[PATCH v3 0/7] efi: CapsuleUpdate: support for dynamic UUIDs

[Heinrich Schuchardt]

On 5/31/24 15:50, Caleb Connolly wrote:
> As more boards adopt support for the EFI CapsuleUpdate mechanism, there
> is a growing issue of being able to target updates to them properly. The
> current mechanism of hardcoding UUIDs for each board at compile time is
> unsustainable, and maintaining lists of GUIDs is similarly cumbersome.
>
> In this series, I propose that we adopt v5 GUIDs, these are generated
> by using a well-known salt GUID as well as board specific information
> (like the model/revision), these are hashed together and the result is
> truncated to form a new UUID.
>
> The well-known salt GUID can be specific to the architecture (SoC
> vendor), or OEM. It is defined in the board defconfig so that vendors
> can easily bring their own.
>
> Specifically, the following fields are used to generate a GUID for a
> particular fw_image:
>
> * namespace salt
> * board compatible (usually the first entry in the dt root compatible
>    array).
> * fw_image name (the string identifying the specific image, especially
>    relevant for board that can update multiple images).
>
> == Usage ==
>
> Boards can integrate dynamic UUID support as follows:
>
> 1. Adjust Kconfig to depend on EFI_CAPSULE_DYNAMIC_UUIDS if
>     EFI_HAVE_CAPSULE_SUPPORT.
> 2. Skip setting the fw_images image_type_id property.
> 3. Generate a UUID and set CONFIG_EFI_CAPSULE_NAMESPACE_UUID in your
>     defconfig.

Why should we have two alternatives?

If we have the dynamic UUIDs, please, get rid of static ones.

>
> == Limitations ==
>
> * Changing GUIDs
>
> The primary limitation with this approach is that if any of the source
> fields change, so will the GUID for the board. It is therefore pretty
> important to ensure that GUID changes are caught during development.
>
> * Supporting multiple boards with a single image
>
> This now requires having an entry with the GUID for every board which
> might lead to larger UpdateCapsule images.

Do we have a test case were a capsule contains images that shall not be
installed?

>
> == Tooling ==
>
> This series introduces a new tool: genguid. This can be used to generate
> the same GUIDs that the board would at runtime.

     the GUIDs that the board requires at runtime.

Best regards

Heinrich

>
> This series follows a related discussion started by Ilias:
> https://lore.kernel.org/u-boot/CAC_iWjJNHa4gMF897MqYZNdbgjFG8K4kwGsTXWuy72WkYLizrw@mail.gmail.com/
>
> ---
> Changes in v3:
> - Add manpage for genguid
> - Add dedicated CONFIG_TOOLS_GENGUID option
> - Minor code fixes addressing v2 feedback
> - Link to v2: https://lore.kernel.org/r/20240529-b4-dynamic-uuid-v2-0-c26f31057bbe@linaro.org
>
> Changes in v2:
> - Move namespace UUID to be defined in defconfig
> - Add tests and tooling
> - Only use the first board compatible to generate UUID.
> - Link to v1: https://lore.kernel.org/r/20240426-b4-dynamic-uuid-v1-0-e8154e00ec44@linaro.org
>
> ---
> Caleb Connolly (7):
>        lib: uuid: add UUID v5 support
>        efi: add a helper to generate dynamic UUIDs
>        doc: uefi: document dynamic UUID generation
>        sandbox: switch to dynamic UUIDs
>        lib: uuid: supporting building as part of host tools
>        tools: add genguid tool
>        test: lib/uuid: add unit tests for dynamic UUIDs
>
>   arch/Kconfig                                       |   1 +
>   board/sandbox/sandbox.c                            |  16 ---
>   configs/sandbox_defconfig                          |   1 +
>   configs/sandbox_flattree_defconfig                 |   1 +
>   doc/develop/uefi/uefi.rst                          |  31 +++++
>   doc/genguid.1                                      |  52 +++++++
>   include/sandbox_efi_capsule.h                      |   6 +-
>   include/uuid.h                                     |  21 ++-
>   lib/Kconfig                                        |   8 ++
>   lib/efi_loader/Kconfig                             |  23 +++
>   lib/efi_loader/efi_capsule.c                       |   1 +
>   lib/efi_loader/efi_firmware.c                      |  66 +++++++++
>   lib/uuid.c                                         |  81 +++++++++--
>   test/lib/uuid.c                                    |  88 ++++++++++++
>   .../test_efi_capsule/test_capsule_firmware_fit.py  |   2 +-
>   .../test_efi_capsule/test_capsule_firmware_raw.py  |   8 +-
>   .../test_capsule_firmware_signed_fit.py            |   2 +-
>   .../test_capsule_firmware_signed_raw.py            |   4 +-
>   test/py/tests/test_efi_capsule/version.dts         |   6 +-
>   tools/Kconfig                                      |   7 +
>   tools/Makefile                                     |   3 +
>   tools/binman/etype/efi_capsule.py                  |   2 +-
>   tools/binman/ftest.py                              |   2 +-
>   tools/genguid.c                                    | 154 +++++++++++++++++++++
>   24 files changed, 538 insertions(+), 48 deletions(-)
> ---
> change-id: 20240422-b4-dynamic-uuid-1a5ab1486c27
> base-commit: 2e682a4a406fc81ef32e05c28542cc8067f1e15f
>
> // Caleb (they/them)
>