From: Willy Tarreau <w@1wt.eu>
To: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>,
Kees Cook <keescook@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
"security@kernel.org" <security@kernel.org>,
X86 ML <x86@kernel.org>, Sasha Levin <sasha.levin@oracle.com>,
LKML <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH 2/2] x86/ldt: allow to disable modify_ldt at runtime
Date: Tue, 4 Aug 2015 08:00:54 +0200 [thread overview]
Message-ID: <20150804060054.GA24152@1wt.eu> (raw)
In-Reply-To: <20150804035451.GC31787@nazgul.tnic>
On Tue, Aug 04, 2015 at 05:54:51AM +0200, Borislav Petkov wrote:
> On Mon, Aug 03, 2015 at 11:45:24AM -0700, Andy Lutomirski wrote:
> > P.P.P.S. Who thought that IRET faults unmasking NMIs made any sense
> > whatsoever when NMIs run on an IST stack? Seriously, people?
>
> What happened with asking Intel for a sane IRET-NG?
>
> Should be relatively easy - take the current IRET microcode, get rid
> of the nasty crap, allocate a new opcode and done. Validation should
> actually have *less* to do and can reuse all current test cases.
Even easier, just add a few flags (probably 2 or 3 only) that IRET can
check to adjust its behaviour. Basically "don't re-enable NMIs yet",
maybe something to adjust the behaviour on bad CS/SS/SP/IP and a few
such things could possibly help. Maybe all of this could be summarized
as a single flag "I'm in a fault handler".
Willy
next prev parent reply other threads:[~2015-08-04 6:01 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-03 18:23 [PATCH 0/2] x86: allow to enable/disable modify_ldt at run time Willy Tarreau
2015-08-03 18:23 ` [PATCH 1/2] sysctl: add a new generic strategy to make permanent changes on negative values Willy Tarreau
2015-08-03 18:33 ` Andy Lutomirski
2015-08-03 18:33 ` Andy Lutomirski
2015-08-03 18:50 ` Willy Tarreau
2015-08-03 18:50 ` Willy Tarreau
2015-08-03 18:23 ` Willy Tarreau
2015-08-03 18:23 ` [PATCH 2/2] x86/ldt: allow to disable modify_ldt at runtime Willy Tarreau
2015-08-03 18:45 ` Andy Lutomirski
2015-08-03 18:45 ` Andy Lutomirski
2015-08-03 19:01 ` Willy Tarreau
2015-08-03 19:06 ` Andy Lutomirski
2015-08-03 19:18 ` Willy Tarreau
2015-08-03 19:18 ` Willy Tarreau
2015-08-03 19:06 ` Andy Lutomirski
2015-08-03 19:01 ` Willy Tarreau
2015-08-04 3:54 ` Borislav Petkov
2015-08-04 3:54 ` Borislav Petkov
2015-08-04 6:00 ` Willy Tarreau [this message]
2015-08-04 6:00 ` Willy Tarreau
2015-08-03 22:35 ` Kees Cook
2015-08-03 23:19 ` Willy Tarreau
2015-08-04 1:36 ` Kees Cook
2015-08-04 1:36 ` Kees Cook
2015-08-03 23:19 ` Willy Tarreau
2015-08-03 22:35 ` Kees Cook
2015-08-03 18:23 ` Willy Tarreau
2015-08-04 8:49 ` [PATCH v3 1/1] x86: allow to enable/disable modify_ldt at run time Willy Tarreau
2015-08-05 8:00 ` Ingo Molnar
2015-08-05 8:00 ` Ingo Molnar
2015-08-05 8:08 ` Willy Tarreau
2015-08-05 8:08 ` Willy Tarreau
2015-08-05 8:26 ` Ingo Molnar
2015-08-05 9:03 ` Willy Tarreau
2015-08-05 9:03 ` Willy Tarreau
2015-08-05 9:10 ` Ingo Molnar
2015-08-05 9:10 ` Ingo Molnar
2015-08-05 8:26 ` Ingo Molnar
2015-08-04 8:49 ` Willy Tarreau
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