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 the DT root compatible string, 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 enable dynamic UUID support by simply not setting the efi_fw_image image_type_id property. Vendors may also wish to set a custom namespace GUID (by setting CONFIG_EFI_CAPSULE_NAMESPACE_GUID).
== 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.
== Tooling ==
The mkeficapsule command is updated to add a new guidgen subcommand, this can generate GUIDs that match those the board would generate at runtime. It accepts an optional namespace GUID (if the default isn't used), a path to the board DTB, and a list of firmware image names.
This series follows a related discussion started by Ilias: https://lore.kernel.org/u-boot/CAC_iWjJNHa4gMF897MqYZNdbgjFG8K4kwGsTXWuy72Wk...
CI run for this series: https://source.denx.de/u-boot/custodians/u-boot-snapdragon/-/pipelines/21419
--- Changes in v4: - Make UUID v5 support always enabled rather than being optional. - Fix endianness issues (thanks Vincent and Ilias) - Merge genguid tool into mkeficapsule. - And move mkeficapsule over to using U-Boot's UUID code rather than libuuid. - Provide a default namespace UUID for all U-Boot boards. - Link to v3: https://lore.kernel.org/r/20240531-b4-dynamic-uuid-v3-0-ca4a4865db00@linaro....
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....
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....
--- Caleb Connolly (10): efi: define struct efi_guid 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 include: export uuid.h tools: mkeficapsule: use u-boot UUID library tools: mkeficapsule: support generating dynamic GUIDs test: lib/uuid: add unit tests for dynamic UUIDs
arch/arm/mach-rockchip/board.c | 2 +- board/cobra5272/flash.c | 2 +- board/gardena/smart-gateway-mt7688/board.c | 2 +- board/sandbox/sandbox.c | 16 -- board/socrates/socrates.c | 2 +- board/xilinx/common/board.c | 2 +- cmd/efi.c | 2 +- cmd/efi_common.c | 2 +- cmd/flash.c | 2 +- cmd/gpt.c | 2 +- cmd/nvedit_efi.c | 2 +- cmd/x86/hob.c | 2 +- common/flash.c | 2 +- disk/part_efi.c | 2 +- doc/develop/uefi/uefi.rst | 27 +++ doc/mkeficapsule.1 | 23 +++ drivers/firmware/arm-ffa/arm-ffa-uclass.c | 2 +- env/sf.c | 2 +- fs/btrfs/btrfs.c | 2 +- fs/btrfs/compat.h | 2 +- fs/btrfs/disk-io.c | 2 +- fs/ext4/ext4fs.c | 2 +- include/efi.h | 2 +- include/fwu.h | 2 +- include/part.h | 2 +- include/rkmtd.h | 2 +- include/sandbox_efi_capsule.h | 6 +- include/{ => u-boot}/uuid.h | 21 ++- lib/Kconfig | 1 + lib/acpi/acpi_dp.c | 2 +- lib/acpi/acpigen.c | 2 +- lib/efi/efi_app.c | 2 +- lib/efi_loader/Kconfig | 12 ++ lib/efi_loader/efi_capsule.c | 1 + lib/efi_loader/efi_device_path.c | 2 +- lib/efi_loader/efi_firmware.c | 52 +++++ lib/efi_loader/efi_variable.c | 2 +- lib/fwu_updates/fwu_mtd.c | 2 +- lib/uuid.c | 102 +++++++--- lib/vsprintf.c | 2 +- net/bootp.c | 2 +- test/dm/acpi_dp.c | 2 +- test/dm/acpigen.c | 2 +- test/lib/uuid.c | 84 ++++++++- .../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/Makefile | 11 +- tools/binman/etype/efi_capsule.py | 2 +- tools/binman/ftest.py | 2 +- tools/eficapsule.h | 2 +- tools/mkeficapsule.c | 210 ++++++++++++++++----- 54 files changed, 512 insertions(+), 148 deletions(-) --- change-id: 20240422-b4-dynamic-uuid-1a5ab1486c27 base-commit: a5c0ba7a9f65aa3843f360d09ea986dcade112f5
// Caleb (they/them)