[Zope-Checkins] CVS: ZODB3/ZEO/zrpc - smac.py:1.38.6.2

[Jeremy Hylton]

Update of /cvs-repository/ZODB3/ZEO/zrpc
In directory cvs.zope.org:/tmp/cvs-serv25006/ZEO/zrpc

Modified Files:
      Tag: Zope-2_7-branch
	smac.py 
Log Message:
Fix security problem in ZEO authentication code.

There were two serious bugs:

- The smac layer would accept a message without a MAC even after the
  session key was established.

- The client never initialized its session key, so it never checked
  incoming messages or created MACs for outgoing messags.

Fixed both, but still need to change the smac layer so that it has
separate HMAC objects for each end of the connection.


=== ZODB3/ZEO/zrpc/smac.py 1.38.6.1 => 1.38.6.2 ===
--- ZODB3/ZEO/zrpc/smac.py:1.38.6.1	Mon Sep 15 19:21:59 2003
+++ ZODB3/ZEO/zrpc/smac.py	Fri Sep 19 15:01:28 2003
@@ -150,16 +150,18 @@
                 inp = "".join(inp)
 
             offset = 0
-            expect_mac = 0
+            has_mac = 0
             while (offset + msg_size) <= input_len:
                 msg = inp[offset:offset + msg_size]
                 offset = offset + msg_size
                 if not state:
                     msg_size = struct.unpack(">I", msg)[0]
-                    expect_mac = msg_size & MAC_BIT
-                    if expect_mac:
+                    has_mac = msg_size & MAC_BIT
+                    if has_mac:
                         msg_size ^= MAC_BIT
                         msg_size += 20
+                    elif self.__hmac:
+                        raise ValueError("Received message without MAC")
                     state = 1
                 else:
                     msg_size = 4
@@ -174,7 +176,7 @@
                     # incoming call to be handled.  During all this
                     # time, the __input_lock is held.  That's a good
                     # thing, because it serializes incoming calls.
-                    if expect_mac:
+                    if has_mac:
                         mac = msg[:20]
                         msg = msg[20:]
                         if self.__hmac:
@@ -245,7 +247,7 @@
     def message_output(self, message):
         if __debug__:
             if self._debug:
-                log('message_output %d bytes: %s' %
+                log("message_output %d bytes: %s" %
                     (len(message), short_repr(message)),
                     level=zLOG.TRACE)