From: Paolo Bonzini <pbonzini@redhat.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Matthew Garrett <matthew.garrett@nebula.com>,
Borislav Petkov <bp@alien8.de>, Kees Cook <keescook@chromium.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "x86@kernel.org" <x86@kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH] x86: Lock down MSR writing in secure boot
Date: Wed, 13 Feb 2013 09:27:13 +0100 [thread overview]
Message-ID: <511B4E61.1040604@redhat.com> (raw)
In-Reply-To: <511B33BC.9080307@zytor.com>
Il 13/02/2013 07:33, H. Peter Anvin ha scritto:
>>
>>> Sounds like you are thinking of CAP_SYS_ADMIN, but I don't really see a
>>> huge difference between MSRs and I/O control registers... just different
>>> address spaces.
>>
>> Not having CAP_SYS_RAWIO blocks various SCSI commands, for instance.
>> These might result in the ability to write individual blocks or destroy
>> the device firmware, but do any of them permit modifying the running
>> kernel?
No, they cannot.
> That is just batshit crazy. If you have CAP_SYS_RAWIO you can do iopl()
> which means you can reprogram your northbridge, at which point you most
> definitely *can* modify the running kernel.
>
> And some SCSI driver requires this??!
No, and that's why there is a patchset floating that lets you toggle
this ability with a sysfs control. This way you do not need
CAP_SYS_RAWIO anymore.
On non-x86 machines CAP_SYS_RAWIO is much less dangerous, especially
when coupled with file DAC.
Paolo
next prev parent reply other threads:[~2013-02-13 8:27 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-08 19:12 [PATCH] x86: Lock down MSR writing in secure boot Kees Cook
2013-02-08 19:17 ` H. Peter Anvin
[not found] ` <00780235-deac-4f80-b936-867834e05661-2ueSQiBKiTY7tOexoI0I+QC/G2K4zDHf@public.gmane.org>
2013-02-08 19:18 ` Kees Cook
2013-02-08 19:42 ` H. Peter Anvin
2013-02-08 20:14 ` Kees Cook
[not found] ` <CAGXu5j+_mGzR+72YqORhErMUY1aF1H2urczZ8SwuJHZK-oZL6g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-08 20:18 ` H. Peter Anvin
2013-02-08 20:28 ` Kees Cook
[not found] ` <CAGXu5jLAufTRm=sDST0br_WEkn4o0Hpjv2jDP2Na=cCvuM+MGg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-08 20:34 ` Matthew Garrett
2013-02-08 21:02 ` Kees Cook
[not found] ` <CAGXu5jKo2PfMBO4A0ZgQcrPuj8OHNaff+CjAesOAWkZc0vB9+Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-08 21:07 ` Matthew Garrett
[not found] ` <1360357636.18083.19.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-08 21:14 ` Josh Boyer
2013-02-08 23:09 ` Andy Lutomirski
2013-02-08 22:30 ` H. Peter Anvin
2013-02-08 23:06 ` Borislav Petkov
2013-02-08 23:26 ` Matthew Garrett
[not found] ` <1360366012.18083.21.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-09 1:22 ` H. Peter Anvin
2013-02-09 1:29 ` Matthew Garrett
[not found] ` <1360373383.18083.23.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-09 6:45 ` Kees Cook
[not found] ` <CAGXu5j+xvJ3L5ejxtZ-Jw3F6rV7OsrE0_HZCGu_er0rH2_PwKA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-09 9:29 ` Borislav Petkov
2013-02-09 15:10 ` Kees Cook
[not found] ` <20130209092925.GA17728-fF5Pk5pvG8Y@public.gmane.org>
2013-02-09 15:11 ` Matthew Garrett
2013-02-13 0:48 ` H. Peter Anvin
2013-02-13 5:39 ` Matthew Garrett
[not found] ` <1360733962.18083.30.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-13 6:12 ` H. Peter Anvin
2013-02-13 6:27 ` Matthew Garrett
2013-02-13 6:33 ` H. Peter Anvin
[not found] ` <511B33BC.9080307-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2013-02-13 6:41 ` Matthew Garrett
[not found] ` <1360737709.18083.36.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-13 17:20 ` H. Peter Anvin
2013-02-13 17:26 ` Matthew Garrett
2013-02-13 17:51 ` Casey Schaufler
[not found] ` <511BD291.1040003-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
2013-02-13 17:56 ` Matthew Garrett
2013-02-13 18:44 ` H. Peter Anvin
2013-02-13 18:51 ` Matthew Garrett
2013-02-13 22:26 ` H. Peter Anvin
2013-02-13 22:58 ` Casey Schaufler
[not found] ` <511C1A94.8020804-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
2013-02-14 0:25 ` H. Peter Anvin
2013-02-14 0:44 ` Casey Schaufler
[not found] ` <511C3389.5090604-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
2013-02-14 1:04 ` Matthew Garrett
[not found] ` <1360803872.18083.46.camel-+5W/JHIUVxg@public.gmane.org>
2013-02-14 1:08 ` H. Peter Anvin
[not found] ` <511C3927.90603-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2013-02-14 2:46 ` Matthew Garrett
2013-02-14 1:34 ` Casey Schaufler
2013-02-13 8:27 ` Paolo Bonzini [this message]
2013-02-13 17:21 ` H. Peter Anvin
[not found] ` <511B4E61.1040604-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-02-13 17:22 ` H. Peter Anvin
2013-02-13 19:55 ` Paolo Bonzini
[not found] ` <511B EFAD.1050206@redhat.com>
[not found] ` <511BEFAD.1050206-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-02-13 22:24 ` H. Peter Anvin
2013-02-08 19:17 ` Matthew Garrett
2013-02-08 19:21 ` Kees Cook
[not found] ` <CAGXu5j+aXxQb_Jyn6G+JUdjNOF2EGo9pTw8dBYuZUTb+S1vWow-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-08 19:27 ` Matthew Garrett
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