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Re: [PATCH v6 0/5] /dev/random - a new approach

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Am Dienstag, 16. August 2016, 15:28:45 CEST schrieb H. Peter Anvin:

Hi Peter,

> > 
> > There are two motivations for that:
> > 
> > - the current /dev/random is compliant to NTG.1 from AIS 20/31 which
> > requires (in brief words) that entropy comes from auditible noise
> > sources. Currently in my LRNG only RDRAND is a fast noise source which is
> > not auditible (and it is designed to cause a VM exit making it even
> > harder to assess it). To make the LRNG to comply with NTG.1, RDRAND can
> > provide entropy but must not become the sole entropy provider which is
> > the case now with that change.
> > 
> > - the current /dev/random implementation follows the same concept with the
> > exception of 3.15 and 3.16 where RDRAND was not rate-limited. In later
> > versions, this was changed.
> 
> I'm not saying it should be *sole*.  I am questioning the value in
> limiting it, as it seems to me that it could only ever produce a worse
> result.

It is not about the limiting of the data. It is all about the entropy estimate 
for those noise sources and how they affect the entropy estimator behind /dev/
random. If that fast noise source injects large amount of data but does not 
increase the entropy estimator, it is of no concern.

Ciao
Stephan

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[PATCH v6 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-08-11 14:30 +0200
  Re: [PATCH v6 0/5] /dev/random - a new approach Theodore Ts'o <tytso@mit.edu> - 2016-08-11 23:40 +0200
    Re: [PATCH v6 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-08-12 11:40 +0200
      Re: [PATCH v6 0/5] /dev/random - a new approach Theodore Ts'o <tytso@mit.edu> - 2016-08-12 21:30 +0200
        Re: [PATCH v6 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-08-15 08:20 +0200
          Re: [PATCH v6 0/5] /dev/random - a new approach Theodore Ts'o <tytso@mit.edu> - 2016-08-15 17:10 +0200
    Re: [PATCH v6 0/5] /dev/random - a new approach Pavel Machek <pavel@ucw.cz> - 2016-08-17 23:50 +0200
      Re: [PATCH v6 0/5] /dev/random - a new approach Theodore Ts'o <tytso@mit.edu> - 2016-08-19 03:20 +0200
        Re: [PATCH v6 0/5] /dev/random - a new approach Pavel Machek <pavel@ucw.cz> - 2016-08-19 03:30 +0200
          Re: [PATCH v6 0/5] /dev/random - a new approach Theodore Ts'o <tytso@mit.edu> - 2016-08-19 05:20 +0200
            Re: [PATCH v6 0/5] /dev/random - a new approach Herbert Xu <herbert@gondor.apana.org.au> - 2016-08-19 08:00 +0200
              Re: [PATCH v6 0/5] /dev/random - a new approach "H. Peter Anvin" <hpa@linux.intel.com> - 2016-08-19 19:30 +0200
                Re: [PATCH v6 0/5] /dev/random - a new approach Herbert Xu <herbert@gondor.apana.org.au> - 2016-08-21 05:20 +0200
            Re: [PATCH v6 0/5] /dev/random - a new approach Pavel Machek <pavel@ucw.cz> - 2016-08-19 09:50 +0200
  Re: [PATCH v6 0/5] /dev/random - a new approach "H. Peter Anvin" <hpa@linux.intel.com> - 2016-08-15 22:50 +0200
    Re: [PATCH v6 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-08-16 07:50 +0200
      Re: [PATCH v6 0/5] /dev/random - a new approach "H. Peter Anvin" <hpa@linux.intel.com> - 2016-08-17 00:30 +0200
        Re: [PATCH v6 0/5] /dev/random - a new approach "H. Peter Anvin" <hpa@linux.intel.com> - 2016-08-17 00:50 +0200
        Re: [PATCH v6 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-08-17 07:30 +0200

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