From: Lars-Peter Clausen lars@metafoo.de

stable inclusion from stable-v4.19.221 commit f5deab10ced368c807866283f8b79144c4823be8 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9S271 CVE: CVE-2021-47500

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

--------------------------------

commit cd0082235783f814241a1c9483fb89e405f4f892 upstream.

The mma8452 driver directly assigns a trigger to the struct iio_dev. The IIO core when done using this trigger will call `iio_trigger_put()` to drop the reference count by 1.

Without the matching `iio_trigger_get()` in the driver the reference count can reach 0 too early, the trigger gets freed while still in use and a use-after-free occurs.

Fix this by getting a reference to the trigger before assigning it to the IIO device.

Fixes: ae6d9ce05691 ("iio: mma8452: Add support for interrupt driven triggers.") Signed-off-by: Lars-Peter Clausen lars@metafoo.de Link: https://lore.kernel.org/r/20211024092700.6844-1-lars@metafoo.de Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zhang Changzhong zhangchangzhong@huawei.com --- drivers/iio/accel/mma8452.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c index 421a0a8..db815ba 100644 --- a/drivers/iio/accel/mma8452.c +++ b/drivers/iio/accel/mma8452.c @@ -1465,7 +1465,7 @@ static int mma8452_trigger_setup(struct iio_dev *indio_dev) if (ret) return ret;

- indio_dev->trig = trig; + indio_dev->trig = iio_trigger_get(trig);

return 0; }