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Skype 5-way Calling Limit Cracked 427

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."
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Skype 5-way Calling Limit Cracked

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  • "Arbitrary"? (Score:5, Interesting)

    by v1 ( 525388 ) on Saturday March 04, 2006 @12:21PM (#14850065) Homepage Journal
    Since this limit was "arbitrary", that means the only deciding factor was not technology, but money. I wonder how much the block cost Intel?

    And now that it's in the open, (like that was going to take very long?) I wonder if they'll remove the block?
  • by augustz ( 18082 ) on Saturday March 04, 2006 @12:24PM (#14850077) Homepage
    Skype made a lot of noise in their press release saying that the 10-way feature was "optimized" for Intel chips. This was picked up by the media of course as well as evidence of AMD's poor performance.

    I'm having trouble understanding what this optimization that used the special features of Intel chips (presumably their high power) was. It looks from the patch that they just check who the manufacturer is, and if it is not AMD, they pretend your computer doesn't have the power to host 10 participants.

    What's also interesting is that folks likely signed up for SkypeOut and other paid products not realizing that they would be treated differently depending on what chipsets they happen to use, especially as that choice matters almost no where else. They should give more warning about this to paid users.

    This focus on locking software into specific vendor chips seems a dangerous one. No longer will it be the best chip that will win, but the focus goes to competing on locking up software applications. The proprietary unix'es went down that path, and it would be sad if Intel managed to get that to happen here.
  • by dubl-u ( 51156 ) * <> on Saturday March 04, 2006 @12:30PM (#14850108)
    I'm having trouble understanding what this optimization that used the special features of Intel chips (presumably their high power) was. It looks from the patch that they just check who the manufacturer is, and if it is not AMD, they pretend your computer doesn't have the power to host 10 participants.

    My guess, like yours, is that this is blatant marketing crap. But it would be nice to see some tests of how many people can be usefully conferenced on different hardware. Skype is a CPU pig, and it's possible that they really have optimized it for some Intel-specific feature.
  • Limit (Score:5, Interesting)

    by Eightyford ( 893696 ) on Saturday March 04, 2006 @12:33PM (#14850119) Homepage
    So what is now limiting the conference calls to 10 people now? Is that a phone company limit, or another arbitrary limit?
  • by Anonymous Coward on Saturday March 04, 2006 @12:40PM (#14850144)
    It's not even illegal, is it? I get a free Disney toy with my Happy Meal, so I can get 5 free extra conference callers with my Intel chip.
    Skype are acting like utter jackasses, and this is a nice big point for OSS in the open-vs-closed software wars, but it's really just marketing bullshit - Skype can do what they want with their software and caveat emptor... if it was something serious like Ford removing your car's side impact guards if you own a Hitachi garage door opener then maaaybe there would be a lawsuit there...
  • Re:"Arbitrary"? (Score:5, Interesting)

    by BVis ( 267028 ) on Saturday March 04, 2006 @12:57PM (#14850207)
    It'd be an interesting test case for the DMCA, wouldn't it? In this case it's not specifically copy or content protection software that's being circumvented, but a feature designed to maintain (potentially) a marketing agreement, if in fact that's what this turns out to be.
  • by Mignon ( 34109 ) <> on Saturday March 04, 2006 @01:01PM (#14850219)
    The code seems to be calling the cpuid instruction, so as far as the "Windows-only" patch, could anyone comment on patching the Linux kernel to essentially lie to the Skype client?

    Or, so as not to break other programs that use cpuid (to determine which instructions they can run, for example) perhaps this could be done in a user-space way.

    I'm thinking of artsdp as a model, so you would just launch your Skype client with something like "cpufake --cpuid='Genuine Intel Dual Core We Like Skype' skype.bin" (or whatever it's called.)

    I've got no idea how such a program would work, but the article did say the code was encrypted so I wonder if that would be an issue.

  • by zerocool^ ( 112121 ) on Saturday March 04, 2006 @01:21PM (#14850299) Homepage Journal

    What I'd like to see is benchmarks, on Intel and Amd, with 10 clients attached. That way, we can see if the code is indeed optimized for Intel, or if it's just crap. I suspect it's crap.

