Re: [PATCH V2] kasan: fix last shadow judgement in memory_is_poisoned_16()

Andrey Ryabinin
2015-09-09T10:02:01Z

On 09/08/2015 03:12 PM, Xishi Qiu wrote:
> The shadow which correspond 16 bytes memory may span 2 or 3 bytes. If the
> memory is aligned on 8, then the shadow takes only 2 bytes. So we check
> "shadow_first_bytes" is enough, and need not to call "memory_is_poisoned_1(addr + 15);".
> But the code "if (likely(!last_byte))" is wrong judgement.
>
> e.g. addr=0, so last_byte = 15 & KASAN_SHADOW_MASK = 7, then the code will
> continue to call "memory_is_poisoned_1(addr + 15);"
>
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>

Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>