bpo-40791: Use CRYPTO_memcmp() for compare_digest (#20456)
hashlib.compare_digest uses OpenSSL's CRYPTO_memcmp() function
when OpenSSL is available.
Note: The _operator module is a builtin module. I don't want to add
libcrypto dependency to libpython. Therefore I duplicated the wrapper
function and added a copy to _hashopenssl.c.
diff --git a/Lib/test/test_hmac.py b/Lib/test/test_hmac.py
index 7a52e39..6daf22c 100644
--- a/Lib/test/test_hmac.py
+++ b/Lib/test/test_hmac.py
@@ -8,12 +8,16 @@
from test.support import hashlib_helper
+from _operator import _compare_digest as operator_compare_digest
+
try:
from _hashlib import HMAC as C_HMAC
from _hashlib import hmac_new as c_hmac_new
+ from _hashlib import compare_digest as openssl_compare_digest
except ImportError:
C_HMAC = None
c_hmac_new = None
+ openssl_compare_digest = None
def ignore_warning(func):
@@ -505,87 +509,101 @@
class CompareDigestTestCase(unittest.TestCase):
- def test_compare_digest(self):
+ def test_hmac_compare_digest(self):
+ self._test_compare_digest(hmac.compare_digest)
+ if openssl_compare_digest is not None:
+ self.assertIs(hmac.compare_digest, openssl_compare_digest)
+ else:
+ self.assertIs(hmac.compare_digest, operator_compare_digest)
+
+ def test_operator_compare_digest(self):
+ self._test_compare_digest(operator_compare_digest)
+
+ @unittest.skipIf(openssl_compare_digest is None, "test requires _hashlib")
+ def test_openssl_compare_digest(self):
+ self._test_compare_digest(openssl_compare_digest)
+
+ def _test_compare_digest(self, compare_digest):
# Testing input type exception handling
a, b = 100, 200
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = 100, b"foobar"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = b"foobar", 200
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = "foobar", b"foobar"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = b"foobar", "foobar"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
# Testing bytes of different lengths
a, b = b"foobar", b"foo"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
a, b = b"\xde\xad\xbe\xef", b"\xde\xad"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing bytes of same lengths, different values
a, b = b"foobar", b"foobaz"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
a, b = b"\xde\xad\xbe\xef", b"\xab\xad\x1d\xea"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing bytes of same lengths, same values
a, b = b"foobar", b"foobar"
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
a, b = b"\xde\xad\xbe\xef", b"\xde\xad\xbe\xef"
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
# Testing bytearrays of same lengths, same values
a, b = bytearray(b"foobar"), bytearray(b"foobar")
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
# Testing bytearrays of different lengths
a, b = bytearray(b"foobar"), bytearray(b"foo")
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing bytearrays of same lengths, different values
a, b = bytearray(b"foobar"), bytearray(b"foobaz")
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing byte and bytearray of same lengths, same values
a, b = bytearray(b"foobar"), b"foobar"
- self.assertTrue(hmac.compare_digest(a, b))
- self.assertTrue(hmac.compare_digest(b, a))
+ self.assertTrue(compare_digest(a, b))
+ self.assertTrue(compare_digest(b, a))
# Testing byte bytearray of different lengths
a, b = bytearray(b"foobar"), b"foo"
- self.assertFalse(hmac.compare_digest(a, b))
- self.assertFalse(hmac.compare_digest(b, a))
+ self.assertFalse(compare_digest(a, b))
+ self.assertFalse(compare_digest(b, a))
# Testing byte and bytearray of same lengths, different values
a, b = bytearray(b"foobar"), b"foobaz"
- self.assertFalse(hmac.compare_digest(a, b))
- self.assertFalse(hmac.compare_digest(b, a))
+ self.assertFalse(compare_digest(a, b))
+ self.assertFalse(compare_digest(b, a))
# Testing str of same lengths
a, b = "foobar", "foobar"
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
# Testing str of different lengths
a, b = "foo", "foobar"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing bytes of same lengths, different values
a, b = "foobar", "foobaz"
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
# Testing error cases
a, b = "foobar", b"foobar"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = b"foobar", "foobar"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = b"foobar", 1
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = 100, 200
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
a, b = "fooä", "fooä"
- self.assertRaises(TypeError, hmac.compare_digest, a, b)
+ self.assertRaises(TypeError, compare_digest, a, b)
# subclasses are supported by ignore __eq__
class mystr(str):
@@ -593,22 +611,22 @@
return False
a, b = mystr("foobar"), mystr("foobar")
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
a, b = mystr("foobar"), "foobar"
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
a, b = mystr("foobar"), mystr("foobaz")
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
class mybytes(bytes):
def __eq__(self, other):
return False
a, b = mybytes(b"foobar"), mybytes(b"foobar")
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
a, b = mybytes(b"foobar"), b"foobar"
- self.assertTrue(hmac.compare_digest(a, b))
+ self.assertTrue(compare_digest(a, b))
a, b = mybytes(b"foobar"), mybytes(b"foobaz")
- self.assertFalse(hmac.compare_digest(a, b))
+ self.assertFalse(compare_digest(a, b))
if __name__ == "__main__":