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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A47DC77B7A for ; Thu, 18 May 2023 19:58:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229493AbjERT65 convert rfc822-to-8bit (ORCPT ); Thu, 18 May 2023 15:58:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbjERT64 (ORCPT ); Thu, 18 May 2023 15:58:56 -0400 Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEE41E45; Thu, 18 May 2023 12:58:54 -0700 (PDT) Received: from omf10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 5B407A0989; Thu, 18 May 2023 19:58:53 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: joe@perches.com) by omf10.hostedemail.com (Postfix) with ESMTPA id F2FA032; Thu, 18 May 2023 19:58:50 +0000 (UTC) Message-ID: Subject: Re: [PATCH] checkpatch: Warn about 0-length and 1-element arrays From: Joe Perches To: Kees Cook , Andy Whitcroft Cc: Dwaipayan Ray , Lukas Bulwahn , "Gustavo A . R . Silva" , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Date: Thu, 18 May 2023 12:58:49 -0700 In-Reply-To: <20230517204530.never.151-kees@kernel.org> References: <20230517204530.never.151-kees@kernel.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) MIME-Version: 1.0 X-Stat-Signature: puwyt1swyp41oowuiiowm11we38kzxpn X-Rspamd-Server: rspamout08 X-Rspamd-Queue-Id: F2FA032 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Session-ID: U2FsdGVkX1+QD/3IXieWNNZePhd0mmr+m+MoTjTlcfQ= X-HE-Tag: 1684439930-789484 X-HE-Meta: U2FsdGVkX1/R7LzBAcxWckEg3KFE0ItBSO2do6msyznA+8otsM8C2GluhqU4y0waxsgNs9ZBDx2mAZIK9Up33w== Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org * On Wed, 2023-05-17 at 13:45 -0700, Kees Cook wrote: > Fake flexible arrays have been deprecated since last millennium. Proper > C99 flexible arrays must be used throughout the kernel so > CONFIG_FORTIFY_SOURCE and CONFIG_UBSAN_BOUNDS can provide proper array > bounds checking. I don't think this does what you want. After adding this patch to checkpatch with this diff: No warning ----------------------- diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 4f4f79532c6cf..513cb102b3b38 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -73,6 +73,11 @@ static DEFINE_SPINLOCK(target_list_lock); */ static struct console netconsole_ext; +struct foobar { + int a; + int b[1]; +}; + /** * struct netconsole_target - Represents a configured netconsole target. * @list: Links this target into the target_list. ----------------------- because $context_function is DEFINE_SPINLOCK I think you want something like: --- scripts/checkpatch.pl | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b30114d637c40..778a0808c37cf 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -7418,6 +7418,18 @@ sub process { } } + # check for array definition/declarations that should use flexible arrays instead + if ($sline =~ /^[\+ ]\s*}\s*;\s*$/ && + $prevline =~ /^\+\s*$Type\s*$Ident\s*\[\s*(0|1)\s*\]\s*;\s*$/) { + if ($1 =~ '0') { + WARN("ZERO_LENGTH_ARRAY", + "Prefer C99 flexible arrays instead of zero-length arrays - see https://github.com/KSPP/linux/issues/78\n" . $hereprev); + } else { + WARN("ONE_ELEMENT_ARRAY", + "Prefer C99 flexible arrays instead of one-element arrays - see https://github.com/KSPP/linux/issues/79\n" . $hereprev); + } + } + # nested likely/unlikely calls if ($line =~ /\b(?:(?:un)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) { WARN("LIKELY_MISUSE",