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efi: libstub: Remove zboot signing from build options

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The zboot decompressor series introduced a feature to sign the PE/COFF
kernel image for secure boot as part of the kernel build. This was
necessary because there are actually two images that need to be signed:
the kernel with the EFI stub attached, and the decompressor application.

This is a bit of a burden, because it means that the images must be
signed on the the same system that performs the build, and this is not
realistic for distros.

During the next cycle, we will introduce changes to the zboot code so
that the inner image no longer needs to be signed. This means that the
outer PE/COFF image can be handled as usual, and be signed later in the
release process.

Let's remove the associated Kconfig options now so that they don't end
up in a LTS release while already being deprecated.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-10-17 12:48:46 +02:00
parent 9abf2313ad
commit f57fb375a2
2 changed files with 4 additions and 47 deletions
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22
drivers/firmware/efi/Kconfig
View File

@ -124,28 +124,6 @@ config EFI_ZBOOT
is supported by the encapsulated image. (The compression algorithm
used is described in the zboot image header)
config EFI_ZBOOT_SIGNED
def_bool y
depends on EFI_ZBOOT_SIGNING_CERT != ""
depends on EFI_ZBOOT_SIGNING_KEY != ""
config EFI_ZBOOT_SIGNING
bool "Sign the EFI decompressor for UEFI secure boot"
depends on EFI_ZBOOT
help
Use the 'sbsign' command line tool (which must exist on the host
path) to sign both the EFI decompressor PE/COFF image, as well as the
encapsulated PE/COFF image, which is subsequently compressed and
wrapped by the former image.
config EFI_ZBOOT_SIGNING_CERT
string "Certificate to use for signing the compressed EFI boot image"
depends on EFI_ZBOOT_SIGNING
config EFI_ZBOOT_SIGNING_KEY
string "Private key to use for signing the compressed EFI boot image"
depends on EFI_ZBOOT_SIGNING
config EFI_ARMSTUB_DTB_LOADER
bool "Enable the DTB loader"
depends on EFI_GENERIC_STUB && !RISCV && !LOONGARCH

29
drivers/firmware/efi/libstub/Makefile.zboot
View File

@ -20,22 +20,11 @@ zboot-size-len-y := 4
zboot-method-$(CONFIG_KERNEL_GZIP) := gzip
zboot-size-len-$(CONFIG_KERNEL_GZIP) := 0
quiet_cmd_sbsign = SBSIGN $@
cmd_sbsign = sbsign --out $@ $< \
--key $(CONFIG_EFI_ZBOOT_SIGNING_KEY) \
--cert $(CONFIG_EFI_ZBOOT_SIGNING_CERT)
$(obj)/$(EFI_ZBOOT_PAYLOAD).signed: $(obj)/$(EFI_ZBOOT_PAYLOAD) FORCE
$(call if_changed,sbsign)
ZBOOT_PAYLOAD-y := $(EFI_ZBOOT_PAYLOAD)
ZBOOT_PAYLOAD-$(CONFIG_EFI_ZBOOT_SIGNED) := $(EFI_ZBOOT_PAYLOAD).signed
$(obj)/vmlinuz: $(obj)/$(ZBOOT_PAYLOAD-y) FORCE
$(obj)/vmlinuz: $(obj)/$(EFI_ZBOOT_PAYLOAD) FORCE
$(call if_changed,$(zboot-method-y))
OBJCOPYFLAGS_vmlinuz.o := -I binary -O $(EFI_ZBOOT_BFD_TARGET) \
--rename-section .data=.gzdata,load,alloc,readonly,contents
--rename-section .data=.gzdata,load,alloc,readonly,contents
$(obj)/vmlinuz.o: $(obj)/vmlinuz FORCE
$(call if_changed,objcopy)
@ -53,18 +42,8 @@ LDFLAGS_vmlinuz.efi.elf := -T $(srctree)/drivers/firmware/efi/libstub/zboot.lds
$(obj)/vmlinuz.efi.elf: $(obj)/vmlinuz.o $(ZBOOT_DEPS) FORCE
$(call if_changed,ld)
ZBOOT_EFI-y := vmlinuz.efi
ZBOOT_EFI-$(CONFIG_EFI_ZBOOT_SIGNED) := vmlinuz.efi.unsigned
OBJCOPYFLAGS_$(ZBOOT_EFI-y) := -O binary
$(obj)/$(ZBOOT_EFI-y): $(obj)/vmlinuz.efi.elf FORCE
OBJCOPYFLAGS_vmlinuz.efi := -O binary
$(obj)/vmlinuz.efi: $(obj)/vmlinuz.efi.elf FORCE
$(call if_changed,objcopy)
targets += zboot-header.o vmlinuz vmlinuz.o vmlinuz.efi.elf vmlinuz.efi
ifneq ($(CONFIG_EFI_ZBOOT_SIGNED),)
$(obj)/vmlinuz.efi: $(obj)/vmlinuz.efi.unsigned FORCE
$(call if_changed,sbsign)
endif
targets += $(EFI_ZBOOT_PAYLOAD).signed vmlinuz.efi.unsigned