From: Kaixin Wang <kxwang23@m.fudan.edu.cn>

[ Upstream commit 609366e7a06d035990df78f1562291c3bf0d4a12 ]

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>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
---
 drivers/i3c/master/i3c-master-cdns.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 35b90bb686ad..c5a37f58079a 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -1667,6 +1667,7 @@ static int 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);
-- 
2.25.1

On Mon, Jan 06, 2025 at 10:29:39AM +0800, jianqi.ren.cn@windriver.com wrote:
> From: Kaixin Wang <kxwang23@m.fudan.edu.cn>
> 
> [ Upstream commit 609366e7a06d035990df78f1562291c3bf0d4a12 ]

Again, sorry, but no, I will not take any more stable backports from
your company at this point in time.  Please go tell your managers this
as somehow the previous emails from me seem to have been ignored.

greg k-h