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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 91780C433F4 for ; Mon, 27 Aug 2018 09:21:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54A57208E8 for ; Mon, 27 Aug 2018 09:21:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54A57208E8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727020AbeH0NHb (ORCPT ); Mon, 27 Aug 2018 09:07:31 -0400 Received: from mx2.suse.de ([195.135.220.15]:58178 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726802AbeH0NHb (ORCPT ); Mon, 27 Aug 2018 09:07:31 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id BBB94ADFE; Mon, 27 Aug 2018 09:21:39 +0000 (UTC) Message-ID: <1535361211.9321.6.camel@suse.com> Subject: Re: [PATCH v2] usb: iowarrior: replace kmalloc with kmalloc_array From: Oliver Neukum To: "Gustavo A. R. Silva" , Greg Kroah-Hartman Cc: Kees Cook , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Date: Mon, 27 Aug 2018 11:13:31 +0200 In-Reply-To: <20180823174415.GA26008@embeddedor.com> References: <20180823174415.GA26008@embeddedor.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Do, 2018-08-23 at 12:44 -0500, Gustavo A. R. Silva wrote: > A common flaw in the kernel is integer overflow during memory allocation > size calculations. In an effort to reduce the frequency of these bugs, > kmalloc_array was implemented, which allocates memory for an array, > while at the same time detects integer overflow. > > This patch replaces cases of: > > kmalloc(a * b, gfp) > > with: > kmalloc_array(a * b, gfp) I am afraid there is a problem here. The driver currently is a gross violation of the DMA rules. Unfortunately your patch does not fix that. That is on anyrhing other than x86 you cannot take the size of a report, but you must use the size of a cache line. Regards Oliver