Skype 5-way Calling Limit Cracked

BobPaul writes "It turns out when Skype limited 10 way calling to Intel Processors only it really was arbitrary! Maxxus has a patched version of Skype that allows 10-way calling regardless of the processor installed. There's also info about the patch: "The patch is the result of two phases: code analysis and design of the patch. The code analysis, or reverse engineering, reveals the relevant code block, which overrides Skype's limitation for Intel's dual-core CPUs. The patch design isolates the minimal set of instructions that need to be modified to cancel this limitation." Windows only so far."

Re:Emulation would have worked too?

[yuriismaster]

The drop from 64 bit to 32 bit is one thing, however, in this case, the Skype code specifically queried the hardware for the GenuineIntel. If I remember this correctly from another /. post (not mine)

The opcode used in Skype, when activated on the processor, sets 3 4-byte registers on the processor as an identifier. This is burned into the silicon, basically.

For Intel Chips, the registers become
Genu, ineI, ntel - Genuine Intel

For AMD:
Auth, enti, cAMD - Authentic AMD

Like I said, since it's burned into the chip, there's no real way of 'masking' those registers as something else. This crack skips the verification, basically telling Skype that 'any processor is cool to run 10way' as opposed 'only GeniuneIntel chips can run 10way'

BitTorrent Mirror

[Anonymous Coward]

BitTorrent Mirror here [mininova.org]

Re:Optimization is where?

[LLuthor]

due to use of Intel-only prefetch instructions or whatever

The AMD instruction set is a strict superset of the Intel instruction set. There are no Intel-only instructions anymore. There are however many AMD-only instructions (3dnow, 3dnow+, etc.), so if the situation were reversed, there might have been a legitimate claim, but since the AMD CPUs were locked out, it is clearly a bribe^Wmarketing descision.

Negative.

[Anonymous Coward]

>I get a free Disney toy with my Happy Meal

The difference is that Skype is getting paid to make sure their software does NOT work fully with a competitor to Intel. That's a whole different ball game as far as the law is concerned. If this was 'Buy Skype and get a X% off of your next Intel Purchase' no one would give it a second thought. They're not making it BETTER on Intel, they're making it WORSE on AMD. This is very different.

(if this post is redundant it might be because I have to wait no less than 15 minutes in order to post it -- I wish this system could take into account the moderation of my earlier anonymous posts. But maybe that's patented? :-\)

Need Open Standards

[fastdecade]

Just goes to show why we need open protocols and open code for the future of VOIP. It's too important to leave to a single company, which is why I prefer SIP and clients like Google Talk and Gizmo [gizmoproject.com] where possible.

Re:"Arbitrary", but they already admitted it

[djtack]

In the first article [com.com]on this deal that slashdot linked, Intel admitted the limit was arbitrary, and the result of a marketing deal:

But there are no specific instructions in Intel's current Pentium D or Core Duo chips that enhance the performance of VoIP applications, an Intel representative said. Skype is using an operation called "Get CPU ID" to identify the type of processor running on the PC. The Skype software has been preset to only accept Intel's chips as having the performance necessary to host conference calls of more than five people, the representative said.

Re:An encrypted binary?

[quantum bit]

No black helicopters here -- just greed. This is the same company that created Kazaa and bundled a bunch of spyware with it. So enterprising hackers modified it to remove the spyware, as well as the built-in advertising banners, and released Kazaa Lite.

The Skype binary is encrypted to try to prevent a similar thing from happening (removal of ads, addition of features that are technically possible but they might want to limit for marketing reasons). Up until now Skype hasn't done any sufficiently annoying advertising to drive anyone to publicly break the encryption. However, as I predicted [slashdot.org], it didn't take long for someone to bypass once there was a reason to.

Not a bribe...

[Saeed al-Sahaf]

Because the huge cash bribe they received (from Zilog or say Motorola) to do so is not permitted. Duh.

There is no bribe here, it's a business agreement. Happens AL THE TIME in business. One business says to the other, "If you make your product exclusive to my product, I'll pay you some money". This is n ot called a "bribe". Get your facts straight.

Re:An encrypted binary?

[Jugalator]

This is the same company that created Kazaa

Yes. [wikipedia.org]

and bundled a bunch of spyware with it.

No. [wikipedia.org]

Re:Optimization is where?

[aka1nas]

The SSE implementation on the AthlonXP wasn't particularly fast. IIRC, then just added some logic that decoded SSE ops into FPU ops and let the AthlonXPs nice FPU crunch it. This is part of why there wasn't really any speedup in SSE-optimized apps for the Athlon. Now the K8 may be a different beast in this regard. I haven't seen any recent benchmarks, however.

Learn What a Bribe Is Before You Open Your Mouth

[Skye16]

bribe
n.
1. Something, such as money or a favor, offered or given to a person in a position of trust to influence that person's views or conduct.
2. Something serving to influence or persuade.

Re:Law suit bullshit...

[Slack3r78]

If you hold monopoly status in the market (which is what AMD is alledging) then making a deal that locks potential competitors out of the market violates antitrust rules.

Re:Need Open Standards

[beasstman]

In fact SIP has supported dial in/out for years -- you can get termination for SIP compliant phones from Vonage, using Free World Dialup, or from smaller termination only providers (similar to Skype Out/In) like EXGN -- there are literally hundreds of them. ALL the commercial gateways sold by Cisco and the other major players are SIP to PSTN (regular telephone system) gateway (or Cisco proprietary Call manager -- but not Skype). Even Skype themselves in the backend is almost certainly using SIP to get to the public phone network for their Skype In/Out system, since none of the major gateway companies build anything else, and Skype isn't building one off hardware, it simply wouldn't be economically practical.

