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=-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,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 4249AC35656 for ; Fri, 21 Feb 2020 15:21:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1151120679 for ; Fri, 21 Feb 2020 15:21:51 +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="HYvMQ3Yf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729081AbgBUPVu (ORCPT ); Fri, 21 Feb 2020 10:21:50 -0500 Received: from gateway23.websitewelcome.com ([192.185.50.108]:43558 "EHLO gateway23.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727161AbgBUPVt (ORCPT ); Fri, 21 Feb 2020 10:21:49 -0500 Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway23.websitewelcome.com (Postfix) with ESMTP id 383E9137BA for ; Fri, 21 Feb 2020 09:21:48 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 5A7gjQAxFRP4z5A7gjq16w; Fri, 21 Feb 2020 09:21:48 -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=mbhHTsBgIffHJnD7OUNCvU+hJ6hifOkFE9ZfyrbhK7c=; b=HYvMQ3Yfb1whcHJDfjqzPEwLEy KC+iRTimOeHW3Vps+7wMOwwyM/FxW1HAQ5rJj9T5BiZ4QoprE5t/oXk27d/bjFZM8KYohWQBX5O5V n7CDhSN2phieFPdb4070Yuy0ylRzxuPKGR2mDpfkDQkf6LXoeb6Kbu75LG4W1FYYS3wLpZNb4gOMs 6F2aN0Vdmg5hwVNIXwNDlllfUGKu7lFFCkhSHO/9Tz1QhRUmAFWmpVVUFG7X0qI5YgauNFhc2/wbQ qfUsNEzXak2oFbYFKC1hxhxTNDFE8+JGuSxKT0NJtsAn/jHV+icGo9z9ECkIyKPkKB3tOMbXZv/HE wCf8LNfQ==; Received: from [200.68.141.13] (port=15204 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j5A7e-003dbj-4k; Fri, 21 Feb 2020 09:21:46 -0600 Date: Fri, 21 Feb 2020 09:24:30 -0600 From: "Gustavo A. R. Silva" To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] efi/apple-properties: Replace zero-length array with flexible-array member Message-ID: <20200221152430.GA20788@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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: 200.68.141.13 X-Source-L: No X-Exim-ID: 1j5A7e-003dbj-4k X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.141.13]:15204 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 16 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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/firmware/efi/apple-properties.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/apple-properties.c b/drivers/firmware/efi/apple-properties.c index 5ccf39986a14..084942846f4d 100644 --- a/drivers/firmware/efi/apple-properties.c +++ b/drivers/firmware/efi/apple-properties.c @@ -31,7 +31,7 @@ __setup("dump_apple_properties", dump_properties_enable); struct dev_header { u32 len; u32 prop_count; - struct efi_dev_path path[0]; + struct efi_dev_path path[]; /* * followed by key/value pairs, each key and value preceded by u32 len, * len includes itself, value may be empty (in which case its len is 4) @@ -42,7 +42,7 @@ struct properties_header { u32 len; u32 version; u32 dev_count; - struct dev_header dev_header[0]; + struct dev_header dev_header[]; }; static void __init unmarshal_key_value_pairs(struct dev_header *dev_header, -- 2.25.0