Apply performance patch from bug#901591

ChangeLog

@@ -1,3 +1,6 @@
+2012-02-03 Version 0.5.1
+    - Apply performance patch from <https://launchpad.net/bugs/901591>
+
 2011-10-26 Version 0.5
     - Add test case and fix for <https://launchpad.net/bugs/644046>
     - Add test case and fix for <https://launchpad.net/bugs/737311>

dkim/__init__.py

@@ -450,8 +450,7 @@ class DKIM(object):
     self.logger.debug("sign headers: %r" % self.signed_headers)
 
     try:
-        sig2 = RSASSA_PKCS1_v1_5_sign(
+        sig2 = RSASSA_PKCS1_v1_5_sign(h, pk)
-            h, pk['privateExponent'], pk['modulus'])
     except DigestTooLargeError:
         raise ParameterError("digest too large for modulus")
     sig_value += base64.b64encode(bytes(sig2))
@@ -545,8 +544,7 @@ class DKIM(object):
     try:
         self.signature_fields = sig
         signature = base64.b64decode(re.sub(br"\s+", b"", sig[b'b']))
-        return RSASSA_PKCS1_v1_5_verify(
+        return RSASSA_PKCS1_v1_5_verify(h, signature, pk)
-            h, signature, pk['publicExponent'], pk['modulus'])
     except (TypeError,DigestTooLargeError) as e:
         raise KeyFormatError("digest too large for modulus: %s"%e)
 

dkim/crypto.py

@@ -213,41 +213,60 @@ def int2str(n, length=-1):
     return r
 
 
-def perform_rsa(message, exponent, modulus, mlen):
+def rsa_decrypt(message, pk, mlen):
-    """Perform RSA signing or verification.
+    """Perform RSA decryption/signing
 
     @param message: byte string to operate on
-    @param exponent: public or private key exponent
+    @param pk: private key data
-    @param modulus: key modulus
     @param mlen: desired output length
     @return: byte string result of the operation
     """
-    return int2str(pow(str2int(message), exponent, modulus), mlen)
+    c = str2int(message)
+
+    m1 = pow(c, pk['exponent1'], pk['prime1'])
+    m2 = pow(c, pk['exponent2'], pk['prime2'])
+
+    if m1 < m2:
+        h = pk['coefficient'] * (m1 + pk['prime1'] - m2) % pk['prime1']
+    else:
+        h = pk['coefficient'] * (m1 - m2) % pk['prime1']
+
+    return int2str(m2 + h * pk['prime2'], mlen)
 
 
-def RSASSA_PKCS1_v1_5_sign(hash, private_exponent, modulus):
+def rsa_encrypt(message, pk, mlen):
+    """Perform RSA encryption/verification
+
+    @param message: byte string to operate on
+    @param pk: public key data
+    @param mlen: desired output length
+    @return: byte string result of the operation
+    """
+    m = str2int(message)
+    return int2str(pow(m, pk['publicExponent'], pk['modulus']), mlen)
+
+
+def RSASSA_PKCS1_v1_5_sign(hash, private_key):
     """Sign a digest with RFC3447 RSASSA-PKCS1-v1_5.
 
     @param hash: hash object to sign
-    @param private_exponent: private key exponent
+    @param private_key: private key data
-    @param modulus: key modulus
     @return: signed digest byte string
     """
-    modlen = len(int2str(modulus))
+    modlen = len(int2str(private_key['modulus']))
     encoded_digest = EMSA_PKCS1_v1_5_encode(hash, modlen)
-    return perform_rsa(encoded_digest, private_exponent, modulus, modlen)
+    return rsa_decrypt(encoded_digest, private_key, modlen)
 
 
-def RSASSA_PKCS1_v1_5_verify(hash, signature, public_exponent, modulus):
+def RSASSA_PKCS1_v1_5_verify(hash, signature, public_key):
     """Verify a digest signed with RFC3447 RSASSA-PKCS1-v1_5.
 
     @param hash: hash object to check
     @param signature: signed digest byte string
-    @param public_exponent: public key exponent
+    @param public_key: public key data
-    @param modulus: key modulus
     @return: True if the signature is valid, False otherwise
     """
-    modlen = len(int2str(modulus))
+    modlen = len(int2str(public_key['modulus']))
     encoded_digest = EMSA_PKCS1_v1_5_encode(hash, modlen)
-    signed_digest = perform_rsa(signature, public_exponent, modulus, modlen)
+    signed_digest = rsa_encrypt(signature, public_key, modlen)
     return encoded_digest == signed_digest

