August 27, 2004 11:43 AM PDT

Microsoft tackles AMD conflict in SP2

A problem in the Service Pack 2 update for Windows XP may keep owners of AMD-based computers from using the long-awaited security package under certain circumstances, according to Microsoft.

In an article posted in the Knowledge Base section of its Web site, Microsoft says that Service Pack 2 may not work with computers running Advanced Micro Devices' 64-bit microprocessors. The Redmond, Wash.-based company said earlier that owners of such PCs may want to bypass the update completely, but has now come up with a workaround.

AMD's 64-bit chips include the Athlon 64 for PCs and the Opteron for servers.

A Microsoft representative declined to comment directly on the AMD-related issue but said the company "continually investigates all issues and vulnerabilities" reported to it regarding SP2 and other products.

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However, an AMD representatives said the chipmaker believes the problem has only occurred, so far, with one application, Sigma Designs' Realmagic Hollywood Plus DVD Decoder. Microsoft also identifies the application as being able to cause the problem.

Microsoft said in its advisory that PCs with 64-bit AMD processors may restart repeatedly after installing Service Pack 2, if those machines are also configured to enforce so-called data execution prevention (DEP) and contain hardware that requires a driver software known as Mpegport.sys. Sigma Designs' Realmagic Hollywood Plus DVD decoder application is one such application that uses the driver, the software maker said.

Microsoft says users may be able to resolve the problem by configuring a so-called DEP exception. AMD also recommends that people affected by the problem do so. Earlier, Microsoft had advised AMD users to remove SP2 altogether.

The AMD problem is the latest in a slew of issues that have dogged SP2 since it was first released to PC manufacturers at the beginning of August. By mid-month, Microsoft had detailed some 50 different software applications and games that may encounter problems with the update.

The potential for conflicts caused some high-profile businesses, including IBM, to order their employees to avoid installing SP2 until its ramifications can be better understood. Other organizations are moving forward with the update, expecting that its security enhancements outweigh the integration issues.

Microsoft has launched a do-it-yourself kit to help IT professionals assess their software's compatibility with the update. The compatibility guide, which can be retrieved from Microsoft's Download Center, is designed to help administrators "test and mitigate application compatibility issues."


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Re: Windows update harbors AMD conflict
The article is very, very misleading! There is no conflict between SP2 and AMD64 processors! There is a conflict with software that violates the NX capability of the AMD64. You can either turn off the Data Execution Prevention (DEP) feature in SP2, or, you can get updated software that is written to function appropriately in the new invironment!
Posted by R.T.F.M. (12 comments )
Reply Link Flag
what a clinker of an article
The headline sure caught my eye, but after actually *reading* the Knowledge Base article, it's clear there almost nothing to it.

This article is terribly misleading. Tsk tsk! I ask the author of the article, do you have agenda regarding SP2, or don't you understand the Knowledge Base article?
Posted by foomonkey249702348 (5 comments )
Link Flag
Downright misleading
Yet another slanderous article in cnet's apparant anti-SP2 crusade.

Anyone who reads the actual knowledge base article will note that the flaw only occurs in a very specific software package.
The fact that it affects only AMD's 64-bit processor is because Intel's don't feature the NX flag.

Yet the title of the article clearly insinuates otherwise. Even the subtitle doesn't mention the fact that it's due to a third party software flaw and is totally unrelated to AMD's line of 64 bit processors.

The more articles like this I encouter, the more I begin question the accuracy of other news brought by cnet.
When your reports on SP2 are so biased to being downright untrue, I am quickly loosing confidence in your ability to accuratly report ICT news.
Posted by Jan Modaal (40 comments )
Reply Link Flag
Of course
You're right. Matt Hines has no clue what he's writing about. He should step away from the keyboard, take a deep breath, and go back to Mac Users Anonymous...
Posted by (1 comment )
Link Flag
This is not a glitch, this is performing as designed!
This is not a glitch; this is a security measure performing precisely as designed! Here's what's actually happening:

XP SP2 contains a new feature called Data Execution Prevention, usually called NX for short ("no-execute"). It requires all of memory to be marked as either "code pages" (which contain only executable programs) or "data pages" (which contain everything else.) This helps alleviate the problem of buffer overflows, where a hacker injects specially crafted data containing program code into a running program, causing it to execute the hacker's code instead of the program's own. What Data Execution Prevention does is place an extra restriction on execution -- if at any point the CPU is instructed to execute code in a data page, it throws an access violation (which generally crashes the offending program.) Thus, if your hacker tries to use a buffer overflow, he successfully writes his malicious code into memory, but he's written it to a data page -- and thus when he tries to run his code, instead of it doing what he wants, all it does is crash the program he's exploiting. Thus, a root-compromise security hole (allowing the hacker to take control of the system, steal data, format the hard drive, or whatever) becomes only a denial-of-service (allowing the hacker to crash a single app.) This is a good feature.

