From: Casey Schaufler <casey@schaufler-ca.com>
To: Matthew Garrett <matthew.garrett@nebula.com>
Cc: "H. Peter Anvin" <hpa@zytor.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 09:51:13 -0800 [thread overview]
Message-ID: <511BD291.1040003@schaufler-ca.com> (raw)
In-Reply-To: <1360776399.18083.39.camel@x230.lan>
On 2/13/2013 9:26 AM, Matthew Garrett wrote:
> On Wed, 2013-02-13 at 09:20 -0800, H. Peter Anvin wrote:
>
>> Problem:
>>
>> Someone adds SYS_CAP_RAWIO to some places it definitely does not
>> belong.
>>
>> Solution:
>>
>> Break all the *appropriate* (as defined)uses of SYS_CAP_RAWIO?
> Problem:
>
> CAP_SYS_RAWIO has been used in a bunch of arguably inappropriate places.
> Removing CAP_SYS_RAWIO from the set of possible capabilities on a system
> will prevent userspace from doing things that userspace should be
> permitted to do. Removing CAP_SYS_RAWIO from the places that it
> currently exists will allow userspace to do too much. Replacing
> CAP_SYS_RAWIO with CAP_SYS_ADMIN will prevent userspace from doing
> things that it can currently do.
>
> Solution:
>
> Admit that CAP_SYS_RAWIO is fucked up beyond rescue. Add a new
> capability with well-defined semantics.
You can't add a new capability where there is an existing capability
that can be remotely argued to be appropriate.
If you tried to "fix" CAP_SYS_RAWIO and/or CAP_SYS_ADMIN you'd end
up with hundreds of capabilities.
Your particular problem is *not* so important that you get a
capability all to yourself.
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next prev parent reply other threads:[~2013-02-13 17:50 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
2013-02-13 17:20 ` H. Peter Anvin
2013-02-13 17:26 ` Matthew Garrett
2013-02-13 17:51 ` Casey Schaufler [this message]
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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