linux-kernel - RE: [RFC PATCH v1 00/52] Audit kernel random number use

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Message-ID: <98bd30f23b374ccbb61dd46125dc9669@AcuMS.aculab.com>
Date:   Sun, 29 Mar 2020 12:21:46 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'George Spelvin' <lkml@....ORG>,
        Dan Williams <dan.j.williams@...el.com>
CC:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Qian Cai <cai@....pw>, Kees Cook <keescook@...omium.org>,
        Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux MM <linux-mm@...ck.org>
Subject: RE: [RFC PATCH v1 00/52] Audit kernel random number use

From: George Spelvin
> Sent: 28 March 2020 18:28
...
> 20..23: Changes to the prandom_u32() generator itself.  Including
>     switching to a stronger & faster PRNG.

Does this remove the code that used 'xor' to combine the output
of (about) 5 LFSR?
Or is that somewhere else?
I didn't spot it in the patches - so it might already have gone.

Using xor was particularly stupid.
The whole generator was then linear and trivially reversable.
Just using addition would have made it much stronger.

	David

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