    If anything, I'd suspect we'd see Intel being, what, 10% or 15% less load. Which would be something, but not something which justifies a 50% crippling of AMD hardware. And it'd be funny if AMD actually performed better.

    Yeah, someone should benchmark:
    Origional Executable, 5 clients, Intel
    Origional Executable, 5 clients, AMD
    Origional Executable, 10 clients, Intel (for reference against modifications)
    Modified Executable, 10 clients, Intel
    Modified Executable, 10 clients, AMD

    and let us know what the real beef is.

  • by patcito ( 932676 ) on Saturday March 04, 2006 @01:27PM (#14850330)
    openwengo [] not only uses open standard protocol but is also fully GPL.
  • Optimizing for AMD (Score:3, Interesting)

    by JFMulder ( 59706 ) on Saturday March 04, 2006 @01:29PM (#14850335)
    Being in a company who worked exclusively on Intel and nVidia chips until recently, it is possible to have horrible performance when switching to AMD and ATI. In our case, we didn't use any nVidia specific GL calls. As for SS2, it is supported on both platform so in theory it shouldn't be an issue. The reality is, unless you are making a game and using what I'd call "game-oriented opengl calls", the performance is going to vary a LOT between ATI and nVidia. Don't believe the hype of these companies when they say that they support full OpenGL. Some either have very bad hardware for 2d ops with OpenGL or literally do software "decelleration". Benchmarks have shown speed dropping as much as 200% in some areas. As for AMD and Intel, after patching the executable, the performance was different, sometimes in favor of Intel, sometimes on AMD.

    With that being said, no platform specific instructions or features were used. I suspect the Skype guys may have simply used Intel machines for so long and never bothered using AMD machines for development and then were too lazy to simply rewrite some of the code so that it runs normally on AMD. This happens especially when you write tight assembly loops by taking into account instruction latencies for one processor and then realize the performance sucks on another platform. You then have the choice, rewrite it so that the performance is similar, or slap a OPTIMIZED FOR INTEL on the box.

    Thankfully we rewrote.
  • 10, or more? (Score:3, Interesting)

    by sam0737 ( 648914 ) <.sam. .at.> on Saturday March 04, 2006 @01:40PM (#14850379)

    Of interest here is also the code marked with (*). It reveals that the string is somehow used if a certain memory location has the value 4. Theory is, this 4 means "4 additional conference members";

    Is that possible that by modifying some variables...we can have unlimited number of user in the conference?

  • Intel compiler? (Score:3, Interesting)

    by kryptx ( 894550 ) on Saturday March 04, 2006 @01:43PM (#14850390)
    This sounds an awful lot like the type of code built by Intel's compilers, for which they're being sued by AMD. Is it possible Skype is using that very compiler, and just couldn't figure out how to make it work on AMD machines (presumably pre-lawsuit)?
  • Re:Indeed... (Score:5, Interesting)

    by bobcat7677 ( 561727 ) on Saturday March 04, 2006 @01:47PM (#14850415) Homepage
    Svartalf, you are indeed insightful today. Personally I use Asterisk meetme conferences for all my conferencing needs. Only limited to my server horsepower and available bandwidth. Can have almost an unlimited number of people call into it through SIP, IAX2 or an IAX2 trunked PTSN #.

    I tried skype a couple times (mostly because some girl talked me into it), but she wasn't worth it. The lack on interoperability totally killed it. The last thing I need is yet another app running on my main console all the time. Asterisk runs happilly on my server in the corner and rings my normal home phones all over the house if someone is trying to reach me. I might even pay for a skype IAX2 or SIP access account. But being a closed system they are too much trouble to deal with.
  • Re:Lawsuit (Score:5, Interesting)

    by cmoney ( 216557 ) on Saturday March 04, 2006 @01:56PM (#14850453)
    Yeah, except they're not locking out just AMD users. They're also locking out anybody who has an Intel chip that doesn't meet their arbitrary requirements. So to me it sounds more like a forced obsolescence plan to get people to upgrade to higher end PCs.
  • by m50d ( 797211 ) on Saturday March 04, 2006 @02:16PM (#14850517) Homepage Journal
    Like I said, since it's burned into the chip, there's no real way of 'masking' those registers as something else.

