[6.1.y] i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

Commit Message

Ren, Jianqi (Jacky) (CN) Dec. 10, 2024, 8:20 a.m. UTC

From: Kaixin Wang <[e-mail]>

[ 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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>
Signed-off-by: Jianqi Ren <[e-mail]>
---
 drivers/i3c/master/i3c-master-cdns.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index b9cfda6ae9ae..4473c0b1ae2e 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -1668,6 +1668,7 @@  static int cdns_i3c_master_remove(struct platform_device *pdev)
 	struct cdns_i3c_master *master = platform_get_drvdata(pdev);
 	int ret;
 
+	cancel_work_sync(&master->hj_work);
 	ret = i3c_master_unregister(&master->base);
 	if (ret)
 		return ret;