Re: [PATCH, RFC] random: introduce getrandom(2) system call

[Andy Lutomirski]

On Thu, Jul 17, 2014 at 2:28 PM, Theodore Ts'o <tytso@xxxxxxx> wrote:
> On Thu, Jul 17, 2014 at 01:35:15PM -0700, Andy Lutomirski wrote:
>>
>> Can we please have a mode in which getrandom(2) can neither block nor
>> fail?  If that gets added, then this can replace things like AT_RANDOM.
>
> AT_RANDOM has been around for a long time; it's not something we can
> remove.

I'm not suggesting removing AT_RANDOM.  To the contrary, I'm
suggesting that libraries that need to seed some kind of
non-cryptographic, non-security-related RNG could use getrandom(2)
with appropriate flags rather than screwing around with getpid,
clock_gettime, etc.

For example:

unsigned int seed;
getrandom(&seed, sizeof(seed), GRND_BEST_EFFORT); /* Never fails on
new enough kernels */
srand(seed);

No error checking, no weird cases, and if the RNG isn't well seeded,
then I tried my best.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/