From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id F3CEE9000BD for ; Tue, 27 Sep 2011 15:39:06 -0400 (EDT) Received: by bkbzs2 with SMTP id zs2so9699237bkb.14 for ; Tue, 27 Sep 2011 12:39:02 -0700 (PDT) Date: Tue, 27 Sep 2011 23:38:10 +0400 From: Vasiliy Kulikov Subject: Re: [PATCH 2/2] mm: restrict access to /proc/meminfo Message-ID: <20110927193810.GA5416@albatros> References: <20110927175453.GA3393@albatros> <20110927175642.GA3432@albatros> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110927175642.GA3432@albatros> Sender: owner-linux-mm@kvack.org List-ID: To: kernel-hardening@lists.openwall.com, Christoph Lameter , Pekka Enberg , Matt Mackall , Andrew Morton Cc: linux-mm@kvack.org, Kees Cook , Dave Hansen , Valdis.Kletnieks@vt.edu, Linus Torvalds , David Rientjes , Alan Cox , linux-kernel@vger.kernel.org On Tue, Sep 27, 2011 at 21:56 +0400, Vasiliy Kulikov wrote: > /proc/meminfo stores information related to memory pages usage, which > may be used to monitor the number of objects in specific caches (and/or > the changes of these numbers). This might reveal private information > similar to /proc/slabinfo infoleaks. To remove the infoleak, just > restrict meminfo to root. If it is used by unprivileged daemons, > meminfo permissions can be altered the same way as slabinfo: > > groupadd meminfo > usermod -a -G meminfo $MONITOR_USER > chmod g+r /proc/meminfo > chgrp meminfo /proc/meminfo Just to make it clear: since this patch breaks "free", I don't propose it anymore. > Signed-off-by: Vasiliy Kulikov > CC: Kees Cook > CC: Dave Hansen > CC: Christoph Lameter > CC: Pekka Enberg > CC: Valdis.Kletnieks@vt.edu > CC: Linus Torvalds > CC: David Rientjes > CC: Alan Cox > --- > fs/proc/meminfo.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > -- > diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c > index 5861741..949bdee 100644 > --- a/fs/proc/meminfo.c > +++ b/fs/proc/meminfo.c > @@ -187,7 +187,7 @@ static const struct file_operations meminfo_proc_fops = { > > static int __init proc_meminfo_init(void) > { > - proc_create("meminfo", 0, NULL, &meminfo_proc_fops); > + proc_create("meminfo", S_IFREG | S_IRUSR, NULL, &meminfo_proc_fops); > return 0; > } > module_init(proc_meminfo_init); -- Vasiliy Kulikov http://www.openwall.com - bringing security into open computing environments -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org