FIX: An ISAPI extension that calls the WriteClient function 65,535 or more times sends an incomplete response in IIS 7.5

Symptoms

Consider the following scenario:

  • You install Internet Information Services (IIS) 7.5 and the Internet Server API (ISAPI) Extensions module on a computer that is running Windows 7 or Windows Server 2008 R2.

  • You create an ISAPI extension that calls the WriteClient¬†function 65,535 or more times.

  • You enable the ISAPI extension to run on the computer.

  • A client request accesses a path that calls the ISAPI extension.


In this scenario, the WriteClient function call fails. Therefore, the client request is not processed correctly.

Cause

This problem occurs because an ERROR_ARITHMETIC_OVERFLOW error occurs when the WriteClient function is called 65,535 or more times.

Resolution

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website:

http://support.microsoft.com/contactus/?ws=supportNote In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

You must have the ISAPI Extensions module installed in IIS 7.5 to apply this hotfix. Additionally, the computer must be running one of the following operating systems:

  • Windows 7

  • Windows 7 Service Pack 1 (SP1)

  • Windows Server 2008 R2

  • Windows Server 2008 R2 Service Pack 1 (SP1)


Restart information

You do not have to restart the computer after you apply this hotfix.

Replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows 7 and Windows Server 2008 R2 file information notes

The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files are extremely important to maintain the state of the updated components.

For all supported x86-based versions of Windows 7

File name

File version

File size

Date

Time

Platform

Isapi.dll

7.5.7600.21009

106,496

15-Jul-2011

07:19

x86

Isapi.dll

7.5.7601.21771

106,496

15-Jul-2011

05:42

x86


For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Isapi.dll

7.5.7600.21009

120,320

15-Jul-2011

07:21

x64

Isapi.dll

7.5.7601.21771

120,320

15-Jul-2011

05:17

x64

Isapi.dll

7.5.7600.21009

106,496

15-Jul-2011

07:19

x86

Isapi.dll

7.5.7601.21771

106,496

15-Jul-2011

05:42

x86


For all supported IA-64-based versions of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Isapi.dll

7.5.7600.21009

244,736

15-Jul-2011

07:13

IA-64

Isapi.dll

7.5.7601.21771

244,736

15-Jul-2011

04:06

IA-64

Isapi.dll

7.5.7600.21009

106,496

15-Jul-2011

07:19

x86

Isapi.dll

7.5.7601.21771

106,496

15-Jul-2011

05:42

x86


Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about the WriteClient function, visit the following Microsoft Developer Network (MSDN) website:

WriteClient Function

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

File name

Update.mum

File version

Not Applicable

File size

2,868

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

X86_1ba711089cfd23cd5b56abe95dd072d0_31bf3856ad364e35_6.1.7601.21771_none_9243a8fcd187592e.manifest

File version

Not Applicable

File size

715

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

X86_cfa1d95fc28689be127256a4a39638f8_31bf3856ad364e35_6.1.7600.21009_none_dd63dd8a79924841.manifest

File version

Not Applicable

File size

715

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

X86_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7600.21009_none_67a492aa659251cf.manifest

File version

Not Applicable

File size

3,321

Date (UTC)

15-Jul-2011

Time (UTC)

08:00

Platform

Not Applicable

File name

X86_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7601.21771_none_693765ca62f88358.manifest

File version

Not Applicable

File size

3,321

Date (UTC)

15-Jul-2011

Time (UTC)

06:13

Platform

Not Applicable


Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

Amd64_6752b03ee4f9ce72ed95ff8ec068b471_31bf3856ad364e35_6.1.7600.21009_none_d38296dd8f46f929.manifest

File version

Not Applicable

File size

1,080

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Amd64_cf7e70c30f75f084da07c35ae4be9d76_31bf3856ad364e35_6.1.7601.21771_none_491a43356b1003b8.manifest

File version

Not Applicable

File size

1,080

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Amd64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7600.21009_none_c3c32e2e1defc305.manifest

File version

Not Applicable

File size

3,327

Date (UTC)

15-Jul-2011

Time (UTC)

08:49

Platform

Not Applicable

File name

Amd64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7601.21771_none_c556014e1b55f48e.manifest

File version

Not Applicable

File size

3,327

Date (UTC)

15-Jul-2011

Time (UTC)

07:00

Platform

Not Applicable

File name

Update.mum

File version

Not Applicable

File size

3,306

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Wow64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7600.21009_none_ce17d88052508500.manifest

File version

Not Applicable

File size

2,998

Date (UTC)

15-Jul-2011

Time (UTC)

07:43

Platform

Not Applicable

File name

Wow64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7601.21771_none_cfaaaba04fb6b689.manifest

File version

Not Applicable

File size

2,998

Date (UTC)

15-Jul-2011

Time (UTC)

06:02

Platform

Not Applicable


Additional files for all supported IA-64-based versions of Windows Server 2008 R2

File name

Ia64_03057c400e62e0ed18b2f9890a48a829_31bf3856ad364e35_6.1.7601.21771_none_94748f243d69b85b.manifest

File version

Not Applicable

File size

1,078

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Ia64_18d28e3ddfe11e0d46164e2fe9ef1c53_31bf3856ad364e35_6.1.7600.21009_none_8abd4e84a410bc1f.manifest

File version

Not Applicable

File size

1,078

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Ia64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7600.21009_none_67a636a065905acb.manifest

File version

Not Applicable

File size

3,324

Date (UTC)

15-Jul-2011

Time (UTC)

08:45

Platform

Not Applicable

File name

Ia64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7601.21771_none_693909c062f68c54.manifest

File version

Not Applicable

File size

3,324

Date (UTC)

15-Jul-2011

Time (UTC)

07:25

Platform

Not Applicable

File name

Update.mum

File version

Not Applicable

File size

2,347

Date (UTC)

15-Jul-2011

Time (UTC)

11:29

Platform

Not Applicable

File name

Wow64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7600.21009_none_ce17d88052508500.manifest

File version

Not Applicable

File size

2,998

Date (UTC)

15-Jul-2011

Time (UTC)

07:43

Platform

Not Applicable

File name

Wow64_microsoft-windows-i..iextensionsbinaries_31bf3856ad364e35_6.1.7601.21771_none_cfaaaba04fb6b689.manifest

File version

Not Applicable

File size

2,998

Date (UTC)

15-Jul-2011

Time (UTC)

06:02

Platform

Not Applicable


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