mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-11 13:04:03 +08:00
02c587733c
CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack
instrumentation, but we should only need one config, so that we remove
CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable. see [1].
When enable KASAN stack instrumentation, then for gcc we could do no
prompt and default value y, and for clang prompt and default value n.
This patch fixes the following compilation warning:
include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef]
[akpm@linux-foundation.org: fix merge snafu]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221 [1]
Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com
Fixes: d9b571c885 ("kasan: fix KASAN_STACK dependency for HW_TAGS")
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
200 lines
6.7 KiB
Plaintext
200 lines
6.7 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
|
|
# This config refers to the generic KASAN mode.
|
|
config HAVE_ARCH_KASAN
|
|
bool
|
|
|
|
config HAVE_ARCH_KASAN_SW_TAGS
|
|
bool
|
|
|
|
config HAVE_ARCH_KASAN_HW_TAGS
|
|
bool
|
|
|
|
config HAVE_ARCH_KASAN_VMALLOC
|
|
bool
|
|
|
|
config CC_HAS_KASAN_GENERIC
|
|
def_bool $(cc-option, -fsanitize=kernel-address)
|
|
|
|
config CC_HAS_KASAN_SW_TAGS
|
|
def_bool $(cc-option, -fsanitize=kernel-hwaddress)
|
|
|
|
# This option is only required for software KASAN modes.
|
|
# Old GCC versions don't have proper support for no_sanitize_address.
|
|
# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89124 for details.
|
|
config CC_HAS_WORKING_NOSANITIZE_ADDRESS
|
|
def_bool !CC_IS_GCC || GCC_VERSION >= 80300
|
|
|
|
menuconfig KASAN
|
|
bool "KASAN: runtime memory debugger"
|
|
depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
|
|
(HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \
|
|
CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \
|
|
HAVE_ARCH_KASAN_HW_TAGS
|
|
depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
|
|
select STACKDEPOT
|
|
help
|
|
Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
|
|
designed to find out-of-bounds accesses and use-after-free bugs.
|
|
See Documentation/dev-tools/kasan.rst for details.
|
|
|
|
if KASAN
|
|
|
|
choice
|
|
prompt "KASAN mode"
|
|
default KASAN_GENERIC
|
|
help
|
|
KASAN has three modes:
|
|
1. generic KASAN (similar to userspace ASan,
|
|
x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC),
|
|
2. software tag-based KASAN (arm64 only, based on software
|
|
memory tagging (similar to userspace HWASan), enabled with
|
|
CONFIG_KASAN_SW_TAGS), and
|
|
3. hardware tag-based KASAN (arm64 only, based on hardware
|
|
memory tagging, enabled with CONFIG_KASAN_HW_TAGS).
|
|
|
|
All KASAN modes are strictly debugging features.
|
|
|
|
For better error reports enable CONFIG_STACKTRACE.
|
|
|
|
config KASAN_GENERIC
|
|
bool "Generic mode"
|
|
depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
|
|
select SLUB_DEBUG if SLUB
|
|
select CONSTRUCTORS
|
|
help
|
|
Enables generic KASAN mode.
|
|
|
|
This mode is supported in both GCC and Clang. With GCC it requires
|
|
version 8.3.0 or later. Any supported Clang version is compatible,
|
|
but detection of out-of-bounds accesses for global variables is
|
|
supported only since Clang 11.
|
|
|
|
This mode consumes about 1/8th of available memory at kernel start
|
|
and introduces an overhead of ~x1.5 for the rest of the allocations.
|
|
The performance slowdown is ~x3.
|
|
|
|
Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
|
|
(the resulting kernel does not boot).
|
|
|
|
config KASAN_SW_TAGS
|
|
bool "Software tag-based mode"
|
|
depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
|
|
select SLUB_DEBUG if SLUB
|
|
select CONSTRUCTORS
|
|
help
|
|
Enables software tag-based KASAN mode.
|
|
|
|
This mode require software memory tagging support in the form of
|
|
HWASan-like compiler instrumentation.
|
|
|
|
Currently this mode is only implemented for arm64 CPUs and relies on
|
|
Top Byte Ignore. This mode requires Clang.
|
|
|
|
This mode consumes about 1/16th of available memory at kernel start
|
|
and introduces an overhead of ~20% for the rest of the allocations.
