From patchwork Thu Mar 19 21:29:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 208050 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=-13.1 required=3.0 tests=DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 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 298F5C4332D for ; Thu, 19 Mar 2020 21:50:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDD9F2076F for ; Thu, 19 Mar 2020 21:50:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="JviXO3L7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbgCSVup (ORCPT ); Thu, 19 Mar 2020 17:50:45 -0400 Received: from gateway34.websitewelcome.com ([192.185.149.72]:25045 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726619AbgCSVup (ORCPT ); Thu, 19 Mar 2020 17:50:45 -0400 X-Greylist: delayed 1252 seconds by postgrey-1.27 at vger.kernel.org; Thu, 19 Mar 2020 17:50:44 EDT Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 8AB674018C for ; Thu, 19 Mar 2020 16:29:52 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id F2jgjY8kh8vkBF2jgjPAuP; Thu, 19 Mar 2020 16:29:52 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Type:MIME-Version:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=clKI7nARFTFO5GFD0Ih3lvAENgeNhLrB6NvEoRgvUuk=; b=JviXO3L7PfFv8CDg2Dp7utxg+D B18IncsSGyIoi0uznb7dFep0uW5P2LsgTsPKW6GX64Fx42NbG7E3d2YI/MKU5txg0y+u3QRAmKKsv lJOe4o8TBduUkmHqKQYbNp9Mbq/jSLroljBO1P7DfdwjTPLIyDHWnnuVAPOLdzxtThxejHOJOcNGk PqKoO+8SfCkb8EYYB0yLqUPvDqrFjaPQVZdRMGx/+Ar2QDRpAzfuQRdBSi0ntYLQHS/KYY4wIukAF tP54Qi28yh4oiCLaB6nGi/Cpkjyl8vJUpQt9PidZZeYZHtW/4VoxMqRujdiGv/wpGdo5j1em+rk2g G+QDSBcg==; Received: from cablelink-189-218-116-241.hosts.intercable.net ([189.218.116.241]:53318 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jF2je-001cPg-UB; Thu, 19 Mar 2020 16:29:51 -0500 Date: Thu, 19 Mar 2020 16:29:50 -0500 From: "Gustavo A. R. Silva" To: Srinivas Pandruvada , Jiri Kosina , Benjamin Tissoires Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] intel-ish-hid: ishtp: hbm.h: Replace zero-length array with flexible-array member Message-ID: <20200319212950.GA9155@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.218.116.241 X-Source-L: No X-Exim-ID: 1jF2je-001cPg-UB X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:53318 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 19 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- drivers/hid/intel-ish-hid/ishtp/hbm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/intel-ish-hid/ishtp/hbm.h b/drivers/hid/intel-ish-hid/ishtp/hbm.h index bb85985b1620..7c445b203f2a 100644 --- a/drivers/hid/intel-ish-hid/ishtp/hbm.h +++ b/drivers/hid/intel-ish-hid/ishtp/hbm.h @@ -82,7 +82,7 @@ struct ishtp_msg_hdr { struct ishtp_bus_message { uint8_t hbm_cmd; - uint8_t data[0]; + uint8_t data[]; } __packed; /**