Re: [PATCH 1/2] random32: make prandom_u32() output unpredictable

Willy Tarreau
2020-09-01T13:19:21Z

On Tue, Sep 01, 2020 at 01:10:18PM +0000, David Laight wrote:
> From: Willy Tarreau
> > Sent: 01 September 2020 07:43
> ...
> > +/*
> > + * Generate some initially weak seeding values to allow
> > + * the prandom_u32() engine to be started.
> > + */
> > +static int __init prandom_init_early(void)
> > +{
> > + int i;
> > + unsigned long v0, v1, v2, v3;
> > +
> > + if (!arch_get_random_long(&v0))
> > + v0 = jiffies;
>
> Isn't jiffies likely to be zero here?

I don't know. But do we really care ? I'd personally have been fine
with not even assigning it in this case and leaving whatever was in
the stack in this case, though it could make some static code analyzer
unhappy.

Willy