DOCUMENT:Q216766 16-MAY-2002 [winnt] TITLE :FIX: Windows NT 4.0 w/ SP4 Causes Data Corruption in RPC Calls PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0 SP4 OPER/SYS: KEYWORDS:kbRPC kbOSWinNT400sp4bug kbOSWinNT400sp4fix kbWinNT400sp5fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 SP4, Terminal Server Edition - Microsoft Windows NT Server version 4.0 SP4 - Microsoft Windows NT Server, Enterprise Edition version 4.0 SP4 ------------------------------------------------------------------------------- SYMPTOMS ======== If you have a pointer to conformant structure as a field of a complex structure under Windows NT 4.0 with Service Pack 4 (SP4), the unmarshaling side gets uninitialized data. If such a data structure is an [in] parameter, the server manager routine sees the corruption. If it is an [out] parameter the corruption, the client sees the corruption. The same problem appears if your RPC application is running on Windows 95 with DCOM95 1.2 update or Windows 98 with DCOM98 update as documented in the following article in the Microsoft Knowledge Base: Q216889 FIX: DCOM95 1.2 or DCOM98 Causes Data Corruption in RPC Calls Data Structure: typedef struct tagConformantStruct { unsigned long size; [size_is(size)] char data[]; } ConformantStruct; typedef enum tagColor { Red, Blue, Green } Color; typedef union tagMyUnion switch (Color type) u { case Red : long longArm; case Blue: short shortArm; case Green: char charArm; } MyUnion; typedef struct tagComplexStruct { unsigned long numUnions; ConformantStruct* pConfStruct; // PROBLEM! pointer to conformant struct. [size_is(numUnions)] MyUnion myUnions[]; // Makes the struct complex. } ComplexStruct; CAUSE ===== A defect in the rpcrt4.dll that is shipped with Windows Service Pack 4 (DCOM95 1.2) and DCOM98 prevents the conformant part of the conformant structure to be marshaled. The unmarshaling side expects the conformant part and unmarshals from a possibly uninitialized part of the RPC buffer. This causes data corruption. RESOLUTION ========== Windows NT 4.0 -------------- To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to: - http://www.microsoft.com/Windows/ServicePacks/ -or- - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS Windows NT Server 4.0, Terminal Server Edition ---------------------------------------------- To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base: Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack STATUS ====== Microsoft has confirmed this to be a problem in Windows NT 4.0 Service Pack 4 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4. This problem was first corrected in Windows NT version 4.0 Service Pack 5 and Windows NT Server 4.0, Terminal Server Edition Service Pack 5. Additional query words: 4.00 conformant complex wts tse ====================================================================== Keywords : kbRPC kbOSWinNT400sp4bug kbOSWinNT400sp4fix kbWinNT400sp5fix Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp4 kbWinNTS400sp4 kbWinNTS400search kbNTTermServ400sp4 kbNTTermServSearch Version : winnt:4.0 SP4 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.