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kasan: introduce CONFIG_KASAN_HW_TAGS

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This patch adds a configuration option for a new KASAN mode called
hardware tag-based KASAN.  This mode uses the memory tagging approach like
the software tag-based mode, but relies on arm64 Memory Tagging Extension
feature for tag management and access checking.

Link: https://lkml.kernel.org/r/44906a209d3a44f9c6f5a21841e90988e365601e.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2020-12-22 12:01:20 -08:00 committed by Linus Torvalds
parent 96e0279df6
commit 6a63a63ff1
1 changed files with 44 additions and 17 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

59
lib/Kconfig.kasan
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@ -6,6 +6,9 @@ config HAVE_ARCH_KASAN
config HAVE_ARCH_KASAN_SW_TAGS
bool
config HAVE_ARCH_KASAN_HW_TAGS
bool
config HAVE_ARCH_KASAN_VMALLOC
bool
@ -15,16 +18,19 @@ config CC_HAS_KASAN_GENERIC
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)
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)
depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS
select CONSTRUCTORS
select STACKDEPOT
help
Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
@ -37,18 +43,24 @@ 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).
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).
Both generic and tag-based KASAN are strictly debugging features.
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.
@ -61,8 +73,6 @@ config KASAN_GENERIC
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).
@ -70,11 +80,15 @@ 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 requires Top Byte Ignore support by the CPU and therefore
is only supported for arm64. This mode requires Clang.
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.
@ -82,15 +96,27 @@ config KASAN_SW_TAGS
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).
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
@ -114,6 +140,7 @@ endchoice
config KASAN_STACK_ENABLE
bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
depends on KASAN_GENERIC || KASAN_SW_TAGS
help
The LLVM stack address sanitizer has a know problem that
causes excessive stack usage in a lot of functions, see