Re: [PATCH 2/2] kasan: Fix a type conversion error

[Vladimir Murzin <vladimir.murzin@arm.com>]

On 09/09/15 04:59, Wang Long wrote:
> The current KASAN code can find the following out-of-bounds

Should it be "cannot"?

Vladimir

> bugs:
> 	char *ptr;
> 	ptr = kmalloc(8, GFP_KERNEL);
> 	memset(ptr+7, 0, 2);
> 
> the cause of the problem is the type conversion error in
> *memory_is_poisoned_n* function. So this patch fix that.
> 
> Signed-off-by: Wang Long <long.wanglong@huawei.com>
> ---
>  mm/kasan/kasan.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
> index 7b28e9c..5d65d06 100644
> --- a/mm/kasan/kasan.c
> +++ b/mm/kasan/kasan.c
> @@ -204,7 +204,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr,
>  		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
>  
>  		if (unlikely(ret != (unsigned long)last_shadow ||
> -			((last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
> +			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
>  			return true;
>  	}
>  	return false;
> 

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