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=-11.2 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 C124CC43466 for ; Mon, 21 Sep 2020 16:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C416239D0 for ; Mon, 21 Sep 2020 16:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706346; bh=V+hMxe2Lwr/FAnvCw25sVauwGTJ4DqBLe1JJIdJzaaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hoCS94ZjqsqRVthzbBaFi8pH3DasJMuKi3HvNQWbC4unisCPpnwHMPOEMrGk9twJz ckBaZ1vE8VjndIa4A8XgUFtB4p2b9yu4HJ/lrV4Uoi/D+GxBFKlJe8ANP6vOPMNHWd +2604FkbafBLg2D7/IOydCSZgBCjT7OjYeE6gdw0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729207AbgIUQi4 (ORCPT ); Mon, 21 Sep 2020 12:38:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:40382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729203AbgIUQi4 (ORCPT ); Mon, 21 Sep 2020 12:38:56 -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 4E423206DC; Mon, 21 Sep 2020 16:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706331; bh=V+hMxe2Lwr/FAnvCw25sVauwGTJ4DqBLe1JJIdJzaaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Co01a6iQ6mOl9MgewHfDepY12GW0AAOByvQbjHCh/55Tn2p+NThzOrkCMU9h2HEtn +2iZZviS5lgAsRVNozShQXhwPDb4hY4wCfTFG+XgDpNgQdieU8/lXtqwbF0721N7S9 9uL+Sqp/SvgCRG4BjZvv/JEfEMjO/cTC9kpW7o/I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Srinivas Pandruvada , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.14 27/94] iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak. Date: Mon, 21 Sep 2020 18:27:14 +0200 Message-Id: <20200921162036.806621492@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit a6f86f724394de3629da63fe5e1b7a4ab3396efe 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 a 16 byte 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 ensured by use of an explicit c structure. This data is allocated with kzalloc so no data can leak appart from previous readings. Fixes tag is beyond some major refactoring so likely manual backporting would be needed to get that far back. Whilst the force alignment of the ts is not strictly necessary, it does make the code less fragile. Fixes: 3bbec9773389 ("iio: bmc150_accel: add support for hardware fifo") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Acked-by: Srinivas Pandruvada Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/accel/bmc150-accel-core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/drivers/iio/accel/bmc150-accel-core.c +++ b/drivers/iio/accel/bmc150-accel-core.c @@ -197,6 +197,14 @@ struct bmc150_accel_data { struct mutex mutex; u8 fifo_mode, watermark; s16 buffer[8]; + /* + * Ensure there is sufficient space and correct alignment for + * the timestamp if enabled + */ + struct { + __le16 channels[3]; + s64 ts __aligned(8); + } scan; u8 bw_bits; u32 slope_dur; u32 slope_thres; @@ -933,15 +941,16 @@ static int __bmc150_accel_fifo_flush(str * now. */ for (i = 0; i < count; i++) { - u16 sample[8]; int j, bit; j = 0; for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) - memcpy(&sample[j++], &buffer[i * 3 + bit], 2); + memcpy(&data->scan.channels[j++], &buffer[i * 3 + bit], + sizeof(data->scan.channels[0])); - iio_push_to_buffers_with_timestamp(indio_dev, sample, tstamp); + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, + tstamp); tstamp += sample_period; }