Q172634: SNA Server Access Violation in Function Sapascp()
Article: Q172634
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.0,2.1,2.11 SP1,3.0,3.0 SP1
Operating System(s):
Keyword(s): kbnetwork
Last Modified: 12-JUN-2001
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The information in this article applies to:
- Microsoft SNA Server, versions 2.0, 2.1, 2.11 SP1, 3.0, 3.0 SP1
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SYMPTOMS
========
SNA Server may encounter an access violation in SnaServer.exe if a 3270 emulator
sends it an invalid OPEN SSCP request with no element data. This will cause the
following entry to be logged in the Windows NT application event log:
Event: 624
Source: SNA Server
Description: Creating dump file C:\SNA\traces\snadump.log for
Snaservr.exe
Also, an <Ntroot>\Drwtsn32.log entry may be created, indicating the
following failure:
Application exception occurred:
App: snaservr.DBG (pid=<process ID>)
When: <date and time>
Exception number: c0000005 (access violation)
CAUSE
=====
The SNA Server service is not properly handling an invalid OPEN SSCP request
from a third-party 3270 emulator. This problem can occur if the OPEN SSCP
request contains no element data. The 3270 Emulator Interface Specification
included in softcopy form on the SNA Server CD-ROM describes the proper format
of the OPEN SSCP request.
STATUS
======
Microsoft has confirmed this to be a problem in SNA Server versions 2.0 and 2.1.
We are currently researching this issue and will post more information here in
the Microsoft Knowledge Base as it becomes available.
Microsoft has confirmed this to be a problem in SNA Server version 2.11.
A supported fix for SNA Server 2.11 SP2 is now available, but has not been fully
regression-tested and should be applied only to systems experiencing this
specific problem. Unless you are severely impacted by this specific problem,
Microsoft recommends that you wait for the next Service Pack that contains this
fix. Contact Microsoft Technical Support for more information.
Microsoft has confirmed this to be a problem in SNA Server versions 3.0 and 3.0
Service Pack 1 (SP1). This problem was corrected in the latest SNA Server
version 3.0 U.S. Service Pack. For information on obtaining this Service Pack,
query on the following word in the Microsoft Knowledge Base (without the
spaces):
S E R V P A C K
MORE INFORMATION
================
State Dump for Thread Id <thread ID>
eax=00000000 ebx=00000000 ecx=014677f6 edx=014677f6 esi=01460000
edi=00000000
eip=0030a3fc esp=0125fef0 ebp=014677e4 iopl=0 nv up ei pl zr na
po
nc
cs=001b ss=0023 ds=0023 es=0023 fs=0038 gs=0000
efl=00000246
function: sapascp
0030a3da 33ff xor edi,edi
0030a3dc 66897c2416 mov [esp+0x16],di
ss:0256e8f8=????
0030a3e1 8b4c2448 mov ecx,[esp+0x48]
ss:0256e8f7=????????
0030a3e5 668939 mov [ecx],di
ds:014677f6=0101
0030a3e8 8b442444 mov eax,[esp+0x44]
ss:0256e8f7=????????
0030a3ec 8b28 mov ebp,[eax]
ds:00000000=????????
0030a3ee 8d4d12 lea ecx,[ebp+0x12]
ss:027761ea=????????
0030a3f1 8b4504 mov eax,[ebp+0x4]
ss:027761ea=????????
0030a3f4 894c2420 mov [esp+0x20],ecx
ss:0256e8f7=????????
0030a3f8 8944241c mov [esp+0x1c],eax
ss:0256e8f7=????????
FAULT ->0030a3fc 0fbf5004 movsx edx,word ptr [eax+0x4]
ds:0130ea07=e2f2
0030a400 0fbf4006 movsx eax,word ptr [eax+0x6]
ds:0130ea07=e2f2
0030a404 2bc2 sub eax,edx
0030a406 83f822 cmp eax,0x22
0030a409 7c1c jl sapascp+0x57 (0030a427)
0030a40b 807d2412 cmp byte ptr [ebp+0x24],0x12
ss:027761ea=??
0030a40f 7416 jz sapascp+0x57 (0030a427)
0030a411 8b4c241c mov ecx,[esp+0x1c]
ss:0256e8f7=????????
0030a415 8a440a2a mov al,[edx+ecx+0x2a]
ds:027761fd=??
0030a419 fec8 dec al
0030a41b 3c01 cmp al,0x1
0030a41d 1ac0 sbb al,al
*----> Stack Back Trace <----*
FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name
0125ff28 0030847c 00000002 0125ff70 0125ff6e 000000ff snaservr!sapascp
(FPO: [EBP 0x000000ff] [3,11,4])
0125ff50 0030c566 00000002 0125ff70 0125ff6e 00000000 snaservr!sapmain
(FPO: [EBP 0x000000ff] [3,2,4])
0125ff70 0030d1f4 0125ffec 001435a8 00000001 77f0178e snaservr!sbpcdin
(FPO: [0,3,1])
0125ff88 0030d7f5 009811c0 00000001 001435a8 77f8fe94 snaservr!sbpsched
(FPO: [EBP 0x0125ffec] [0,1,4])
0125ff8c 009811c0 00000001 001435a8 77f8fe94 001435a0 snaservr!sbpgmain
(FPO: [0,0,0])
0125ffa8 77dd8f76 00000001 001435a8 77f9b340 77f04f2c
snasvc!ServiceMainFunction (FPO: [2,1,3])
0125ffec 00000000 77dd8f68 001435a0 00000000 00000000
advapi32!RegisterServiceCtrlHandlerA
00000000 00000000 00000000 00000000 00000000 00000000
snaservr!<nosymbols>
With the fix applied, SNA Server sends an OPEN SSCP negative response with operr1
set to Invalid message (BADSAMSG - 0A08) and operr2 set to Format / protocol
error (CSREFORM - 4).
NOTE: The 3270 emulator that sent this invalid message will receive this negative
response. The emulator may display the error to the user, though this may vary
depending on the emulator being used. The error may appear in hex (operr1 =
0xA08, operr2 = 0x4) or decimal (operr1 = 2568, operr2 = 4). Since this problem
indicates a logic error in the 3270 emulator being used, this problem should be
reported to the emulator vendor.
Additional query words: sapascp drwatson
======================================================================
Keywords : kbnetwork
Technology : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ200 kbSNAServ210 kbSNAServ211SP1 kbSNAServ300SP1
Version : WINDOWS:2.0,2.1,2.11 SP1,3.0,3.0 SP1
Issue type : kbbug
Solution Type : kbfix
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