Re: [PATCH v4 3/3] kasan: add memory corruption identification support for hardware tag-based mode
From: Marco Elver <elver@google.com>
Date: 2021-06-28 06:01:28
Also in:
linux-mediatek, linux-mm, lkml
On Sat, 26 Jun 2021 at 12:09, Kuan-Ying Lee [off-list ref] wrote:
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. Signed-off-by: Kuan-Ying Lee <redacted> Suggested-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Marco Elver <elver@google.com>
quoted hunk ↗ jump to hunk
--- lib/Kconfig.kasan | 2 +- mm/kasan/kasan.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index fdb4a08dba83..1e2d10f86011 100644 --- a/lib/Kconfig.kasan +++ b/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 increaseddiff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 952df2db7fdd..f58672f6029a 100644 --- a/mm/kasan/kasan.h +++ b/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 --2.18.0
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