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From: "H. Peter Anvin" <hpa@zytor.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
	Matthew Garrett <matthew.garrett@nebula.com>
Cc: linux-kernel@vger.kernel.org, keescook@chromium.org,
	gregkh@linuxfoundation.org, linux-efi@vger.kernel.org,
	jmorris@namei.org, linux-security-module@vger.kernel.org
Subject: Re: [PATCH 12/12] Add option to automatically set trusted_kernel when in Secure Boot mode
Date: Wed, 26 Feb 2014 14:47:06 -0800	[thread overview]
Message-ID: <530E6EEA.3080003@zytor.com> (raw)
In-Reply-To: <20140226224141.1741a746@alan.etchedpixels.co.uk>

On 02/26/2014 02:41 PM, One Thousand Gnomes wrote:
> On Wed, 26 Feb 2014 15:11:13 -0500
> Matthew Garrett <matthew.garrett@nebula.com> wrote:
> 
>> UEFI Secure Boot provides a mechanism for ensuring that the firmware will
>> only load signed bootloaders and kernels. Certain use cases may also
>> require that the kernel prevent userspace from inserting untrusted kernel
>> code at runtime. Add a configuration option that enforces this automatically
>> when enabled.
> 
> I think you have a load more cases to attempt to paper over before you
> even pretend to achieve that goal. Firewire for example. Also it only
> remotely begins to work if you also force CAP_SYS_RAWIO off globally as
> you need to force off things like raw command issuing to various
> controllers (especially as some of that code is written on the basis that
> 'its RAWIO, screw making it secure and doing all the checks we could
> bother with'.
> 
> RAWIO also disables things like CPU msr access - which is also quite
> adequate for subverting a kernel.
> 
> Another issue that needs addressing is firmware. Quite a few of our
> request_firmware cases load device firmware which is not signed into DMA
> capable hardware. Probably also worth checking what the
> architectural guarantees on bogus microcode updates is. Maybe we need
> firmware signing for such cases to match the mod signing ?
> 
> I'm trying to think what else. Possibly disabling it on Pentium-M with
> the rep movs erratum (Y19) as it's quite possible to set up suitable
> adjacent page sets in user space via the graphics.
> 

I have been arguing for a long time that this should disable RAWIO.  The
argument was that apparently some SCSI controllers started requiring
RAWIO to do things like update firmware... which is arguably equally
problematic, but either way is (a) clearly wrong and (b) started a long,
never-ending discussion...

	-hpa



  reply	other threads:[~2014-02-26 22:47 UTC|newest]

