The patch titled
Subject: kasan: introduce CONFIG_KASAN_HW_TAGS
has been added to the -mm tree. Its filename is
kasan-introduce-config_kasan_hw_tags.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-introduce-config_kasan_hw_tags.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-introduce-config_kasan_hw_tags.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: introduce CONFIG_KASAN_HW_TAGS
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/55d90be0a5815917f0e1bd468ea0a257f72e7e46.1605046192.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/Kconfig.kasan | 58 +++++++++++++++++++++++++++++++-------------
1 file changed, 41 insertions(+), 17 deletions(-)
--- a/lib/Kconfig.kasan~kasan-introduce-config_kasan_hw_tags
+++ a/lib/Kconfig.kasan
@@ -6,7 +6,10 @@ config HAVE_ARCH_KASAN
config HAVE_ARCH_KASAN_SW_TAGS
bool
-config HAVE_ARCH_KASAN_VMALLOC
+config HAVE_ARCH_KASAN_HW_TAGS
+ bool
+
+config HAVE_ARCH_KASAN_VMALLOC
bool
config CC_HAS_KASAN_GENERIC
@@ -20,11 +23,11 @@ config CC_HAS_WORKING_NOSANITIZE_ADDRESS
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 +40,24 @@ 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).
+
+ All KASAN modes are strictly debugging features.
- Both generic and tag-based KASAN 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 +70,6 @@ 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 +77,15 @@ 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 +93,27 @@ 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 +137,7 @@ 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
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-drop-unnecessary-gpl-text-from-comment-headers.patch
kasan-kasan_vmalloc-depends-on-kasan_generic.patch
kasan-group-vmalloc-code.patch
s390-kasan-include-asm-pageh-from-asm-kasanh.patch
kasan-shadow-declarations-only-for-software-modes.patch
kasan-rename-unpoison_shadow-to-unpoison_memory.patch
kasan-rename-kasan_shadow_-to-kasan_granule_.patch
kasan-only-build-initc-for-software-modes.patch
kasan-split-out-shadowc-from-commonc.patch
kasan-define-kasan_granule_page.patch
kasan-rename-report-and-tags-files.patch
kasan-dont-duplicate-config-dependencies.patch
kasan-hide-invalid-free-check-implementation.patch
kasan-decode-stack-frame-only-with-kasan_stack_enable.patch
kasan-arm64-only-init-shadow-for-software-modes.patch
kasan-arm64-only-use-kasan_depth-for-software-modes.patch
kasan-arm64-move-initialization-message.patch
kasan-arm64-rename-kasan_init_tags-and-mark-as-__init.patch
kasan-rename-addr_has_shadow-to-addr_has_metadata.patch
kasan-rename-print_shadow_for_address-to-print_memory_metadata.patch
kasan-kasan_non_canonical_hook-only-for-software-modes.patch
kasan-rename-shadow-layout-macros-to-meta.patch
kasan-separate-metadata_fetch_row-for-each-mode.patch
kasan-arm64-dont-allow-sw_tags-with-arm64_mte.patch
kasan-introduce-config_kasan_hw_tags.patch
arm64-kasan-align-allocations-for-hw_tags.patch
arm64-kasan-add-arch-layer-for-memory-tagging-helpers.patch
kasan-define-kasan_granule_size-for-hw_tags.patch
kasan-x86-s390-update-undef-config_kasan.patch
kasan-arm64-expand-config_kasan-checks.patch
kasan-arm64-implement-hw_tags-runtime.patch
kasan-arm64-print-report-from-tag-fault-handler.patch
kasan-mm-reset-tags-when-accessing-metadata.patch
kasan-arm64-enable-config_kasan_hw_tags.patch
kasan-add-documentation-for-hardware-tag-based-mode.patch
