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=-8.6 required=3.0 tests=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_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 DE862C433DF for ; Sun, 5 Jul 2020 11:44:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE60E20739 for ; Sun, 5 Jul 2020 11:44:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593949442; bh=Mp0OZ78nKDygctQuSPpG5pCPpNwfGBfIkMaAgxyxlgk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=oLswJqou3gkJ/bayBdXL3eza7fyHxVseL9+UnsmovdUZfn/bEDAxFNhgmjY3Lo97U ewO9JCiQog0R6pemjqs8j9n6x6PzFrgZlS8dl2RAApLUcb5wYEXHCPfQtXw1wT8QT9 JGnA6V2u2OrkeAI5DfxMrP2tQwRGktLuBE6yLRRE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726480AbgGELoC (ORCPT ); Sun, 5 Jul 2020 07:44:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:54538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726454AbgGELoB (ORCPT ); Sun, 5 Jul 2020 07:44:01 -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 3EB1F20723; Sun, 5 Jul 2020 11:44:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593949441; bh=Mp0OZ78nKDygctQuSPpG5pCPpNwfGBfIkMaAgxyxlgk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=UUqEYHLz1jzcke1pGxQF9VXIJDx/1mfdx+z3QmWqqtQ4KIThRRoLhXQdkpNn5FuXD LNi6xLl4LfXQ2/W/hMaofuy69VuKg7KHNhwjuPFF/WT3NcySR2um8KN4hK0t4x4Fib EB4BR9YRTa66ilVKuo+ECqxw8CrLYx3ifZgu2sK8= Date: Sun, 5 Jul 2020 12:43:57 +0100 From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , Linus Walleij Subject: Re: [PATCH 13/32] iio:magnetometer:ak8974: Fix alignment and data leak issues Message-ID: <20200705124357.1fc7316d@archlinux> In-Reply-To: <20200607155408.958437-14-jic23@kernel.org> References: <20200607155408.958437-1-jic23@kernel.org> <20200607155408.958437-14-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 Sun, 7 Jun 2020 16:53:49 +0100 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 > Reviewed-by: Linus Walleij > Signed-off-by: Jonathan Cameron Applied to the fixes-togreg branch of iio.git. I'm picking up all the ones in the series which I have had positive feedback on. Thanks, Jonathan > --- > drivers/iio/magnetometer/ak8974.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c > index c2260c84f7f1..ea09b549ec4e 100644 > --- a/drivers/iio/magnetometer/ak8974.c > +++ b/drivers/iio/magnetometer/ak8974.c > @@ -192,6 +192,11 @@ struct ak8974 { > bool drdy_irq; > struct completion drdy_complete; > bool drdy_active_low; > + /* Ensure timestamp is naturally aligned */ > + struct { > + __le16 channels[3]; > + s64 ts __aligned(8); > + } scan; > }; > > static const char ak8974_reg_avdd[] = "avdd"; > @@ -657,7 +662,6 @@ static void ak8974_fill_buffer(struct iio_dev *indio_dev) > { > struct ak8974 *ak8974 = iio_priv(indio_dev); > int ret; > - __le16 hw_values[8]; /* Three axes + 64bit padding */ > > pm_runtime_get_sync(&ak8974->i2c->dev); > mutex_lock(&ak8974->lock); > @@ -667,13 +671,13 @@ static void ak8974_fill_buffer(struct iio_dev *indio_dev) > dev_err(&ak8974->i2c->dev, "error triggering measure\n"); > goto out_unlock; > } > - ret = ak8974_getresult(ak8974, hw_values); > + ret = ak8974_getresult(ak8974, ak8974->scan.channels); > if (ret) { > dev_err(&ak8974->i2c->dev, "error getting measures\n"); > goto out_unlock; > } > > - iio_push_to_buffers_with_timestamp(indio_dev, hw_values, > + iio_push_to_buffers_with_timestamp(indio_dev, &ak8974->scan, > iio_get_time_ns(indio_dev)); > > out_unlock: