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authorGregory P. Smith <greg@mad-scientist.com>2007-11-06 00:19:03 (GMT)
committerGregory P. Smith <greg@mad-scientist.com>2007-11-06 00:19:03 (GMT)
commite1ac4f19301aa0a4d28fc25b91c71c477c37cb21 (patch)
treef73016435d33c9db6aff9667061b79ff92057718
parent91f9429bc34aa8879fd65fcbcbe81b5e923fc8cb (diff)
downloadcpython-e1ac4f19301aa0a4d28fc25b91c71c477c37cb21.zip
cpython-e1ac4f19301aa0a4d28fc25b91c71c477c37cb21.tar.gz
cpython-e1ac4f19301aa0a4d28fc25b91c71c477c37cb21.tar.bz2
Fixes Issue 1385: The hmac module now computes the correct hmac when using
hashes with a block size other than 64 bytes (such as sha384 and sha512).
-rw-r--r--Doc/library/hashlib.rst10
-rw-r--r--Lib/hmac.py20
-rw-r--r--Lib/test/test_hmac.py164
-rw-r--r--Misc/NEWS3
4 files changed, 189 insertions, 8 deletions
diff --git a/Doc/library/hashlib.rst b/Doc/library/hashlib.rst
index 59d65a7..8bba718 100644
--- a/Doc/library/hashlib.rst
+++ b/Doc/library/hashlib.rst
@@ -48,6 +48,10 @@ repetition'``::
>>> m.update(" the spammish repetition")
>>> m.digest()
'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'
+ >>> m.digest_size
+ 16
+ >>> m.block_size
+ 64
More condensed::
@@ -72,7 +76,11 @@ returned by the constructors:
.. data:: digest_size
- The size of the resulting digest in bytes.
+ The size of the resulting hash in bytes.
+
+.. data:: block_size
+
+ The internal block size of the hash algorithm in bytes.
A hash object has the following methods:
diff --git a/Lib/hmac.py b/Lib/hmac.py
index 88c3fd5..729ef38 100644
--- a/Lib/hmac.py
+++ b/Lib/hmac.py
@@ -3,6 +3,8 @@
Implements the HMAC algorithm as described by RFC 2104.
"""
+import warnings as _warnings
+
trans_5C = "".join ([chr (x ^ 0x5C) for x in xrange(256)])
trans_36 = "".join ([chr (x ^ 0x36) for x in xrange(256)])
@@ -16,7 +18,7 @@ digest_size = None
_secret_backdoor_key = []
class HMAC:
- """RFC2104 HMAC class.
+ """RFC 2104 HMAC class. Also complies with RFC 4231.
This supports the API for Cryptographic Hash Functions (PEP 247).
"""
@@ -48,7 +50,21 @@ class HMAC:
self.inner = self.digest_cons()
self.digest_size = self.inner.digest_size
- blocksize = self.blocksize
+ if hasattr(self.inner, 'block_size'):
+ blocksize = self.inner.block_size
+ if blocksize < 16:
+ # Very low blocksize, most likely a legacy value like
+ # Lib/sha.py and Lib/md5.py have.
+ _warnings.warn('block_size of %d seems too small; using our '
+ 'default of %d.' % (blocksize, self.blocksize),
+ RuntimeWarning, 2)
+ blocksize = self.blocksize
+ else:
+ _warnings.warn('No block_size attribute on given digest object; '
+ 'Assuming %d.' % (self.blocksize),
+ RuntimeWarning, 2)
+ blocksize = self.blocksize
+
if len(key) > blocksize:
key = self.digest_cons(key).digest()
diff --git a/Lib/test/test_hmac.py b/Lib/test/test_hmac.py
index d28490d..6c18715 100644
--- a/Lib/test/test_hmac.py
+++ b/Lib/test/test_hmac.py
@@ -1,6 +1,7 @@
import hmac
-from hashlib import sha1
+import hashlib
import unittest
+import warnings
from test import test_support
class TestVectorsTestCase(unittest.TestCase):
@@ -43,7 +44,7 @@ class TestVectorsTestCase(unittest.TestCase):
