Do not trust sent content.

slapos/libnetworkcache.py

@@ -209,7 +209,11 @@ class NetworkcacheClient(object):
       headers=self.shadir_header_dict)
     data = urllib2.urlopen(request).read()
     # Filtering...
+    try:
       data_list = json.loads(data)
+    except Exception:
+      raise DirectoryNotFound('It was impossible to parse json response:\n%s'%
+        traceback.format_exc())
     filtered_data_list = []
     if self.signature_certificate_list is not None:
       for data in data_list:
@@ -227,8 +231,17 @@ class NetworkcacheClient(object):
                'Entries: %s.' % (key, str(data_list)))
 
     information_json, signature = filtered_data_list[0]
+    try:
       information_dict = json.loads(information_json)
+    except Exception:
+      raise DirectoryNotFound('It was impossible to parse json-in-json '
+        'response:\n%s' % traceback.format_exc())
+    try:
       sha512 = information_dict.get('sha512')
+    except Exception:
+      raise DirectoryNotFound('It was impossible to fetch sha512 from '
+        'directory response (%r):\n%s' % (information_dict,
+          traceback.format_exc()))
     return self.download(sha512)
 
   def _getSignatureString(self, content):