[UNSTABLE][PATCH 0/3] Support builtin revoked certificates

Dimitri John Ledkov dimitri.ledkov at canonical.com
Tue Jun 15 15:40:01 UTC 2021


Upstream linux kernel now supports configuring built-in revoked
certificates for the .blacklist keyring.

Add support in our kernel configuration to have built-in revoked

Revoke UEFI amd64 & arm64 2012 signing certificate.

Under UEFI Secureboot with lockdown, shim may attempt to communicate
revoked certificates to the kernel and depending on how good EFI
firmware is, this may or may not succeed.

By having these built-in, it will be prohibited to kexec file_load
older kernels that were signed with now revoked certificates, however
one boots.

[Test Plan]

 * Boot kernel directly, or just with grub, and without shim

 * Check that

$ sudo keyctl list %:.blacklist

Contains assymetric 2012 key.

[Where problems could occur]

 * Derivative and per-arch kernels may need to revoke different keys,
   thus this should be evaluated on per arch & flavour basis as to
   which keys to revoke.

[Other Info]

 * In theory, this only needs to be revoked on amd64 and arm64, but
   empty revocation list is not allowed by the kernel configury, thus
   at the moment revoking 2012 UEFI cert for all architectures.

Dimitri John Ledkov (3):
  UBUNTU: [Packaging] build canonical-revoked-certs.pem from branch/arch
  UBUNTU: [Packaging] Revoke 2012 UEFI signing certificate as built-in
  UBUNTU: [Config] Configure CONFIG_SYSTEM_REVOCATION_KEYS with revoked

 debian.master/config/annotations              |  1 +
 debian.master/config/config.common.ubuntu     |  2 +-
 .../revoked-certs/canonical-uefi-2012-all.pem | 86 +++++++++++++++++++
 debian/rules                                  | 14 ++-
 4 files changed, 101 insertions(+), 2 deletions(-)
 create mode 100644 debian/revoked-certs/canonical-uefi-2012-all.pem


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