[personal profile] mjg59
Since there are probably going to be some questions about this in the near future:

The UEFI secure boot protocol is part of recent UEFI specification releases. It permits one or more signing keys to be installed into a system firmware. Once enabled, secure boot prevents executables or drivers from being loaded unless they're signed by one of these keys. Another set of keys (Pkek) permits communication between an OS and the firmware. An OS with a Pkek matching that installed in the firmware may add additional keys to the whitelist. Alternatively, it may add keys to a blacklist. Binaries signed with a blacklisted key will not load.

There is no centralised signing authority for these UEFI keys. If a vendor key is installed on a machine, the only way to get code signed with that key is to get the vendor to perform the signing. A machine may have several keys installed, but if you are unable to get any of them to sign your binary then it won't be installable.

This impacts both software and hardware vendors. An OS vendor cannot boot their software on a system unless it's signed with a key that's included in the system firmware. A hardware vendor cannot run their hardware inside the EFI environment unless their drivers are signed with a key that's included in the system firmware. If you install a new graphics card that either has unsigned drivers, or drivers that are signed with a key that's not in your system firmware, you'll get no graphics support in the firmware.

Microsoft requires that machines conforming to the Windows 8 logo program and running a client version of Windows 8 ship with secure boot enabled. The two alternatives here are for Windows to be signed with a Microsoft key and for the public part of that key to be included with all systems, or alternatively for each OEM to include their own key and sign the pre-installed versions of Windows. The second approach would make it impossible to run boxed copies of Windows on Windows logo hardware, and also impossible to install new versions of Windows unless your OEM provided a new signed copy. The former seems more likely.

A system that ships with only OEM and Microsoft keys will not boot a generic copy of Linux.

Now, obviously, we could provide signed versions of Linux. This poses several problems. Firstly, we'd need a non-GPL bootloader. Grub 2 is released under the GPLv3, which explicitly requires that we provide the signing keys. Grub is under GPLv2 which lacks the explicit requirement for keys, but it could be argued that the requirement for the scripts used to control compilation includes that. It's a grey area, and exploiting it would be a pretty good show of bad faith. Secondly, in the near future the design of the kernel will mean that the kernel itself is part of the bootloader. This means that kernels will also have to be signed. Making it impossible for users or developers to build their own kernels is not practical. Finally, if we self-sign, it's still necessary to get our keys included by ever OEM.

There's no indication that Microsoft will prevent vendors from providing firmware support for disabling this feature and running unsigned code. However, experience indicates that many firmware vendors and OEMs are interested in providing only the minimum of firmware functionality required for their market. It's almost certainly the case that some systems will ship with the option of disabling this. Equally, it's almost certainly the case that some systems won't.

It's probably not worth panicking yet. But it is worth being concerned.

GPLv3 and signing keys

Date: 2011-09-20 10:12 pm (UTC)
From: (Anonymous)
There is a lot of misunderstanding of the GPLv3 requirement for signing keys. The requirement that you provide "installation information" (which includes signing keys) applies to object code distributed for a "User Product" that is distributed AS PART OF a transaction in which the right of possession of the "User Product" changes hands.

A "User Product" is a tangible person property or goods designed for installation in a dwelling.

The gist of what GPLv3 is saying is that if you sell someone some hardware that includes GPLv3 firmware, you have to give them the keys to install new firmware of their choice.

Since Red Hat sells their software for use on other people's hardware, rather than selling their software bundled with hardware as part of the sale of that hardware, Red Hat can ship signed GPLv3 code without being obligated to provide the keys.

Re: GPLv3 and signing keys

Date: 2011-09-20 11:08 pm (UTC)
From: (Anonymous)
Note that GPLv2 is also unclear. Nobody has ever tested what the scripts/install bits of the licence means in this area. The kernel is also "booby trapped" with some GPLv2 code which contains headers specifying clearly the interpretation they apply.

