linux-kernel - Re: + fully-honor-vdso_enabled.patch added to -mm tree

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]

Date:	Fri, 02 Mar 2007 17:19:44 -0500
From:	Chuck Ebbert <cebbert@...hat.com>
To:	John Reiser <jreiser@...Wagon.com>
CC:	Oleg Nesterov <oleg@...sign.ru>, Andi Kleen <ak@...e.de>,
	Ingo Molnar <mingo@...e.hu>,
	Arjan van de Ven <arjan@...radead.org>,
	Paul Mundt <lethal@...ux-sh.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: + fully-honor-vdso_enabled.patch added to -mm tree

John Reiser wrote:
> The value of ->sysenter_return is interpreted in user space by the
> sysexit instruction; nobody else cares what the value is.  The kernel
> is not required to provide a good value when vdso_enabled is zero,
> because the kernel has not told the process that sysenter is valid
> (by setting AT_SYSINFO.)

Doesn't matter because a malicious user can still execute sysenter.
We do have to deal with that somehow, so we have to put something
safe in there.

> Correct.  Changing vdso_enabled from 0 to non-zero must be prepared
> to lose this race if it is not prevented.  Ordinarily it won't matter
> because the administrator will perform such changes at a "quiet" time.
> 

We have to deal with all the possibilities here, too.
-
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/