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    SubjectRe: [PATCH v7 00/17] Enroll kernel keys thru MOK
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    On Mon, 2021-11-15 at 19:15 -0500, Eric Snowberg wrote:
    > Back in 2013 Linus requested a feature to allow end-users to have the
    > ability "to add their own keys and sign modules they trust". This was
    > his *second* order outlined here [1]. There have been many attempts
    > over the years to solve this problem, all have been rejected.  Many
    > of the failed attempts loaded all preboot firmware keys into the kernel,
    > including the Secure Boot keys. Many distributions carry one of these
    > rejected attempts [2], [3], [4]. This series tries to solve this problem
    > with a solution that takes into account all the problems brought up in
    > the previous attempts.
    >
    > On UEFI based systems, this series introduces a new Linux kernel keyring
    > containing the Machine Owner Keys (MOK) called machine. It also defines
    > a new MOK variable in shim. This variable allows the end-user to decide
    > if they want to load MOK keys into the machine keyring. Mimi has suggested
    > that only CA keys contained within the MOK be loaded into the machine
    > keyring. All other certs will load into the platform keyring instead.
    >
    > By default, nothing changes; MOK keys are not loaded into the machine
    > keyring.  They are only loaded after the end-user makes the decision
    > themselves.  The end-user would set this through mokutil using a new
    > --trust-mok option [5]. This would work similar to how the kernel uses
    > MOK variables to enable/disable signature validation as well as use/ignore
    > the db. Any kernel operation that uses either the builtin or secondary
    > trusted keys as a trust source shall also reference the new machine
    > keyring as a trust source.
    >
    > Secure Boot keys will never be loaded into the machine keyring.  They
    > will always be loaded into the platform keyring.  If an end-user wanted
    > to load one, they would need to enroll it into the MOK.
    >
    > Steps required by the end user:
    >
    > Sign kernel module with user created key:
    > $ /usr/src/kernels/$(uname -r)/scripts/sign-file sha512 \
    >    machine_signing_key.priv machine_signing_key.x509 my_module.ko
    >
    > Import the key into the MOK
    > $ mokutil --import machine_signing_key.x509
    >
    > Setup the kernel to load MOK keys into the .machine keyring
    > $ mokutil --trust-mok
    >
    > Then reboot, the MokManager will load and ask if you want to trust the
    > MOK key and enroll the MOK into the MOKList.  Afterwards the signed kernel
    > module will load.
    >
    > I have included  a link to the mokutil [5] changes I have made to support
    > this new functionality.  The shim changes have now been accepted
    > upstream [6].
    >
    > [1] https://marc.info/?l=linux-kernel&m=136185386310140&w=2
    > [2] https://lore.kernel.org/lkml/1479737095.2487.34.camel@linux.vnet.ibm.com/
    > [3] https://lore.kernel.org/lkml/1556221605.24945.3.camel@HansenPartnership.com/
    > [4] https://lore.kernel.org/linux-integrity/1e41f22b1f11784f1e943f32bf62034d4e054cdb.camel@HansenPartnership.com/
    > [5] https://github.com/esnowberg/mokutil/tree/mokvars-v3
    > [6] https://github.com/rhboot/shim/commit/4e513405b4f1641710115780d19dcec130c5208f
    >
    > Eric Snowberg (17):
    >   integrity: Introduce a Linux keyring called machine
    >   integrity: Do not allow machine keyring updates following init
    >   KEYS: Create static version of public_key_verify_signature
    >   X.509: Parse Basic Constraints for CA
    >   KEYS: CA link restriction
    >   integrity: restrict INTEGRITY_KEYRING_MACHINE to restrict_link_by_ca
    >   integrity: Fix warning about missing prototypes
    >   integrity: add new keyring handler for mok keys
    >   KEYS: Rename get_builtin_and_secondary_restriction
    >   KEYS: add a reference to machine keyring
    >   KEYS: Introduce link restriction for machine keys
    >   KEYS: integrity: change link restriction to trust the machine keyring
    >   KEYS: link secondary_trusted_keys to machine trusted keys
    >   integrity: store reference to machine keyring
    >   efi/mokvar: move up init order
    >   integrity: Trust MOK keys if MokListTrustedRT found
    >   integrity: Only use machine keyring when uefi_check_trust_mok_keys is
    >     true
    >
    >  certs/system_keyring.c                        | 44 ++++++++++-
    >  crypto/asymmetric_keys/restrict.c             | 43 +++++++++++
    >  crypto/asymmetric_keys/x509_cert_parser.c     |  9 +++
    >  drivers/firmware/efi/mokvar-table.c           |  2 +-
    >  include/crypto/public_key.h                   | 15 ++++
    >  include/keys/system_keyring.h                 | 14 ++++
    >  security/integrity/Kconfig                    | 12 +++
    >  security/integrity/Makefile                   |  1 +
    >  security/integrity/digsig.c                   | 23 +++++-
    >  security/integrity/integrity.h                | 17 +++-
    >  .../platform_certs/keyring_handler.c          | 18 ++++-
    >  .../platform_certs/keyring_handler.h          |  5 ++
    >  security/integrity/platform_certs/load_uefi.c |  4 +-
    >  .../platform_certs/machine_keyring.c          | 77 +++++++++++++++++++
    >  14 files changed, 273 insertions(+), 11 deletions(-)
    >  create mode 100644 security/integrity/platform_certs/machine_keyring.c
    >
    >
    > base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf

    Does shim have the necessary features in a release?

    /Jarkko

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