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: <200903271154.22450.rusty@rustcorp.com.au>
Date:	Fri, 27 Mar 2009 11:54:20 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
Cc:	lguest@...abs.org, Ingo Molnar <mingo@...hat.com>,
	linux-kernel@...r.kernel.org,
	virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 3/5] lguest: avoid accidental recycling of pgdir pages

On Friday 27 March 2009 10:47:32 Jeremy Fitzhardinge wrote:
> Rusty Russell wrote:
> > Impact: potential bugfix
> >
> > In theory, the kernel could reuse the same page as pgdir for a new process
> > while the hypervisor keeps it cached.  This would have undesirable results.
> >   
> 
> You can't just do this in tlb flush?

I don't think so.  The problem is that lguest tracks 4 toplevels, using random
replacement.  This cache is indexed by cr3 value.

Lguest assumes it's told about all pte removals or changes, but simple
additions get faulted in.  If a pgdir page gets reused we'll potentially have
stale values from its previous life as a pgdir, no?

Now, I haven't *seen* this happen...
Rusty.
--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