Compare certificate hashes to determine if Lemur already has a synced certificate

lemur/common/utils.py

@@ -12,6 +12,7 @@ import string
 import sqlalchemy
 from cryptography import x509
 from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
 from cryptography.hazmat.primitives.asymmetric import rsa, ec
 from cryptography.hazmat.primitives.serialization import load_pem_private_key
 from flask_restful.reqparse import RequestParser
@@ -226,3 +227,13 @@ def truthiness(s):
     """If input string resembles something truthy then return True, else False."""
 
     return s.lower() in ('true', 'yes', 'on', 't', '1')
+
+
+def find_matching_certificates_by_hash(cert, matching_certs):
+    """Given a Cryptography-formatted certificate cert, and Lemur-formatted certificates (matching_certs),
+    determine if any of the certificate hashes match and return the matches."""
+    matching = []
+    for c in matching_certs:
+        if parse_certificate(c.body).fingerprint(hashes.SHA256()) == cert.fingerprint(hashes.SHA256()):
+            matching.append(c)
+    return matching

lemur/sources/service.py

@@ -17,7 +17,7 @@ from lemur.endpoints import service as endpoint_service
 from lemur.destinations import service as destination_service
 
 from lemur.certificates.schemas import CertificateUploadInputSchema
-from lemur.common.utils import parse_certificate
+from lemur.common.utils import find_matching_certificates_by_hash, parse_certificate
 from lemur.common.defaults import serial
 
 from lemur.plugins.base import plugins
@@ -126,7 +126,8 @@ def sync_certificates(source, user):
 
         if not exists:
             cert = parse_certificate(certificate['body'])
-            exists = certificate_service.get_by_serial(serial(cert))
+            matching_serials = certificate_service.get_by_serial(serial(cert))
+            exists = find_matching_certificates_by_hash(cert, matching_serials)
 
         if not certificate.get('owner'):
             certificate['owner'] = user.email