[PATCH AUTOSEL 6.11 30/76] i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

Sasha Levin
2024-10-04T18:19:21Z

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: Sasha Levin <sashal@kernel.org>
---
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 c1627f3552ce3..c2d26beb3da2b 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -1666,6 +1666,7 @@ 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);
--
2.43.0