From patchwork Tue Feb 25 01:11:51 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: 11402357 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D9D8214BC for ; Tue, 25 Feb 2020 01:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8A6F218AC for ; Tue, 25 Feb 2020 01:09:12 +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="oBmrIz9l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728626AbgBYBJH (ORCPT ); Mon, 24 Feb 2020 20:09:07 -0500 Received: from gateway30.websitewelcome.com ([192.185.196.18]:41269 "EHLO gateway30.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728529AbgBYBJG (ORCPT ); Mon, 24 Feb 2020 20:09:06 -0500 Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway30.websitewelcome.com (Postfix) with ESMTP id 758D4CFF8 for ; Mon, 24 Feb 2020 19:09:04 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 6OiejcXQA8vkB6OiejY0k2; Mon, 24 Feb 2020 19:09:04 -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=c98g6WeC58NkLgTxbAHyTHrMsSRtYF/+CmdBm9wFx1c=; b=oBmrIz9lcLMYNVxyceXUi64LhN R8bn0YkI5rDDRrS/advScUhcNp+BYBkCreXmX/0S4G+jGoBdPwIxm3cR9VMB55ECU1Zt8t/pFwYzj wnTS+gDFDxK3HRygcf2W8jZGc1m/99WeWur14UrZ11trJZHygvdSRcfZzYUge9nSEhF9MUuNHxaTC mTJuL5Hlcq3iB+Jyn4EJ+2t3HAVyd1ZQUndUfOVAXMt7Sp69zvtnLfR/sFpc7+nlxDMlvEsUSntx8 TEvBW0idcOql4aAo1KnpVJdPmCVKgAREfEafCLkGTxQhu6QzoDdgDaIzLudK+b7vCEAnL7aCQThOj 7ygB7Rkg==; Received: from [201.166.190.254] (port=58460 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j6Oib-002rNH-ID; Mon, 24 Feb 2020 19:09:01 -0600 Date: Mon, 24 Feb 2020 19:11:51 -0600 From: "Gustavo A. R. Silva" To: Jouni Malinen , Kalle Valo , "David S. Miller" Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] hostap: Replace zero-length array with flexible-array member Message-ID: <20200225011151.GA30675@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: 201.166.190.254 X-Source-L: No X-Exim-ID: 1j6Oib-002rNH-ID X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.190.254]:58460 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 4 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@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/net/wireless/intersil/hostap/hostap_common.h | 2 +- drivers/net/wireless/intersil/hostap/hostap_wlan.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/intersil/hostap/hostap_common.h b/drivers/net/wireless/intersil/hostap/hostap_common.h index 22543538239b..dd29a8e8d349 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_common.h +++ b/drivers/net/wireless/intersil/hostap/hostap_common.h @@ -322,7 +322,7 @@ struct prism2_download_param { u32 addr; /* wlan card address */ u32 len; void __user *ptr; /* pointer to data in user space */ - } data[0]; + } data[]; }; #define PRISM2_MAX_DOWNLOAD_AREA_LEN 131072 diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h index 487883fbb58c..dd2603d9b5d3 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h +++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h @@ -615,7 +615,7 @@ struct prism2_download_data { u32 addr; /* wlan card address */ u32 len; u8 *data; /* allocated data */ - } data[0]; + } data[]; };