i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

In the cdns_i3c_master_probe function, &master->hj_work is bound with
cdns_i3c_master_hj. And cdns_i3c_master_interrupt can call
cnds_i3c_master_demux_ibis function to start the work.

If we remove the module which will call cdns_i3c_master_remove to
make cleanup, it will free master->base through i3c_master_unregister
while the work mentioned above will be used. The sequence of operations
that may lead to a UAF bug is as follows:

CPU0                                      CPU1

                                     | cdns_i3c_master_hj
cdns_i3c_master_remove               |
i3c_master_unregister(&master->base) |
device_unregister(&master->dev)      |
device_release                       |
//free master->base                  |
                                     | i3c_master_do_daa(&master->base)
                                     | //use master->base

Fix it by ensuring that the work is canceled before proceeding with
the cleanup in cdns_i3c_master_remove.

Signed-off-by: Kaixin Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: Kaixin Wang

drivers/i3c/master/i3c-master-cdns.c

@@ -1667,6 +1667,7 @@ static void cdns_i3c_master_remove(struct platform_device *pdev)
 {
 	struct cdns_i3c_master *master = platform_get_drvdata(pdev);
 
+	cancel_work_sync(&master->hj_work);
 	i3c_master_unregister(&master->base);
 
 	clk_disable_unprepare(master->sysclk);