Re: [PATCH v2] random: avoid mis-detecting a slow counter as a cycle counter

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Eric,

Thanks. This looks better.

On Thu, Apr 21, 2022 at 04:31:52PM -0700, Eric Biggers wrote:
> Therefore, increase the number of counter comparisons from 1 to 3, to
> greatly reduce the rate of false positive cycle counter detections.
> +	for (i = 0; i < 3; i++) {
> +		unsigned long entropy = random_get_entropy();
 
Wondering: why do you do 3 comparisons rather than 2? What does 3 get
you that 2 doesn't already? I thought the only real requirement was that
in the event where (a)!=(b), (b) is read as meaningfully close as
possible to when the counter changes.

Jason



[Index of Archives]     [Kernel]     [Gnu Classpath]     [Gnu Crypto]     [DM Crypt]     [Netfilter]     [Bugtraq]

  Powered by Linux