Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 25 Feb 2013 14:26:09 -0700
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security@...ts.openwall.com
CC: "Jason A. Donenfeld" <Jason@...c4.com>
Subject: Re: kernel: tmpfs use-after-free

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 02/25/2013 12:50 PM, Jason A. Donenfeld wrote:
> Hey all,
> 
> While everyone's going wild hndl->dump'ing with CVE-2013-1763,
> there's apparently been another silent security fix with 
> 5f00110f7273f9ff04ac69a5f85bb535a4fd0987 [1]:
> 
>> tmpfs: fix use-after-free of mempolicy object
>> 
>> The tmpfs remount logic preserves filesystem mempolicy if the
>> mpol=M option is not specified in the remount request.  A new
>> policy can be specified if mpol=M is given.
>> 
>> Before this patch remounting an mpol bound tmpfs without
>> specifying mpol= mount option in the remount request would set
>> the filesystem's mempolicy object to a freed mempolicy object.
>> 
>> How far back does this issue go? I see it in both 2.6.36 and 3.3.
>> I did not look back further.
> 
> 
> The commit message goes on with details on how to trigger it. Note 
> that as of 5eaf563e53294d6696e651466697eb9d491f3946 [2], you can
> now mount filesystems as an unprivileged user after a call to 
> unshare(CLONE_NEWUSER | CLONE_NEWNS), or a similar clone(2) call.
> This means all those random random filesystem bugs you have laying
> around in the junk bin are now quite useful. ++tricks;
> 
> Cheers, Jason
> 
> 
> [1]
> http://git.zx2c4.com/linux/commit/?id=5f00110f7273f9ff04ac69a5f85bb535a4fd0987
>
> 
[2]
http://git.zx2c4.com/linux/commit/?id=5eaf563e53294d6696e651466697eb9d491f3946
> 
> -- Jason A. Donenfeld www.zx2c4.com
> 

Please use CVE-2013-1767 for this issue.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.13 (GNU/Linux)
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=sB1j
-----END PGP SIGNATURE-----

Powered by blists - more mailing lists

Your e-mail address:

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.