svn commit: r346358 - in head: . sys/dev/random sys/libkern sys/mips/conf sys/sys

Enji Cooper yaneurabeya at gmail.com
Fri Apr 19 05:56:36 UTC 2019


> On Apr 18, 2019, at 13:48, Conrad Meyer <cem at freebsd.org> wrote:
> 
> Author: cem
> Date: Thu Apr 18 20:48:54 2019
> New Revision: 346358
> URL: https://svnweb.freebsd.org/changeset/base/346358
> 
> Log:
>  random(4): Restore availability tradeoff prior to r346250
> 
>  As discussed in that commit message, it is a dangerous default.  But the
>  safe default causes enough pain on a variety of platforms that for now,
>  restore the prior default.
> 
>  Some of this is self-induced pain we should/could do better about; for
>  example, programmatic CI systems and VM managers should introduce entropy
>  from the host for individual VM instances.  This is considered a future work
>  item.
> 
>  On modern x86 and Power9 systems, this may be wholly unnecessary after
>  D19928 lands (even in the non-ideal case where early /boot/entropy is
>  unavailable), because they have fast hardware random sources available early
>  in boot.  But D19928 is not yet landed and we have a host of architectures
>  which do not provide fast random sources.
> 
>  This change adds several tunables and diagnostic sysctls, documented
>  thoroughly in UPDATING and sys/dev/random/random_infra.c.

Thank you for doing this Conrad!

One request: can these sysctls/tunables please be documented in random(4)? Not everyone has access to UPDATING with binary distributions.

Thank you so very much!
-Enji


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