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  1. #1
    Theo de Raadt
    Re: Sun M-class hardware denial of service
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    Thread Starter

    Re: Sun M-class hardware denial of service

    > While having to power cycle the remainder of the frame may be a pain, the
    > fact it isolates the fault to only power off the affected domain suggests to
    > me that it is working as designed (the relative virtue of the design not up
    > for debate). The power cycle of the remainder of the frame can be done at
    > your leisure.


    Didn't you read the advisory?

    You don't get any crashed domain back until you power cycle the entire
    machine. If you need that domain back, you have to make a very nasty
    choice. It is a denial of service.

    > It is for this reason I would not class this as a DoS attack,
    > as the "attacker" could not affect the availability of the other domains,
    > only the admin could.


    The admin is forced to choose between "bring the crashed domain back
    now by calling Sun and then powering the whole machine down" and
    "accept that the crashed domain is down until you call Sun and power
    the whole machine down". How is that not a denial of service? Do you
    work for Sun?

    If that is not a denial of service, I don't know what is.

    > You don't state what privileges are required on the affected domain to
    > initiate the fault.


    This was very obvious from the advisory.

    > If this is executable by unprivileged users, then I
    > would agree with you that this represents a DoS issue for *that domain*.


    Have you ever used vmware? I don't see how Sun domains are supposed
    to be any different from vmware in that case. Obviously you are
    handing sub-admins control over a domain so that they can run any OS
    they need to. There hardware isolation is not supposed to be a joke. It
    is serious stuff. It has to work.

    Obviously you expect that what a sub-admin does in his domain should
    not affect the rest of your machine; ie. force you to power it off.
    But that is exactly what is required -- a power off of the whole chassis
    and all the existing domains. You cannot even do the equivelant of VMotion.

    The admin eventually MUST take all his other domains down. That is a
    denial of service.

    > It
    > sounds like the XSCF is monitoring the domain for certain events, and
    > mistaking legitimate operation for one of these events which leads it to
    > disable a component in the domain. While I haven't worked with the M-class
    > systems, I have some experience with the F15K/E25K range, and it sounds like
    > the XSCF is blacklisting some component (likely a system board). Requiring
    > a power cycle of the whole frame to clear a fault with a single (or even
    > multiple) components is fairly poor, the most I would expect is to power
    > cycle the domain components.


    That's what you expect, but that is not what happens. It requires a
    service call out to Sun to repair the machine, followed by a power
    down of the entire machine. That is just "fairly poor"?? What the
    hell do you think people are paying so much money for? A complete
    illusion of reliability??

    > I'm not surprised you didn't get any interest from Fujitsu/Sun security
    > people, for the reasons stated above. As for engineering, I would expect
    > they will only address the issue if they see a commercial or reputational
    > benefit in doing so (i.e. someone wants to spend a *lot* of money on
    > hardware to run OpenBSD, and this issue is a show-stopper).


    As the advisory made clear, we are certain that someone could write a
    Solaris kernel module that would trigger this same behaviour.

    In other worse, please learn to read. You'll get further in life.


  2. #2
    Bob Beck
    Re: Sun M-class hardware denial of service
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    Thread Starter

    Re: Sun M-class hardware denial of service

    >
    > Yet you don't know what it is that causes the issue? What's Sun's
    > support arrangement for OpenBSD on SPARC? If it is reproduced in
    > Solaris, then I'm sure Sun would address it, but where is the benefit
    > for them to do so at present?


    It's not about OpenBSD on sparc - the OpenBSD people don't
    really care - the fact that it's possible at all means anyone with
    clue and a less than black hat can go take an OpenBSD kernel, figure
    out what it's doing there, and likely make a solaris kernel module
    to do the same thing - then they have a nice little tool. This indicates
    that something is broken, and can likely be taken advantage of.

    Frankly, the OpenBSD people aren't going to bother doing it.
    They're only interested in making OpenBSD go. I can think of several
    people I've met in bars on the other hand who might be interested
    in having a domain-instabrick module for solaris.

    -Bob


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