\r\n') # b64 encoded 'fake'
@requires_hashdigest('md5')
def test_login_cram_md5_bytes(self):
class AuthHandler(SimpleIMAPHandler):
capabilities = 'LOGINDISABLED AUTH=CRAM-MD5'
@ -387,6 +389,7 @@ class NewIMAPTestsMixin():
ret, _ = client.login_cram_md5("tim", b"tanstaaftanstaaf")
self.assertEqual(ret, "OK")
@requires_hashdigest('md5')
def test_login_cram_md5_plain_text(self):
class AuthHandler(SimpleIMAPHandler):
capabilities = 'LOGINDISABLED AUTH=CRAM-MD5'
@ -797,6 +800,7 @@ class ThreadedNetworkedTests(unittest.TestCase):
b'ZmFrZQ==\r\n') # b64 encoded 'fake'
@reap_threads
@requires_hashdigest('md5')
def test_login_cram_md5(self):
class AuthHandler(SimpleIMAPHandler):

2
Lib/test/test_poplib.py
View File

@ -309,9 +309,11 @@ class TestPOP3Class(TestCase):
def test_rpop(self):
self.assertOK(self.client.rpop('foo'))
@test_support.requires_hashdigest('md5')
def test_apop_normal(self):
self.assertOK(self.client.apop('foo', 'dummypassword'))
@test_support.requires_hashdigest('md5')
def test_apop_REDOS(self):
# Replace welcome with very long evil welcome.
# NB The upper bound on welcome length is currently 2048.

11
Lib/test/test_smtplib.py
View File

@ -4,6 +4,7 @@ import email.mime.text
from email.message import EmailMessage
from email.base64mime import body_encode as encode_base64
import email.utils
import hashlib
import hmac
import socket
import smtpd
@ -21,6 +22,7 @@ import unittest
from test import support, mock_socket
from test.support import HOST
from test.support import threading_setup, threading_cleanup, join_thread
from test.support import requires_hashdigest
from unittest.mock import Mock
@ -1009,6 +1011,7 @@ class SMTPSimTests(unittest.TestCase):
self.assertEqual(resp, (235, b'Authentication Succeeded'))
smtp.close()
@requires_hashdigest('md5')
def testAUTH_CRAM_MD5(self):
self.serv.add_feature("AUTH CRAM-MD5")
smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=15)
@ -1025,7 +1028,13 @@ class SMTPSimTests(unittest.TestCase):
smtp.close()
def test_auth_function(self):
supported = {'CRAM-MD5', 'PLAIN', 'LOGIN'}
supported = {'PLAIN', 'LOGIN'}
try:
hashlib.md5()
except ValueError:
pass
else:
supported.add('CRAM-MD5')
for mechanism in supported:
self.serv.add_feature("AUTH {}".format(mechanism))
for mechanism in supported:

