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=-12.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 70F4BC2D0E3 for ; Tue, 15 Sep 2020 23:13:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 322C6212CC for ; Tue, 15 Sep 2020 23:13:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600211607; bh=VGJv8aXi4Qyx5bLJOiwCUyFkNUt3vXInlFcB/HmLKyI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=U9o8KTMRsVEWwGSgMOSOSdieePDFxkqyh1vZrpMAm520H3e5kCi/XzXPQzfp01D0U GdVAw33rlz344ELSaSh89TkCBtIDYvdS5Ri6UpgMKp0QN/gW/8lbmQCYno9M8qzdi4 xw73x0EoWqcTjUk49w+5RxPZAkyjPgPlyyBnKm/o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726986AbgIOXN0 (ORCPT ); Tue, 15 Sep 2020 19:13:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:48832 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgIOOki (ORCPT ); Tue, 15 Sep 2020 10:40:38 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 3E12723D22; Tue, 15 Sep 2020 14:30:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180208; bh=VGJv8aXi4Qyx5bLJOiwCUyFkNUt3vXInlFcB/HmLKyI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t2hLV9FCUdy4vdVLbg1qCVRMH81LtLudyV6yG5+mW9M6rsESPNySDcRAjSBSKEzHk vxupZJ7+59BYCJpSvbBPK3Vr7szhCvM7plxZvAJBZv/42FxfGkvGV6/qcSZgLs+cda +QD3XC8xOA4XS5mbRyA7HLUovR43MUkKcj+VVX60= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Narcisa Ana Maria Vasile , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 5.8 121/177] iio:chemical:ccs811: Fix timestamp alignment and prevent data leak. Date: Tue, 15 Sep 2020 16:13:12 +0200 Message-Id: <20200915140659.445024980@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140653.610388773@linuxfoundation.org> References: <20200915140653.610388773@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jonathan Cameron commit eb1a148ef41d8ae8d9201efc3f1b145976290331 upstream. 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 with alignment explicitly requested. This data is allocated with kzalloc so no data can leak appart from previous readings. The explicit alignment of ts is necessary to ensure consistent padding for x86_32 in which the ts would otherwise be 4 byte aligned. Fixes: 283d26917ad6 ("iio: chemical: ccs811: Add triggered buffer support") Reported-by: Lars-Peter Clausen Cc: Narcisa Ana Maria Vasile Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/chemical/ccs811.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/drivers/iio/chemical/ccs811.c +++ b/drivers/iio/chemical/ccs811.c @@ -78,6 +78,11 @@ struct ccs811_data { struct iio_trigger *drdy_trig; struct gpio_desc *wakeup_gpio; bool drdy_trig_on; + /* Ensures correct alignment of timestamp if present */ + struct { + s16 channels[2]; + s64 ts __aligned(8); + } scan; }; static const struct iio_chan_spec ccs811_channels[] = { @@ -327,17 +332,17 @@ static irqreturn_t ccs811_trigger_handle struct iio_dev *indio_dev = pf->indio_dev; struct ccs811_data *data = iio_priv(indio_dev); struct i2c_client *client = data->client; - s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */ int ret; - ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4, - (u8 *)&buf); + ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, + sizeof(data->scan.channels), + (u8 *)data->scan.channels); if (ret != 4) { dev_err(&client->dev, "cannot read sensor data\n"); goto err; } - iio_push_to_buffers_with_timestamp(indio_dev, buf, + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); err: