42633ed852
Clang emits a asan.module_ctor constructor to each object file when KASAN is enabled, and these functions are indirectly called in do_ctors. With CONFIG_CFI_CLANG, the compiler also emits a CFI type hash before each address-taken global function so they can pass indirect call checks. However, in commit0c3e806ec0("x86/cfi: Add boot time hash randomization"), x86 implemented boot time hash randomization, which relies on the .cfi_sites section generated by objtool. As objtool is run against vmlinux.o instead of individual object files with X86_KERNEL_IBT (enabled by default), CFI types in object files that are not part of vmlinux.o end up not being included in .cfi_sites, and thus won't get randomized and trip CFI when called. Only .vmlinux.export.o and init/version-timestamp.o are linked into vmlinux separately from vmlinux.o. As these files don't contain any functions, disable KASAN for both of them to avoid breaking hash randomization. Link: https://github.com/ClangBuiltLinux/linux/issues/1742 Fixes:0c3e806ec0("x86/cfi: Add boot time hash randomization") Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230112224948.1479453-2-samitolvanen@google.com
1.8 KiB
SPDX-License-Identifier: GPL-2.0
Makefile for the linux kernel.
ccflags-y := -fno-function-sections -fno-data-sections
obj-y := main.o version.o mounts.o ifneq ($(CONFIG_BLK_DEV_INITRD),y) obj-y += noinitramfs.o else obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o endif obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
obj-y += init_task.o
mounts-y := do_mounts.o mounts-$(CONFIG_BLK_DEV_RAM) += do_mounts_rd.o mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o
UTS_VERSION
smp-flag-$(CONFIG_SMP) := SMP preempt-flag-$(CONFIG_PREEMPT_BUILD) := PREEMPT preempt-flag-$(CONFIG_PREEMPT_DYNAMIC) := PREEMPT_DYNAMIC preempt-flag-$(CONFIG_PREEMPT_RT) := PREEMPT_RT
build-version = $(or $(KBUILD_BUILD_VERSION), $(build-version-auto)) build-timestamp = $(or $(KBUILD_BUILD_TIMESTAMP), $(build-timestamp-auto))
Maximum length of UTS_VERSION is 64 chars
filechk_uts_version =
utsver=$$(echo '$(pound)'"$(build-version)" $(smp-flag-y) $(preempt-flag-y) "$(build-timestamp)" | cut -b -64);
echo '$(pound)'define UTS_VERSION ""$${utsver}""
Build version.c with temporary UTS_VERSION
$(obj)/utsversion-tmp.h: FORCE $(call filechk,uts_version)
clean-files += utsversion-tmp.h
$(obj)/version.o: $(obj)/utsversion-tmp.h CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
Build version-timestamp.c with final UTS_VERSION
include/generated/utsversion.h: build-version-auto = $(shell $(srctree)/$(src)/build-version) include/generated/utsversion.h: build-timestamp-auto = $(shell LC_ALL=C date) include/generated/utsversion.h: FORCE $(call filechk,uts_version)
$(obj)/version-timestamp.o: include/generated/utsversion.h CFLAGS_version-timestamp.o := -include include/generated/utsversion.h KASAN_SANITIZE_version-timestamp.o := n