Re: 4.14 "random: add a config option to trust the CPU's hwrng"

From: Greg KH
Date: Thu Feb 07 2019 - 06:28:14 EST


On Wed, Feb 06, 2019 at 02:26:13PM -0500, Sasha Levin wrote:
> On Wed, Feb 06, 2019 at 11:44:36AM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote:
> > Hi stable maintainers,
> >
> > Can you consider including these "random" patches in 4.14.y?
> >
> > These are very useful in fixing esp. first-bootup delays of VMs due to
> > entropy starvation.
> >
> >
> > commit 39a8883a2b989d1d21bd8dd99f5557f0c5e89694
> > Author: Theodore Ts'o <tytso@xxxxxxx>
> > Date: Tue Jul 17 18:24:27 2018 -0400
> >
> > random: add a config option to trust the CPU's hwrng
> >
> > commit 9b25436662d5fb4c66eb527ead53cab15f596ee0
> > Author: Kees Cook <keescook@xxxxxxxxxxxx>
> > Date: Mon Aug 27 14:51:54 2018 -0700
> >
> > random: make CPU trust a boot parameter
>
> This really looks like a new feature to me. The "old" behaviour of not
> trusting RDRAND-like randomness was by-design rather than an oversight.

I agree with Sasha, this looks like a new feature. If you really want
this new functionality, just use 4.19 or newer, right?

thanks,

greg k-h