Re: [RESEND] [PATCH] Revert "efi/random: Treat EFI_RNG_PROTOCOL output as bootloader randomness"

[Ivan T. Ivanov]

> On 13 Oct 2021, at 12:51, Ivan T. Ivanov <iivanov@xxxxxxx> wrote:
> 
> Hi,
> 
>> On 13 Oct 2021, at 10:50, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
>> 
>> On Wed, 13 Oct 2021 at 09:30, Ivan T. Ivanov <iivanov@xxxxxxx> 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 doesn’t boot. I just changed following and kernel panics.  
> 
> - credit_entropy
> + credit_entropy_bits
> 
> Please see attached file.
> 

Ah, sorry. I missed file attachment. Now it should be fine.

Attachment: panic.log
Description: Binary data

Ivan