It raises some interesting questions, ones I am sure regulators will be looking hard at, such as whether this is a cartel between the h/w vendors and a certain large software company. But if some vendors are sane then a very public 'Wintendo' list of bad machines plus an active all OS campaign to send back misdescribed systems, phone tech support, demand fixes and file advertising complaints about boxes not clearly marked as being Wintendo systems ought to be enough to push the incredible narrow margins the OEMs work to past the point they are making a loss on each Wintendo sold that isn't clearly advertised as junk.

Re: GPLv3 and signing keys

Date: 2011-09-21 12:12 am (UTC)
From: (Anonymous)
IAAL (tax). I won't weigh in on the copyright issues, though, as that is not within my primary practice area.

From http://www.policylibrary.tax.virginia.gov/OTP/policy.nsf/df8f027f3fea473a8525697a00730e76/83fa6068bb91d6c885256f010063f827?OpenDocument
Black's Law Dictionary defines tangible personal property as "property such as a chair or watch which may be touched or felt in contrast to a contract." Black's Law Dictionary, Fifth Edition. West Publishing Company, St Paul Minnesota, 1979. [Emphasis added.]

Intangible property, on the other hand, consists of rights not related to physical things, but merely are relationships between persons, natural or corporate, which the law recognizes by attaching to them certain sanctions enforceable in the courts. Intangible property may be evidenced by a document with no intrinsic value, such as a stock certificate. According to this widely accepted definition, contracts fall under the definition of "intangible property."


The laws of the various states concerning the status of software licenses is not uniform. There is an interesting map, with state-specific reference links at http://www.softwareone.com/en-us/Licensing/Licensing/Pages/Electronic-Software-Distribution.aspx

The IRS says: "Off-the-shelf computer software placed in service during the tax year is qualifying property for purposes of the section 179 deduction. This is computer software that is readily available for purchase by the general public, is subject to a nonexclusive license, and has not been substantially modified. It includes any program designed to cause a computer to perform a desired function. However, a database or similar item is not considered computer software unless it is in the public domain and is incidental to the operation of otherwise qualifying software." (http://www.irs.gov/publications/p946/ch02.html#en_US_2010_publink1000107395).

Pennsylvania declares that "Software Licenses Are Tangible Personal Property" and "renewals of licenses to use ‘‘canned’’ software, whether transmitted electronically or on a physical medium, is taxable as the sale of tangible personal property; the computer program is stored on a computer’s hardware, takes up space on the hard drive, and is physically perceived by checking the computer’s files. Graham Packaging Co., LP, v. Commonwealth, 882 A.2d 1076, 1086—1087 (Pa. Cmwlth. 2005)." PA defines "Canned software—Computer software that does not qualify as custom software."
http://www.pacode.com/secure/data/061/chapter60/s60.19.html

California, however, has a different view concerning downloads:
"Canned software and license agreements are taxable if delivered via tangible media, such as diskette or cd-rom. Canned software is not taxable if delivered electronically or loaded by the vendor. Canned software is a pre-written program developed for general or repeated sale or lease."
http://accounting.ucdavis.edu/ta/salesanduse.cfm

Re: GPLv3 and signing keys

Date: 2011-09-24 04:36 am (UTC)
From: (Anonymous)
The relevant "User Product" is the computer that would be running the GPLv3 code, not the CD-ROM, which is just a distribution medium. Even if you were to argue that the CD-ROM is also a "User Product", that is not a problem, as GPLv3 says: "But this requirement does not apply if neither you nor any third party retains the ability to install modified object code on the User Product (for example, the work has been installed in ROM)".

Re: GPLv3 and signing keys

Date: 2011-09-22 11:25 pm (UTC)
cjwatson: (Default)
From: [personal profile] cjwatson
Regardless of whether one might be able to find some construction under which shipping signed images without allowing the user to produce equivalently-functional modified images is in compliance with either version of the GPL, it's not in our interests to do so. The freedom to modify (yes, even the boot loader!) is of practical importance as well as ideological: we *want* people to be able to tinker, in part because that's a large part of how we get new developers.

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Matthew Garrett

About Matthew

Power management, mobile and firmware developer on Linux. Security developer at Nebula. Member of the Linux Foundation Technical Advisory Board. Ex-biologist. @mjg59 on Twitter. Content here should not be interpreted as the opinion of my employer.

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