From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f178.google.com (mail-ob0-f178.google.com [209.85.214.178]) by kanga.kvack.org (Postfix) with ESMTP id 406986B0038 for ; Mon, 7 Sep 2015 21:47:04 -0400 (EDT) Received: by obqa2 with SMTP id a2so72002517obq.3 for ; Mon, 07 Sep 2015 18:47:04 -0700 (PDT) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com. [119.145.14.66]) by mx.google.com with ESMTPS id y3si1067157oie.0.2015.09.07.18.47.02 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 07 Sep 2015 18:47:03 -0700 (PDT) Message-ID: <55EE3D03.8000502@huawei.com> Date: Tue, 8 Sep 2015 09:42:27 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: [PATCH] kasan: fix last shadow judgement in memory_is_poisoned_16() Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Andrey Ryabinin , adech.fo@gmail.com, rusty@rustcorp.com.au, mmarek@suse.cz Cc: Linux MM , LKML , zhongjiang@huawei.com The shadow which correspond 16 bytes may span 2 or 3 bytes. If shadow only take 2 bytes, we can return in "if (likely(!last_byte)) ...", but it calculates wrong, so fix it. Signed-off-by: Xishi Qiu --- mm/kasan/kasan.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 7b28e9c..8da2114 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -135,12 +135,11 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) if (unlikely(*shadow_addr)) { u16 shadow_first_bytes = *(u16 *)shadow_addr; - s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK; if (unlikely(shadow_first_bytes)) return true; - if (likely(!last_byte)) + if (likely(IS_ALIGNED(addr, 8))) return false; return memory_is_poisoned_1(addr + 15); -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752403AbbIHBmr (ORCPT ); Mon, 7 Sep 2015 21:42:47 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:53563 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751197AbbIHBmp (ORCPT ); Mon, 7 Sep 2015 21:42:45 -0400 Message-ID: <55EE3D03.8000502@huawei.com> Date: Tue, 8 Sep 2015 09:42:27 +0800 From: Xishi Qiu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Andrew Morton , Andrey Ryabinin , , , CC: Linux MM , LKML , Subject: [PATCH] kasan: fix last shadow judgement in memory_is_poisoned_16() Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.25.179] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090201.55EE3D12.000B,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 792afbc3fe2f1342020ea9cb31f4381c Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The shadow which correspond 16 bytes may span 2 or 3 bytes. If shadow only take 2 bytes, we can return in "if (likely(!last_byte)) ...", but it calculates wrong, so fix it. Signed-off-by: Xishi Qiu --- mm/kasan/kasan.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 7b28e9c..8da2114 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -135,12 +135,11 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) if (unlikely(*shadow_addr)) { u16 shadow_first_bytes = *(u16 *)shadow_addr; - s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK; if (unlikely(shadow_first_bytes)) return true; - if (likely(!last_byte)) + if (likely(IS_ALIGNED(addr, 8))) return false; return memory_is_poisoned_1(addr + 15); -- 1.7.1