Re: [PATCH] random: limit the contribution of the hw rng to at most half

2014-07-18 Thread Theodore Ts'o
On Thu, Jul 17, 2014 at 04:33:36PM -0700, H. Peter Anvin wrote: > > I just want to make sure we don't negatively impact the real security of > users because of "optics". We already have a lot of problems with > people extracting long-living keys from /dev/urandom because /dev/random > is too slow

Re: [PATCH] random: limit the contribution of the hw rng to at most half

2014-07-17 Thread H. Peter Anvin
On 07/17/2014 03:08 PM, Theodore Ts'o wrote: > > There was another complaint more recently, that wasn't related to > nordrand. And I was rather disturbed that in > add_interrupt_randomness() 97% of the entropy was coming from RDSEED. > I'm willing to have some of the entropy come from RDSEED by d

Re: [PATCH] random: limit the contribution of the hw rng to at most half

2014-07-17 Thread Theodore Ts'o
On Thu, Jul 17, 2014 at 10:39:57AM -0700, H. Peter Anvin wrote: > > I saw exactly one complaint to that nature, but that was from someone > who really wanted the "nordrand" option (at which point I observed that > it had inadvertently left RDSEED enabled which quickly got rectified.) > The implica

Re: [PATCH] random: limit the contribution of the hw rng to at most half

2014-07-17 Thread H. Peter Anvin
On 07/17/2014 03:03 AM, Theodore Ts'o wrote: > For people who don't trust a hardware RNG which can not be audited, > the changes to add support for RDSEED can be troubling since 97% or > more of the entropy will be contributed from the in-CPU hardware RNG. > > We now have a in-kernel khwrngd, so f

[PATCH] random: limit the contribution of the hw rng to at most half

2014-07-17 Thread Theodore Ts'o
For people who don't trust a hardware RNG which can not be audited, the changes to add support for RDSEED can be troubling since 97% or more of the entropy will be contributed from the in-CPU hardware RNG. We now have a in-kernel khwrngd, so for those people who do want to implicitly trust the CPU