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From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Vasiliy Kulikov <segoon@openwall.com>
Cc: kernel-hardening@lists.openwall.com,
	Andrew Morton <akpm@linux-foundation.org>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Lameter <cl@linux-foundation.org>,
	Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Dan Rosenberg <drosenberg@vsecurity.com>,
	Theodore Tso <tytso@mit.edu>, Alan Cox <alan@linux.intel.com>,
	Jesper Juhl <jj@chaosbits.net>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo
Date: Wed, 14 Sep 2011 08:18:25 -0700	[thread overview]
Message-ID: <1316013505.4478.50.camel@nimitz> (raw)
In-Reply-To: <20110914131630.GA7001@albatros>

On Wed, 2011-09-14 at 17:16 +0400, Vasiliy Kulikov wrote:
> > World readable slabinfo simplifies kernel developers' job of debugging
> > kernel bugs (e.g. memleaks), but I believe it does more harm than
> > benefits.  For most users 0444 slabinfo is an unreasonable attack vector.
> 
> Please tell if anybody has complains about the restriction - whether it
> forces someone besides kernel developers to do "chmod/chgrp".  But if
> someone want to debug the kernel, it shouldn't significantly influence
> on common users, especially it shouldn't create security issues. 

Ubuntu ships today with a /etc/init/mounted-proc.conf that does:

	chmod 0400 "${MOUNTPOINT}"/slabinfo

After cursing Kees's name a few times, I commented it out and it hasn't
bothered me again.  

I expect that the folks that really care about this (and their distros)
will probably have a similar mechanism.  I guess the sword cuts both
ways in this case: it obviously _works_ to have the distros do it, but
it was a one-time inconvenience for me to override that.

In other words, I dunno.  If we do this in the kernel, can we at least
do something like CONFIG_INSECURE to both track these kinds of things
and make it easy to get them out of a developer's way?

-- Dave

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  reply	other threads:[~2011-09-14 15:46 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20110910164001.GA2342@albatros>
2011-09-10 16:41 ` [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo Vasiliy Kulikov
2011-09-12 15:06   ` Cyrill Gorcunov
2011-09-13  6:28     ` Vasiliy Kulikov
2011-09-14 13:16   ` Vasiliy Kulikov
2011-09-14 15:18     ` Dave Hansen [this message]
2011-09-14 15:42       ` [kernel-hardening] " Vasiliy Kulikov
2011-09-14 15:48         ` Vasiliy Kulikov
2011-09-14 18:24         ` Dave Hansen
2011-09-14 18:41   ` Dave Hansen
2011-09-14 19:14     ` Vasiliy Kulikov
2011-09-14 19:27   ` Kees Cook
2011-09-18 17:05     ` [kernel-hardening] " Vasiliy Kulikov
2011-09-19 13:42       ` Christoph Lameter
2011-09-19 14:30       ` Pekka Enberg
2011-09-19 14:46         ` Vasiliy Kulikov
2011-09-19 15:13           ` Pekka Enberg
2011-09-19 15:57             ` Vasiliy Kulikov
2011-09-19 16:11               ` Pekka Enberg
2011-09-19 16:18                 ` Vasiliy Kulikov
2011-09-19 17:31                   ` Pekka Enberg
2011-09-19 17:35                     ` Vasiliy Kulikov
2011-09-19 17:51                       ` Christoph Lameter
2011-09-19 19:59                         ` Valdis.Kletnieks
2011-09-19 20:02                           ` Christoph Lameter
2011-09-19 20:36                             ` Valdis.Kletnieks
2011-09-19 17:51                       ` Pekka Enberg
2011-09-19 17:58                         ` Vasiliy Kulikov
2011-09-19 18:46                           ` Pekka Enberg
2011-09-19 18:55                             ` Vasiliy Kulikov
2011-09-19 19:20                               ` Pekka Enberg
2011-09-19 19:33                               ` Pekka Enberg
2011-09-19 18:55                             ` Linus Torvalds
2011-09-19 19:18                               ` Pekka Enberg
2011-09-19 19:45                                 ` Pekka Enberg
2011-09-19 20:59                                 ` David Rientjes
2011-09-19 18:03                         ` Dave Hansen
2011-09-19 18:21                           ` Pekka Enberg
2011-09-19 19:45           ` Valdis.Kletnieks
2011-09-19 19:55             ` Alan Cox
2011-09-21 17:05               ` Vasiliy Kulikov
2011-09-22  2:20                 ` Valdis.Kletnieks

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