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    SubjectRe: [PATCH v4 2/5] random: Add and use arch_get_rng_seed
    On Thu, Jul 17, 2014 at 11:22:17AM -0700, Andy Lutomirski wrote:
    > Currently, init_std_data contains its own logic for using arch
    > random sources. This logic is a bit strange: it reads one long of
    > arch random data per byte of internal state.

    This isn't true. Check out the init_std_data() a bit more closely.

    unsigned long rv;

    ...

    for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) {
    ...

    In particular, note the "i -= sizeof(rv)". We are reading one bit per
    bit of internal state beeing seeded.

    > Assuming the arch sources are perfect, this is the right thing to
    > do. They're not, though, so the followup patch attempts to
    > implement the correct logic on x86.

    ... and that's not a problem because we aren't giving any entropy
    credit --- and this is deliberate, because we don't want to trust
    un-auditable hardware. We are deliberately trying to be conservative
    here.

    So I don't think either this patch or the next one is needed. It adds
    far more complexity than is warranted.

    Regards,

    - Ted


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