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 BADC6C43461 for ; Wed, 16 Sep 2020 00:02:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8637020756 for ; Wed, 16 Sep 2020 00:02:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600214560; bh=EDVv896TceHhVeYzKL22auYiOC7JXoZvz2BrJjVgdPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ey+x58RjB+DS4czjLrzz/iu9WTLDNM1BY3XeCwEc2m96dMSZ/gzxyI2WFWTWnv0nk sH567Dvd44w6LeXEKNKSrutZusyGyvly73MCNMRbI9euWGFcKthKIVCJD2I+N49wdm SfA5uREwh0l0WCoEj5g0QIQ0DFUFj7nUNt3Yv7EQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727063AbgIPACg (ORCPT ); Tue, 15 Sep 2020 20:02:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:41424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727000AbgIOOaP (ORCPT ); Tue, 15 Sep 2020 10:30:15 -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 3C4142224D; Tue, 15 Sep 2020 14:21:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179706; bh=EDVv896TceHhVeYzKL22auYiOC7JXoZvz2BrJjVgdPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UiR+0ufrrXyGR2icj4WjQjm0f6GodhzHtqw60sCUPEAz1AHAcBu/+lCx9ilxqT8Tg rHN8IDTx1pV3gpoWY6bIEY03GJEWoJos+UUlQMNkzUmx7JcAjQlmZW9MDUZYF2suKw 7FuVpz18HO172R3Vo3Piwi1wVpfk7RczoOG3uE/8= 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 5.4 086/132] iio:chemical:ccs811: Fix timestamp alignment and prevent data leak. Date: Tue, 15 Sep 2020 16:13:08 +0200 Message-Id: <20200915140648.407249588@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@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 @@ -75,6 +75,11 @@ struct ccs811_data { struct ccs811_reading buffer; struct iio_trigger *drdy_trig; 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[] = { @@ -306,17 +311,17 @@ 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: