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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 6580AC433DF for ; Wed, 26 Aug 2020 23:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F519207CD for ; Wed, 26 Aug 2020 23:57:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726803AbgHZX5v (ORCPT ); Wed, 26 Aug 2020 19:57:51 -0400 Received: from smtprelay0132.hostedemail.com ([216.40.44.132]:48980 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726238AbgHZX5u (ORCPT ); Wed, 26 Aug 2020 19:57:50 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id 132A318000BE0; Wed, 26 Aug 2020 23:57:45 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: ocean54_1a016df27068 X-Filterd-Recvd-Size: 3604 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf15.hostedemail.com (Postfix) with ESMTPA; Wed, 26 Aug 2020 23:57:42 +0000 (UTC) Message-ID: <77428f28620d4e5ecad1556396f2b0f8f0daef41.camel@perches.com> Subject: Re: [PATCH v3] lib/string.c: implement stpcpy From: Joe Perches To: Kees Cook , Masahiro Yamada Cc: Nick Desaulniers , clang-built-linux , stable , Andy Lavr , Arvind Sankar , Rasmus Villemoes , Sami Tolvanen , Andrew Morton , Andy Shevchenko , Alexandru Ardelean , Yury Norov , Linux Kernel Mailing List Date: Wed, 26 Aug 2020 16:57:41 -0700 In-Reply-To: <202008261627.7B2B02A@keescook> References: <20200825135838.2938771-1-ndesaulniers@google.com> <202008261627.7B2B02A@keescook> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2020-08-26 at 16:38 -0700, Kees Cook wrote: > On Thu, Aug 27, 2020 at 07:59:45AM +0900, Masahiro Yamada wrote: [] > > OK, then stpcpy(), strcpy() and sprintf() > > have the same level of unsafety. > > Yes. And even snprintf() is dangerous because its return value is how > much it WOULD have written, which when (commonly) used as an offset for > further pointer writes, causes OOB writes too. :( > https://github.com/KSPP/linux/issues/105 > > > strcpy() is used everywhere. > > Yes. It's very frustrating, but it's not an excuse to continue > using it nor introducing more bad APIs. > > $ git grep '\bstrcpy\b' | wc -l > 2212 > $ git grep '\bstrncpy\b' | wc -l > 751 > $ git grep '\bstrlcpy\b' | wc -l > 1712 > > $ git grep '\bstrscpy\b' | wc -l > 1066 > > https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy > https://github.com/KSPP/linux/issues/88 > > https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings > https://github.com/KSPP/linux/issues/89 > > https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > https://github.com/KSPP/linux/issues/90 > > We have no way right now to block the addition of deprecated API usage, > which makes ever catching up on this replacement very challenging. These could be added to checkpatch's deprecated_api test. --- scripts/checkpatch.pl | 3 +++ 1 file changed, 3 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 149518d2a6a7..f9ccb2a63a95 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -605,6 +605,9 @@ foreach my $entry (@mode_permission_funcs) { $mode_perms_search = "(?:${mode_perms_search})"; our %deprecated_apis = ( + "strcpy" => "strscpy", + "strncpy" => "strscpy", + "strlcpy" => "strscpy", "synchronize_rcu_bh" => "synchronize_rcu", "synchronize_rcu_bh_expedited" => "synchronize_rcu_expedited", "call_rcu_bh" => "call_rcu",