These patches add support for embedding the public key efi signature list(esl) file into the platform's device tree. The current solution for the Qemu arm64 platform has the public key as part of an overlay, and stored on the Efi System Partition(ESP). Having the provision to embed the public key into the platform's dtb which is then concatenated with the u-boot binary is a better approach, recommended by Heinrich[1].
Patch 1 removes the existing additional check for authenticating the capsule using the env variable.
Patch 2 add two config symbols, EFI_PKEY_DTB_EMBED and EFI_PKEY_FILE which are used for enabling embedding of the public key in the dtb, and specifying the esl file name.
Patch 3 adds a function for retrieving the public key which has been embedded in the platform's dtb.
Patch 4 adds the functionality to embed the esl file into the platform's dtb during the platform build.
I have tested this functionality on the STM32MP157C DK2 board, and it works as expected.
[1] - https://lists.denx.de/pipermail/u-boot/2021-March/442867.html
Changes since V1:
* As pointed out by Heinrich in the review, remove the extra check of the env variable 'capsule_authentication_enabled'for authenticating the capsule. The capsule authentication will now be done based on whether the corresponding config symbol is enabled. * Provide a default name for public key file, eficapsule.esl as suggested by Heinrich. * Remove the superfluous default n statement for EFI_PKEY_DTB_EMBED * Remove the weak function, and add the functionality to retrieve the public key under the config symbol CONFIG_EFI_PKEY_DTB_EMBED.
Sughosh Ganu (4): efi_loader: capsule: Remove the check for capsule_authentication_enabled environment variable efi_loader: Kconfig: Add symbols for embedding the public key into the platform's dtb efi_capsule: Add a function to get the public key needed for capsule authentication Makefile: Add provision for embedding public key in platform's dtb
Makefile | 10 +++++++ board/emulation/common/qemu_capsule.c | 6 ---- lib/efi_loader/Kconfig | 15 ++++++++++ lib/efi_loader/efi_capsule.c | 43 +++++++++++++++++++++++---- lib/efi_loader/efi_firmware.c | 5 ++-- 5 files changed, 65 insertions(+), 14 deletions(-)