In the Linux kernel, the following vulnerability has been resolved:
i2c: imx: Cancel hrtimer before clearing slave pointer
In i2c_imx_unreg_slave(), the slave pointer is set to NULL after disabling interrupts. However, a pending interrupt might already have started the hrtimer (i2c_imx_slave_timeout) before the pointer was cleared. If the hrtimer fires after i2c_imx->slave is set to NULL, the timer callback i2c_imx_slave_finish_op() will call i2c_imx_slave_event() with a NULL slave pointer, which results in a use-after-free / NULL pointer dereference.
Fix by canceling the hrtimer and waiting for it to complete after disabling interrupts, before clearing the slave pointer.
References
- https://git.kernel.org/stable/c/6ac7702b6cc2b94aaed9ef2d95bfbefcdc90061f
- https://git.kernel.org/stable/c/753060f2b77ff2f386addbd3ecadb95b9f90cddd
- https://git.kernel.org/stable/c/a8a1f9ac3d763e721586f15479ef9140b216ddf3
- https://git.kernel.org/stable/c/affd62f5719a78135b7441aa49c8cab3c3b5e838
- https://git.kernel.org/stable/c/dab4762ee7f3fd0a01980d5407ba48d0261d3bff