From patchwork Tue Feb 25 00:27:46 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: 11402315 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 C02721395 for ; Tue, 25 Feb 2020 00:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 856D621D7E for ; Tue, 25 Feb 2020 00:25:03 +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="cef/4pH9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728489AbgBYAZC (ORCPT ); Mon, 24 Feb 2020 19:25:02 -0500 Received: from gateway32.websitewelcome.com ([192.185.145.122]:49100 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726751AbgBYAZB (ORCPT ); Mon, 24 Feb 2020 19:25:01 -0500 Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway32.websitewelcome.com (Postfix) with ESMTP id 62DD76983C6 for ; Mon, 24 Feb 2020 18:25:00 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 6O20jhq5hRP4z6O20j6xHb; Mon, 24 Feb 2020 18:25:00 -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=StD8K7B/IbLHb+7gq2AVQ24d9PrxX4zRAlmjceGLxBI=; b=cef/4pH9Y7gkNa2Rujz7TwrUuz ao2dsiqnIm0nORidRrr4/fvQ8RILopsIHSo7ARSdrOk05VwGXag8B6MtXnfeaaYqLBgD6djtps/0c A/LJQv9eO0E6TXTo9JCPFPyzXu4ZHczCKsIh7pgRpnmHMn53qfYJ7iSXtaJc6mW/ZZpbR0d2El6sF VstH3V3fOY61qg7nprMZvqzVNVkf54FB4jQZYVNSEBvw342NRGtX9uLSCu1HA2sG4g8FXvnwh4W0D c4yBXY3CfKPmfJs0m5q+yJFguVmCdxz2EBJ8WcXBlHT3q57lZlQjW8quMCujZpGm5iRTuUpVJJU08 llHgKSIw==; Received: from [201.166.191.153] (port=54744 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j6O1x-002VtX-VX; Mon, 24 Feb 2020 18:24:58 -0600 Date: Mon, 24 Feb 2020 18:27:46 -0600 From: "Gustavo A. R. Silva" To: Jes Sorensen , Kalle Valo , "David S. Miller" , Ping-Ke Shih , Yan-Hsuan Chuang Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] wireless: realtek: Replace zero-length array with flexible-array member Message-ID: <20200225002746.GA26789@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: 201.166.191.153 X-Source-L: No X-Exim-ID: 1j6O1x-002VtX-VX X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.191.153]:54744 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 38 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/realtek/rtl8xxxu/rtl8xxxu.h | 2 +- drivers/net/wireless/realtek/rtlwifi/wifi.h | 6 +++--- drivers/net/wireless/realtek/rtw88/fw.h | 2 +- drivers/net/wireless/realtek/rtw88/main.h | 2 +- 4 files changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h index 6598c8d786ea..440d164443bc 100644 --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h @@ -627,7 +627,7 @@ struct rtl8xxxu_firmware_header { u32 reserved4; u32 reserved5; - u8 data[0]; + u8 data[]; }; /* diff --git a/drivers/net/wireless/realtek/rtlwifi/wifi.h b/drivers/net/wireless/realtek/rtlwifi/wifi.h index 1cff9f07c9e9..13421cf2d201 100644 --- a/drivers/net/wireless/realtek/rtlwifi/wifi.h +++ b/drivers/net/wireless/realtek/rtlwifi/wifi.h @@ -1051,13 +1051,13 @@ struct rtl_hdr_3addr { u8 addr2[ETH_ALEN]; u8 addr3[ETH_ALEN]; __le16 seq_ctl; - u8 payload[0]; + u8 payload[]; } __packed; struct rtl_info_element { u8 id; u8 len; - u8 data[0]; + u8 data[]; } __packed; struct rtl_probe_rsp { @@ -1068,7 +1068,7 @@ struct rtl_probe_rsp { /*SSID, supported rates, FH params, DS params, * CF params, IBSS params, TIM (if beacon), RSN */ - struct rtl_info_element info_element[0]; + struct rtl_info_element info_element[]; } __packed; /*LED related.*/ diff --git a/drivers/net/wireless/realtek/rtw88/fw.h b/drivers/net/wireless/realtek/rtw88/fw.h index ccd27bd45775..414827800a5f 100644 --- a/drivers/net/wireless/realtek/rtw88/fw.h +++ b/drivers/net/wireless/realtek/rtw88/fw.h @@ -36,7 +36,7 @@ enum rtw_c2h_cmd_id_ext { struct rtw_c2h_cmd { u8 id; u8 seq; - u8 payload[0]; + u8 payload[]; } __packed; enum rtw_rsvd_packet_type { diff --git a/drivers/net/wireless/realtek/rtw88/main.h b/drivers/net/wireless/realtek/rtw88/main.h index c074cef22120..46c0ebceb177 100644 --- a/drivers/net/wireless/realtek/rtw88/main.h +++ b/drivers/net/wireless/realtek/rtw88/main.h @@ -1641,7 +1641,7 @@ struct rtw_dev { struct rtw_wow_param wow; /* hci related data, must be last */ - u8 priv[0] __aligned(sizeof(void *)); + u8 priv[] __aligned(sizeof(void *)); }; #include "hci.h"