Merge pull request #6 from chadgates/extract_certificate_info

Extract certificate information to dictionary function.

pyas2lib/utils.py

@@ -8,6 +8,7 @@
 from io import BytesIO
 
 from pyas2lib.exceptions import AS2Exception
+from datetime import datetime
 
 
 def unquote_as2name(quoted_name):
@@ -185,3 +186,50 @@ def verify_certificate_chain(cert_str, trusted_certs, ignore_self_signed=True):
 
     except crypto.X509StoreContextError as e:
         raise AS2Exception('Partner Certificate Invalid: %s' % e.args[-1][-1])
+
+
+def extract_certificate_info(cert):
+    """
+    Extract validity information from the certificate and return a dictionary.
+    Provide either key with certificate (private) or public certificate
+    :param cert: the certificate as byte string in PEM or DER format
+    :return: a dictionary holding certificate information:
+                valid_from (datetime)
+                valid_to (datetime)
+                subject (list of name, value tuples)
+                issuer (list of name, value tuples)
+                serial (int)
+    """
+
+    # initialize the cert_info dictionary
+    cert_info = {
+        'valid_from': None,
+        'valid_to': None,
+        'subject': None,
+        'issuer': None,
+        'serial': None
+    }
+
+    # get certificate to DER list
+    der = pem_to_der(cert)
+
+    # iterate through the list to find the certificate
+    for _item in der:
+        try:
+            # load the certificate. if element is key, exception is triggered and next element is tried
+            certificate = crypto.load_certificate(crypto.FILETYPE_ASN1, _item)
+
+            # on successful load, extract the various fields into the dictionary
+            cert_info['valid_from'] = datetime.strptime(certificate.get_notBefore().decode('utf8'), "%Y%m%d%H%M%SZ")
+            cert_info['valid_to'] = datetime.strptime(certificate.get_notAfter().decode('utf8'), "%Y%m%d%H%M%SZ")
+            cert_info['subject'] = [tuple(item.decode('utf8') for item in sets)
+                                    for sets in certificate.get_subject().get_components()]
+            cert_info['issuer'] = [tuple(item.decode('utf8') for item in sets)
+                                   for sets in certificate.get_issuer().get_components()]
+            cert_info['serial'] = certificate.get_serial_number()
+            break
+        except crypto.Error:
+            continue
+
+    # return the dictionary
+    return cert_info

tests/__init__.py

@@ -3,7 +3,7 @@
 import sys
 sys.path.insert(0, os.path.abspath('..'))
 
-from pyas2lib import as2, exceptions
+from pyas2lib import as2, exceptions, utils
 
 
 class Pyas2TestCase(unittest.TestCase):
@@ -46,3 +46,19 @@ def setUpClass(cls):
         with open(os.path.join(
                 cls.TEST_DIR, 'cert_sb2bi_public.ca'), 'rb') as fp:
             cls.sb2bi_public_ca = fp.read()
+
+        with open(os.path.join(
+                cls.TEST_DIR, 'cert_extract_private.cer'), 'rb') as fp:
+            cls.private_cer = fp.read()
+
+        with open(os.path.join(
+                cls.TEST_DIR, 'cert_extract_private.pem'), 'rb') as fp:
+            cls.private_pem = fp.read()
+
+        with open(os.path.join(
+                cls.TEST_DIR, 'cert_extract_public.cer'), 'rb') as fp:
+            cls.public_pem = fp.read()
+
+        with open(os.path.join(
+                cls.TEST_DIR, 'cert_extract_public.cer'), 'rb') as fp:
+            cls.public_cer = fp.read()

tests/fixtures/cert_extract_private.pem

@@ -0,0 +1,49 @@
+-----BEGIN ENCRYPTED PRIVATE KEY-----
+MIIFHzBJBgkqhkiG9w0BBQ0wPDAbBgkqhkiG9w0BBQwwDgQIgfSzwLtO4wsCAggA
+MB0GCWCGSAFlAwQBKgQQfAIjuBBfqCedJyQh0fvnRASCBNDbGjojvuy02uUpmPCr
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+xdyjWRJ0zmheL2NFYxIAmlrOquMwHMkU8YJb+9jI6RkNq8szkFenIKfCMgb9yfrX
+P0aGOz3AvKRlTpcIgY1TDNoGQ0pSlMjW/VmhJJEfeOjbsQdJVr+XObmggXBYv8wE
+DJhQXvVSV83iuyq7rCuEEjPs5gpKkq+K5AqXmTtJzFtVMcQ/BmJdVDssPEnjNmL8
+visz5I234/hl2utyZOj4yTSiYg==
+-----END ENCRYPTED PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----
+MIIDBDCCAewCCQC+x6S5XDiB+TANBgkqhkiG9w0BAQsFADBEMQswCQYDVQQGEwJB
+VTETMBEGA1UECAwKU29tZS1TdGF0ZTERMA8GA1UECgwIcHlhczJsaWIxDTALBgNV
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+bIUOY/Wbp1BQvVEBxALc34yxWOcUbSamIm6KYSLoMpWOsZAoyuQa2rAXIwAZwejY
+9RfBSn/YWSo=
+-----END CERTIFICATE-----

tests/fixtures/cert_extract_public.pem

@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----
+MIIDBDCCAewCCQC+x6S5XDiB+TANBgkqhkiG9w0BAQsFADBEMQswCQYDVQQGEwJB
+VTETMBEGA1UECAwKU29tZS1TdGF0ZTERMA8GA1UECgwIcHlhczJsaWIxDTALBgNV
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+bIUOY/Wbp1BQvVEBxALc34yxWOcUbSamIm6KYSLoMpWOsZAoyuQa2rAXIwAZwejY
+9RfBSn/YWSo=
+-----END CERTIFICATE-----

tests/test_advanced.py

@@ -1,8 +1,8 @@
 from __future__ import unicode_literals, absolute_import, print_function
-from . import Pyas2TestCase, as2
+from . import Pyas2TestCase, as2, utils
 import os
 import base64
-
+import datetime
 
 class TestAdvanced(Pyas2TestCase):
 
@@ -325,6 +325,28 @@ def test_load_private_key(self):
             except as2.AS2Exception as e:
                 self.fail('Failed to load pem private key: %s' % e)
 
+    def test_extract_certificate_info(self):
+        """ Test case that extracts data from private and public certificates in PEM or DER format"""
+
+        cert_info = {'valid_from': datetime.datetime(2019, 6, 3, 11, 32, 57),
+                     'valid_to': datetime.datetime(2029, 5, 31, 11, 32, 57),
+                     'subject': [('C', 'AU'), ('ST', 'Some-State'), ('O', 'pyas2lib'), ('CN', 'test')],
+                     'issuer': [('C', 'AU'), ('ST', 'Some-State'), ('O', 'pyas2lib'), ('CN', 'test')],
+                     'serial': 13747137503594840569}
+        cert_empty = {'valid_from': None,
+                     'valid_to': None,
+                     'subject': None,
+                     'issuer': None,
+                     'serial': None}
+
+        # compare result of function with cert_info dict.
+        self.assertEqual(utils.extract_certificate_info(self.private_pem), cert_info)
+        self.assertEqual(utils.extract_certificate_info(self.private_cer), cert_info)
+        self.assertEqual(utils.extract_certificate_info(self.public_pem), cert_info)
+        self.assertEqual(utils.extract_certificate_info(self.public_cer), cert_info)
+        self.assertEqual(utils.extract_certificate_info(b''), cert_empty)
+
+
     def find_org(self, headers):
         return self.org