avoid duplicate credentials

confidant/routes/credentials.py

@@ -592,6 +592,7 @@ def create_credential():
                      correct format, or a required field was not provided.
     :statuscode 403: Client does not have access to create credentials.
     '''
+    logger.info("Creating credential")
     if not acl_module_check(resource_type='credential', action='create'):
         msg = "{} does not have access to create credentials".format(
             authnz.get_logged_in_user()
@@ -627,6 +628,16 @@ def create_credential():
     for key, value in credential_pairs.items():
         value = escape(value)
         credential_pairs[key] = value
+
+    # Verify this credential is not a duplicate of an existing credential
+    is_duplicate, duplicate_id = credentialmanager.is_key_value_pair_duplicate(
+        credential_pairs
+    )
+    if is_duplicate:
+        msg = '''Credential with the same key value pairs already exists. 
+        See id: {0}'''.format(duplicate_id)
+        return jsonify({'error': msg, 'reference': duplicate_id}), 409
+
     credential_pairs = json.dumps(credential_pairs)
     data_key = keymanager.create_datakey(encryption_context={'id': id})
     cipher = CipherManager(data_key['plaintext'], version=2)
@@ -837,6 +848,10 @@ def update_credential(id):
         _cred.revision
     )
     if 'credential_pairs' in data:
+        # Ensure the credential is not empty
+        if data['credential_pairs'] == {}:
+            return jsonify({'error': 'Credential Pairs cannot be empty'}), 400
+
         # Ensure credential pair keys are lowercase
         credential_pairs = credentialmanager.lowercase_credential_pairs(
             data['credential_pairs']
@@ -865,6 +880,16 @@ def update_credential(id):
         # this is a new credential pair and update last_rotation_date
         if credential_pairs != _cred.decrypted_credential_pairs:
             update['last_rotation_date'] = misc.utcnow()
+
+        # Verify if after update the credential will not be a duplicate
+        is_duplicate, duplicate_id = credentialmanager.is_key_value_pair_duplicate(
+            credential_pairs
+        )
+        if is_duplicate:
+            msg = '''Credential with the same key value pairs already exists.
+            See id: {0}'''.format(duplicate_id)
+            return jsonify({'error': msg, 'reference': duplicate_id}), 409
+
         data_key = keymanager.create_datakey(encryption_context={'id': id})
         cipher = CipherManager(data_key['plaintext'], version=2)
         update['credential_pairs'] = cipher.encrypt(

confidant/services/credentialmanager.py

@@ -59,6 +59,19 @@ def pair_key_conflicts_for_credentials(credential_ids, blind_credential_ids):
     return conflicts
 
 
+def is_key_value_pair_duplicate(key_pairs):
+    logger.info("Checking if key value pair is duplicate")
+    logger.info("checking key_pairs: %s", key_pairs)
+
+    all_credentials = Credential.data_type_date_index.query('credential')
+
+    for cred in all_credentials:
+        if cred.decrypted_credential_pairs == key_pairs:
+            return True, cred.id
+
+    return False, None
+
+
 def check_credential_pair_values(credential_pairs):
     for key, val in credential_pairs.items():
         if isinstance(val, dict) or isinstance(val, list):