Sorry not a completed patch.
Please skip this mail.
BR,
Yee
On Wed, 2021-06-23 at 21:35 +0800, yee.lee@xxxxxxxxxxxx wrote:
> From: Yee Lee <yee.lee@xxxxxxxxxxxx>
>
> Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite
> the redzone with unaligned object size.
>
> An additional memzero_explicit() path is added to replacing hwtag
> initialization
> at SLUB deubg mode.
>
> Signed-off-by: Yee Lee <yee.lee@xxxxxxxxxxxx>
> Suggested-by: Marco Elver <elver@xxxxxxxxxx>
> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
> Cc: Alexander Potapenko <glider@xxxxxxxxxx>
> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
> mm/kasan/kasan.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index d8faa64614b7..e984a9ac814d 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -387,10 +387,12 @@ static inline void kasan_unpoison(const void
> *addr, size_t size, bool init)
>
> if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
> return;
> + #if IS_ENABLED(CONFIG_SLUB_DEBUG)
> if (init && ((unsigned long)size & KASAN_GRANULE_MASK)) {
> init = false;
> - memset((void *)addr, 0, size);
> + memzero_explicit((void *)addr, size);
> }
> + #endif
> size = round_up(size, KASAN_GRANULE_SIZE);
> hw_set_mem_tag_range((void *)addr, size, tag, init);
> }
