On 2020-06-23, Kees Cook wrote:
In preparation for adding --orphan-handling=warn to more architectures,
make sure unwanted sections don't end up appearing under the .init
section prefix that libstub adds to itself during objcopy.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/firmware/efi/libstub/Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 75daaf20374e..9d2d2e784bca 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -66,6 +66,9 @@ lib-$(CONFIG_X86) += x86-stub.o
CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
+# Remove unwanted sections first.
+STUBCOPY_FLAGS-y += --remove-section=.note.gnu.property
+
#
# For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the
# .bss section, so the .bss section of the EFI stub needs to be included in the
arch/arm64/Kconfig enables ARM64_PTR_AUTH by default. When the config is on
ifeq ($(CONFIG_ARM64_BTI_KERNEL),y)
branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET_BTI) := -mbranch-protection=pac-ret+leaf+bti
else
branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf
endif
This option creates .note.gnu.property:
% readelf -n drivers/firmware/efi/libstub/efi-stub.o
Displaying notes found in: .note.gnu.property
Owner Data size Description
GNU 0x00000010 NT_GNU_PROPERTY_TYPE_0
Properties: AArch64 feature: PAC
If .note.gnu.property is not desired in drivers/firmware/efi/libstub, specifying
-mbranch-protection=none can override -mbranch-protection=pac-ret+leaf
