linux-kernel - Re: [PATCH 1/3] x86, random: Enable the RDSEED instruction

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 5 Mar 2014 09:43:59 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	"H. Peter Anvin" <hpa@...ux.intel.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ted Ts'o <tytso@....edu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] x86, random: Enable the RDSEED instruction


* H. Peter Anvin <hpa@...ux.intel.com> wrote:

> From: "H. Peter Anvin" <hpa@...ux.intel.com>
> 
> Upcoming Intel silicon adds a new RDSEED instruction.  Whereas RDRAND
> returns output from a PRNG, the RDSEED instruction returns fully
> conditioned entropy that is suitable for use as seeds to a PRNG.
> 
> The RDSEED instruction takes the same time to execute as RDRAND, but
> RDSEED unlike RDRAND can legitimately return failure (CF=0) due to
> entropy exhaustion if too many threads on too many cores are hammering
> the RDSEED instruction at the same time.  Therefore, we have to be
> more conservative and only use it in places where we can tolerate
> failures.
> 
> This patch introduces the primitives arch_get_random_seed_{int,long}()
> but does not use it yet.
> 
> Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
> ---
>  arch/x86/include/asm/archrandom.h | 34 +++++++++++++++++++++++++++++++++-
>  include/linux/random.h            | 16 ++++++++++++++++
>  2 files changed, 49 insertions(+), 1 deletion(-)

Reviewed-by: Ingo Molnar <mingo@...nel.org>

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/