SNA Server Access Violation in Function S1pimcrc

• Microsoft SNA Server, versions 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2, 4.0

SYMPTOMS

The SNA Server service (Snaservr.exe) may fail unexpectedly with an access violation. When the problem occurs, all users connecting through SNA Server will lose their host sessions and the SNA Server service will no longer be running. The Windows NT application event log should indicate an Event 624, logged by SNA Server. Also, the following entry will be logged in the <Ntroot>\Drwtsn32.log file, indicating an access violation in function "s1pimcrc":

   Application exception occurred:
        App: snaservr.exe (<process ID>)
        Exception number: c0000005 (access violation)

   [...]

   State Dump for Thread Id 0x8c

   eax=00000000 ebx=002bff62 ecx=000056f1 edx=04000400 esi=00cc4480 
   edi=00000000
   eip=00426412 esp=002bff28 ebp=00000000 iopl=0  nv up ei pl nz ac po nc
   cs=001b  ss=0023  ds=0023  es=0023  fs=0038  gs=0000             efl=00000216

function: s1pimcrc
   004263f0 56               push    esi
   004263f1 33c0             xor     eax,eax
   004263f3 a0aa6f4800       mov     al,[sncurrnt (00486faa)] ds:00486faa=4a
   004263f8 8d0440           lea     eax,[eax+eax*2]  ds:00000000=????????
   004263fb c1e002           shl     eax,0x2
   004263fe 0fbf888ef64800   movsx  ecx,word ptr [eax+0x48f68e] ds:0048f68e=0000

   00426405 8bb084f64800     mov     esi,[eax+0x48f684]     ds:0048f684=00000000
   0042640b 8b048d7c3f4a00                 ds:000056f1=????????
                             mov     eax,[s1seccb+0x1335c (004a3f7c)+ecx*4]
FAULT ->00426412 80781701    cmp     byte ptr [eax+0x17],0x1      
   ds:005de922=??

*----> Stack Back Trace <----*

   FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
   00000000 00000000 00000000 00000000 00000000 00000000 snaservr!s1pimcrc
   00000010 00000000 00000000 00000000 00000000 00000000 snaservr!<nosymbols> 

CAUSE

In one instance, the SNA Server failed to check if an LU6.2 control block was valid when receiving a message from a client machine.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2 and 4.0.

This problem was corrected in the latest SNA Server versions 3.0 and 4.0 U.S. Service Packs. For information on obtaining these Service Packs, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words:

Keywords : kbbug4.00 prodsna kbbug3.00 kbbug3.00.sp2 kbfix3.00.sp3 kbbug2.11.sp2 kbbug3.00.sp1 snaserverservice
Version : WINDOWS:2.11 SP2,3.0,3.0 SP1,3.0 SP2,4.0
Platform : WINDOWS
Issue type : kbbug