Re: [PATCH] API for true Random Number Generators to add entropy (2.6.11)

Jeff Garzik
2005-03-24T12:50:40Z

Evgeniy Polyakov wrote:
> On Thu, 2005-03-24 at 14:27 +1000, David McCullough wrote:
>
>>Hi all,
>>
>>Here is a small patch for 2.6.11 that adds a routine:
>>
>> add_true_randomness(__u32 *buf, int nwords);
>>
>>so that true random number generator device drivers can add a entropy
>>to the system. Drivers that use this can be found in the latest release
>>of ocf-linux, an asynchronous crypto implementation for linux based on
>>the *BSD Cryptographic Framework.
>>
>> http://ocf-linux.sourceforge.net/
>>
>>Adding this can dramatically improve the performance of /dev/random on
>>small embedded systems which do not generate much entropy.
>
>
> People will not apply any kind of such changes.
> Both OCF and acrypto already handle all RNG cases - no need for any kind
> of userspace daemon or entropy (re)injection mechanism.
> Anyone who want to use HW randomness may use OCF/acrypto mechanism.
> For example here is patch to enable acrypto support for hw_random.c
> It is very simple and support only upto 4 bytes request, of course it
> is
> not interested for anyone, but it is only 2-minutes example:

If you want to add entropy to the kernel entropy pool from hardware RNG,
you should use the userland daemon, which detects non-random (broken)
hardware and provides throttling, so that RNG data collection does not
consume 100% CPU.

If you want to use the hardware RNG directly, it's simple: just open
/dev/hw_random.

Hardware RNG should not go kernel->kernel without adding FIPS tests and
such.

Jeff