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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 D3CA2C433DF for ; Sun, 7 Jun 2020 14:43:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B0D94206A4 for ; Sun, 7 Jun 2020 14:43:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591540991; bh=C1MGID1Ql+htrqwUGJ65/TlfhHS1QG30CrqwQIJccCM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=GdLhLMu21FMBrBo8UA6qoyDBSnxYazmurFA+xVz/ATCNIRPJkCH80xYj5jOZBTUCv /VcsCNLC2fbshfmdyRFdLZ9NuWvCvXVmRuELBW9X//A9ahTjeRLulma1w5mJlEfP8E 39cYWAgXA0wC3jT05tYaf9fDq9/4VFwkltXqzYMQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726673AbgFGOnL (ORCPT ); Sun, 7 Jun 2020 10:43:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:37054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726663AbgFGOnL (ORCPT ); Sun, 7 Jun 2020 10:43:11 -0400 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (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 8874120663; Sun, 7 Jun 2020 14:43:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591540990; bh=C1MGID1Ql+htrqwUGJ65/TlfhHS1QG30CrqwQIJccCM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=M0HdunJwW8GnWsphy67cAyd0o7kXBxLRPQjskcQ8C6E+UxI/pjgJUurFfuUeLyj9O t3IkpfuzY/1voRdGYzO1OgSluWGGdvUDOzaTc2w8EP83ZMz92NG+0Z8gWgeKKDyivH Xvhv68MN18aHdt7+qC4+J7a4WjVqSv97KwoYyirc= Date: Sun, 7 Jun 2020 15:43:06 +0100 From: Jonathan Cameron To: Linus Walleij Cc: linux-iio , Jonathan Cameron , Lars-Peter Clausen Subject: Re: [PATCH 06/25] iio:magnetometer:ak8974: Fix alignment and data leak issues Message-ID: <20200607154306.712d2a3d@archlinux> In-Reply-To: References: <20200525170628.503283-1-jic23@kernel.org> <20200525170628.503283-7-jic23@kernel.org> X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Tue, 26 May 2020 11:24:40 +0200 Linus Walleij wrote: > On Mon, May 25, 2020 at 7:09 PM Jonathan Cameron wrote: > > > From: Jonathan Cameron > > > > One of a class of bugs pointed out by Lars in a recent review. > > iio_push_to_buffers_with_timestamp assumes the buffer used is aligned > > to the size of the timestamp (8 bytes). This is not guaranteed in > > this driver which uses an array of smaller elements on the stack. > > As Lars also noted this anti pattern can involve a leak of data to > > userspace and that indeed can happen here. We close both issues by > > moving to a suitable structure in the iio_priv() data. > > > > This data is allocated with kzalloc so no data can leak appart from > > previous readings. > > > > Fixes: 7c94a8b2ee8cf ("iio: magn: add a driver for AK8974") > > Reported-by: Lars-Peter Clausen > > Signed-off-by: Jonathan Cameron > > Cc: Linus Walleij > > Whoa, good catch! Definitely my mindless coding. > Reviewed-by: Linus Walleij I've tweaked this slightly fro v2 to add an __aligned(8) to the ts. This is driven by the need for some cases to be careful on x86_32 where the s64 might be 4 byte aligned and the padding come out wrong. It doesn't actually matter in this case but I'd rather be explicit. Have kept the reviewed-by as not a material change on this one. Thanks, Jonathan > > Yours, > Linus Walleij