diff options
| -rw-r--r-- | Doc/library/hashlib.rst | 10 | ||||
| -rw-r--r-- | Lib/hmac.py | 20 | ||||
| -rw-r--r-- | Lib/test/test_hmac.py | 164 |
3 files changed, 186 insertions, 8 deletions
diff --git a/Doc/library/hashlib.rst b/Doc/library/hashlib.rst index 0f8a742..a725e07 100644 --- a/Doc/library/hashlib.rst +++ b/Doc/library/hashlib.rst @@ -52,6 +52,10 @@ spammish repetition'``:: >>> m.update(b" the spammish repetition") >>> m.digest() b'\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:: @@ -76,7 +80,11 @@ 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 1911689..6f2ae2e 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 = bytes((x ^ 0x5C) for x in range(256)) trans_36 = bytes((x ^ 0x36) for x in range(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). """ @@ -52,7 +54,21 @@ 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 c654e87..d8c03db 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(b"\x0b" * 20, @@ -75,6 +76,161 @@ class TestVectorsTestCase(unittest.TestCase): b"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 = b'\x0b'*20, + data = b'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 = b'Jefe', + data = b'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 = b'\xaa'*20, + data = b'\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 = bytes(x for x in range(0x01, 0x19+1)), + data = b'\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 = b'\xaa'*131, + data = b'Test Using Larger Than Block-Siz' + b'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 = b'\xaa'*131, + data = b'This is a test using a larger th' + b'an block-size key and a larger t' + b'han block-size data. The key nee' + b'ds to be hashed before being use' + b'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(b'a', b'b', digestmod=MockCrazyHash) + except RuntimeWarning: + pass + else: + self.fail('Expected warning about missing block_size') + + MockCrazyHash.block_size = 1 + try: + hmac.HMAC(b'a', b'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(b"key", b"", sha1) + h = hmac.HMAC(b"key", b"", 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(b"key") self.assertEqual(h.digest_cons, hashlib.md5) |