From mboxrd@z Thu Jan  1 00:00:00 1970
From: Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH v3 2/5] random,x86: Add arch_get_slow_rng_u64
Date: Thu, 17 Jul 2014 06:33:24 -0400
Message-ID: <20140717103324.GJ1491@thunk.org>
References: <cover.1405546879.git.luto@amacapital.net>
 <5778e65d5ca52bebbaa023e177d863e44f098e96.1405546879.git.luto@amacapital.net>
 <53C6F5A9.80400@zytor.com>
 <CALCETrVwT1g-S1hLyyB_uAVwffYCnFacTfUhJeD8Bb5j3X0mkg@mail.gmail.com>
 <CALCETrVCrJEwYokasRoqQTKJWKtzq9XUMNqHoT4-ZjgyZ-mBow@mail.gmail.com>
 <53C703ED.2010605@zytor.com>
 <CALCETrVSG_Lp=OSw-U+QK+_VsEhKBS=rBQ3ojTrnO9kAKR+Qag@mail.gmail.com>
 <53C75733.8060507@zytor.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Andy Lutomirski <luto@amacapital.net>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>, X86 ML <x86@kernel.org>,
	Bandan Das <bsd@redhat.com>, Gleb Natapov <gleb@kernel.org>,
	kvm list <kvm@vger.kernel.org>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Daniel Borkmann <dborkman@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <53C75733.8060507@zytor.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On Wed, Jul 16, 2014 at 09:55:15PM -0700, H. Peter Anvin wrote:
> On 07/16/2014 05:03 PM, Andy Lutomirski wrote:
> >>
> > I meant that prandom isn't using rdrand for early seeding.
> > 
> 
> We should probably fix that.

It wouldn't hurt to explicitly use arch_get_random_long() in prandom,
but it does use get_random_bytes() in early seed, and for CPU's with
RDRAND present, we do use it in init_std_data() in
drivers/char/random.c, so prandom is already getting initialized via
an RNG (which is effectively a DRBG even if it doesn't pass all of
NIST's rules) which is derived from RDRAND.

Cheers,

					- Ted