From owner-freebsd-security@freebsd.org  Sun Mar 19 15:12:41 2017
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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Konstantin Belousov <kostikbel@gmail.com>
Cc: freebsd-security@freebsd.org, Steven Chamberlain <steven@pyro.eu.org>,
 freebsd-hackers@freebsd.org
Subject: Re: arc4random weakness
References: <CAD2Ti28acbW+pGQR5UihECWvg9WduGmVzkVFug_2ZWRF2zyTBw@mail.gmail.com>
 <20170313220639.GB65190@pyro.eu.org>
 <20170315130615.GC25448@pyro.eu.org>
 <5160183b-9778-59aa-6cf9-118014a588eb@freebsd.org>
 <86k27pz8sy.fsf@desk.des.no> <20170316131946.GN16105@kib.kiev.ua>
Date: Sun, 19 Mar 2017 16:12:29 +0100
In-Reply-To: <20170316131946.GN16105@kib.kiev.ua> (Konstantin Belousov's
 message of "Thu, 16 Mar 2017 15:19:46 +0200")
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Konstantin Belousov <kostikbel@gmail.com> writes:
> Dag-Erling Sm=C3=B8rgrav <des@des.no> writes:
> > Wouldn't it be possible to just set up the page entry but leave it
> > unmapped, so that it is paged in (and zeroed if necessary) on first
> > access?  Thus, a process that uses arc4random() and fork()s would not
> > incur a penalty until (and unless) the child uses arc4random() too.
> This is how the forking code works, without any additional coding,
> for the INHERIT_ZERO regions as well.

Well then I don't see the problem...  I just assumed from ache@'s
objection that it wasn't the case.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no