From: Matthew Garrett <matthew.garrett@nebula.com> To: "gnomes@lxorguk.ukuu.org.uk" <gnomes@lxorguk.ukuu.org.uk> Cc: "keescook@chromium.org" <keescook@chromium.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "jmorris@namei.org" <jmorris@namei.org>, "hpa@zytor.com" <hpa@zytor.com>, "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>, "linux-security-module@vger.kernel.org" <linux-security-module@vger.kernel.org>, "linux-efi@vger.kernel.org" <linux-efi@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 22:48:38 +0000 [thread overview] Message-ID: <1393454916.14900.54.camel@x230> (raw) In-Reply-To: <20140226224141.1741a746@alan.etchedpixels.co.uk> [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain; charset="utf-8", Size: 2011 bytes --] On Wed, 2014-02-26 at 22:41 +0000, One Thousand Gnomes wrote: > 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'. Physical presence is required to do anything meaningful with firewire, and UEFI secure boot isn't intended to protect against that. Which controllers will trigger arbitrary DMA in response to raw commands? > RAWIO also disables things like CPU msr access - which is also quite > adequate for subverting a kernel. Patch 7. > 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 ? Vendors keep telling me that they're validating firmware for new hardware, and I keep tending not to believe them. Meh. The big problem with firmware signatures is that we don't necessarily have the right to distribute modified versions of the firmware, so we'd need detached signature support. I'm certainly not against this. > 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. Quirking this out when the hardware makes it impossible to provide any guarantees seems reasonable. -- Matthew Garrett <matthew.garrett@nebula.com> ÿôèº{.nÇ+·®+%Ëÿ±éݶ\x17¥wÿº{.nÇ+·¥{±þG«éÿ{ayº\x1dÊÚë,j\a¢f£¢·hïêÿêçz_è®\x03(éÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?¨èÚ&£ø§~á¶iOæ¬z·vØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?I¥
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From: Matthew Garrett <matthew.garrett@nebula.com> To: "gnomes@lxorguk.ukuu.org.uk" <gnomes@lxorguk.ukuu.org.uk> Cc: "keescook@chromium.org" <keescook@chromium.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "jmorris@namei.org" <jmorris@namei.org>, "hpa@zytor.com" <hpa@zytor.com>, "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>, "linux-security-module@vger.kernel.org" <linux-security-module@vger.kernel.org>, "linux-efi@vger.kernel.org" <linux-efi@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 22:48:38 +0000 [thread overview] Message-ID: <1393454916.14900.54.camel@x230> (raw) In-Reply-To: <20140226224141.1741a746@alan.etchedpixels.co.uk> On Wed, 2014-02-26 at 22:41 +0000, One Thousand Gnomes wrote: > 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'. Physical presence is required to do anything meaningful with firewire, and UEFI secure boot isn't intended to protect against that. Which controllers will trigger arbitrary DMA in response to raw commands? > RAWIO also disables things like CPU msr access - which is also quite > adequate for subverting a kernel. Patch 7. > 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 ? Vendors keep telling me that they're validating firmware for new hardware, and I keep tending not to believe them. Meh. The big problem with firmware signatures is that we don't necessarily have the right to distribute modified versions of the firmware, so we'd need detached signature support. I'm certainly not against this. > 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. Quirking this out when the hardware makes it impossible to provide any guarantees seems reasonable. -- Matthew Garrett <matthew.garrett@nebula.com>
next prev parent reply other threads:[~2014-02-26 22:48 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 2014-02-26 22:48 ` Matthew Garrett [this message] 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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