i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due...

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 <kxwang23@m.fudan.edu.cn>
Link: https://lore.kernel.org/r/20240911153544.848398-1-kxwang23@m.fudan.edu.cn
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index ee555255f1a2404944628f4f6927c5e93b7e835a..fe4d59833ad5f4e77a32b7f195b8c8e32af895d8 100644 (file)
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/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);