From patchwork Fri Feb 8 00:56:08 2019 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: 1038423 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43wdK36ZcYz9s4V for ; Fri, 8 Feb 2019 12:44:39 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727080AbfBHBoj (ORCPT ); Thu, 7 Feb 2019 20:44:39 -0500 Received: from gateway24.websitewelcome.com ([192.185.50.71]:38469 "EHLO gateway24.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726876AbfBHBoi (ORCPT ); Thu, 7 Feb 2019 20:44:38 -0500 X-Greylist: delayed 1500 seconds by postgrey-1.27 at vger.kernel.org; Thu, 07 Feb 2019 20:44:38 EST Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway24.websitewelcome.com (Postfix) with ESMTP id CFA20802E3 for ; Thu, 7 Feb 2019 18:56:09 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id ruSfgENN7iQerruSfgUlfE; Thu, 07 Feb 2019 18:56:09 -0600 X-Authority-Reason: nr=8 Received: from [189.250.49.191] (port=47436 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1gruSf-004Ccg-01; Thu, 07 Feb 2019 18:56:09 -0600 Date: Thu, 7 Feb 2019 18:56:08 -0600 From: "Gustavo A. R. Silva" To: Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" Cc: netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH net-next] netfilter: xt_recent: Use struct_size() in kvzalloc() Message-ID: <20190208005608.GA16399@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: 189.250.49.191 X-Source-L: No X-Exim-ID: 1gruSf-004Ccg-01 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.49.191]:47436 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 29 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; size = sizeof(struct foo) + count * sizeof(void *); instance = alloc(size, GFP_KERNEL) Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: size = struct_size(instance, entry, count); instance = alloc(size, GFP_KERNEL) Notice that, in this case, variable sz is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- net/netfilter/xt_recent.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index f44de4bc2100..1664d2ec8b2f 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -337,7 +337,6 @@ static int recent_mt_check(const struct xt_mtchk_param *par, unsigned int nstamp_mask; unsigned int i; int ret = -EINVAL; - size_t sz; net_get_random_once(&hash_rnd, sizeof(hash_rnd)); @@ -387,8 +386,7 @@ static int recent_mt_check(const struct xt_mtchk_param *par, goto out; } - sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size; - t = kvzalloc(sz, GFP_KERNEL); + t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL); if (t == NULL) { ret = -ENOMEM; goto out;