From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B6B8C04AB1 for ; Mon, 13 May 2019 03:40:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D771F20882 for ; Mon, 13 May 2019 03:40:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727504AbfEMDkG (ORCPT ); Sun, 12 May 2019 23:40:06 -0400 Received: from mail.windriver.com ([147.11.1.11]:41009 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727202AbfEMDkG (ORCPT ); Sun, 12 May 2019 23:40:06 -0400 Received: from ALA-HCA.corp.ad.wrs.com ([147.11.189.40]) by mail.windriver.com (8.15.2/8.15.1) with ESMTPS id x4D3doEo017640 (version=TLSv1 cipher=AES128-SHA bits=128 verify=FAIL); Sun, 12 May 2019 20:39:51 -0700 (PDT) Received: from [128.224.162.183] (128.224.162.183) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.3.439.0; Sun, 12 May 2019 20:39:50 -0700 Subject: Re: [PATCH] kdb: Fix bound check compiler warning To: Daniel Thompson CC: , , , References: <1557280359-202637-1-git-send-email-wenlin.kang@windriver.com> <20190508081640.tvtnazr4tf5jijh7@holly.lan> <20190512090003.de52davu55rrg7kn@wychelm.lan> From: Wenlin Kang Message-ID: <0c5121f7-645c-3651-cccc-2ae836d415b6@windriver.com> Date: Mon, 13 May 2019 11:39:47 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190512090003.de52davu55rrg7kn@wychelm.lan> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [128.224.162.183] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/12/19 5:00 PM, Daniel Thompson wrote: > On Thu, May 09, 2019 at 10:56:03AM +0800, Wenlin Kang wrote: >> On 5/8/19 4:16 PM, Daniel Thompson wrote: >>> On Wed, May 08, 2019 at 09:52:39AM +0800, Wenlin Kang wrote: >>>> The strncpy() function may leave the destination string buffer >>>> unterminated, better use strlcpy() instead. >>>> >>>> This fixes the following warning with gcc 8.2: >>>> >>>> kernel/debug/kdb/kdb_io.c: In function 'kdb_getstr': >>>> kernel/debug/kdb/kdb_io.c:449:3: warning: 'strncpy' specified bound 256 equals destination size [-Wstringop-truncation] >>>> strncpy(kdb_prompt_str, prompt, CMD_BUFLEN); >>>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> >>>> Signed-off-by: Wenlin Kang >>>> --- >>>> kernel/debug/kdb/kdb_io.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c >>>> index 6a4b414..7fd4513 100644 >>>> --- a/kernel/debug/kdb/kdb_io.c >>>> +++ b/kernel/debug/kdb/kdb_io.c >>>> @@ -446,7 +446,7 @@ static char *kdb_read(char *buffer, size_t bufsize) >>>> char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt) >>>> { >>>> if (prompt && kdb_prompt_str != prompt) >>>> - strncpy(kdb_prompt_str, prompt, CMD_BUFLEN); >>>> + strlcpy(kdb_prompt_str, prompt, CMD_BUFLEN); >>> Shouldn't that be strscpy? >> >> Hi Daniel >> >> I thought about strscpy, but I think strlcpy is better, because it only copy >> the real number of characters if src string less than that size. > Sorry, I'm confused by this. What behavior does strscpy() have that you > consider undesirable in this case? Hi Daniel I checked strscpy() again, and think either is fine to me, if you think strscpy() is better, I can change it to this, and send v2, thanks for your review. > > Daniel. > -- Thanks, Wenlin Kang