From: Chuck Ebbert <cebbert@redhat.com>
To: John Reiser <jreiser@BitWagon.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>, Andi Kleen <ak@suse.de>,
Ingo Molnar <mingo@elte.hu>,
Arjan van de Ven <arjan@infradead.org>,
Paul Mundt <lethal@linux-sh.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: + fully-honor-vdso_enabled.patch added to -mm tree
Date: Fri, 02 Mar 2007 17:19:44 -0500 [thread overview]
Message-ID: <45E8A300.9020001@redhat.com> (raw)
In-Reply-To: <45E891E6.7090807@BitWagon.com>
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.
next prev parent reply other threads:[~2007-03-02 22:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-01 17:52 + fully-honor-vdso_enabled.patch added to -mm tree Oleg Nesterov
2007-03-02 3:48 ` Paul Mundt
2007-03-02 19:32 ` Oleg Nesterov
2007-03-02 21:19 ` John Reiser
2007-03-03 17:38 ` Oleg Nesterov
2007-03-02 21:06 ` John Reiser
2007-03-02 22:18 ` Oleg Nesterov
2007-03-05 10:12 ` Paul Mundt
2007-03-05 10:54 ` Oleg Nesterov
2007-03-05 10:56 ` Paul Mundt
2007-03-02 22:19 ` Chuck Ebbert [this message]
2007-03-02 23:11 ` Oleg Nesterov
2007-03-02 23:33 ` John Reiser
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