[Bug 1851897] Re: devicetree command should be disabled in Secure Boot mode

dann frazier dann.frazier at canonical.com
Sat Nov 23 01:16:06 UTC 2019


bionic verification:


                             GNU GRUB  version 2.02

   Minimal BASH-like line editing is supported. For the first word, TAB   
   lists possible command completions. Anywhere else TAB lists possible   
   device or file completions. ESC at any time exits.                     


grub> device-tree foo
error: can't find command `device-tree'.
grub> devicetree foo
error: Secure Boot forbids loading devicetree from foo.
grub> 


** Tags removed: verification-needed verification-needed-bionic
** Tags added: verification-done verification-done-bionic

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https://bugs.launchpad.net/bugs/1851897

Title:
  devicetree command should be disabled in Secure Boot mode

Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2-signed package in Ubuntu:
  Fix Released
Status in grub2 source package in Bionic:
  Fix Committed
Status in grub2-signed source package in Bionic:
  Fix Committed
Status in grub2 source package in Disco:
  Fix Committed
Status in grub2-signed source package in Disco:
  Fix Committed
Status in grub2 source package in Eoan:
  Fix Released
Status in grub2-signed source package in Eoan:
  Fix Released
Status in grub2 source package in Focal:
  Fix Released
Status in grub2-signed source package in Focal:
  Fix Released
Status in grub2 package in Debian:
  Fix Released

Bug description:
  [Impact]
  A devicetree command could be used to load an unsigned device tree file, which will override the hardware configuration exposed to the kernel. This could potentially be used to subvert Secure Boot.

  [Test Case]
  grub> devicetree foo
  error: Secure Boot forbids loading devicetree from foo.

  [Regression Risk]
  The idea of Secure Boot and externally provided devicetree are inherently incompatible - there's no known system that requires this config, but it is of course possible someone somewhere is doing it.

  The code involved is restricted to devicetree code, so impact would be
  restricted to ARM systems.

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