From: Pavel Machek <pavel@ucw.cz>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>,
linux-kernel@vger.kernel.org, security@kernel.org,
stable@kernel.org
Subject: Re: [PATCH] Restrict unprivileged access to kernel syslog
Date: Wed, 17 Nov 2010 11:03:21 +0100 [thread overview]
Message-ID: <20101117100321.GB1574@ucw.cz> (raw)
In-Reply-To: <20101109120649.62b487e8@lxorguk.ukuu.org.uk>
On Tue 2010-11-09 12:06:49, Alan Cox wrote:
> On Mon, 08 Nov 2010 22:28:58 -0500
> Dan Rosenberg <drosenberg@vsecurity.com> wrote:
>
> > The kernel syslog contains debugging information that is often useful
> > during exploitation of other vulnerabilities, such as kernel heap
> > addresses. Rather than futilely attempt to sanitize hundreds (or
> > thousands) of printk statements and simultaneously cripple useful
> > debugging functionality, it is far simpler to create an option that
> > prevents unprivileged users from reading the syslog.
>
> Except for anything that appears on the screen - which is remotely
> readable via the screen access APIs. Looks sane to me (pointless but
> sane) and the checks match the ones needed to redirect the console so you
> need CAP_SYS_ADMIN either way.
/dev/vcsa is only protected by filesystem permissions IIRC.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2010-11-17 10:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-09 3:28 Dan Rosenberg
2010-11-09 5:34 ` Kees Cook
2010-11-09 5:39 ` [Security] " Eugene Teo
2010-11-09 11:23 ` Ingo Molnar
2010-11-09 12:11 ` Dan Rosenberg
2010-11-09 12:27 ` Arjan van de Ven
2010-11-09 14:20 ` Ingo Molnar
2010-11-09 12:06 ` Alan Cox
2010-11-17 10:03 ` Pavel Machek [this message]
2010-11-09 14:25 Dan Rosenberg
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