Underscores should not be in hostnames (#728)

lemur/certificates/models.py

@@ -12,6 +12,8 @@ from flask import current_app
 from cryptography import x509
 from cryptography.hazmat.primitives.asymmetric import rsa
 
+from idna.core import InvalidCodepoint
+
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql.expression import case
 from sqlalchemy.ext.hybrid import hybrid_property
@@ -244,6 +246,8 @@ class Certificate(db.Model):
         return_extensions = {
             'sub_alt_names': {'names': []}
         }
+
+        try:
             cert = lemur.common.utils.parse_certificate(self.body)
             for extension in cert.extensions:
                 value = extension.value
@@ -286,6 +290,8 @@ class Certificate(db.Model):
                 # TODO: Not supporting custom OIDs yet. https://github.com/Netflix/lemur/issues/665
                 else:
                     current_app.logger.warning('Custom OIDs not yet supported for clone operation.')
+        except InvalidCodepoint as e:
+            current_app.logger.warning('Unable to parse extensions due to underscore in dns name')
 
         return return_extensions