mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-24 13:42:05 +07:00
13e945631c
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.
Fixes: a1d642266c
("iio: chemical: add support for Plantower PMS7003 sensor")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <Stable@vger.kernel.org>
Acked-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
353 lines
8.6 KiB
C
353 lines
8.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Plantower PMS7003 particulate matter sensor driver
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*
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* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
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*/
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#include <asm/unaligned.h>
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#include <linux/completion.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/serdev.h>
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#define PMS7003_DRIVER_NAME "pms7003"
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#define PMS7003_MAGIC 0x424d
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/* last 2 data bytes hold frame checksum */
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#define PMS7003_MAX_DATA_LENGTH 28
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#define PMS7003_CHECKSUM_LENGTH 2
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#define PMS7003_PM10_OFFSET 10
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#define PMS7003_PM2P5_OFFSET 8
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#define PMS7003_PM1_OFFSET 6
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#define PMS7003_TIMEOUT msecs_to_jiffies(6000)
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#define PMS7003_CMD_LENGTH 7
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#define PMS7003_PM_MAX 1000
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#define PMS7003_PM_MIN 0
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enum {
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PM1,
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PM2P5,
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PM10,
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};
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enum pms7003_cmd {
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CMD_WAKEUP,
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CMD_ENTER_PASSIVE_MODE,
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CMD_READ_PASSIVE,
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CMD_SLEEP,
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};
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/*
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* commands have following format:
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*
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* +------+------+-----+------+-----+-----------+-----------+
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* | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
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* +------+------+-----+------+-----+-----------+-----------+
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*/
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static const u8 pms7003_cmd_tbl[][PMS7003_CMD_LENGTH] = {
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[CMD_WAKEUP] = { 0x42, 0x4d, 0xe4, 0x00, 0x01, 0x01, 0x74 },
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[CMD_ENTER_PASSIVE_MODE] = { 0x42, 0x4d, 0xe1, 0x00, 0x00, 0x01, 0x70 },
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[CMD_READ_PASSIVE] = { 0x42, 0x4d, 0xe2, 0x00, 0x00, 0x01, 0x71 },
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[CMD_SLEEP] = { 0x42, 0x4d, 0xe4, 0x00, 0x00, 0x01, 0x73 },
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};
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struct pms7003_frame {
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u8 data[PMS7003_MAX_DATA_LENGTH];
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u16 expected_length;
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u16 length;
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};
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struct pms7003_state {
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struct serdev_device *serdev;
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struct pms7003_frame frame;
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struct completion frame_ready;
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struct mutex lock; /* must be held whenever state gets touched */
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/* Used to construct scan to push to the IIO buffer */
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struct {
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u16 data[3]; /* PM1, PM2P5, PM10 */
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s64 ts;
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} scan;
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};
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static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd)
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{
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int ret;
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ret = serdev_device_write(state->serdev, pms7003_cmd_tbl[cmd],
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PMS7003_CMD_LENGTH, PMS7003_TIMEOUT);
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if (ret < PMS7003_CMD_LENGTH)
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return ret < 0 ? ret : -EIO;
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ret = wait_for_completion_interruptible_timeout(&state->frame_ready,
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PMS7003_TIMEOUT);
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if (!ret)
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ret = -ETIMEDOUT;
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return ret < 0 ? ret : 0;
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}
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static u16 pms7003_get_pm(const u8 *data)
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{
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return clamp_val(get_unaligned_be16(data),
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PMS7003_PM_MIN, PMS7003_PM_MAX);
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}
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static irqreturn_t pms7003_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct pms7003_state *state = iio_priv(indio_dev);
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struct pms7003_frame *frame = &state->frame;
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int ret;
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mutex_lock(&state->lock);
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ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
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if (ret) {
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mutex_unlock(&state->lock);
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goto err;
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}
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state->scan.data[PM1] =
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pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET);
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state->scan.data[PM2P5] =
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pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET);
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state->scan.data[PM10] =
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pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET);
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mutex_unlock(&state->lock);
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iio_push_to_buffers_with_timestamp(indio_dev, &state->scan,
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iio_get_time_ns(indio_dev));
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err:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static int pms7003_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct pms7003_state *state = iio_priv(indio_dev);
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struct pms7003_frame *frame = &state->frame;
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_PROCESSED:
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switch (chan->type) {
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case IIO_MASSCONCENTRATION:
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mutex_lock(&state->lock);
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ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
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if (ret) {
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mutex_unlock(&state->lock);
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return ret;
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}
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*val = pms7003_get_pm(frame->data + chan->address);
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mutex_unlock(&state->lock);
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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return -EINVAL;
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}
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static const struct iio_info pms7003_info = {
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.read_raw = pms7003_read_raw,
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};
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#define PMS7003_CHAN(_index, _mod, _addr) { \
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.type = IIO_MASSCONCENTRATION, \
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.modified = 1, \
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.channel2 = IIO_MOD_ ## _mod, \
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.address = _addr, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
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.scan_index = _index, \
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.scan_type = { \
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.sign = 'u', \
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.realbits = 10, \
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.storagebits = 16, \
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.endianness = IIO_CPU, \
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}, \
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}
