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    SubjectRe: Fw: signed kernel modules?
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    On Wed, 2004-10-13 at 10:11 +1000, Rusty Russell (IBM) wrote:
    > Here's the level of paranoia required for the simplest case, that of
    > signing the entire module. The last Howells patches I saw didn't even
    > do any of *this*, let alone checking the rest of the module:

    It's work in progress, and from my limited and third-hand understanding
    of what went on before this thread became public, you seemed to be
    railing against the _concept_ not against the implementation.

    We agree that the checks you cite are required. In fact we should have
    been doing a lot of these checks even _before_ we thought about signing
    modules.

    That said, I think it was perfectly reasonable for David to leave the
    implementation of this level of paranoia till last, after working out
    the details of how the signatures actually work.

    After all, until the precise signature scheme is agreed upon we don't
    really know how much of the ELF we should be paranoid about, and how
    much we can trust because it's signed.

    In David's original scheme, the signature covered only the relevant
    parts of the module, so it survives the removal of debug info, and it
    survives the further 'strip' it gets on being put into an initrd -- but
    the signature _doesn't_ survive anything which would actually change
    what happens when the module is loaded.

    If your objection to that is purely on the perfectly reasonable grounds
    that we're overly trusting of what could be invalid ELF, and could kill
    us before we actually get to checking the signature, we can just wait
    for him to complete what he's working on at the moment and all will
    presumably be well.

    I had the impression you were rabidly against any scheme which didn't
    sign the _whole_ module, irrelevant parts and all.

    --
    dwmw2

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