From: Matthew Garrett <matthew.garrett@nebula.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: 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 06:41:54 +0000 [thread overview]
Message-ID: <1360737709.18083.36.camel@x230.lan> (raw)
In-Reply-To: <511B33BC.9080307@zytor.com>
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On Tue, 2013-02-12 at 22:33 -0800, H. Peter Anvin wrote:
> 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.
Well right, that's the point of this patchset - it adds some extra
permission checks to some of the existing CAP_SYS_RAWIO checks.
CAP_SYS_RAWIO hasn't meant "I can perform arbitrary pio and mmio" for
years - it means "I can do things that might maybe break something
somehow". So sure, removing CAP_SYS_RAWIO would give us basically all
the security we want in a secure boot environment, but it would also
block things that we *want* to work.
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next prev parent reply other threads:[~2013-02-13 6:42 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
2013-02-08 19:18 ` Kees Cook
2013-02-08 19:42 ` H. Peter Anvin
2013-02-08 20:14 ` Kees Cook
2013-02-08 20:18 ` H. Peter Anvin
2013-02-08 20:28 ` Kees Cook
2013-02-08 20:34 ` Matthew Garrett
2013-02-08 21:02 ` Kees Cook
2013-02-08 21:07 ` Matthew Garrett
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
2013-02-09 1:22 ` H. Peter Anvin
2013-02-09 1:29 ` Matthew Garrett
2013-02-09 6:45 ` Kees Cook
2013-02-09 9:29 ` Borislav Petkov
2013-02-09 15:10 ` Kees Cook
2013-02-09 15:11 ` Matthew Garrett
2013-02-13 0:48 ` H. Peter Anvin
2013-02-13 5:39 ` Matthew Garrett
2013-02-13 6:12 ` H. Peter Anvin
2013-02-13 6:27 ` Matthew Garrett
2013-02-13 6:33 ` H. Peter Anvin
2013-02-13 6:41 ` Matthew Garrett [this message]
2013-02-13 17:20 ` H. Peter Anvin
2013-02-13 17:26 ` Matthew Garrett
2013-02-13 17:51 ` Casey Schaufler
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
2013-02-14 0:25 ` H. Peter Anvin
2013-02-14 0:44 ` Casey Schaufler
2013-02-14 1:04 ` Matthew Garrett
2013-02-14 1:08 ` H. Peter Anvin
2013-02-14 2:46 ` Matthew Garrett
2013-02-14 1:34 ` Casey Schaufler
2013-02-13 8:27 ` Paolo Bonzini
2013-02-13 17:21 ` H. Peter Anvin
2013-02-13 17:22 ` H. Peter Anvin
2013-02-13 19:55 ` Paolo Bonzini
2013-02-13 22:24 ` H. Peter Anvin
2013-02-08 19:17 ` Matthew Garrett
2013-02-08 19:21 ` Kees Cook
2013-02-08 19:27 ` Matthew Garrett
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