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    SubjectRe: [PATCH] paravirt.h
    Alan Cox wrote:
    > It would be nice not to export it at all or to protect it, paravirt_ops
    > is a rootkit authors dream ticket. I'm opposed to paravirt_ops until it
    > is properly protected, its an unpleasantly large security target if not.

    Do you have an example of an attack which would become significantly
    easier with pv_ops in use? I agree it might make a juicy target, but
    surely it is just a matter of degree given that any attacker who can get
    to pv_ops can do pretty much anything else.

    > It would be a lot safer if we could have the struct paravirt_ops in
    > protected read-only const memory space, set it up in the core kernel
    > early on in boot when we play "guess todays hypervisor" and then make
    > sure it stays in read only (even to kernel) space.

    Yes, I'd thought about doing something like that, but as Arjan pointed
    out, nothing is actually read-only in the kernel when using a 2M
    mapping. It's also ameliorated by the fact that some of the entrypoints
    are never used at runtime, because the code has been patched inline (but
    I don't think it would ever be desirable to patch every entrypoint,
    since some are just not worth the effort, complexity or obfuscation
    which result from patching).

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      Last update: 2006-08-22 17:05    [W:0.027 / U:33.008 seconds]
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