From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80AC8C433E1 for ; Fri, 31 Jul 2020 17:06:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4630922B3F for ; Fri, 31 Jul 2020 17:06:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="GAtSmDC2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4630922B3F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E706E8D0050; Fri, 31 Jul 2020 13:06:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E210F8D000B; Fri, 31 Jul 2020 13:06:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC2488D0050; Fri, 31 Jul 2020 13:06:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id AE4E38D000B for ; Fri, 31 Jul 2020 13:06:51 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 71FBD1EE6 for ; Fri, 31 Jul 2020 17:06:51 +0000 (UTC) X-FDA: 77099000622.02.camp95_470638226f85 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 4E69010097AA3 for ; Fri, 31 Jul 2020 17:06:51 +0000 (UTC) X-HE-Tag: camp95_470638226f85 X-Filterd-Recvd-Size: 2827 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf47.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jul 2020 17:06:50 +0000 (UTC) Received: from embeddedor (187-162-31-110.static.axtel.net [187.162.31.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3255C2074B; Fri, 31 Jul 2020 17:06:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596215210; bh=+VUSWtEU2obYc+ePK90t3RP8I0yTyfzAx4iIOrUuZ74=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GAtSmDC2w2Ln8WEh56WQL62yee5akpVM/VnuiX7LQro9A/Sugff2KEgX4ZZhQfEjt AXtxfpZPx3m5Ximt3xarWPZ9mJHS/3AZd/8YL4lrbbEMgE983KIrz+1CvhlmfuC4/W lBnYRB/UOVWASkawWXD+zIapf/NNgOuCqNtAFETk= Date: Fri, 31 Jul 2020 12:12:53 -0500 From: "Gustavo A. R. Silva" To: linux-kernel@vger.kernel.org Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, "Gustavo A. R. Silva" Subject: [PATCH 1/2][next] mm: memcontrol: Use flex_array_size() helper in memcpy() Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Rspamd-Queue-Id: 4E69010097AA3 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Make use of the flex_array_size() helper to calculate the size of a flexible array member within an enclosing structure. This helper offers defense-in-depth against potential integer overflows, while at the same time makes it explicitly clear that we are dealing with a flexible array member. Also, remove unnecessary braces. Signed-off-by: Gustavo A. R. Silva --- mm/memcontrol.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e84c2b5596f2..bd7f972ceea4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4246,10 +4246,9 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, new->size = size; /* Copy thresholds (if any) to new array */ - if (thresholds->primary) { - memcpy(new->entries, thresholds->primary->entries, (size - 1) * - sizeof(struct mem_cgroup_threshold)); - } + if (thresholds->primary) + memcpy(new->entries, thresholds->primary->entries, + flex_array_size(new, entries, size - 1)); /* Add new threshold */ new->entries[size - 1].eventfd = eventfd; -- 2.27.0