def test_sha_vectors(self):
def shatest(key, data, digest):
- h = hmac.HMAC(key, data, digestmod=sha1)
+ h = hmac.HMAC(key, data, digestmod=hashlib.sha1)
self.assertEqual(h.hexdigest().upper(), digest.upper())
shatest(chr(0x0b) * 20,
@@ -75,6 +76,161 @@ class TestVectorsTestCase(unittest.TestCase):
"and Larger Than One Block-Size Data"),
"e8e99d0f45237d786d6bbaa7965c7808bbff1a91")
+ def _rfc4231_test_cases(self, hashfunc):
+ def hmactest(key, data, hexdigests):
+ h = hmac.HMAC(key, data, digestmod=hashfunc)
+ self.assertEqual(h.hexdigest().lower(), hexdigests[hashfunc])
+
+ # 4.2. Test Case 1
+ hmactest(key = '\x0b'*20,
+ data = 'Hi There',
+ hexdigests = {
+ hashlib.sha224: '896fb1128abbdf196832107cd49df33f'
+ '47b4b1169912ba4f53684b22',
+ hashlib.sha256: 'b0344c61d8db38535ca8afceaf0bf12b'
+ '881dc200c9833da726e9376c2e32cff7',
+ hashlib.sha384: 'afd03944d84895626b0825f4ab46907f'
+ '15f9dadbe4101ec682aa034c7cebc59c'
+ 'faea9ea9076ede7f4af152e8b2fa9cb6',
+ hashlib.sha512: '87aa7cdea5ef619d4ff0b4241a1d6cb0'
+ '2379f4e2ce4ec2787ad0b30545e17cde'
+ 'daa833b7d6b8a702038b274eaea3f4e4'
+ 'be9d914eeb61f1702e696c203a126854',
+ })
+
+ # 4.3. Test Case 2
+ hmactest(key = 'Jefe',
+ data = 'what do ya want for nothing?',
+ hexdigests = {
+ hashlib.sha224: 'a30e01098bc6dbbf45690f3a7e9e6d0f'
+ '8bbea2a39e6148008fd05e44',
+ hashlib.sha256: '5bdcc146bf60754e6a042426089575c7'
+ '5a003f089d2739839dec58b964ec3843',
+ hashlib.sha384: 'af45d2e376484031617f78d2b58a6b1b'
+ '9c7ef464f5a01b47e42ec3736322445e'
+ '8e2240ca5e69e2c78b3239ecfab21649',
+ hashlib.sha512: '164b7a7bfcf819e2e395fbe73b56e0a3'
+ '87bd64222e831fd610270cd7ea250554'
+ '9758bf75c05a994a6d034f65f8f0e6fd'
+ 'caeab1a34d4a6b4b636e070a38bce737',
+ })
+
+ # 4.4. Test Case 3
+ hmactest(key = '\xaa'*20,
+ data = '\xdd'*50,
+ hexdigests = {
+ hashlib.sha224: '7fb3cb3588c6c1f6ffa9694d7d6ad264'
+ '9365b0c1f65d69d1ec8333ea',
+ hashlib.sha256: '773ea91e36800e46854db8ebd09181a7'
+ '2959098b3ef8c122d9635514ced565fe',
+ hashlib.sha384: '88062608d3e6ad8a0aa2ace014c8a86f'
+ '0aa635d947ac9febe83ef4e55966144b'
+ '2a5ab39dc13814b94e3ab6e101a34f27',
+ hashlib.sha512: 'fa73b0089d56a284efb0f0756c890be9'
+ 'b1b5dbdd8ee81a3655f83e33b2279d39'
+ 'bf3e848279a722c806b485a47e67c807'
+ 'b946a337bee8942674278859e13292fb',
+ })
+
+ # 4.5. Test Case 4
+ hmactest(key = ''.join([chr(x) for x in xrange(0x01, 0x19+1)]),
+ data = '\xcd'*50,
+ hexdigests = {
+ hashlib.sha224: '6c11506874013cac6a2abc1bb382627c'
+ 'ec6a90d86efc012de7afec5a',
+ hashlib.sha256: '82558a389a443c0ea4cc819899f2083a'
+ '85f0faa3e578f8077a2e3ff46729665b',
+ hashlib.sha384: '3e8a69b7783c25851933ab6290af6ca7'
+ '7a9981480850009cc5577c6e1f573b4e'
+ '6801dd23c4a7d679ccf8a386c674cffb',
+ hashlib.sha512: 'b0ba465637458c6990e5a8c5f61d4af7'
+ 'e576d97ff94b872de76f8050361ee3db'
+ 'a91ca5c11aa25eb4d679275cc5788063'
+ 'a5f19741120c4f2de2adebeb10a298dd',
+ })
+
+ # 4.7. Test Case 6
+ hmactest(key = '\xaa'*131,
+ data = 'Test Using Larger Than Block-Siz'
+ 'e Key - Hash Key First',
+ hexdigests = {
+ hashlib.sha224: '95e9a0db962095adaebe9b2d6f0dbce2'
+ 'd499f112f2d2b7273fa6870e',
