[PATCH] i3c: master: svc: Fix use after free vulnerability in svc_i3c_master Driver Due to Race Condition

[Kaixin Wang]

In the svc_i3c_master_probe function, &master->hj_work is bound with
svc_i3c_master_hj_work, &master->ibi_work is bound with
svc_i3c_master_ibi_work. And svc_i3c_master_ibi_work  can start the
hj_work, svc_i3c_master_irq_handler can start the ibi_work.

If we remove the module which will call svc_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

                                    | svc_i3c_master_hj_work
svc_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 svc_i3c_master_remove.

Signed-off-by: Kaixin Wang <kxwang23@xxxxxxxxxxxxxx>
---
 drivers/i3c/master/svc-i3c-master.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 0a68fd1b81d4..e084ba648b4a 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1775,6 +1775,7 @@ static void svc_i3c_master_remove(struct platform_device *pdev)
 {
 	struct svc_i3c_master *master = platform_get_drvdata(pdev);
 
+	cancel_work_sync(&master->hj_work);
 	i3c_master_unregister(&master->base);
 
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
-- 
2.25.1