dkim/tests/test_crypto.py

@@ -27,7 +27,6 @@ from dkim.crypto import (
     int2str,
     parse_pem_private_key,
     parse_public_key,
-    perform_rsa,
     RSASSA_PKCS1_v1_5_sign,
     RSASSA_PKCS1_v1_5_verify,
     str2int,
@@ -50,6 +49,37 @@ TEST_KEY_PRIVATE_EXPONENT = int(
     '489900956461640273471526152019568303807247290486052565153701534491987040'
     '131529720476525111651818771481293273124837542067061293644354088836358900'
     '29771161475005043329')
+TEST_KEY_PRIME1 = int(
+    '127343333492908149956322715568115237787784712176275919666517073343689103'
+    '280591709737233188193431204382936008602497360201661766158158969883295914'
+    '16266272177')
+TEST_KEY_PRIME2 = int(
+    '125793967926229270607412639516115399484604596465353856808629588968254772'
+    '302339293254103556785310783521521266982500068526354237606773478050287350'
+    '33316975853')
+TEST_KEY_EXPONENT1 = int(
+    '971401692373919639404678505179789291960987093676634885925231250693661495'
+    '080125935714710587508461815572290443270923375888685273287584323569222368'
+    '5450962737')
+TEST_KEY_EXPONENT2 = int(
+    '405135004809332318340885085107137607293826268763328174261828392259785080'
+    '028911220030572618988900118679333717167345003034279703551607153395397272'
+    '3014807045')
+TEST_KEY_COEFFICIENT = int(
+    '933140693852464192207530806898449261372116224159220632563973880414444021'
+    '989007318611849609226428922185905596238131661588470844906391982906126973'
+    '1282880267')
+TEST_PK = {
+    'version': 0,
+    'modulus': TEST_KEY_MODULUS,
+    'publicExponent': TEST_KEY_PUBLIC_EXPONENT,
+    'privateExponent': TEST_KEY_PRIVATE_EXPONENT,
+    'prime1': TEST_KEY_PRIME1,
+    'prime2': TEST_KEY_PRIME2,
+    'exponent1': TEST_KEY_EXPONENT1,
+    'exponent2': TEST_KEY_EXPONENT2,
+    'coefficient': TEST_KEY_COEFFICIENT,
+}
 
 
 class TestStrIntConversion(unittest.TestCase):
@@ -71,9 +101,7 @@ class TestParseKeys(unittest.TestCase):
 
     def test_parse_pem_private_key(self):
         key = parse_pem_private_key(read_test_data('test.private'))
-        self.assertEqual(key['modulus'], TEST_KEY_MODULUS)
+        self.assertEqual(key, TEST_PK)
-        self.assertEqual(key['publicExponent'], TEST_KEY_PUBLIC_EXPONENT)
-        self.assertEqual(key['privateExponent'], TEST_KEY_PRIVATE_EXPONENT)
 
     def test_parse_public_key(self):
         data = read_test_data('test.txt')
@@ -109,27 +137,6 @@ class TestEMSA_PKCS1_v1_5(unittest.TestCase):
             EMSA_PKCS1_v1_5_encode, hash, 45)
 
 
-class TestRSA(unittest.TestCase):
-
-    message = binascii.unhexlify(b'0004fb')
-    modulus = 186101
-    modlen = 3
-    public_exponent = 907
-    private_exponent = 2851
-
-    def test_perform(self):
-        signed = perform_rsa(
-            self.message, self.private_exponent, self.modulus, self.modlen)
-        self.assertEqual(binascii.unhexlify(b'01f140'), signed)
-
-    def test_sign_and_verify(self):
-        signed = perform_rsa(
-            self.message, self.private_exponent, self.modulus, self.modlen)
-        unsigned = perform_rsa(
-            signed, self.public_exponent, self.modulus, self.modlen)
-        self.assertEqual(self.message, unsigned)
-
-
 class TestRSASSA(unittest.TestCase):
 
     def setUp(self):
@@ -144,19 +151,18 @@ class TestRSASSA(unittest.TestCase):
         b'39d2d6ab8b215b19be0e69ef490885004a474eb26d747a219693e8c')
 
     def test_sign_and_verify(self):
-        signature = RSASSA_PKCS1_v1_5_sign(
+        signature = RSASSA_PKCS1_v1_5_sign(self.hash, TEST_PK)
-            self.hash, TEST_KEY_PRIVATE_EXPONENT, TEST_KEY_MODULUS)
         self.assertEqual(self.test_signature, signature)
         self.assertTrue(
             RSASSA_PKCS1_v1_5_verify(
-                self.hash, signature, TEST_KEY_PUBLIC_EXPONENT,
+                self.hash, signature, TEST_PK))
-                TEST_KEY_MODULUS))
 
     def test_invalid_signature(self):
+        invalid_key = TEST_PK.copy()
+        invalid_key['modulus'] += 1
         self.assertFalse(
             RSASSA_PKCS1_v1_5_verify(
-                self.hash, self.test_signature, TEST_KEY_PUBLIC_EXPONENT,
+                self.hash, self.test_signature, invalid_key))
-                TEST_KEY_MODULUS + 1))
 
 
 def test_suite():