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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
63 lines
1.8 KiB
Makefile
63 lines
1.8 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Makefile for the linux kernel.
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#
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ccflags-y := -fno-function-sections -fno-data-sections
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obj-y := main.o version.o mounts.o
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ifneq ($(CONFIG_BLK_DEV_INITRD),y)
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obj-y += noinitramfs.o
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else
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obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
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endif
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obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
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obj-y += init_task.o
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mounts-y := do_mounts.o
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mounts-$(CONFIG_BLK_DEV_RAM) += do_mounts_rd.o
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mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o
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#
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# UTS_VERSION
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#
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smp-flag-$(CONFIG_SMP) := SMP
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preempt-flag-$(CONFIG_PREEMPT_BUILD) := PREEMPT
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preempt-flag-$(CONFIG_PREEMPT_DYNAMIC) := PREEMPT_DYNAMIC
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preempt-flag-$(CONFIG_PREEMPT_RT) := PREEMPT_RT
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build-version = $(or $(KBUILD_BUILD_VERSION), $(build-version-auto))
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build-timestamp = $(or $(KBUILD_BUILD_TIMESTAMP), $(build-timestamp-auto))
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# Maximum length of UTS_VERSION is 64 chars
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filechk_uts_version = \
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utsver=$$(echo '$(pound)'"$(build-version)" $(smp-flag-y) $(preempt-flag-y) "$(build-timestamp)" | cut -b -64); \
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echo '$(pound)'define UTS_VERSION \""$${utsver}"\"
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#
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# Build version.c with temporary UTS_VERSION
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#
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$(obj)/utsversion-tmp.h: FORCE
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$(call filechk,uts_version)
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clean-files += utsversion-tmp.h
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$(obj)/version.o: $(obj)/utsversion-tmp.h
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CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
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#
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# Build version-timestamp.c with final UTS_VERSION
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#
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include/generated/utsversion.h: build-version-auto = $(shell $(srctree)/$(src)/build-version)
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include/generated/utsversion.h: build-timestamp-auto = $(shell LC_ALL=C date)
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include/generated/utsversion.h: FORCE
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$(call filechk,uts_version)
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$(obj)/version-timestamp.o: include/generated/utsversion.h
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CFLAGS_version-timestamp.o := -include include/generated/utsversion.h
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KASAN_SANITIZE_version-timestamp.o := n
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