+ hashlib.sha256: '60e431591ee0b67f0d8a26aacbf5b77f'
+ '8e0bc6213728c5140546040f0ee37f54',
+ hashlib.sha384: '4ece084485813e9088d2c63a041bc5b4'
+ '4f9ef1012a2b588f3cd11f05033ac4c6'
+ '0c2ef6ab4030fe8296248df163f44952',
+ hashlib.sha512: '80b24263c7c1a3ebb71493c1dd7be8b4'
+ '9b46d1f41b4aeec1121b013783f8f352'
+ '6b56d037e05f2598bd0fd2215d6a1e52'
+ '95e64f73f63f0aec8b915a985d786598',
+ })
+
+ # 4.8. Test Case 7
+ hmactest(key = '\xaa'*131,
+ data = 'This is a test using a larger th'
+ 'an block-size key and a larger t'
+ 'han block-size data. The key nee'
+ 'ds to be hashed before being use'
+ 'd by the HMAC algorithm.',
+ hexdigests = {
+ hashlib.sha224: '3a854166ac5d9f023f54d517d0b39dbd'
+ '946770db9c2b95c9f6f565d1',
+ hashlib.sha256: '9b09ffa71b942fcb27635fbcd5b0e944'
+ 'bfdc63644f0713938a7f51535c3a35e2',
+ hashlib.sha384: '6617178e941f020d351e2f254e8fd32c'
+ '602420feb0b8fb9adccebb82461e99c5'
+ 'a678cc31e799176d3860e6110c46523e',
+ hashlib.sha512: 'e37b6a775dc87dbaa4dfa9f96e5e3ffd'
+ 'debd71f8867289865df5a32d20cdc944'
+ 'b6022cac3c4982b10d5eeb55c3e4de15'
+ '134676fb6de0446065c97440fa8c6a58',
+ })
+
+ def test_sha224_rfc4231(self):
+ self._rfc4231_test_cases(hashlib.sha224)
+
+ def test_sha256_rfc4231(self):
+ self._rfc4231_test_cases(hashlib.sha256)
+
+ def test_sha384_rfc4231(self):
+ self._rfc4231_test_cases(hashlib.sha384)
+
+ def test_sha512_rfc4231(self):
+ self._rfc4231_test_cases(hashlib.sha512)
+
+ 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.digest_size = self._x.digest_size
+ def update(self, v):
+ self._x.update(v)
+ def digest(self):
+ return self._x.digest()
+
+ warnings.simplefilter('error', RuntimeWarning)
+ try:
+ try:
+ hmac.HMAC('a', 'b', digestmod=MockCrazyHash)
+ except RuntimeWarning:
+ pass
+ else:
+ self.fail('Expected warning about missing block_size')
+
+ MockCrazyHash.block_size = 1
+ try:
+ hmac.HMAC('a', 'b', digestmod=MockCrazyHash)
+ except RuntimeWarning:
+ pass
+ else:
+ self.fail('Expected warning about small block_size')
+ finally:
+ warnings.resetwarnings()
+
+
class ConstructorTestCase(unittest.TestCase):
@@ -95,9 +251,8 @@ class ConstructorTestCase(unittest.TestCase):
def test_withmodule(self):
# Constructor call with text and digest module.
- from hashlib import sha1
try:
- h = hmac.HMAC("key", "", sha1)
+ h = hmac.HMAC("key", "", hashlib.sha1)
except:
self.fail("Constructor call with hashlib.sha1 raised exception.")
@@ -106,7 +261,6 @@ class SanityTestCase(unittest.TestCase):
def test_default_is_md5(self):
# Testing if HMAC defaults to MD5 algorithm.
# NOTE: this whitebox test depends on the hmac class internals
- import hashlib
h = hmac.HMAC("key")
self.failUnless(h.digest_cons == hashlib.md5)
diff --git a/Misc/NEWS b/Misc/NEWS
index c2a93d3..502b182 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -364,6 +364,9 @@ Library
- md5 now raises a DeprecationWarning upon import.
+- Issue1385: The hmac module now computes the correct hmac when using hashes
+ with a block size other than 64 bytes (such as sha384 and sha512).
+
- mimify now raises a DeprecationWarning upon import.
- MimeWriter now raises a DeprecationWarning upon import.