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Message-ID: <20110927193810.GA5416@albatros> Date: Tue, 27 Sep 2011 23:38:10 +0400 From: Vasiliy Kulikov <segoon@...nwall.com> To: kernel-hardening@...ts.openwall.com, Christoph Lameter <cl@...ux-foundation.org>, Pekka Enberg <penberg@...nel.org>, Matt Mackall <mpm@...enic.com>, Andrew Morton <akpm@...ux-foundation.org> Cc: linux-mm@...ck.org, Kees Cook <kees@...ntu.com>, Dave Hansen <dave@...ux.vnet.ibm.com>, Valdis.Kletnieks@...edu, Linus Torvalds <torvalds@...ux-foundation.org>, David Rientjes <rientjes@...gle.com>, Alan Cox <alan@...ux.intel.com>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 2/2] mm: restrict access to /proc/meminfo 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 <segoon@...nwall.com> > CC: Kees Cook <kees@...ntu.com> > CC: Dave Hansen <dave@...ux.vnet.ibm.com> > CC: Christoph Lameter <cl@...two.org> > CC: Pekka Enberg <penberg@...helsinki.fi> > CC: Valdis.Kletnieks@...edu > CC: Linus Torvalds <torvalds@...ux-foundation.org> > CC: David Rientjes <rientjes@...gle.com> > CC: Alan Cox <alan@...ux.intel.com> > --- > 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
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