cros_ec_sensors_push_data() reads some `indio_dev` states (e.g. iio_buffer_enabled() and `indio_dev->active_scan_mask`) without holding the `mlock`. An use-after-free on `indio_dev->active_scan_mask` was observed. The call trace: [...] _find_next_bit cros_ec_sensors_push_data cros_ec_sensorhub_event blocking_notifier_call_chain cros_ec_irq_thread It was caused by a race condition: one thread just freed `active_scan_mask` at [1]; while another thread tried to access the memory at [2]. Fix it by acquiring the `mlock` before accessing the `indio_dev` states. [1]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/industrialio-buffer.c#L1189 [2]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c#L198 Cc: stable@xxxxxxxxxxxxxxx Fixes: aa984f1ba4a4 ("iio: cros_ec: Register to cros_ec_sensorhub when EC supports FIFO") Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx> --- drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c index b72d39fc2434..a514d0dbafc7 100644 --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c @@ -182,17 +182,20 @@ int cros_ec_sensors_push_data(struct iio_dev *indio_dev, s16 *data, s64 timestamp) { + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); struct cros_ec_sensors_core_state *st = iio_priv(indio_dev); s16 *out; s64 delta; unsigned int i; + mutex_lock(&iio_dev_opaque->mlock); + /* * Ignore samples if the buffer is not set: it is needed if the ODR is * set but the buffer is not enabled yet. */ if (!iio_buffer_enabled(indio_dev)) - return 0; + goto exit; out = (s16 *)st->samples; for_each_set_bit(i, @@ -210,6 +213,8 @@ int cros_ec_sensors_push_data(struct iio_dev *indio_dev, iio_push_to_buffers_with_timestamp(indio_dev, st->samples, timestamp + delta); +exit: + mutex_unlock(&iio_dev_opaque->mlock); return 0; } EXPORT_SYMBOL_GPL(cros_ec_sensors_push_data); -- 2.42.0.rc1.204.g551eb34607-goog
