Invalid Named Pipe Message Causes SNABASE.EXE Exception

ID: Q106524

The information in this article applies to:

Microsoft SNA Server, versions 2.0, 2.1, 2.11
on the following platforms: NT

SYMPTOMS

SNA Server generates a Dr. Watson error in SNABASE.EXE when it receives an invalid message over a Named Pipe connection from a client. The SNA Server also logs an Event ID 624 in the Windows NT Application Log (as shown in the Event Viewer) indicating that an SNADUMP.LOG was created for SNABASE.EXE. The following is an excerpt from a DRWTSN32.LOG that is created following one of these SNABASE errors:

Application exception occurred:
App: snabase.DBG (pid=148)
When: 10/31/1995 @ 11:29:1.2
Exception number: c0000005 (access violation)

NOTE: Your DRWTSN32.LOG file will appear somewhat different than this example.

CAUSE

SNABASE.EXE on the SNA Server is not properly handling an invalid incoming NewPipe messages from SNA Server clients over Named Pipe connections. The NewPipe messages are only sent to the SNA Server when the WNAP (16-bit) or SNABASE (32-bit) process is initializing on SNA Server clients.

WORKAROUND

For Win 3.x clients, a potential workaround is to start WNAP in advance (by adding WNAP.EXE to the startup group of Windows or Windows for Workgroups), so that it's not automatically invoked when an SNA application or emulator is started.

RESOLUTION

Microsoft has updated the following files to correct this problem:

<winroot>\SYSTEM\SNALM.DLL
<winroot>\SYSTEM\SNAIP.DLL
<winroot>\SYSTEM\SNANW.DLL
<winroot>\SYSTEM\SNAAT.DLL
<winroot>\SYSTEM\SNABV.DLL
<winroot>\SYSTEM\SNANB.DLL

These corrected files increase validity checking on incoming NewPipe messages received from clients over Named Pipe connections as well as the other client/server protocols supported by SNA Server. In addition, SNA Server now logs an Event 631 in the Application Log when it receives an invalid NewPipe message from a client.

STATUS

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This problem was corrected in the latest SNA Server for Windows NT, 2.11 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: prodsna

Keywords : kbnetwork ntnetserv kbbug2.00 kbbug2.10 kbbug2.11
Version : WINDOWS:2.0,2.1,2.11
Platform : WINDOWS
Issue type :