However, the feature requires support from the CPU, allowing pages to be marked as code or data. And currently, the only CPU that has this support is the AMD Athlon64. In a few months, all the new Intel Pentium 4s will have it, too, as will AMD's new low-end Sempron chip. This is not a problem with AMD's chip -- it's just that people with AMD's chip are the only ones using this new feature yet!

Now, an app executing code on its data pages is a no-no. You're not supposed to do that. However, a few apps do, generally for copy-protection purposes (for instance, decrypting themselves into memory then running the decrypted code.) For those apps, Microsoft provides a simple way to exclude an application from Data Execution Prevention. For that matter, if you really want to, you could turn the feature off altogether, and be no worse off buffer-overflow-wise than you were in SP1, while still maintaining all of XP SP2's other great security features. Why someone at Microsoft suggested uninstalling SP2 to deal with this problem is a complete mystery to me -- just unsecure the one offending program, or even disable the one offending feature; don't roll back the entire security upgrade!

The particular problem here is that apparently Sigma Designs' Realmagic Hollywood Plus DVD Decoder does do the trick of executing its own data pages on purpose. Thus, Data Execution Prevention falsely identifies it as an attack and crashes the program. The unfortunate part is that rather than running as an application like everything else, Realmagic runs as a device driver (which is why it has a filename ending in .sys). Device drivers run privileged at Ring 0, in kernel mode. If Data Execution Prevention killed off a normal application, it would just crash the application -- no big deal. But crashing something that runs in kernel mode results in a lovely blue screen that says "STOP 0x0000001E: KMODE_EXCEPTION_NOT_HANDLED." Not a good user experience by any means.

The lessons here are not, as the press seems to think, "There is a bug in XP SP2" or "XP SP2 is incompatible with AMD Athlon64 processors." No, there are two lessons here, and they're both for software developers:

1.) Don't try to execute data pages. In a few months, everybody will have this feature and nobody will be able to run your app. Lay off the copy protection a bit and just write normal applications.
2.) For crying out loud, don't run in kernel mode! If there is any way whatsoever to do what you want to do in user mode, do not under any circumstances run anything in kernel. Running in kernel means that if you do anything wrong anywhere, you bring down the entire system. This is a risk you do not need.

The Microsoft of three years ago wouldn't have included this feature, because it "breaks application compatibility." The Microsoft of today is not so foolish; security trumps application compatibility now, and application developers will need to get used to thinking about security as well.
Posted by (1 comment )
Reply Link Flag
This is Irresposnsible Reporting!!!
The article is mis-leading! And Cnet/Zdnet is mis-leading its readers!!

AMD designed the AMD64 with the NX instruction and collaborated with Microsoft to incorporate this feature in SP2! So, everything is working EXACTLY as it is supposed to.

So, the author of this article, if he/she has any morals/integrity, should make this abunduntly clear to their readers and quit spreading malicious lies!!
Posted by Jack Schitt (1 comment )
Reply Link Flag
Microsoft SP-2
I downloaded windows SP-2 yesturday,the only change I have noticed is the computer is running a little faster. No problems on down loading.
Posted by (1 comment )
Reply Link Flag
Would you do the world a favor...
and not have any children. The world does not need anymore idiots running around, and definately not writing in any sort of mass-distributed medium. If you do have kids, please give them up for adoption right away, and give them a chance to not grow up mis-representing the truth either intentionally or just by being stupid.
Posted by (3 comments )
Reply Link Flag
When is CNet going to Report Accurately???
Why do you insist on perpetuating FUD?

The problem is not with the AMD64 and SP2. They are functioning exactly as they were intended to by design.

You are mileading readers with you stupid, irresponsible articles!!
Posted by R.T.F.M. (12 comments )
Reply Link Flag
When is CNet going to Report Accurately???
Why do you insist on perpetuating FUD?

The problem is not with the AMD64 and SP2. They are functioning exactly as they were intended to by design.

You are mileading readers with your stupid, irresponsible articles!!
Posted by R.T.F.M. (12 comments )
Reply Link Flag

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