From: Solar Designer <solar@openwall.com>
To: kernel-hardening@lists.openwall.com
Cc: Vasiliy Kulikov <segoon@openwall.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, balbir@linux.vnet.ibm.com,
akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
rientjes@google.com, wilsons@start.ca, security@kernel.org,
eparis@redhat.com, Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/2] proc: restrict access to /proc/PID/io
Date: Tue, 28 Jun 2011 02:37:12 +0400 [thread overview]
Message-ID: <20110627223712.GA8685@openwall.com> (raw)
In-Reply-To: <20110627085242.GA6635@albatros>
On Mon, Jun 27, 2011 at 12:52:42PM +0400, Vasiliy Kulikov wrote:
> As to random bytes - if it is very predictable (e.g. rand() % 10000) one
> may restore the original value. But it would still do much harm to good
> programs (io stats going up and down!). Adding really random bytes
> seems somewhat too complicated for these needs to me.
Random noise doesn't help very much even if it's totally unpredictable
and even if it's much louder than the signal. It will only increase the
number of samples needed to see the signal through the noise.
More effective ways to deal with side-channel attacks are to make things
appear constant or, better yet, to remove the side-channel altogether
if possible. I'd happily break iotop for non-admins on many of my
systems, so please give me a way to do it.
http://en.wikipedia.org/wiki/Side_channel_attack#Countermeasures
Alexander
next prev parent reply other threads:[~2011-06-27 22:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-24 12:08 [PATCH 1/2] proc: restrict access to /proc/PID/io Vasiliy Kulikov
2011-06-27 2:58 ` KOSAKI Motohiro
2011-06-27 7:03 ` Vasiliy Kulikov
2011-06-27 7:33 ` KOSAKI Motohiro
2011-06-27 8:52 ` Vasiliy Kulikov
2011-06-27 10:07 ` KOSAKI Motohiro
2011-06-27 10:59 ` Vasiliy Kulikov
2011-06-27 22:37 ` Solar Designer [this message]
2011-06-28 1:24 ` Balbir Singh
2011-06-28 7:50 ` Vasiliy Kulikov
2011-06-29 1:16 ` Balbir Singh
2011-06-29 11:20 ` Vasiliy Kulikov
2011-06-28 1:13 ` Balbir Singh
2011-06-28 1:15 ` Balbir Singh
2011-06-28 7:50 ` Vasiliy Kulikov
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=20110627223712.GA8685@openwall.com \
--to=solar@openwall.com \
--cc=akpm@linux-foundation.org \
--cc=balbir@linux.vnet.ibm.com \
--cc=eparis@redhat.com \
--cc=kernel-hardening@lists.openwall.com \
--cc=kosaki.motohiro@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rientjes@google.com \
--cc=security@kernel.org \
--cc=segoon@openwall.com \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
--cc=wilsons@start.ca \
/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