56
Lib/test/test_tarfile.py
View File

@ -1,7 +1,7 @@
import sys
import os
import io
from hashlib import md5
from hashlib import sha256
from contextlib import contextmanager
from random import Random
import pathlib
@ -11,7 +11,7 @@ import unittest.mock
import tarfile
from test import support
from test.support import script_helper
from test.support import script_helper, requires_hashdigest
# Check for our compression modules.
try:
@ -27,8 +27,8 @@ try:
except ImportError:
lzma = None
def md5sum(data):
return md5(data).hexdigest()
def sha256sum(data):
return sha256(data).hexdigest()
TEMPDIR = os.path.abspath(support.TESTFN) + "-tardir"
tarextdir = TEMPDIR + '-extract-test'
@ -39,8 +39,12 @@ xzname = os.path.join(TEMPDIR, "testtar.tar.xz")
tmpname = os.path.join(TEMPDIR, "tmp.tar")
dotlessname = os.path.join(TEMPDIR, "testtar")
md5_regtype = "65f477c818ad9e15f7feab0c6d37742f"
md5_sparse = "a54fbc4ca4f4399a90e1b27164012fc6"
sha256_regtype = (
"e09e4bc8b3c9d9177e77256353b36c159f5f040531bbd4b024a8f9b9196c71ce"
)
sha256_sparse = (
"4f05a776071146756345ceee937b33fc5644f5a96b9780d1c7d6a32cdf164d7b"
)
class TarTest:
@ -95,7 +99,7 @@ class UstarReadTest(ReadTest, unittest.TestCase):
data = fobj.read()
self.assertEqual(len(data), tarinfo.size,
"regular file extraction failed")
self.assertEqual(md5sum(data), md5_regtype,
self.assertEqual(sha256sum(data), sha256_regtype,
"regular file extraction failed")
def test_fileobj_readlines(self):
@ -178,7 +182,7 @@ class UstarReadTest(ReadTest, unittest.TestCase):
with self.tar.extractfile("ustar/regtype") as fobj:
fobj = io.TextIOWrapper(fobj)
data = fobj.read().encode("iso8859-1")
self.assertEqual(md5sum(data), md5_regtype)
self.assertEqual(sha256sum(data), sha256_regtype)
try:
fobj.seek(100)
except AttributeError:
@ -543,13 +547,13 @@ class MiscReadTestBase(CommonReadTest):
self.addCleanup(support.unlink, os.path.join(TEMPDIR, "ustar/lnktype"))
with open(os.path.join(TEMPDIR, "ustar/lnktype"), "rb") as f:
data = f.read()
self.assertEqual(md5sum(data), md5_regtype)
self.assertEqual(sha256sum(data), sha256_regtype)
tar.extract("ustar/symtype", TEMPDIR)
self.addCleanup(support.unlink, os.path.join(TEMPDIR, "ustar/symtype"))
with open(os.path.join(TEMPDIR, "ustar/symtype"), "rb") as f:
data = f.read()
self.assertEqual(md5sum(data), md5_regtype)
self.assertEqual(sha256sum(data), sha256_regtype)
def test_extractall(self):
# Test if extractall() correctly restores directory permissions
@ -684,7 +688,7 @@ class StreamReadTest(CommonReadTest, unittest.TestCase):
data = fobj.read()
self.assertEqual(len(data), tarinfo.size,
"regular file extraction failed")
self.assertEqual(md5sum(data), md5_regtype,
self.assertEqual(sha256sum(data), sha256_regtype,
"regular file extraction failed")
def test_provoke_stream_error(self):
@ -796,8 +800,8 @@ class MemberReadTest(ReadTest, unittest.TestCase):
def _test_member(self, tarinfo, chksum=None, **kwargs):
if chksum is not None:
with self.tar.extractfile(tarinfo) as f:
self.assertEqual(md5sum(f.read()), chksum,
"wrong md5sum for %s" % tarinfo.name)
self.assertEqual(sha256sum(f.read()), chksum,
"wrong sha256sum for %s" % tarinfo.name)
kwargs["mtime"] = 0o7606136617
kwargs["uid"] = 1000
@ -812,11 +816,11 @@ class MemberReadTest(ReadTest, unittest.TestCase):
def test_find_regtype(self):
tarinfo = self.tar.getmember("ustar/regtype")
self._test_member(tarinfo, size=7011, chksum=md5_regtype)
self._test_member(tarinfo, size=7011, chksum=sha256_regtype)
def test_find_conttype(self):
tarinfo = self.tar.getmember("ustar/conttype")
