From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754664AbbIIJCT (ORCPT ); Wed, 9 Sep 2015 05:02:19 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]:6434 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754290AbbIIJCI convert rfc822-to-8bit (ORCPT ); Wed, 9 Sep 2015 05:02:08 -0400 Message-ID: <55EFF585.80603@arm.com> Date: Wed, 09 Sep 2015 10:01:57 +0100 From: Vladimir Murzin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Wang Long , "ryabinin.a.a@gmail.com" , "adech.fo@gmail.com" CC: "akpm@linux-foundation.org" , "rusty@rustcorp.com.au" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "wanglong@laoqinren.net" , "peifeiyue@huawei.com" , "morgan.wang@huawei.com" Subject: Re: [PATCH 2/2] kasan: Fix a type conversion error References: <1441771180-206648-1-git-send-email-long.wanglong@huawei.com> <1441771180-206648-3-git-send-email-long.wanglong@huawei.com> In-Reply-To: <1441771180-206648-3-git-send-email-long.wanglong@huawei.com> X-OriginalArrivalTime: 09 Sep 2015 09:02:02.0839 (UTC) FILETIME=[31882670:01D0EADE] X-MC-Unique: -nxQDqXxQQueOLkw3Exs3A-1 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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; >