There is also signifcant work to make SIP P2P to eliminate the central servers http://www.p2psip.org/ [p2psip.org] from SIP going on right now. As an aside, Skype isn't really even that P2P -- it uses central auth servers, so it is more of a hybrid system -- ala Napster -- in reality.

And with a SIP phone you can use *any* of those SIP providers. With Skype, you have one choice.

Skype is very good at making things work out of the box, hence the popularity, but there really isn't much (if anything) it can do that SIP can't. It isn't even that the P2P mattered. Skype's success is a matter of a very nice UI and user experience. They gained market on ease of use and marketing -- not bad things mind you -- not better technology. Kudos to Skype for making it easy for users to use VoIP, which was (and still is) notoriously hard to use with other providers. But the technology is different to allow Skype to lock up users, not to make things better from a technical standpoint.

Re:Need Open Standards

[Anonymous Coward]

"Open standards would certainly be a good thing, but Skype also does some things that are likely inherently proprietary for the foreseeable future."

Inherently proprietary, huh? And what makes it so, when there are countless other clients and platforms that do the same on an open platform.

Try gizmoproject or openwengo. I have tried the former and the voice quality is better than Skype's while offering me full interoperability through SIP. Damn easy to use and it actually has a good and improving Linux client compared to Skype's pathetic one, which I have the displeasure of using. I even payed for Skype Out and Skype-in and they are pathetic on linux.

I also don't want to do to VoIP what we have done to instant messaging by creating islands of non-interoperable communities. It should be like email, why is this so hard to understand.

"With Skype Out and Skype In, you can call regular telephones and receive calls from them. This requires that someone builds out connectivity to the phone system. I would be all for standardizing this part as well, but any solution would likely be as much regulatory as technical."

See me mentions before of gizmoproject and openwengo.

"As distasteful as this current incident is, Skype still provides an incredibly useful solution for VOIP, and AFAIK, there aren't any open solutions with the same capabilities."

You haven't looked very far, have you? Even better, by the way, are real SIP phones that you plug into your router so that you don't even need a computer to be on. Check them out at sipphone.com

Later.

Re:No shit

[pavera]

You'd have to set up the Asterisk server, but then there are tons of SIP clients that you can give out to your friends/family pre configured, that will connect to asterisk. Of course you aren't going to have the defacto standard of skype, but I do this with about 40 of my friends and family, the server sits in my basement on a dsl connection and we all talk for free whenever we want, and have conferences of up to 30 people...

the main client we use is the xlite softphone, there is a gui configuration menu, basically all they have to put in is a username and password, and the address of the asterisk server, or you can pre-configure it with an xml file if you want to do that, more headache on your side I suppose and putting in a username and password is not that difficult (you have to do the same thing with skype).

Re:Lawsuit

[TheGavster]

In Vista, your graphics card needs to support certain shader instructions defined in whatever shader/DX spec Vista asks for. It doesn't check to see if your card is an ATI or an nVidia, it checks to see whether it pukes when it gets hit with Vista's shaders.

Re:Aaaah Maxxuss

[idiot900]

This seems to be the same Niels Ferguson who now works for Microsoft, and over whose dead body [msdn.com] Vista will include a goverment backdoor for its cryto file storage feature. That is to say, he's against the idea. Good for him.

Re:Interoperability?

[LocalH]

As far as I know, that was actually hashed out in Sega v. Accolade, where Sega was trying to prevent unlicensed cartridges by requiring software to contain the trademark "SEGA" and to write it at a specific hardware register (the infamous TMSS or "trademark security system"). The court found that it was legal for Accolade to include the TMSS for the purposes of making their own code work on the system, as the TMSS was initally intended to help fight counterfeiters (by counterfeiting such a cartridge, it would display the "SEGA" mark that shows up before all games on a Genesis 2 or 3).

For more indepth information, read Sega v. Accolade [digital-law-online.info].

Re:It -is- AMD theyre locking out.

[Lehk228]

this could easily allow AMD to have their chip be configurable to return GenuineIntel

there was already a case decided involving sega that using a trademark to lock out interoperability is not permitted.

Re:Emulation would have worked too?

[larry bagina]

f00f bug workarounds don't scan the binary for the invalid instruction, they do tricks with the exception handler so that a page fault (or some other error) will occur, at which point you can generate the correct exception rather than locking up.

Re:I don't know that this is such a big deal...

[Anonymous Coward]

Skype actually is pretty hardcore. The binary is encrypted multiple times and there are multiple checksums. It will not run under a debugger or SoftICE. You cannot even throw an int 3 breakpoint in without setting off the memory change detection. Of course, if you bothered to RTFA you would know at least some of these things.

Re:Don't Believe the Skype

[John Sullivan]

Not really. CPUID is an untrappable ring 3 instruction, so all callers get basically an honest answer. You'd have to single-step the entire program, or do a speculative emulation to identify the call points then breakpoint them, or something similar, to subvert it.

Re:Emulation would have worked too?

[maxwell demon]

You can get all the other data from the CPUID instruction as well (by using other values than 0 in EAX on the call). However the interpretation of the resulting values does indeed depend on if your processor is an Intel or an AMD (or something else, for that matter).