From: Andy Lutomirski <luto@amacapital.net>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
X86 ML <x86@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
David Vrabel <david.vrabel@citrix.com>,
Ingo Molnar <mingo@kernel.org>,
Xen Devel <xen-devel@lists.xensource.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
lguest@lists.ozlabs.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-security-module <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH v3 01/11] x86/boot: enumerate documentation for the x86 hardware_subarch
Date: Wed, 24 Feb 2016 17:29:28 -0800 [thread overview]
Message-ID: <CALCETrX3qi7mqw=OmzqnfzzxrUEE7VviXoyomC0eDNtdL8uYbA@mail.gmail.com> (raw)
In-Reply-To: <CAB=NE6X0S-iXV_0t+JEE9zstE-+CfVZrU-WidyMk1dPJMi-hhQ@mail.gmail.com>
On Wed, Feb 24, 2016 at 5:18 PM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
>
> On Feb 24, 2016 8:40 AM, "Andy Lutomirski" <luto@amacapital.net> wrote:
>>
>> On Feb 24, 2016 12:33 AM, "Ingo Molnar" <mingo@kernel.org> wrote:
>> >
>> > For hard coded platform quirks I'd suggest we add x86_platform.quirks
>> > flags. For
>> > example the F00F hack for Xen could be done via:
>> >
>> > x86_platform.quirks.idt_remap = 0;
>> >
>>
>> Don't we unconditionally remap the IDT? I think Kees did it for
>> general purpose hardening due to our complete inability to hide the
>> IDT address. I.e. I think we can remove the f00f condition entirely.
>>
>
> Kees can you confirm ?
>
No need.
/*
* Set the IDT descriptor to a fixed read-only location, so that the
* "sidt" instruction will not leak the location of the kernel, and
* to defend the IDT against arbitrary memory write vulnerabilities.
* It will be reloaded in cpu_init() */
__set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
idt_descr.address = fix_to_virt(FIX_RO_IDT);
IIUI this works around f00f as a side effect. The only other thing
needed is the code that X86_BUG_F00F guards, which is responsible for
fixing up the error generated on attempted F00F exploitation from an
OOPS to a SIGILL. I see no reason why that code couldn't be allowed
to run on even a PV guest on a F00F-affected CPU -- it would never
trigger anyway.
next prev parent reply other threads:[~2016-02-25 1:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-23 7:24 [PATCH v3 00/11] x86/init: replace paravirt_enabled() were possible Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 01/11] x86/boot: enumerate documentation for the x86 hardware_subarch Luis R. Rodriguez
2016-02-23 8:51 ` Ingo Molnar
2016-02-23 10:34 ` Luis R. Rodriguez
2016-02-23 20:41 ` Luis R. Rodriguez
2016-02-24 8:32 ` Ingo Molnar
2016-02-24 16:40 ` Andy Lutomirski
2016-02-25 1:18 ` Luis R. Rodriguez
2016-02-25 1:29 ` Andy Lutomirski [this message]
[not found] ` <CALCETrW=dia7QCDhJVF8rnaKGDx_NNYVZqUNZSs9R87_o=h6NQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-02-25 8:10 ` Ingo Molnar
2016-03-02 0:43 ` Luis R. Rodriguez
2016-03-02 19:40 ` Luis R. Rodriguez
2016-04-07 20:59 ` Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 02/11] tools/lguest: make lguest launcher use X86_SUBARCH_LGUEST explicitly Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 03/11] x86/xen: use X86_SUBARCH_XEN for PV guest boots Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 04/11] x86/init: make ebda depend on PC subarch Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 05/11] tools/lguest: force disable tboot and apm Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 06/11] apm32: remove paravirt_enabled() use Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 07/11] x86/tboot: remove paravirt_enabled() Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 08/11] x86/cpu/intel: replace paravirt_enabled() for f00f work around Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 09/11] x86/boot: add BIT() to boot/bitops.h Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 10/11] x86/rtc: replace paravirt rtc check with x86 specific solution Luis R. Rodriguez
2016-02-23 11:57 ` [Xen-devel] " David Vrabel
2016-02-23 18:10 ` Luis R. Rodriguez
2016-02-23 7:24 ` [PATCH v3 11/11] pnpbios: replace paravirt_enabled() check with subarch checks Luis R. Rodriguez
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