linux/scripts/Makefile.kasan
Paul Lawrence 342061ee4e kasan: support alloca() poisoning
clang's AddressSanitizer implementation adds redzones on either side of
alloca()ed buffers.  These redzones are 32-byte aligned and at least 32
bytes long.

__asan_alloca_poison() is passed the size and address of the allocated
buffer, *excluding* the redzones on either side.  The left redzone will
always be to the immediate left of this buffer; but AddressSanitizer may
need to add padding between the end of the buffer and the right redzone.
If there are any 8-byte chunks inside this padding, we should poison
those too.

__asan_allocas_unpoison() is just passed the top and bottom of the dynamic
stack area, so unpoisoning is simpler.

Link: http://lkml.kernel.org/r/20171204191735.132544-4-paullawrence@google.com
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:42 -08:00

46 lines
1.4 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
ifdef CONFIG_KASAN
ifdef CONFIG_KASAN_INLINE
call_threshold := 10000
else
call_threshold := 0
endif
KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
ifneq ($(CONFIG_COMPILE_TEST),y)
$(warning Cannot use CONFIG_KASAN: \
-fsanitize=kernel-address is not supported by compiler)
endif
else
# -fasan-shadow-offset fails without -fsanitize
CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
$(call cc-option, -fsanitize=kernel-address \
-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
else
# Now add all the compiler specific options that are valid standalone
CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
$(call cc-param,asan-globals=1) \
$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
$(call cc-param,asan-stack=1) \
$(call cc-param,asan-use-after-scope=1) \
$(call cc-param,asan-instrument-allocas=1)
endif
endif
CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope)
CFLAGS_KASAN_NOSANITIZE := -fno-builtin
endif