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* [PATCH] memstick: r592: Fix UAF bug in r592_remove due to race condition
@ 2023-03-07 16:42 Zheng Wang
  0 siblings, 0 replies; 4+ messages in thread
From: Zheng Wang @ 2023-03-07 16:42 UTC (permalink / raw)
  To: maximlevitsky
  Cc: oakad, ulf.hansson, linux-mmc, linux-kernel, hackerzheng666,
	1395428693sheep, alex000young, Zheng Wang

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@163.com>
---
 drivers/memstick/host/r592.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
index 1d35d147552d..2bfa7eaae80a 100644
--- a/drivers/memstick/host/r592.c
+++ b/drivers/memstick/host/r592.c
@@ -829,7 +829,7 @@ 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) {
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH] memstick: r592: Fix UAF bug in r592_remove due to race condition
@ 2023-03-07 16:43 Zheng Wang
  2023-03-09 15:02 ` Ulf Hansson
  0 siblings, 1 reply; 4+ messages in thread
From: Zheng Wang @ 2023-03-07 16:43 UTC (permalink / raw)
  To: maximlevitsky
  Cc: oakad, ulf.hansson, linux-mmc, linux-kernel, hackerzheng666,
	1395428693sheep, alex000young, Zheng Wang

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@163.com>
---
 drivers/memstick/host/r592.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
index 1d35d147552d..2bfa7eaae80a 100644
--- a/drivers/memstick/host/r592.c
+++ b/drivers/memstick/host/r592.c
@@ -829,7 +829,7 @@ 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) {
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2023-03-10 16:25 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-07 16:42 [PATCH] memstick: r592: Fix UAF bug in r592_remove due to race condition Zheng Wang
2023-03-07 16:43 Zheng Wang
2023-03-09 15:02 ` Ulf Hansson
2023-03-10 16:20   ` Zheng Hacker

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