From patchwork Fri Feb 14 17:21:32 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: 208188 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 0900DC2BA83 for ; Fri, 14 Feb 2020 18:05:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF7E120848 for ; Fri, 14 Feb 2020 18:05:13 +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="VwgtKhOr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391537AbgBNSFM (ORCPT ); Fri, 14 Feb 2020 13:05:12 -0500 Received: from gateway31.websitewelcome.com ([192.185.143.40]:34048 "EHLO gateway31.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388160AbgBNSFL (ORCPT ); Fri, 14 Feb 2020 13:05:11 -0500 X-Greylist: delayed 1502 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Feb 2020 13:05:10 EST Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway31.websitewelcome.com (Postfix) with ESMTP id 323D0B096BA for ; Fri, 14 Feb 2020 11:18:56 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 2ecCjnKmsRP4z2ecCjEawi; Fri, 14 Feb 2020 11:18:56 -0600 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=DwN0tYLKM1RUE+OhsFgDl42NF0xbevkKouk6StKQIoA=; b=VwgtKhOrt6SRVJsSNhvt9/B1du IE+tq+o28zw53WJfJDjyVUW433o7aCjpfOOH/vKQudVYLGhbO/KGOa/fAkmDoGBigzC7hcpfXVzwr wRpD/Rkg6U54x4GxK5QFFV+GnkwWYpNHY3m7yJco/gMbtzuk1wVzNx2RADn5lo73uyVuf9rlTei/A rvAITyy9oQftWRXCiaiqga7E/2SfjWZ9sAl/Gw8PzOn3njQYIxas3moOzQOMPhAYm4gk4FpDLaeWm KjFHoSo6Alta92+erukFnQ3S05vczLZDDdbYa9S0aFSsb+ecuYquIfGf8OtIDExTrFa3IJpcJNhdI 4GK7cfSg==; Received: from [200.68.140.137] (port=27873 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j2ecA-003i82-Kw; Fri, 14 Feb 2020 11:18:54 -0600 Date: Fri, 14 Feb 2020 11:21:32 -0600 From: "Gustavo A. R. Silva" To: Dmitry Torokhov Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] Input: cyapa - replace zero-length array with flexible-array member Message-ID: <20200214172132.GA28389@embeddedor> 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: 200.68.140.137 X-Source-L: No X-Exim-ID: 1j2ecA-003i82-Kw X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.140.137]:27873 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 31 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/input/mouse/cyapa_gen5.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/input/mouse/cyapa_gen5.c b/drivers/input/mouse/cyapa_gen5.c index 14239fbd72cf..7f012bfa2658 100644 --- a/drivers/input/mouse/cyapa_gen5.c +++ b/drivers/input/mouse/cyapa_gen5.c @@ -250,7 +250,7 @@ struct cyapa_tsg_bin_image_data_record { struct cyapa_tsg_bin_image { struct cyapa_tsg_bin_image_head image_head; - struct cyapa_tsg_bin_image_data_record records[0]; + struct cyapa_tsg_bin_image_data_record records[]; } __packed; struct pip_bl_packet_start { @@ -271,7 +271,7 @@ struct pip_bl_cmd_head { u8 report_id; /* Bootloader output report id, must be 40h */ u8 rsvd; /* Reserved, must be 0 */ struct pip_bl_packet_start packet_start; - u8 data[0]; /* Command data variable based on commands */ + u8 data[]; /* Command data variable based on commands */ } __packed; /* Initiate bootload command data structure. */ @@ -300,7 +300,7 @@ struct tsg_bl_metadata_row_params { struct tsg_bl_flash_row_head { u8 flash_array_id; __le16 flash_row_id; - u8 flash_data[0]; + u8 flash_data[]; } __packed; struct pip_app_cmd_head { @@ -314,7 +314,7 @@ struct pip_app_cmd_head { * Bit 6-0: command code. */ u8 cmd_code; - u8 parameter_data[0]; /* Parameter data variable based on cmd_code */ + u8 parameter_data[]; /* Parameter data variable based on cmd_code */ } __packed; /* Application get/set parameter command data structure */