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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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  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 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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