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=-13.1 required=3.0 tests=BAYES_00,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_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 52668C433E1 for ; Wed, 22 Jul 2020 15:53:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B0B020717 for ; Wed, 22 Jul 2020 15:53:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433214; bh=BrMikSOSP8rQfuWua//rncDQlSlapCNNxsWOW25/l14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jLqWmt3RV4tvcfb0TzaB2D3Ot6Ae0v67zAVJIr6pmHnP8XMQffFo00SMMVuGp/Y5J c75j88WFn2z2RyOfSjYN7hnNorhHGbKAQkR8lt3Rw9ZLr1bmG5Zho+3PkhE0MbYK7O ewE9uVONE8MIihwH6kT32wuEXaxNGZFNYRDca5OQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729866AbgGVPxd (ORCPT ); Wed, 22 Jul 2020 11:53:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:35748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726427AbgGVPxd (ORCPT ); Wed, 22 Jul 2020 11:53:33 -0400 Received: from localhost.localdomain (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85E95206F5; Wed, 22 Jul 2020 15:53:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595433212; bh=BrMikSOSP8rQfuWua//rncDQlSlapCNNxsWOW25/l14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S4mtAlA83544RlA4UcAlrsCNvm6Lv/JzmG71IvQFUUacScFctovXqNauLKB9hyu7R FuBDnDPvuCETgeB18nuNT9MT8pNKSIY3ZhmBNmdO7wU+rOkg6IqKvhtwDvI7GPweD5 36jsa99k4GuQq7hDVHffTz/fSk5utbBAJ4Uhx36M= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Lars-Peter Clausen , Peter Meerwald , Jonathan Cameron , Lorenzo Bianconi Subject: [PATCH v3 16/27] iio:imu:st_lsm6dsx Fix alignment and data leak issues Date: Wed, 22 Jul 2020 16:50:52 +0100 Message-Id: <20200722155103.979802-17-jic23@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200722155103.979802-1-jic23@kernel.org> References: <20200722155103.979802-1-jic23@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org 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 an array of suitable structures in the iio_priv() data. This data is allocated with kzalloc so no data can leak apart from previous readings. For the tagged path the data is aligned by using __aligned(8) for the buffer on the stack. There has been a lot of churn in this driver, so likely backports may be needed for stable. Fixes: 290a6ce11d93 ("iio: imu: add support to lsm6dsx driver") Reported-by: Lars-Peter Clausen Cc: Lorenzo Bianconi Signed-off-by: Jonathan Cameron --- drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h | 6 ++++ .../iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 36 ++++++++++--------- 2 files changed, 26 insertions(+), 16 deletions(-) diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h index d80ba2e688ed..9275346a9cc1 100644 --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h @@ -383,6 +383,7 @@ struct st_lsm6dsx_sensor { * @iio_devs: Pointers to acc/gyro iio_dev instances. * @settings: Pointer to the specific sensor settings in use. * @orientation: sensor chip orientation relative to main hardware. + * @scan: Temporary buffers used to align data before iio_push_to_buffers() */ struct st_lsm6dsx_hw { struct device *dev; @@ -411,6 +412,11 @@ struct st_lsm6dsx_hw { const struct st_lsm6dsx_settings *settings; struct iio_mount_matrix orientation; + /* Ensure natural alignment of buffer elements */ + struct { + __le16 channels[3]; + s64 ts __aligned(8); + } scan[3]; }; static __maybe_unused const struct iio_event_spec st_lsm6dsx_event = { diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c index 7de10bd636ea..9e0404e3581d 100644 --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c @@ -353,9 +353,6 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) int err, sip, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset; u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE; u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask; - u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; - u8 acc_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; - u8 ext_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; bool reset_ts = false; __le16 fifo_status; s64 ts = 0; @@ -416,19 +413,22 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) while (acc_sip > 0 || gyro_sip > 0 || ext_sip > 0) { if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) { - memcpy(gyro_buff, &hw->buff[offset], - ST_LSM6DSX_SAMPLE_SIZE); - offset += ST_LSM6DSX_SAMPLE_SIZE; + memcpy(hw->scan[ST_LSM6DSX_ID_GYRO].channels, + &hw->buff[offset], + sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels)); + offset += sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels); } if (acc_sip > 0 && !(sip % acc_sensor->decimator)) { - memcpy(acc_buff, &hw->buff[offset], - ST_LSM6DSX_SAMPLE_SIZE); - offset += ST_LSM6DSX_SAMPLE_SIZE; + memcpy(hw->scan[ST_LSM6DSX_ID_ACC].channels, + &hw->buff[offset], + sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels)); + offset += sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels); } if (ext_sip > 0 && !(sip % ext_sensor->decimator)) { - memcpy(ext_buff, &hw->buff[offset], - ST_LSM6DSX_SAMPLE_SIZE); - offset += ST_LSM6DSX_SAMPLE_SIZE; + memcpy(hw->scan[ST_LSM6DSX_ID_EXT0].channels, + &hw->buff[offset], + sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels)); + offset += sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels); } if (ts_sip-- > 0) { @@ -458,19 +458,22 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) { iio_push_to_buffers_with_timestamp( hw->iio_devs[ST_LSM6DSX_ID_GYRO], - gyro_buff, gyro_sensor->ts_ref + ts); + &hw->scan[ST_LSM6DSX_ID_GYRO], + gyro_sensor->ts_ref + ts); gyro_sip--; } if (acc_sip > 0 && !(sip % acc_sensor->decimator)) { iio_push_to_buffers_with_timestamp( hw->iio_devs[ST_LSM6DSX_ID_ACC], - acc_buff, acc_sensor->ts_ref + ts); + &hw->scan[ST_LSM6DSX_ID_ACC], + acc_sensor->ts_ref + ts); acc_sip--; } if (ext_sip > 0 && !(sip % ext_sensor->decimator)) { iio_push_to_buffers_with_timestamp( hw->iio_devs[ST_LSM6DSX_ID_EXT0], - ext_buff, ext_sensor->ts_ref + ts); + &hw->scan[ST_LSM6DSX_ID_EXT0], + ext_sensor->ts_ref + ts); ext_sip--; } sip++; @@ -555,7 +558,8 @@ int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw) { u16 pattern_len = hw->sip * ST_LSM6DSX_TAGGED_SAMPLE_SIZE; u16 fifo_len, fifo_diff_mask; - u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE], tag; + u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE] __aligned(8); + u8 tag; bool reset_ts = false; int i, err, read_len; __le16 fifo_status; -- 2.27.0