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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 CFDB3C433FF for ; Tue, 30 Jul 2019 07:03:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB9A820679 for ; Tue, 30 Jul 2019 07:03:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729477AbfG3HDd (ORCPT ); Tue, 30 Jul 2019 03:03:33 -0400 Received: from smtprelay0043.hostedemail.com ([216.40.44.43]:35977 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728470AbfG3HDc (ORCPT ); Tue, 30 Jul 2019 03:03:32 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id 586E983777EE; Tue, 30 Jul 2019 07:03:31 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: anger88_1e83daf9ea507 X-Filterd-Recvd-Size: 2841 Received: from XPS-9350.home (cpe-23-242-196-136.socal.res.rr.com [23.242.196.136]) (Authenticated sender: joe@perches.com) by omf12.hostedemail.com (Postfix) with ESMTPA; Tue, 30 Jul 2019 07:03:29 +0000 (UTC) Message-ID: <80fbaf63ddbe66cbbf3391256402295af1a3336f.camel@perches.com> Subject: Re: [PATCH 01/12] rdmacg: Replace strncmp with str_has_prefix From: Joe Perches To: Chuhong Yuan , Kees Cook Cc: Tejun Heo , Li Zefan , Johannes Weiner , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Laura Abbott , Michael Ellerman , Steven Rostedt Date: Tue, 30 Jul 2019 00:03:28 -0700 In-Reply-To: References: <20190729151346.9280-1-hslester96@gmail.com> <201907292117.DA40CA7D@keescook> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5-0ubuntu0.18.10.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-07-30 at 14:39 +0800, Chuhong Yuan wrote: > Kees Cook 于2019年7月30日周二 下午12:26写道： > > On Mon, Jul 29, 2019 at 11:13:46PM +0800, Chuhong Yuan wrote: > > > strncmp(str, const, len) is error-prone. > > > We had better use newly introduced > > > str_has_prefix() instead of it. > > > > Wait, stop. :) After Laura called my attention to your conversion series, > > mpe pointed out that str_has_prefix() is almost redundant to strstarts() > > (from 2009), and the latter has many more users. Let's fix strstarts() > > match str_has_prefix()'s return behavior (all the existing callers are > > doing boolean tests, so the change in return value won't matter), and > > then we can continue with this replacement. (And add some documentation > > to Documenation/process/deprecated.rst along with a checkpatch.pl test > > maybe too?) > > > > Thanks for your advice! > Does that mean replacing strstarts()'s implementation with > str_has_prefix()'s and then use strstarts() to substitute > strncmp? > > I am not very clear about how to add the test into checkpatch.pl. > Should I write a check for this pattern or directly add strncmp into > deprecated_apis? After Nitin's patch gets applied: (which btw wasn't cc'd to lkml) (sorry about the bad link, something about it hits some spam filter) open wall . com/lists/kernel-hardening/2019/07/28/1 Add it to deprecated_string_apis And we've had this sort of discussion before: https://lore.kernel.org/patchwork/patch/1026598/ I believe I'm still in favor of global conversion of strstarts to str_has_prefix.