linux-kernel - Re: [PATCH 12/19] CacheFiles: Permit a process's create SID to be overridden

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <XMMS.LNX.4.64.0611151115360.8593@d.namei>
Date:	Wed, 15 Nov 2006 11:19:00 -0500 (EST)
From:	James Morris <jmorris@...ei.org>
To:	David Howells <dhowells@...hat.com>
cc:	Linus Torvalds <torvalds@...l.org>, Andrew Morton <akpm@...l.org>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	trond.myklebust@....uio.no, selinux@...ho.nsa.gov,
	linux-kernel@...r.kernel.org, aviro@...hat.com, steved@...hat.com
Subject: Re: [PATCH 12/19] CacheFiles: Permit a process's create SID to be
 overridden 

On Wed, 15 Nov 2006, David Howells wrote:

> James Morris <jmorris@...ei.org> wrote:
> 
> > > +static u32 selinux_set_fscreate_secid(u32 secid)
> > ...
> > The ability to set this needs to be mediated via MAC policy.
> 
> There could a problem with that...  Is it possible for there to be a race?

Well, the value can be changed at any time, so you could be using a 
temporary fscreate value, or your new value could be overwritten 
immediately by writing to /proc/$$/attr/fscreate

I think we need to add a separate field for this purpose, which can only 
be written to via the in-kernel API and overrides fscreate.

> I have to call the function twice per cache op: once to set the file 
> creation security ID and once to restore it back to what it was.
> 
> However, what happens if I can't restore the original security ID (perhaps the
> rules changed between the two invocations)?  I can't let the task continue as
> it's now running with the wrong security...

Kill the task?



- James
-- 
James Morris
<jmorris@...ei.org>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/