self._test_member(tarinfo, size=7011, chksum=md5_regtype)
self._test_member(tarinfo, size=7011, chksum=sha256_regtype)
def test_find_dirtype(self):
tarinfo = self.tar.getmember("ustar/dirtype")
@ -848,28 +852,28 @@ class MemberReadTest(ReadTest, unittest.TestCase):
def test_find_sparse(self):
tarinfo = self.tar.getmember("ustar/sparse")
self._test_member(tarinfo, size=86016, chksum=md5_sparse)
self._test_member(tarinfo, size=86016, chksum=sha256_sparse)
def test_find_gnusparse(self):
tarinfo = self.tar.getmember("gnu/sparse")
self._test_member(tarinfo, size=86016, chksum=md5_sparse)
self._test_member(tarinfo, size=86016, chksum=sha256_sparse)
def test_find_gnusparse_00(self):
tarinfo = self.tar.getmember("gnu/sparse-0.0")
self._test_member(tarinfo, size=86016, chksum=md5_sparse)
self._test_member(tarinfo, size=86016, chksum=sha256_sparse)
def test_find_gnusparse_01(self):
tarinfo = self.tar.getmember("gnu/sparse-0.1")
self._test_member(tarinfo, size=86016, chksum=md5_sparse)
self._test_member(tarinfo, size=86016, chksum=sha256_sparse)
def test_find_gnusparse_10(self):
tarinfo = self.tar.getmember("gnu/sparse-1.0")
self._test_member(tarinfo, size=86016, chksum=md5_sparse)
self._test_member(tarinfo, size=86016, chksum=sha256_sparse)
def test_find_umlauts(self):
tarinfo = self.tar.getmember("ustar/umlauts-"
"\xc4\xd6\xdc\xe4\xf6\xfc\xdf")
self._test_member(tarinfo, size=7011, chksum=md5_regtype)
self._test_member(tarinfo, size=7011, chksum=sha256_regtype)
def test_find_ustar_longname(self):
name = "ustar/" + "12345/" * 39 + "1234567/longname"
@ -877,7 +881,7 @@ class MemberReadTest(ReadTest, unittest.TestCase):
def test_find_regtype_oldv7(self):
tarinfo = self.tar.getmember("misc/regtype-old-v7")
self._test_member(tarinfo, size=7011, chksum=md5_regtype)
self._test_member(tarinfo, size=7011, chksum=sha256_regtype)
def test_find_pax_umlauts(self):
self.tar.close()
@ -885,7 +889,7 @@ class MemberReadTest(ReadTest, unittest.TestCase):
encoding="iso8859-1")
tarinfo = self.tar.getmember("pax/umlauts-"
"\xc4\xd6\xdc\xe4\xf6\xfc\xdf")
self._test_member(tarinfo, size=7011, chksum=md5_regtype)
self._test_member(tarinfo, size=7011, chksum=sha256_regtype)
class LongnameTest:
@ -947,8 +951,8 @@ class GNUReadTest(LongnameTest, ReadTest, unittest.TestCase):
filename = os.path.join(TEMPDIR, name)
with open(filename, "rb") as fobj:
data = fobj.read()
self.assertEqual(md5sum(data), md5_sparse,
"wrong md5sum for %s" % name)
self.assertEqual(sha256sum(data), sha256_sparse,
"wrong sha256sum for %s" % name)
if self._fs_supports_holes():
s = os.stat(filename)
@ -2443,7 +2447,7 @@ class LinkEmulationTest(ReadTest, unittest.TestCase):
self.tar.extract(name, TEMPDIR)
with open(os.path.join(TEMPDIR, name), "rb") as f:
data = f.read()
self.assertEqual(md5sum(data), md5_regtype)
self.assertEqual(sha256sum(data), sha256_regtype)
# See issues #1578269, #8879, and #17689 for some history on these skips
@unittest.skipIf(hasattr(os.path, "islink"),

1
Lib/test/test_urllib2_localnet.py
View File

@ -322,6 +322,7 @@ class ProxyAuthTests(unittest.TestCase):
PASSWD = "test123"
REALM = "TestRealm"
@support.requires_hashdigest("md5")
def setUp(self):
super(ProxyAuthTests, self).setUp()
# Ignore proxy bypass settings in the environment.

4
Misc/NEWS.d/next/Tests/2019-09-25-12-18-31.bpo-38270._x-9uH.rst Normal file
View File

@ -0,0 +1,4 @@
test.support now has a helper function to check for availibility of a
hash digest function. Several tests are refactored avoid MD5 and use
SHA256 instead. Other tests are marked to use MD5 and skipped when MD5 is
disabled.