linux-kernel - Re: [RFC][PATCH 0/6] /dev/random

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Message-ID: <CAJU7zaL+jYCgq0RzSraCQF6hd6QtxhobkPtxt+_YqxiZ+vfkMw@mail.gmail.com>
Date:	Mon, 25 Apr 2016 10:23:51 +0200
From:	Nikos Mavrogiannopoulos <nmav@...tls.org>
To:	Stephan Mueller <smueller@...onox.de>
Cc:	Ted Tso <tytso@....edu>, Herbert Xu <herbert@...dor.apana.org.au>,
	Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Sandy Harris <sandyinchina@...il.com>
Subject: Re: [RFC][PATCH 0/6] /dev/random - a new approach

On Mon, Apr 25, 2016 at 10:02 AM, Stephan Mueller <smueller@...onox.de> wrote:
>> > One more item to consider: If you do not want to change to use
>> > getrandom(2), the LRNG provides you with another means.
>> The main problem is not about willing to switch to getrandom() or not,
>> but finding any system where getrandom() exists. Today due to libc not
>> having the call, we can only use /dev/urandom and applications would
>> most likely continue to do so long time after getrandom() is
>> introduced to libc.
> Implement the syscall yourself with syscall(). If you get ENOSYS back, revert
> to your old logic of seeding from /dev/urandom.

That's far from a solution and I wouldn't recommend to anyone doing
that. We cannot expect each and every program to do glibc's job. The
purpose of a system call like getrandom is to simplify the complex use
of /dev/urandom and eliminate it, not to make code handling randomness
in applications even worse.

regards,
Nikos