[PATCH v4 03/12] capsule: authenticate: Add capsule public key in platform's dtb

[Simon Glass]

Hi Sughosh,

On Sat, 15 Jul 2023 at 07:46, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
>
> The EFI capsule authentication logic in u-boot expects the public key
> in the form of an EFI Signature List(ESL) to be provided as part of
> the platform's dtb. Currently, the embedding of the ESL file into the
> dtb needs to be done manually.
>
> Add a signature node in the u-boot dtsi file and include the public
> key through the capsule-key property. This file is per architecture,
> and is currently being added for sandbox and arm architectures. It
> will have to be added for other architectures which need to enable
> capsule authentication support.
>
> The path to the ESL file is specified through the
> CONFIG_EFI_CAPSULE_ESL_FILE symbol.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
> Changes since V3:
> * Put the two ifdef statements together in arm architecture's
>   u-boot.dtsi file.
> * Remove the extra blank line in the Kconfig.
>
>  arch/arm/dts/u-boot.dtsi     | 17 +++++++++++++++++
>  arch/sandbox/dts/u-boot.dtsi | 17 +++++++++++++++++
>  lib/efi_loader/Kconfig       | 10 ++++++++++
>  lib/efi_loader/Makefile      |  7 +++++++
>  4 files changed, 51 insertions(+)
>  create mode 100644 arch/arm/dts/u-boot.dtsi
>  create mode 100644 arch/sandbox/dts/u-boot.dtsi

This approach seems OK to me for now. It is a bit strange to specify a
CONFIG option to add something to the DT, but we can always adjust it
later if needed.

>
> diff --git a/arch/arm/dts/u-boot.dtsi b/arch/arm/dts/u-boot.dtsi
> new file mode 100644
> index 0000000000..2a9359c43c
> --- /dev/null
> +++ b/arch/arm/dts/u-boot.dtsi
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*

/**

for multi-line comments

> + * Devicetree file with miscellaneous nodes that will be included
> + * at build time into the DTB. Currently being used for including
> + * capsule related information.
> + *

drop blank line

> + */
> +
> +#ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT
> +#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE

Can you combine these, or can you omit the first one?

> +/ {
> +       signature {
> +               capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
> +       };
> +};
> +#endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
> +#endif /* CONFIG_EFI_HAVE_CAPSULE_SUPPORT */
> diff --git a/arch/sandbox/dts/u-boot.dtsi b/arch/sandbox/dts/u-boot.dtsi
> new file mode 100644
> index 0000000000..60bd004937
> --- /dev/null
> +++ b/arch/sandbox/dts/u-boot.dtsi
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Devicetree file with miscellaneous nodes that will be included
> + * at build time into the DTB. Currently being used for including
> + * capsule related information.
> + *
> + */
> +
> +#ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT
> +/ {
> +#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
> +       signature {
> +               capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
> +       };
> +#endif
> +};
> +#endif /* CONFIG_EFI_HAVE_CAPSULE_SUPPORT */
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index a22e47616f..9abb9a4db3 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -235,6 +235,16 @@ config EFI_CAPSULE_MAX
>           Select the max capsule index value used for capsule report
>           variables. This value is used to create CapsuleMax variable.
>
> +config EFI_CAPSULE_ESL_FILE
> +       string "Path to the EFI Signature List File"
> +       default ""
> +       depends on EFI_CAPSULE_AUTHENTICATE
> +       help
> +         Provides the absolute path to the EFI Signature List
> +         file which will be embedded in the platform's device
> +         tree and used for capsule authentication at the time
> +         of capsule update.

Can you wrap to 72 chars or so?

> +
>  config EFI_DEVICE_PATH_TO_TEXT
>         bool "Device path to text protocol"
>         default y
> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> index 1a8c8d7cab..c52c9d27bd 100644
> --- a/lib/efi_loader/Makefile
> +++ b/lib/efi_loader/Makefile
> @@ -89,3 +89,10 @@ obj-$(CONFIG_EFI_ECPT) += efi_conformance.o
>
>  EFI_VAR_SEED_FILE := $(subst $\",,$(CONFIG_EFI_VAR_SEED_FILE))
>  $(obj)/efi_var_seed.o: $(srctree)/$(EFI_VAR_SEED_FILE)
> +
> +ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),y)
> +EFI_CAPSULE_KEY_PATH := $(subst $\",,$(CONFIG_EFI_CAPSULE_ESL_FILE))
> +ifeq ("$(wildcard $(EFI_CAPSULE_KEY_PATH))","")
> +$(error .esl cerificate not found. Configure your CONFIG_EFI_CAPSULE_ESL_FILE)
> +endif
> +endif
> --
> 2.34.1
>

REgards,
Simon