linux-kernel - [PATCH] i3c: master: cdns: Fix use after free vulnerability in cdns_i3c

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Message-Id: <20240911153544.848398-1-kxwang23@m.fudan.edu.cn>
Date: Wed, 11 Sep 2024 23:35:44 +0800
From: Kaixin Wang <kxwang23@...udan.edu.cn>
To: pgaj@...ence.com
Cc: alexandre.belloni@...tlin.com,
	linux-kernel@...r.kernel.org,
	21210240012@...udan.edu.cn,
	21302010073@...udan.edu.cn,
	Kaixin Wang <kxwang23@...udan.edu.cn>
Subject: [PATCH] i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

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@...udan.edu.cn>
---
 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 ee555255f1a2..fe4d59833ad5 100644
--- 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);
-- 
2.25.1