From patchwork Mon Mar 2 12:23:05 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: 11415417 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 089D11580 for ; Mon, 2 Mar 2020 12:20:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBE4D21739 for ; Mon, 2 Mar 2020 12:20:09 +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="rtImn0oM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727947AbgCBMUJ (ORCPT ); Mon, 2 Mar 2020 07:20:09 -0500 Received: from gateway32.websitewelcome.com ([192.185.145.189]:23962 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727421AbgCBMUI (ORCPT ); Mon, 2 Mar 2020 07:20:08 -0500 Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway32.websitewelcome.com (Postfix) with ESMTP id 15E767F756 for ; Mon, 2 Mar 2020 06:20:07 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 8k3KjY0nDAGTX8k3LjgRAA; Mon, 02 Mar 2020 06:20:07 -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=LzPJ/4uvjh/hNTol+mYUIodA/9OpKpqV2PAXxF3nbT0=; b=rtImn0oMt1FNc1RKrglfJoSYbX ItmzVSPy3kMLLOP7VGbn0W/KpNEz4y8QDPGhFm0zl4awyXhCXyIYjwvQ8j9ZhCT952qCsVfK6cW1G Ics4BQiwBxmb97rpkclGpczXvUfo4ZZ/Dykp26y9RplkObJN4p1iUVG/SQJf8chRXITJCz1Xjp6sC vdBDDbpPLLUciwZxsckcmrVkt+WMyZjqT0ttsLJzCfAr/iyOWJIsSmKX6lJGr5P7vbPc9TmxdZW+c OeSVTRDZrGGYaifbvRW2aFLP0q770wZYhcgaDpkilM8oEU6iF9wcpkviJCmijUZFWoD58a1sjlV+u CmesmJoQ==; Received: from [200.39.29.128] (port=42554 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j8k3J-0046va-1u; Mon, 02 Mar 2020 06:20:05 -0600 Date: Mon, 2 Mar 2020 06:23:05 -0600 From: "Gustavo A. R. Silva" To: "David S. Miller" Cc: linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] r8152: Replace zero-length array with flexible-array member Message-ID: <20200302122305.GA1200@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: 200.39.29.128 X-Source-L: No X-Exim-ID: 1j8k3J-0046va-1u X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.39.29.128]:42554 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 27 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@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/usb/r8152.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c index feedc0f964d8..9adfa2bbf593 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -891,7 +891,7 @@ struct fw_block { struct fw_header { u8 checksum[32]; char version[RTL_VER_SIZE]; - struct fw_block blocks[0]; + struct fw_block blocks[]; } __packed; /** @@ -930,7 +930,7 @@ struct fw_mac { __le32 reserved; __le16 fw_ver_reg; u8 fw_ver_data; - char info[0]; + char info[]; } __packed; /** @@ -982,7 +982,7 @@ struct fw_phy_nc { __le16 bp_start; __le16 bp_num; __le16 bp[4]; - char info[0]; + char info[]; } __packed; enum rtl_fw_type {