iio: imu: st_lsm6dsx: fix iio_chan_spec for sensors without event detection

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: iio: imu: st_lsm6dsx: fix iio_chan_spec for sensors without event detection The st_lsm6dsx_acc_channels array of struct iio_chan_spec has a non-NULL event_spec field, indicating support for IIO events. However, event detection is not supported for all sensors, and if userspace tries to configure accelerometer wakeup events on a sensor device that does not support them (e.g. LSM6DS0), st_lsm6dsx_write_event() dereferences a NULL pointer when trying to write to the wakeup register. Define an additional struct iio_chan_spec array whose members have a NULL event_spec field, and use this array instead of st_lsm6dsx_acc_channels for sensors without event detection capability.

References

• https://git.kernel.org/stable/c/7673167fac9323110973a3300637adba7d45de3a
• https://git.kernel.org/stable/c/4d60ffcdedfe2cdb68a1cde19bb292bc67451629
• https://git.kernel.org/stable/c/81ed6e42d6e555dd978c9dd5e3f7c20cb121221b
• https://git.kernel.org/stable/c/c34e2e2d67b3bb8d5a6d09b0d6dac845cdd13fb3