Make a session-wide set of junk vectors to not request repeatedly

checking curve number and key length in encrypted payload.

minode/connection.py

@@ -384,6 +384,7 @@ class Connection(threading.Thread):
             logging.debug('%s:%s -> %s', self.host_print, self.port, inv)
             to_get = inv.vectors.copy()
             to_get.difference_update(shared.objects.keys())
+            to_get.difference_update(shared.junk_vectors)
             self.vectors_to_get.update(to_get)
             # Do not send objects they already have.
             self.vectors_to_send.difference_update(inv.vectors)
@@ -395,6 +396,8 @@ class Connection(threading.Thread):
             self.vectors_to_get.discard(obj.vector)
             if obj.is_valid() and obj.vector not in shared.objects:
                 with shared.objects_lock:
+                    if obj.is_junk():
+                        return shared.junk_vectors.add(obj.vector)
                     shared.objects[obj.vector] = obj
                 if (
                     obj.object_type == shared.i2p_dest_obj_type

minode/shared.py

@@ -16,6 +16,8 @@ ip_enabled = True
 
 log_level = logging.INFO
 
+curve = 714  # secp256k1
+key_length = 32
 magic_bytes = b'\xe9\xbe\xb4\xd9'
 protocol_version = 3
 services = 3  # NODE_NETWORK, NODE_SSL
@@ -63,4 +65,5 @@ outgoing_connections = 8
 connection_limit = 250
 
 objects = {}
+junk_vectors = set()
 objects_lock = threading.Lock()

minode/structure.py

@@ -132,6 +132,31 @@ class Object():
             return False
         return True
 
+    def is_junk(self):
+        """
+        Returns True if an object with encrypted payload has
+        curve number or key length different from those defined in shared.
+        """
+        if self.object_type not in (1, 2, 3):
+            return False
+        if self.object_type == 2:
+            sp = 0
+        elif self.object_type == 1 and self.version != 4:
+            return False
+        else:
+            sp = 32
+        sp += 16
+        curve = struct.unpack('!H', self.object_payload[sp:sp + 2])[0]
+        if curve != shared.curve:
+            return True
+        length = struct.unpack('!H', self.object_payload[sp + 2:sp + 4])[0]
+        if length > shared.key_length:
+            return True
+        length = struct.unpack('!H', self.object_payload[sp + 36:sp + 38])[0]
+        if length > shared.key_length:
+            return True
+        return False
+
     def pow_target(self):
         """Compute PoW target"""
         data = self.to_bytes()[8:]