Date: Fri, 14 Sep 2012 20:14:24 +0100 From: Ben Laurie <benl@freebsd.org> To: Mark Murray <mark@grondar.org>, Mark Murray <markm@freebsd.org> Cc: Arthur Mesh <arthurmesh@gmail.com>, Ian Lepore <freebsd@damnhippie.dyndns.org>, Doug Barton <dougb@freebsd.org>, freebsd-security@freebsd.org, RW <rwmaillists@googlemail.com>, "Bjoern A. Zeeb" <bz@freebsd.org> Subject: Re: svn commit: r239569 - head/etc/rc.d Message-ID: <CAG5KPzzRxzVX-%2B9fYjRdqjY-wScbM6AA7GYtLmktgMG0Zg8iyQ@mail.gmail.com> In-Reply-To: <E1TCbDG-0002Hz-9D@groundzero.grondar.org> References: <50453686.9090100@FreeBSD.org> <20120911082309.GD72584@dragon.NUXI.org> <504F0687.7020309@FreeBSD.org> <201209121628.18088.jhb@freebsd.org> <5050F477.8060409@FreeBSD.org> <20120912213141.GI14077@x96.org> <20120913052431.GA15052@dragon.NUXI.org> <alpine.BSF.2.00.1209131258210.13080@ai.fobar.qr> <alpine.BSF.2.00.1209141336170.13080@ai.fobar.qr> <E1TCXN0-000NFT-7I@groundzero.grondar.org> <CAG5KPzwOdCkybj3D5uic1KC-pwW-pewgsrqrXg60f5SJjtzYPw@mail.gmail.com> <E1TCbDG-0002Hz-9D@groundzero.grondar.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, Sep 14, 2012 at 8:06 PM, Mark Murray <mark@grondar.org> wrote: > Ben Laurie writes: >> > I'll send patches (untested) in a couple of hours for discussion. >> >> I used to like this idea, but it can break pretty badly if you repeat >> input, so in the end I decided hashes were the only safe way. > > What??! Have you seen how Yarrow does its harvesting?? If you XOR into the as-yet-unharvested buffer, then appropriately aligned repeated input makes the buffer zero. > > Presupposing there is no other source of randomness to get swamped out of the way, > > $ cat /dev/zero > /dev/random # pretend that /dev/zero is finite length. > > ... is harmless, and actually adds a small bit of perturbation to the entropy. > > Please explain how repeating input can "break" things here? > > M > -- > Mark R V Murray > Pi: 132511160 >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAG5KPzzRxzVX-%2B9fYjRdqjY-wScbM6AA7GYtLmktgMG0Zg8iyQ>