2021-06-23 13:37:02

by Yee Lee (李建誼)

Subject: [PATCH v2 1/1] kasan: Add memzero init for unaligned size under SLUB debug

From: Yee Lee <[email protected]>

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 <[email protected]>
Suggested-by: Marco Elver <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrew Morton <[email protected]>
---
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);
}
--
2.18.0

2021-06-23 13:54:46

by Yee Lee (李建誼)

Subject: Re: [PATCH v2 1/1] kasan: Add memzero init for unaligned size under SLUB debug

Sorry not a completed patch.
Please skip this mail.

BR,
Yee

On Wed, 2021-06-23 at 21:35 +0800, [email protected] wrote:
> From: Yee Lee <[email protected]>
>
> 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 <[email protected]>
> Suggested-by: Marco Elver <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Alexander Potapenko <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Andrew Morton <[email protected]>
> ---
> 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);
> }