|
|
This mode may potentially introduce problems relating to pointer
|
|
casting and comparison, as it embeds tags into the top byte of each
|
|
pointer.
|
|
|
|
Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
|
|
(the resulting kernel does not boot).
|
|
|
|
config KASAN_HW_TAGS
|
|
bool "Hardware tag-based mode"
|
|
depends on HAVE_ARCH_KASAN_HW_TAGS
|
|
depends on SLUB
|
|
help
|
|
Enables hardware tag-based KASAN mode.
|
|
|
|
This mode requires hardware memory tagging support, and can be used
|
|
by any architecture that provides it.
|
|
|
|
Currently this mode is only implemented for arm64 CPUs starting from
|
|
ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore.
|
|
|
|
endchoice
|
|
|
|
choice
|
|
prompt "Instrumentation type"
|
|
depends on KASAN_GENERIC || KASAN_SW_TAGS
|
|
default KASAN_OUTLINE
|
|
|
|
config KASAN_OUTLINE
|
|
bool "Outline instrumentation"
|
|
help
|
|
Before every memory access compiler insert function call
|
|
__asan_load*/__asan_store*. These functions performs check
|
|
of shadow memory. This is slower than inline instrumentation,
|
|
however it doesn't bloat size of kernel's .text section so
|
|
much as inline does.
|
|
|
|
config KASAN_INLINE
|
|
bool "Inline instrumentation"
|
|
help
|
|
Compiler directly inserts code checking shadow memory before
|
|
memory accesses. This is faster than outline (in some workloads
|
|
it gives about x2 boost over outline instrumentation), but
|
|
make kernel's .text size much bigger.
|
|
|
|
endchoice
|
|
|
|
config KASAN_STACK
|
|
bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
|
|
depends on KASAN_GENERIC || KASAN_SW_TAGS
|
|
default y if CC_IS_GCC
|
|
help
|
|
The LLVM stack address sanitizer has a know problem that
|
|
causes excessive stack usage in a lot of functions, see
|
|
https://bugs.llvm.org/show_bug.cgi?id=38809
|
|
Disabling asan-stack makes it safe to run kernels build
|
|
with clang-8 with KASAN enabled, though it loses some of
|
|
the functionality.
|
|
This feature is always disabled when compile-testing with clang
|
|
to avoid cluttering the output in stack overflow warnings,
|
|
but clang users can still enable it for builds without
|
|
CONFIG_COMPILE_TEST. On gcc it is assumed to always be safe
|
|
to use and enabled by default.
|
|
|
|
config KASAN_SW_TAGS_IDENTIFY
|
|
bool "Enable memory corruption identification"
|
|
depends on KASAN_SW_TAGS
|
|
help
|
|
This option enables best-effort identification of bug type
|
|
(use-after-free or out-of-bounds) at the cost of increased
|
|
memory consumption.
|
|
|
|
config KASAN_VMALLOC
|
|
bool "Back mappings in vmalloc space with real shadow memory"
|
|
depends on KASAN_GENERIC && HAVE_ARCH_KASAN_VMALLOC
|
|
help
|
|
By default, the shadow region for vmalloc space is the read-only
|
|
zero page. This means that KASAN cannot detect errors involving
|
|
vmalloc space.
|
|
|
|
Enabling this option will hook in to vmap/vmalloc and back those
|
|
mappings with real shadow memory allocated on demand. This allows
|
|
for KASAN to detect more sorts of errors (and to support vmapped
|
|
stacks), but at the cost of higher memory usage.
|
|
|
|
config KASAN_KUNIT_TEST
|
|
tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS
|
|
depends on KASAN && KUNIT
|
|
default KUNIT_ALL_TESTS
|
|
help
|
|
This is a KUnit test suite doing various nasty things like
|
|
out of bounds and use after free accesses. It is useful for testing
|
|
kernel debugging features like KASAN.
|
|
|
|
For more information on KUnit and unit tests in general, please refer
|
|
to the KUnit documentation in Documentation/dev-tools/kunit.
|
|
|
|
config KASAN_MODULE_TEST
|
|
tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
|
|
depends on m && KASAN && !KASAN_HW_TAGS
|
|
help
|
|
This is a part of the KASAN test suite that is incompatible with
|
|
KUnit. Currently includes tests that do bad copy_from/to_user
|
|
accesses.
|
|
|
|
endif # KASAN
|