From: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> Subject: kasan: add memory corruption identification support for hardware tag-based mode Add memory corruption identification support for hardware tag-based mode. We store one old free pointer tag and free backtrace instead of five because hardware tag-based kasan only has 16 different tags. If we store as many stacks as SW tag-based kasan does(5 stacks), there is high probability to find the same tag in the stacks when out-of-bound issues happened and we will mistake out-of-bound issue for use-after-free. Link: https://lkml.kernel.org/r/20210626100931.22794-4-Kuan-Ying.Lee@xxxxxxxxxxxx Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> Suggested-by: Marco Elver <elver@xxxxxxxxxx> Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Chinwen Chang <chinwen.chang@xxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx> Cc: Nicholas Tang <nicholas.tang@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/Kconfig.kasan | 2 +- mm/kasan/kasan.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/lib/Kconfig.kasan~kasan-add-memory-corruption-identification-support-for-hardware-tag-based-mode +++ a/lib/Kconfig.kasan @@ -169,7 +169,7 @@ config KASAN_STACK config KASAN_TAGS_IDENTIFY bool "Enable memory corruption identification" - depends on KASAN_SW_TAGS + depends on KASAN_SW_TAGS || KASAN_HW_TAGS help This option enables best-effort identification of bug type (use-after-free or out-of-bounds) at the cost of increased --- a/mm/kasan/kasan.h~kasan-add-memory-corruption-identification-support-for-hardware-tag-based-mode +++ a/mm/kasan/kasan.h @@ -153,7 +153,7 @@ struct kasan_track { depot_stack_handle_t stack; }; -#ifdef CONFIG_KASAN_TAGS_IDENTIFY +#if defined(CONFIG_KASAN_TAGS_IDENTIFY) && defined(CONFIG_KASAN_SW_TAGS) #define KASAN_NR_FREE_STACKS 5 #else #define KASAN_NR_FREE_STACKS 1 _
