From patchwork Thu Mar 19 23:06:17 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: 11448183 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 866BE1667 for ; Thu, 19 Mar 2020 23:06:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C3BC2076C for ; Thu, 19 Mar 2020 23:06:22 +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="bbqQ6UjB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727671AbgCSXGU (ORCPT ); Thu, 19 Mar 2020 19:06:20 -0400 Received: from gateway20.websitewelcome.com ([192.185.67.41]:46931 "EHLO gateway20.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727138AbgCSXGT (ORCPT ); Thu, 19 Mar 2020 19:06:19 -0400 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway20.websitewelcome.com (Postfix) with ESMTP id 3571A400CCA32 for ; Thu, 19 Mar 2020 16:50:50 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id F4F1jMnSAXVkQF4F1jdtcB; Thu, 19 Mar 2020 18:06:19 -0500 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=EQ6+e94EbbRCvZN1MHbBCIYfPJUa31xR11Y1UAO3a5Y=; b=bbqQ6UjBbYS5lZK6jibj0Q4RXr oGcRafr24mHM8HhpT4wDedr92j84t6b0jdCXWe0is43cEy1Ujyy3ZjOtE9t2enNCbCdei3K+kQkat HXShAyF6UW1HNm+XK2AhwzQVvmS9huGrxmFtLnSUPM/Qb505GQAVwcUbnsi8YKxSfz9tg9UhF5hkr 0hOfKzvPAicZY+VG7ixmCq8Cb8s1ekqv/Tb02B6gotHYfQse5cd+KYmRBUIz921QyaPkz0I8Z4StN 5xvYwQs31KTH7kje1G0n1hvEVxlI8ypofez7QX81axcFUCOHt3YRTWu6f12EgPvgVpm64Knv9zgcm 238nrMFw==; Received: from cablelink-189-218-116-241.hosts.intercable.net ([189.218.116.241]:54032 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jF4Ez-002P1y-OU; Thu, 19 Mar 2020 18:06:17 -0500 Date: Thu, 19 Mar 2020 18:06:17 -0500 From: "Gustavo A. R. Silva" To: 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] net: wireless: wl3501.h: Replace zero-length array with flexible-array member Message-ID: <20200319230617.GA15035@embeddedor.com> 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: 189.218.116.241 X-Source-L: No X-Exim-ID: 1jF4Ez-002P1y-OU X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:54032 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 8 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/wl3501.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h index efdce9ae36ea..b446cb369557 100644 --- a/drivers/net/wireless/wl3501.h +++ b/drivers/net/wireless/wl3501.h @@ -231,7 +231,7 @@ struct iw_mgmt_info_element { u8 id; /* one of enum iw_mgmt_info_element_ids, but sizeof(enum) > sizeof(u8) :-( */ u8 len; - u8 data[0]; + u8 data[]; } __packed; struct iw_mgmt_essid_pset {