This is a note to let you know that I've just added the patch titled
memstick: r592: Fix UAF bug in r592_remove due to race condition
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
memstick-r592-fix-uaf-bug-in-r592_remove-due-to-race.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8da54b1a2d6e76275fff587aa69c9f135034d1cc
Author: Zheng Wang <zyytlz.wz@xxxxxxx>
Date: Wed Mar 8 00:43:38 2023 +0800
memstick: r592: Fix UAF bug in r592_remove due to race condition
[ Upstream commit 63264422785021704c39b38f65a78ab9e4a186d7 ]
In r592_probe, dev->detect_timer was bound with r592_detect_timer.
In r592_irq function, the timer function will be invoked by mod_timer.
If we remove the module which will call hantro_release to make cleanup,
there may be a unfinished work. The possible sequence is as follows,
which will cause a typical UAF bug.
Fix it by canceling the work before cleanup in r592_remove.
CPU0 CPU1
|r592_detect_timer
r592_remove |
memstick_free_host|
put_device; |
kfree(host); |
|
| queue_work
| &host->media_checker //use
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Link: https://lore.kernel.org/r/20230307164338.1246287-1-zyytlz.wz@xxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
index 4728a42d54b88..edb1b5588b7a0 100644
--- a/drivers/memstick/host/r592.c
+++ b/drivers/memstick/host/r592.c
@@ -831,7 +831,7 @@ static void r592_remove(struct pci_dev *pdev)
/* Stop the processing thread.
That ensures that we won't take any more requests */
kthread_stop(dev->io_thread);
-
+ del_timer_sync(&dev->detect_timer);
r592_enable_device(dev, false);
while (!error && dev->req) {
