[Bug 1776996] Re: secureboot-db out of date, missing revocations from Aug 2016

Brian Murray brian at ubuntu.com
Wed Oct 17 23:22:05 UTC 2018


** Description changed:

- A signed variable update for secureboot dbx has been published by
- Microsoft to uefi.org; last updated 2016-08-11:
- http://www.uefi.org/sites/default/files/resources/dbxupdate.zip
+ Impact
+ ------
+ A signed variable update for secureboot dbx has been published by Microsoft to uefi.org; last updated 2016-08-11: http://www.uefi.org/sites/default/files/resources/dbxupdate.zip
  
  This file has not been included in the secureboot-db package in Ubuntu;
  so users who only boot Ubuntu and not Windows will not have these
  revocations applied, meaning their firmware will trust (and possibly be
  exploitable by) whatever binaries these revoked hashes correspond to.
  
- Separately, I seem in testing to be unable to apply this signed database
- update to my system using sbkeysync, despite having the Microsoft CA in
- my KEK.  So it's possible that sbkeysync doesn't work; we may need to
- either fix it, or switch to other code that does work, such as the
- dbxtool in Fedora.
+ Additionally, the attributes of the EFI variables need to be modified
+ before trying to call sbkeysync so that the database update can be
+ applied.
+ 
+ Test Case
+ ---------
+ On a UEFI system with secureboot disabled do the following
+ 1) Check the output of 'mokutil --dbx'
+ 2) Update secureboot-db to the version from -proposed
+ 3) Check the output of 'mokutil --dbx' and verify its different from the first run
+ 
+ Additionally it should be verified that the new package installs on a
+ secureboot-enabled system, in a container, on a BIOS-booted system.
+ 
+ Regression Potential
+ --------------------
+ Its possible the revoked hashes are incorrect so they should be double checked to ensure they match the Microsoft update.
+ 
+ Original Description
+ --------------------
+ Separately, I seem in testing to be unable to apply this signed database update to my system using sbkeysync, despite having the Microsoft CA in my KEK.  So it's possible that sbkeysync doesn't work; we may need to either fix it, or switch to other code that does work, such as the dbxtool in Fedora.

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https://bugs.launchpad.net/bugs/1776996

Title:
  secureboot-db out of date, missing revocations from Aug 2016

Status in secureboot-db package in Ubuntu:
  Fix Released
Status in secureboot-db source package in Trusty:
  Triaged
Status in secureboot-db source package in Xenial:
  Triaged
Status in secureboot-db source package in Bionic:
  Triaged

Bug description:
  Impact
  ------
  A signed variable update for secureboot dbx has been published by Microsoft to uefi.org; last updated 2016-08-11: http://www.uefi.org/sites/default/files/resources/dbxupdate.zip

  This file has not been included in the secureboot-db package in
  Ubuntu; so users who only boot Ubuntu and not Windows will not have
  these revocations applied, meaning their firmware will trust (and
  possibly be exploitable by) whatever binaries these revoked hashes
  correspond to.

  Additionally, the attributes of the EFI variables need to be modified
  before trying to call sbkeysync so that the database update can be
  applied.

  Test Case
  ---------
  On a UEFI system with secureboot disabled do the following
  1) Check the output of 'mokutil --dbx'
  2) Update secureboot-db to the version from -proposed
  3) Check the output of 'mokutil --dbx' and verify its different from the first run

  Additionally it should be verified that the new package installs on a
  secureboot-enabled system, in a container, on a BIOS-booted system.

  Regression Potential
  --------------------
  Its possible the revoked hashes are incorrect so they should be double checked to ensure they match the Microsoft update.

  Original Description
  --------------------
  Separately, I seem in testing to be unable to apply this signed database update to my system using sbkeysync, despite having the Microsoft CA in my KEK.  So it's possible that sbkeysync doesn't work; we may need to either fix it, or switch to other code that does work, such as the dbxtool in Fedora.

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