Re: [RFC PATCH 09/14] khwasan: add hooks implementation

[Anthony Yznaga <anthony.yznaga@oracle.com>]

Hi Andrey,

On 3/2/18 11:44 AM, Andrey Konovalov wrote:
> void kasan_poison_kfree(void *ptr, unsigned long ip)
>  {
> +	struct page *page;
> +
> +	page = virt_to_head_page(ptr)

An untagged addr should be passed to virt_to_head_page(), no?

> +
> +	if (unlikely(!PageSlab(page))) {
> +		if (reset_tag(ptr) != page_address(page)) {
> +			/* Report invalid-free here */
> +			return;
> +		}
> +		kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
> +					khwasan_random_tag());
> +	} else {
> +		__kasan_slab_free(page->slab_cache, ptr, ip);
> +	}
>  }
>  
>  void kasan_kfree_large(void *ptr, unsigned long ip)
>  {
> +	struct page *page = virt_to_page(ptr);
> +	struct page *head_page = virt_to_head_page(ptr);

Same as above and for virt_to_page() as well.

Anthony


> +
> +	if (reset_tag(ptr) != page_address(head_page)) {
> +		/* Report invalid-free here */
> +		return;
> +	}
> +
> +	kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
> +			khwasan_random_tag());
>  }