Thread overview: 130+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-26 20:11 Trusted kernel patchset for Secure Boot lockdown Matthew Garrett
2014-02-26 20:11 ` [PATCH 01/12] Add support for indicating that the booted kernel is externally trusted Matthew Garrett
2014-02-27 19:02   ` Kees Cook
2014-02-27 19:02     ` Kees Cook
2014-03-31 14:49   ` Pavel Machek
2014-02-26 20:11 ` [PATCH 02/12] Enforce module signatures when trusted kernel is enabled Matthew Garrett
2014-02-26 20:11   ` Matthew Garrett
2014-02-26 20:11 ` [PATCH 03/12] PCI: Lock down BAR access when trusted_kernel is true Matthew Garrett
2014-02-26 20:11 ` [PATCH 04/12] x86: Lock down IO port " Matthew Garrett
2014-02-26 20:11 ` [PATCH 05/12] Restrict /dev/mem and /dev/kmem " Matthew Garrett
2014-02-26 20:11 ` [PATCH 06/12] acpi: Limit access to custom_method if " Matthew Garrett
2014-02-26 20:11 ` [PATCH 07/12] acpi: Ignore acpi_rsdp kernel parameter when " Matthew Garrett
2014-02-26 20:11 ` [PATCH 08/12] kexec: Disable at runtime if " Matthew Garrett
2014-02-26 20:11 ` [PATCH 09/12] uswsusp: Disable when " Matthew Garrett
2014-02-26 20:11   ` Matthew Garrett
2014-03-31 14:49   ` Pavel Machek
2014-02-26 20:11 ` [PATCH 10/12] x86: Restrict MSR access " Matthew Garrett
2014-02-26 20:11 ` [PATCH 11/12] asus-wmi: Restrict debugfs interface " Matthew Garrett
2014-02-26 20:11 ` [PATCH 12/12] Add option to automatically set trusted_kernel when in Secure Boot mode Matthew Garrett
2014-02-26 20:11   ` Matthew Garrett
2014-02-26 22:41   ` One Thousand Gnomes
2014-02-26 22:41     ` One Thousand Gnomes
2014-02-26 22:47     ` H. Peter Anvin [this message]
2014-02-26 22:48     ` Matthew Garrett
2014-02-26 22:48       ` Matthew Garrett
2014-02-27 18:48       ` Kees Cook
2014-02-27 18:48         ` Kees Cook
2014-02-26 21:11 ` Trusted kernel patchset for Secure Boot lockdown Kees Cook
2014-02-26 22:21   ` One Thousand Gnomes
2014-02-26 22:21     ` One Thousand Gnomes
2014-02-27  9:54     ` Alon Ziv
2014-03-19 17:42     ` Florian Weimer
2014-03-19 17:42       ` Florian Weimer
2014-02-27 18:04 ` Josh Boyer
2014-02-27 18:04   ` Josh Boyer
2014-02-27 19:07   ` Greg KH
2014-02-27 19:11     ` Josh Boyer
2014-02-27 19:11       ` Josh Boyer
2014-02-28 12:50       ` Josh Boyer
2014-02-28  3:03   ` James Morris
2014-02-28  4:52     ` Matthew Garrett
2014-02-28  4:52       ` Matthew Garrett
2014-03-13  5:01     ` Matthew Garrett
2014-03-13  5:01       ` Matthew Garrett
2014-03-13  6:22       ` Kees Cook
2014-03-13  6:22         ` Kees Cook
2014-03-13  9:33         ` James Morris
2014-03-13  9:33           ` James Morris
2014-03-13 10:12           ` One Thousand Gnomes
2014-03-13 10:12             ` One Thousand Gnomes
2014-03-13 15:54             ` H. Peter Anvin
2014-03-13 15:54               ` H. Peter Anvin
2014-03-13 15:59           ` Matthew Garrett
2014-03-13 15:59             ` Matthew Garrett
2014-03-13 21:24             ` One Thousand Gnomes
2014-03-13 21:24               ` One Thousand Gnomes
2014-03-13 21:28               ` H. Peter Anvin
2014-03-13 21:28                 ` H. Peter Anvin
2014-03-13 21:32                 ` Matthew Garrett
2014-03-13 21:32                   ` Matthew Garrett
2014-03-13 21:30               ` Matthew Garrett
2014-03-13 21:30                 ` Matthew Garrett
2014-03-13 23:21                 ` One Thousand Gnomes
2014-03-13 23:21                   ` One Thousand Gnomes
2014-03-14  1:57                   ` Matthew Garrett
2014-03-14  1:57                     ` Matthew Garrett
2014-03-14 12:22                     ` One Thousand Gnomes
2014-03-14 12:22                       ` One Thousand Gnomes
2014-03-14 12:51                       ` Matthew Garrett
2014-03-14 12:51                         ` Matthew Garrett
2014-03-14 15:23                         ` Kees Cook
2014-03-14 15:23                           ` Kees Cook
2014-03-14 15:46                           ` Matthew Garrett
2014-03-14 15:46                             ` Matthew Garrett
2014-03-14 15:54                             ` Kees Cook
2014-03-14 15:54                               ` Kees Cook
2014-03-14 15:58                               ` Matthew Garrett
2014-03-14 15:58                                 ` Matthew Garrett
2014-03-14 16:28                           ` One Thousand Gnomes
2014-03-14 16:28                             ` One Thousand Gnomes
2014-03-14 17:06                         ` One Thousand Gnomes
2014-03-14 17:06                           ` One Thousand Gnomes
2014-03-14 18:11                           ` Matthew Garrett
2014-03-14 18:11                             ` Matthew Garrett
2014-03-14 19:24                             ` Matthew Garrett
2014-03-14 19:24                               ` Matthew Garrett
2014-03-14 20:37                               ` David Lang
2014-03-14 20:37                                 ` David Lang
2014-03-14 20:43                                 ` Matthew Garrett
2014-03-14 20:43                                   ` Matthew Garrett
2014-03-14 21:58                               ` One Thousand Gnomes
2014-03-14 21:58                                 ` One Thousand Gnomes
2014-03-14 22:04                                 ` Matthew Garrett
2014-03-14 22:04                                   ` Matthew Garrett
2014-03-14 21:48                             ` One Thousand Gnomes
2014-03-14 21:48                               ` One Thousand Gnomes
2014-03-14 21:56                               ` Matthew Garrett
2014-03-14 21:56                                 ` Matthew Garrett
2014-03-14 22:08                                 ` One Thousand Gnomes
2014-03-14 22:08                                   ` One Thousand Gnomes
2014-03-14 22:15                                   ` Matthew Garrett
2014-03-14 22:15                                     ` Matthew Garrett
2014-03-14 22:31                                     ` One Thousand Gnomes
2014-03-14 22:31                                       ` One Thousand Gnomes
2014-03-14 22:52                                       ` Matthew Garrett
2014-03-14 22:52                                         ` Matthew Garrett
2014-03-19 19:50                                       ` Kees Cook
2014-03-19 19:50                                         ` Kees Cook
2014-03-14 23:18                                   ` Theodore Ts'o
2014-03-14 23:18                                     ` Theodore Ts'o
2014-03-15  0:15                                     ` One Thousand Gnomes
2014-03-15  0:15                                       ` One Thousand Gnomes
2014-03-19 17:49                                     ` Florian Weimer
2014-03-19 17:49                                       ` Florian Weimer
2014-03-19 20:16                                     ` Kees Cook
2014-03-19 20:16                                       ` Kees Cook
2014-03-20 14:47                                       ` One Thousand Gnomes
2014-03-20 14:47                                         ` One Thousand Gnomes
2014-03-20 14:55                                       ` tytso
2014-03-20 14:55                                         ` tytso
2014-03-20 17:12                                         ` Matthew Garrett
2014-03-20 17:12                                           ` Matthew Garrett
2014-03-20 18:13                                           ` One Thousand Gnomes
2014-03-20 18:13                                             ` One Thousand Gnomes
2014-03-13 21:26             ` One Thousand Gnomes
2014-03-13 21:26               ` One Thousand Gnomes
2014-03-13 21:31               ` Matthew Garrett
2014-03-13 21:31                 ` Matthew Garrett
2015-03-13 21:38 Trusted kernel patchset Matthew Garrett
2015-03-13 21:38 ` [PATCH 12/12] Add option to automatically set trusted_kernel when in Secure Boot mode Matthew Garrett
2015-04-22 11:36   ` Dan Carpenter

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