    Can't you get the OS to look through the code before it's executed and replace the offending instruction with a simulated version, like they do to workaround the pentium f00f bug?

  • Re:Aaaah Maxxuss (Score:5, Interesting)

    by angulion ( 132742 ) on Saturday March 04, 2006 @02:50PM (#14850588)
    Seems it has allready been done [].
  • by Sycraft-fu ( 314770 ) on Saturday March 04, 2006 @02:50PM (#14850589)
    AMD chips aren't as quick at Intel extensions, or at least so it seems. Audio processing plugins always seem to bench faster on Intel chips than on AMD chips. Usually, they are only optimised for SSE, not 3dnow. So while the AMD chips run them just fine, and aren't dragging along, they don't compare to the Intel chips. I'm poking around on Waves' site but I can't find the document I was looking for. It may only come with their plugins. At any rate it's got them benched on a number of chips, and the Intel chips beat out the AMD chips, where the situation is reversed with the same chips playing games.

    I'd love to see some real comparative benchmarks betweent he chips using different instructions to achieve the same ends and see how they perform, but I'm not aware of any. At any rate, I can easily believe that the AMD chips aren't as good at executing the Intel instructions as the Intel chips are.
  • Re:Aaaah Maxxuss (Score:1, Interesting)

    by Anonymous Coward on Saturday March 04, 2006 @02:50PM (#14850590)
    HDCP is only the transport security protocol used for transmission of data over DVI and HDMI cables. It is NOT some software you will be running on your PC's cpu or gpu - so there is really nothing for windows hackers to crack!

    The purpouse of HDCP is to encrypt data to prevent real-time brute force attacks and ensure only licenced devices are communicating.

    For Blu-ray Disc (and HD DVD if it survives) the copy protection that has to be cracked is in fact AACS.
  • by XMilkProject ( 935232 ) on Saturday March 04, 2006 @03:12PM (#14850686) Homepage
    Skype didn't break any laws, and no one (except /.ers) said they did. It's their software and if they want to intentionally limit their customer based they are more than welcome to do so.

    The reason this issue is important is that it seems likely Intel went to Skype, and in some way coerced/bribed them to do this. This could be extremely strong evidence in helping AMD with their current lawsuit against Intel. Hence AMD issuing a subpoena to Skype, to retrieve information that will show whether or not Intel is to blame for this limitation.

    It's silly to hear people saying AMD should sue Skype. AMD doesn't care about skype, nor are they trying to run a huge campaign of lawsuits. They are only interested in forcing Intel to stop their current tactics which have arguably kept AMD from massive success in the OEM market.
  • Re:DMCA anyone? (Score:4, Interesting)

    by HermanAB ( 661181 ) on Saturday March 04, 2006 @04:41PM (#14850906)
    Maybe you should go and *read* the DMCA. It specifically allows reverse engineering for compatibility reasons.
  • Re:Lawsuit (Score:2, Interesting)

    by wile_e_wonka ( 934864 ) on Saturday March 04, 2006 @05:09PM (#14850986)
    I think I'd have to say no, this is different from that. The "aero" GUI actually requires a better graphic card. That is no different from similar GUIs on Linux--they also require better graphics cards.

    One might argue that it does "force obsolescence" because Windows is so ubiquitous--you want to be able to run Vista, you gotta have an nVidia (sp?). But that isn't the case either, as you can turn off "aero" and use the "classic" look, which requires a less sophisticated graphics card.

    Nice try giving a shot at Bill though...
  • Re:Lawsuit (Score:3, Interesting)

    by TheGavster ( 774657 ) on Saturday March 04, 2006 @05:20PM (#14851013) Homepage
    The restriction isn't of the form "this software uses instruction X, which your processor doesn't support", it's of the form "we don't run unless your processor id string is X". The case is that the AMD chip does everything the Intel chip does (at least in the realm of instructions that the Skype software requires), except that it says "AMD" rather than "Intel" when you ask it where it's from.
  • by Fanboy Troy ( 957025 ) on Saturday March 04, 2006 @05:40PM (#14851099)
    It would lose sales for them, though.