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static const struct iio_chan_spec pms7003_channels[] = {
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PMS7003_CHAN(0, PM1, PMS7003_PM1_OFFSET),
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PMS7003_CHAN(1, PM2P5, PMS7003_PM2P5_OFFSET),
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PMS7003_CHAN(2, PM10, PMS7003_PM10_OFFSET),
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IIO_CHAN_SOFT_TIMESTAMP(3),
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};
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static u16 pms7003_calc_checksum(struct pms7003_frame *frame)
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{
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u16 checksum = (PMS7003_MAGIC >> 8) + (u8)(PMS7003_MAGIC & 0xff) +
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(frame->length >> 8) + (u8)frame->length;
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int i;
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for (i = 0; i < frame->length - PMS7003_CHECKSUM_LENGTH; i++)
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checksum += frame->data[i];
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return checksum;
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}
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static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
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{
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int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
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u16 checksum = get_unaligned_be16(frame->data + offset);
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return checksum == pms7003_calc_checksum(frame);
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}
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static int pms7003_receive_buf(struct serdev_device *serdev,
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const unsigned char *buf, size_t size)
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{
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struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
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struct pms7003_state *state = iio_priv(indio_dev);
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struct pms7003_frame *frame = &state->frame;
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int num;
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if (!frame->expected_length) {
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u16 magic;
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/* wait for SOF and data length */
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if (size < 4)
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return 0;
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magic = get_unaligned_be16(buf);
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if (magic != PMS7003_MAGIC)
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return 2;
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num = get_unaligned_be16(buf + 2);
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if (num <= PMS7003_MAX_DATA_LENGTH) {
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frame->expected_length = num;
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frame->length = 0;
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}
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return 4;
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}
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num = min(size, (size_t)(frame->expected_length - frame->length));
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memcpy(frame->data + frame->length, buf, num);
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frame->length += num;
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if (frame->length == frame->expected_length) {
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if (pms7003_frame_is_okay(frame))
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complete(&state->frame_ready);
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frame->expected_length = 0;
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}
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return num;
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}
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static const struct serdev_device_ops pms7003_serdev_ops = {
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.receive_buf = pms7003_receive_buf,
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.write_wakeup = serdev_device_write_wakeup,
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};
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static void pms7003_stop(void *data)
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{
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struct pms7003_state *state = data;
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pms7003_do_cmd(state, CMD_SLEEP);
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}
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static const unsigned long pms7003_scan_masks[] = { 0x07, 0x00 };
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static int pms7003_probe(struct serdev_device *serdev)
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{
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struct pms7003_state *state;
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struct iio_dev *indio_dev;
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int ret;
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indio_dev = devm_iio_device_alloc(&serdev->dev, sizeof(*state));
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if (!indio_dev)
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return -ENOMEM;
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state = iio_priv(indio_dev);
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serdev_device_set_drvdata(serdev, indio_dev);
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state->serdev = serdev;
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indio_dev->dev.parent = &serdev->dev;
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indio_dev->info = &pms7003_info;
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indio_dev->name = PMS7003_DRIVER_NAME;
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indio_dev->channels = pms7003_channels,
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indio_dev->num_channels = ARRAY_SIZE(pms7003_channels);
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->available_scan_masks = pms7003_scan_masks;
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mutex_init(&state->lock);
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init_completion(&state->frame_ready);
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serdev_device_set_client_ops(serdev, &pms7003_serdev_ops);
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ret = devm_serdev_device_open(&serdev->dev, serdev);
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if (ret)
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return ret;
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serdev_device_set_baudrate(serdev, 9600);
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serdev_device_set_flow_control(serdev, false);
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ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
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if (ret)
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return ret;
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ret = pms7003_do_cmd(state, CMD_WAKEUP);
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if (ret) {
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dev_err(&serdev->dev, "failed to wakeup sensor\n");
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return ret;
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}
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ret = pms7003_do_cmd(state, CMD_ENTER_PASSIVE_MODE);
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if (ret) {
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dev_err(&serdev->dev, "failed to enter passive mode\n");
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return ret;
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}
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ret = devm_add_action_or_reset(&serdev->dev, pms7003_stop, state);
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if (ret)
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return ret;
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ret = devm_iio_triggered_buffer_setup(&serdev->dev, indio_dev, NULL,
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pms7003_trigger_handler, NULL);
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if (ret)
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return ret;
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return devm_iio_device_register(&serdev->dev, indio_dev);
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}
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static const struct of_device_id pms7003_of_match[] = {
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{ .compatible = "plantower,pms1003" },
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{ .compatible = "plantower,pms3003" },
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{ .compatible = "plantower,pms5003" },
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{ .compatible = "plantower,pms6003" },
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{ .compatible = "plantower,pms7003" },
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{ .compatible = "plantower,pmsa003" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, pms7003_of_match);
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static struct serdev_device_driver pms7003_driver = {
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.driver = {
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.name = PMS7003_DRIVER_NAME,
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.of_match_table = pms7003_of_match,
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},
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.probe = pms7003_probe,
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};
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module_serdev_device_driver(pms7003_driver);
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MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
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MODULE_DESCRIPTION("Plantower PMS7003 particulate matter sensor driver");
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MODULE_LICENSE("GPL v2");
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