refacor of PKCS8 parsing, added pkcs8 test

dkim/crypto.py

@@ -145,8 +145,14 @@ def parse_private_key(data):
     """
     try:
         pka = asn1_parse(ASN1_RSAPrivateKey, data)
-    except ASN1FormatError as e:
+    except ASN1FormatError:
-        raise UnparsableKeyError('Unparsable private key: ' + str(e))
+        try:
+            #If it fails it might be because of PKCS#8 (key generated with openSSL 3.X)
+            pkt = asn1_parse(ASN1_PKCS8_PrivateKey, data)
+            pka = asn1_parse(ASN1_RSAPrivateKey, pkt[0][2])
+        except ASN1FormatError as e:
+            raise UnparsableKeyError("Unparsable private key (are your sure it is encoded in PKCS#1 or PKCS#8 standard ?):\n" + str(e))
+
     pk = {
         'version': pka[0][0],
         'modulus': pka[0][1],
@@ -174,13 +180,7 @@ def parse_pem_private_key(data):
         pkdata = base64.b64decode(m.group(1))
     except TypeError as e:
         raise UnparsableKeyError(str(e))
-    try:
+    return parse_private_key(pkdata)
-        pk = parse_private_key(pkdata)
-    except UnparsableKeyError:
-        #If it fails it might be because of PKCS#8 (key generated with openSSL 3.X)
-        pka = asn1_parse(ASN1_PKCS8_PrivateKey, pkdata)
-        pk = parse_private_key(pka[0][2])
-    return pk
 
 
 def EMSA_PKCS1_v1_5_encode(hash, mlen):

dkim/tests/data/2048_testkey_PKCS8.key

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

dkim/tests/data/2048_testkey_PKCS8.key.pub.txt

@@ -0,0 +1 @@
+v=DKIM1; g=*; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA2DBoRKJN+F4lILMzu3LmKYf3cNJZYiNfPsMF9Mm1DcI5JnPPY30TWejhBeQX7sjGAKBwfeg/RISACKl845rxbY2SK2E8s29l/+Appe7sRi4npEhY6wDS9Zsm4N+hSnjAFefbNO/PviK3EE669ROnu6tdu/2EcAhsvimUNEpdgqy/iHT7giuVgCbWE9c0P4dz0P8VHBy51LXpuQToq4O7MHqMXX2VrF7u1nhg2IhTjleaTJnbnhX7p+QiXvDH3RCeGLF6sQsWtsqqzZJZF+EUqYRH8K3lP7L9A7Fo/3mlphQ4WoL3dgMIsSHf5RWBrGNl+xum7P0qk4aAZPRn7URooQIDAQAB

dkim/tests/test_dkim_rsavariants.py

@@ -41,6 +41,7 @@ class TestSignAndVerify(unittest.TestCase):
         self.message = read_test_data("test.message")
         self.key1024 = read_test_data("1024_testkey.key")
         self.key2048 = read_test_data("2048_testkey.key")
+        self.key2048PKCS8 = read_test_data("2048_testkey_PKCS8.key")
 
     def dnsfunc(self, domain, timeout=5):
         _dns_responses = {
@@ -48,6 +49,7 @@ class TestSignAndVerify(unittest.TestCase):
           'test2._domainkey.example.com.': read_test_data("1024_testkey_wo_markers.pub.rsa.txt"),
           'test3._domainkey.example.com.': read_test_data("2048_testkey_wo_markers.pub.txt"),
           'test4._domainkey.example.com.': read_test_data("2048_testkey_wo_markers.pub.rsa.txt"),
+          'test5._domainkey.example.com.': read_test_data("2048_testkey_PKCS8.key.pub.txt")
         }
         try:
             domain = domain.decode('ascii')
@@ -56,7 +58,6 @@ class TestSignAndVerify(unittest.TestCase):
         self.assertTrue(domain in _dns_responses,domain)
         return _dns_responses[domain]
 
-
     def test_verifies_SubjectPublicKeyInfo1024(self):
         # A message verifies after being signed.
         for header_algo in (b"simple", b"relaxed"):
@@ -67,8 +68,6 @@ class TestSignAndVerify(unittest.TestCase):
                 res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
                 self.assertTrue(res)
 
-
-
     def test_verifies_RSAPublicKey1024(self):
         # A message verifies after being signed.
         for header_algo in (b"simple", b"relaxed"):
@@ -102,6 +101,16 @@ class TestSignAndVerify(unittest.TestCase):
                 self.assertTrue(res)
 
 
+    def test_verifies_RSAPublicKey2048PKCS8(self):
+        #A message verifies after being signed (with PKCS8 private key)
+        for header_algo in (b"simple", b"relaxed"):
+            for body_algo in (b"simple", b"relaxed"):
+                sig = dkim.sign(
+                    self.message, b"test5", b"example.com", self.key2048PKCS8,
+                    canonicalize=(header_algo, body_algo))
+                res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
+                self.assertTrue(res)
+
 def test_suite():
     from unittest import TestLoader
     return TestLoader().loadTestsFromName(__name__)