Re: [PATCH v4 RESEND] timekeeping: contribute wall clock to rng on time change

From: Thomas Gleixner
Date: Mon Jul 18 2022 - 08:20:43 EST


On Sun, Jul 17 2022 at 23:53, Jason A. Donenfeld wrote:

> The rng's random_init() function contributes the real time to the rng at
> boot time, so that events can at least start in relation to something
> particular in the real world. But this clock might not yet be set that
> point in boot, so nothing is contributed. In addition, the relation
> between minor clock changes from, say, NTP, and the cycle counter is
> potentially useful entropic data.
>
> This commit addresses this by mixing in a time stamp on calls to
> settimeofday and adjtimex. No entropy is credited in doing so, so it
> doesn't make initialization faster, but it is still useful input to
> have.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: stable@xxxxxxxxxxxxxxx
> Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>