From: Stephan =?ISO-8859-1?Q?M=FCller?= <smueller@chronox.de>
Subject: Re: Question - seeding the hw pseudo random number generator
Date: Sun, 26 Mar 2017 06:10:44 +0200
Message-ID: <1882318.c2IBOhq8iD@positron.chronox.de>
References: <20170318092554.lggkhfg5eko23o3k@kozik-lap> <20170323082307.GB16625@Red> <20170323094406.GA6848@gondor.apana.org.au>
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Cc: Corentin Labbe <clabbe.montjoie@gmail.com>,
        PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>,
        linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Matt Mackall <mpm@selenic.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
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Am Donnerstag, 23. M?rz 2017, 10:44:06 CEST schrieb Herbert Xu:

Hi Herbert,

> On Thu, Mar 23, 2017 at 09:23:07AM +0100, Corentin Labbe wrote:
> > Problem with this conversion, a huge regression for user space.
> > Using hwrng is simple as cat /dev/hwrng.
> > Using algif_rng via AF_ALG is ... unusable for the moment.
> > Perhaps creating an user space tool (prng-tool which provide a cat
> > /dev/hwrng replacement) is mandatory before any convertion.
> Stephan may have a tool to do this.  Stephan?

I added the application kcapi-rng to HEAD of [1]. Create the application with 
the --enable-kcapi-rngapp configure option.

$ kcapi-rng 

Kernel Crypto API Random Number Gatherer

Kernel Crypto API interface library version: libkcapi pre-release 0.13.1
Reported numeric version number 130080

Usage:
        -b --bytes <BYTES>      Number of bytes to generate (required option)
        -h --help       This help information
           --version    Print version
        -v --verbose    Verbose logging, multiple options increase verbosity

Data provided at stdin is used to seed the DRNG

[1] https://github.com/smuellerDD/libkcapi/

Ciao
Stephan