From: Roland McGrath <roland@redhat.com>
To: Kees Cook <kees.cook@canonical.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, Jakub Jelinek <jakub@redhat.com>,
Ulrich Drepper <drepper@redhat.com>,
libc-alpha@sourceware.org
Subject: Re: [PATCH] ELF: implement AT_RANDOM for future glibc use
Date: Mon, 6 Oct 2008 16:58:27 -0700 (PDT) [thread overview]
Message-ID: <20081006235827.59306154271@magilla.localdomain> (raw)
In-Reply-To: Kees Cook's message of Monday, 6 October 2008 15:07:59 -0700 <20081006220759.GM10357@outflux.net>
What mmap randomization and stack randomization actually use is
get_random_int(), not get_random_bytes(). This is one of those weaker
flavors seeded occasionally from the real entropy pool. (As is, it's not a
good choice for getting 16 bytes of random at once, since it usually
returns the same 4 bytes each time when called 4 times in quick succession.)
What glibc wants is some bits with a strength of randomness chosen by the
kernel, and not to worry about the details. I think the strength applied
to mmap and stack randomization is good enough for AT_RANDOM.
Thanks,
Roland
next prev parent reply other threads:[~2008-10-06 23:59 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20081001201116.GD12527@outflux.net>
[not found] ` <48E3EFD6.2010704@redhat.com>
[not found] ` <20081001215657.GH12527@outflux.net>
[not found] ` <20081001220948.GC32107@sunsite.ms.mff.cuni.cz>
[not found] ` <20081001222706.68E7E1544B4@magilla.localdomain>
2008-10-03 0:16 ` [PATCH] ELF: implement AT_RANDOM for future glibc use Kees Cook
2008-10-03 0:43 ` Jakub Jelinek
2008-10-03 5:25 ` Kees Cook
2008-10-03 5:29 ` Kees Cook
2008-10-03 5:57 ` Arjan van de Ven
2008-10-03 6:25 ` Ulrich Drepper
2008-10-03 14:50 ` [PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding Kees Cook
2008-10-03 14:56 ` Ulrich Drepper
2008-10-03 14:57 ` Jakub Jelinek
2008-10-03 17:33 ` Kees Cook
2008-10-03 17:41 ` Ulrich Drepper
2008-10-03 17:59 ` [PATCH v5] " Kees Cook
2008-10-18 5:42 ` Ulrich Drepper
2008-10-21 20:01 ` Andrew Morton
2008-10-21 20:22 ` Ulrich Drepper
2008-10-27 5:46 ` Andrew Morton
2008-10-03 0:52 ` [PATCH] ELF: implement AT_RANDOM for future glibc use Roland McGrath
2008-10-03 5:15 ` Kees Cook
2008-10-03 20:22 ` Roland McGrath
2008-10-06 6:00 ` Andi Kleen
2008-10-06 17:50 ` Kees Cook
2008-10-06 18:25 ` David Wagner
2008-10-06 20:23 ` Andi Kleen
2008-10-06 22:16 ` David Wagner
2008-10-06 19:26 ` Andi Kleen
2008-10-06 22:01 ` Kees Cook
2008-10-06 23:19 ` Andi Kleen
2008-10-06 23:29 ` Kees Cook
2008-10-06 23:44 ` Andi Kleen
2008-10-06 22:07 ` Kees Cook
2008-10-06 23:28 ` Andi Kleen
2008-10-06 23:58 ` Roland McGrath [this message]
2008-10-07 0:08 ` Ulrich Drepper
2008-10-07 0:31 ` Kees Cook
2008-10-07 0:57 ` Ulrich Drepper
2008-10-07 1:44 ` Kees Cook
2008-10-07 1:51 ` Ulrich Drepper
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20081006235827.59306154271@magilla.localdomain \
--to=roland@redhat.com \
--cc=andi@firstfloor.org \
--cc=drepper@redhat.com \
--cc=jakub@redhat.com \
--cc=kees.cook@canonical.com \
--cc=libc-alpha@sourceware.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).