    Exactly. So, why would skype want to make such a move if it obviously would lose sales from it also? If Intel has a hand in this, I don't see how it is legal for Intel and skype to make a deal that would make AMD and/or other CPUs look bad when they most likely can handle the conferences. Or if not, they can probably 'catch up' with Intel really quick. I don't know how the law works in the USA exactly and IANAL, but this sort of defamation is illegal in Europe (I don't know how much this [] is relevant to this situation). It's one thing to add value to skype when you buy Intel (optimize it for intel CPUs) and another thing to remove value when you buy AMD (remove features it probably is capable of handling), ultimately making AMD look bad unfairly.

    I could be sort of ok with this if it was a QoS thing, but if it was, it shouldn't have been implemented by checking for the chips manufacturer and th user should be given the opportunity to "use at his own risk". At least skype should have announced the feature Intel's CPUs have AMD lacks. I think this is a dangerous road to go down. Imagine a future where you would choose the programs you run based on the manufacturer of the CPU you use. Even worse, imagine the deadlocks where you need to run 2 programs that favor different manufacturers. The worst part being that the 'obsticales' are completely artificial. And the competition wouldn't be on each cpu's merits, but on the manufacturer's connections. :(
  • Re:Maxxuss (Score:1, Interesting)

    by Anonymous Coward on Saturday March 04, 2006 @05:52PM (#14851124)
    I disagree with your sentiment.

    I'd rather such cracks were made public and explained clearly by someone with good command of the English language than wrapped up in some lame warez-style .exe with the details known only to a handful of people.

    I am more impressed by his clear explanation of the technique than the crack itself (which is pretty standard stuff, not special or anything)
  • by Wizardry Dragon ( 952618 ) on Saturday March 04, 2006 @06:04PM (#14851143) Homepage Journal
    The requirement is that the Intel chip returns a 'GenuineIntel' signature, which, if the chip IS an Intel chip, any Intel chip (at least since they introduced such ID signatures on chips) should be every single Intel chip. So yes, it pretty much is AMD they're locking out. It should be interesting to see how this revelation pans out in court with AMD already pressing charges to this effect, this article should be all the evidence they really need, although the courts have done weirder things in the past. I hope that such evidence as presented here is allowed into court.
  • Re:Aaaah Maxxuss (Score:1, Interesting)

    by Anonymous Coward on Saturday March 04, 2006 @06:20PM (#14851185)
    A software player will never have to deal with HDCP. The HDCP encryption is added to the transport layer of HDMI / DVD after the data has left the GPU on your gfx card (by a separate chip).

    The chip takes the raw data from the GPU's framebuffer and tranceives it to DVI or HDMI outputs. You will only get uncrypted transfers when the resolution is below or equal to 960x540.

    For all resolutions above 960x540 the chip will enforce HDCP. This enforcement is part of the licence and can not be controlled by software.

    That's why the newst nVidia and ATI gfx cards that supposedly were HDCP compatible turned out to be incompatible. They thought they could add HDCP into the firmware of their cards later, but they soon found out this would have violated the licence for playing HD-DVD.

    So all new cards will have to be mounted with licenced HDCP hardware chips.
  • x86 Apples? (Score:2, Interesting)

    by filterchild ( 834960 ) on Saturday March 04, 2006 @06:24PM (#14851192)
    Has anyone tested whether Skype allows 10-way conference calls on any of the Macs powered by the Intel Core Duo?
  • by svip ( 678490 ) on Sunday March 05, 2006 @04:32AM (#14852885)
    There is no lawsuit vs Skype. AMD has an ongoing anti-trust lawsuit vs Intel, and they subpoenaed Skype to find evidence that Intel had Skype put in the pointless restriction. Many other companies have already been similarly subpoenaed including most major PC manufacturers.

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