190 строки
6.3 KiB
Plaintext
190 строки
6.3 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_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)
|
|
|
|
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)
|
|
depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
|
|
depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS
|
|
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 two modes: generic KASAN (similar to userspace ASan,
|
|
x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
|
|
software tag-based KASAN (a version based on software memory
|
|
tagging, arm64 only, similar to userspace HWASan, enabled with
|
|
CONFIG_KASAN_SW_TAGS).
|
|
|
|
Both generic and tag-based KASAN are strictly debugging features.
|
|
|
|
config KASAN_GENERIC
|
|
bool "Generic mode"
|
|
depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
|
|
depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
|
|
select SLUB_DEBUG if SLUB
|
|
select CONSTRUCTORS
|
|
select STACKDEPOT
|
|
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.
|
|
|
|
For better error detection enable CONFIG_STACKTRACE.
|
|
|
|
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
|
|
depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
|
|
select SLUB_DEBUG if SLUB
|
|
select CONSTRUCTORS
|
|
select STACKDEPOT
|
|
help
|
|
Enables software tag-based KASAN mode.
|
|
|
|
This mode requires Top Byte Ignore support by the CPU and therefore
|
|
is only supported for arm64. 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.
|
|
|
|
For better error detection enable CONFIG_STACKTRACE.
|
|
|
|
Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
|
|
(the resulting kernel does not boot).
|
|
|
|
endchoice
|
|
|
|
choice
|
|
prompt "Instrumentation type"
|
|
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_ENABLE
|
|
bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
|
|
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_STACK
|
|
int
|
|
default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
|
|
default 0
|
|
|
|
config KASAN_S390_4_LEVEL_PAGING
|
|
bool "KASan: use 4-level paging"
|
|
depends on S390
|
|
help
|
|
Compiling the kernel with KASan disables automatic 3-level vs
|
|
4-level paging selection. 3-level paging is used by default (up
|
|
to 3TB of RAM with KASan enabled). This options allows to force
|
|
4-level paging instead.
|
|
|
|
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 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 TEST_KASAN_MODULE
|
|
tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
|
|
depends on m && KASAN
|
|
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
|