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    SubjectRe: [RESEND] Re: [PATCH] Revert "efi/random: Treat EFI_RNG_PROTOCOL output as bootloader randomness"
    On 2021-10-13 10:50, Ard Biesheuvel wrote:
    > On Wed, 13 Oct 2021 at 09:30, Ivan T. Ivanov <iivanov@suse.de> wrote:
    >>
    >> Hi,
    >>
    >> Quoting Dominik Brodowski (2021-10-12 11:40:34)
    >> > Am Tue, Oct 12, 2021 at 11:27:08AM +0300 schrieb Ivan T. Ivanov:
    >> > > This reverts commit 18b915ac6b0ac5ba7ded03156860f60a9f16df2b.
    >> > >
    >> > > When CONFIG_RANDOM_TRUST_BOOTLOADER is enabled add_bootloader_randomness()
    >> > > calls add_hwgenerator_randomness() which might sleep,
    >> >
    >> > Wouldn't it be better to fix add_bootloader_randomness(), considering
    >> > that
    >> > calls to that function are likely to happen quite early during kernel
    >> > initialization? Especially as it seems to have worked beforehand?
    >>
    >> I have tried. I made wait_event_interruptible() optional, but then
    >> crng_reseed() segfault badly. And I don't think crng_reseed() is
    >> something that I could fix easily. Suggestions are welcomed ;-)
    >>
    >
    > How about
    >
    > diff --git a/drivers/char/random.c b/drivers/char/random.c
    > index 605969ed0f96..1828dc691ebf 100644
    > --- a/drivers/char/random.c
    > +++ b/drivers/char/random.c
    > @@ -2297,9 +2297,8 @@ EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
    > */
    > void add_bootloader_randomness(const void *buf, unsigned int size)
    > {
    > + add_device_randomness(buf, size);
    > if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER))
    > - add_hwgenerator_randomness(buf, size, size * 8);
    > - else
    > - add_device_randomness(buf, size);
    > + credit_entropy(&input_pool, size * 8);
    > }
    > EXPORT_SYMBOL_GPL(add_bootloader_randomness);

    This is more or less what I have done. credit_entropy() calls
    crng_reseed() which crash badly.

    Will check again, but I am sure it will give me same result.

    Regards,
    Ivan

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