+ kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch added to -mm tree

+ kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch added to -mm tree

[akpm]

The patch titled
     Subject: kasan: add memzero init for unaligned size under SLUB debug
has been added to the -mm tree.  Its filename is
     kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Yee Lee <yee.lee@mediatek.com>
Subject: kasan: add memzero init for unaligned size under SLUB debug

Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite the
redzone of object with unaligned size.

An additional memzero_explicit() path is added to replacing init by hwtag
instruction for those unaligned size at SLUB debug mode.

Link: https://lkml.kernel.org/r/20210624112624.31215-2-yee.lee@mediatek.com
Signed-off-by: Yee Lee <yee.lee@mediatek.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kasan/kasan.h |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/mm/kasan/kasan.h~kasan-add-memzero-init-for-unaligned-size-under-slub-debug
+++ a/mm/kasan/kasan.h
@@ -387,6 +387,12 @@ static inline void kasan_unpoison(const
 
 	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;
+		memzero_explicit((void *)addr, size);
+	}
+#endif
 	size = round_up(size, KASAN_GRANULE_SIZE);
 
 	hw_set_mem_tag_range((void *)addr, size, tag, init);
_

Patches currently in -mm which might be from yee.lee@mediatek.com are

kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch

Re: + kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch added to -mm tree

[Yee Lee]

Hi Andrew, 

Thanks for your help to add this patch.
Unforunately, we need a little change on codes based on Andrey and
Marco's suggestion.

Please drop this one, and I will send a new version soon.
Appreaciated the work!

Best regards,

Yee

On Thu, 2021-06-24 at 13:54 -0700, akpm@linux-foundation.org wrote:
> The patch titled
>      Subject: kasan: add memzero init for unaligned size under SLUB
> debug
> has been added to the -mm tree.  Its filename is
>      kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
> 
> This patch should soon appear at
>     
> https://ozlabs.org/~akpm/mmots/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
> and later at
>     
> https://ozlabs.org/~akpm/mmotm/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
> 
> Before you just go and hit "reply", please:
>    a) Consider who else should be cc'ed
>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/process/submit-checklist.rst when
> testing your code ***
> 
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
> 
> ------------------------------------------------------
> From: Yee Lee <yee.lee@mediatek.com>
> Subject: kasan: add memzero init for unaligned size under SLUB debug
> 
> Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite
> the
> redzone of object with unaligned size.
> 
> An additional memzero_explicit() path is added to replacing init by
> hwtag
> instruction for those unaligned size at SLUB debug mode.
> 
> Link: 
> https://lkml.kernel.org/r/20210624112624.31215-2-yee.lee@mediatek.com
> Signed-off-by: Yee Lee <yee.lee@mediatek.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/kasan/kasan.h |    6 ++++++
>  1 file changed, 6 insertions(+)
> 
> --- a/mm/kasan/kasan.h~kasan-add-memzero-init-for-unaligned-size-
> under-slub-debug
> +++ a/mm/kasan/kasan.h
> @@ -387,6 +387,12 @@ static inline void kasan_unpoison(const
>  
>  	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;
> +		memzero_explicit((void *)addr, size);
> +	}
> +#endif
>  	size = round_up(size, KASAN_GRANULE_SIZE);
>  
>  	hw_set_mem_tag_range((void *)addr, size, tag, init);
> _
> 
> Patches currently in -mm which might be from yee.lee@mediatek.com are
> 
> kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
>