Re: [PATCH 1/7] capsule: authenticate: Embed capsule public key in platform's dtb

Simon Glass
2023-06-15T09:15:38Z

Hi Sughosh,

On Tue, 13 Jun 2023 at 11:41, Sughosh Ganu <sughosh.ganu@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 script for embedding the ESL used for capsule authentication in
> the platform's dtb, and call this as part of building the dtb(s). This
> brings the embedding of the ESL in the dtb into the u-boot build flow.
>
> The path to the ESL file is specified through the
> CONFIG_EFI_CAPSULE_ESL_FILE symbol.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> ---
> lib/efi_loader/Kconfig | 11 +++++++++++
> scripts/Makefile.lib | 8 ++++++++
> scripts/embed_capsule_key.sh | 25 +++++++++++++++++++++++++
> 3 files changed, 44 insertions(+)
> create mode 100755 scripts/embed_capsule_key.sh
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index c5835e6ef6..1326a1d109 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -234,6 +234,17 @@ 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.
> +
> +
> config EFI_DEVICE_PATH_TO_TEXT
> bool "Device path to text protocol"
> default y
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 7b27224b5d..a4083d0a26 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -192,6 +192,8 @@ dtc_cpp_flags = -Wp,-MD,$(depfile).pre.tmp -nostdinc \
> -D__ASSEMBLY__ \
> -undef -D__DTS__
>
> +export dtc_cpp_flags
> +
> # Finds the multi-part object the current object will be linked into
> modname-multi = $(sort $(foreach m,$(multi-used),\
> $(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))
> @@ -315,6 +317,9 @@ ifeq ($(CONFIG_OF_LIBFDT_OVERLAY),y)
> DTC_FLAGS += -@
> endif
>
> +quiet_cmd_embedcapsulekey = EMBEDCAPSULEKEY $@
> +cmd_embedcapsulekey = $(srctree)/scripts/embed_capsule_key.sh $@
> +
> quiet_cmd_dtc = DTC $@
> # Modified for U-Boot
> # Bring in any U-Boot-specific include at the end of the file
> @@ -333,6 +338,9 @@ cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
>
> $(obj)/%.dtb: $(src)/%.dts FORCE
> $(call if_changed_dep,dtc)
> +ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),y)
> + $(call cmd,embedcapsulekey,$@)
> +endif
>
> pre-tmp = $(subst $(comma),_,$(dot-target).pre.tmp)
> dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp)
> diff --git a/scripts/embed_capsule_key.sh b/scripts/embed_capsule_key.sh
> new file mode 100755
> index 0000000000..1c2e45f758
> --- /dev/null
> +++ b/scripts/embed_capsule_key.sh
> @@ -0,0 +1,25 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0+
> +#
> +# Copyright (C) 2023, Linaro Limited
> +#
> +
> +gen_capsule_signature_file() {
> +cat >> $1 << EOF
> +/dts-v1/;
> +/plugin/;
> +
> +&{/} {
> + signature {
> + capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
> + };
> +};
> +EOF
> +}
> +
> +gen_capsule_signature_file signature.$$.dts > /dev/null 2>&1
> +$CPP $dtc_cpp_flags -x assembler-with-cpp -o signature.$$.tmp signature.$$.dts > /dev/null 2>&1
> +dtc -@ -O dtb -o signature.$$.dtbo signature.$$.tmp > /dev/null 2>&1
> +fdtoverlay -i $1 -o temp.$$.dtb -v signature.$$.dtbo > /dev/null 2>&1
> +mv temp.$$.dtb $1 > /dev/null 2>&1
> +rm -f signature.$$.* > /dev/null 2>&1
> --
> 2.34.1
>

Can you please add this to binman instead?

Regards,
Simon