From: Duoming Zhou <[email protected]>
commit 573601521277119f2e2ba5f28ae6e87fc594f4d4 upstream.
When the cpu5wdt module is removing, the origin code uses del_timer() to
de-activate the timer. If the timer handler is running, del_timer() could
not stop it and will return directly. If the port region is released by
release_region() and then the timer handler cpu5wdt_trigger() calls outb()
to write into the region that is released, the use-after-free bug will
happen.
Change del_timer() to timer_shutdown_sync() in order that the timer handler
could be finished before the port region is released.
Fixes: e09d9c3e9f85 ("watchdog: cpu5wdt.c: add missing del_timer call")
Signed-off-by: Duoming Zhou <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Wim Van Sebroeck <[email protected]>
[Zhe: Fix for CVE-2024-38630. The function timer_shutdown_sync in the
original fix is not introduced to 5.10 yet. But as stated in f571faf6e443
("timers: Provide timer_shutdown[_sync]()"), "timer_shutdown_sync() has the
same functionality as timer_delete_sync() plus the NULL-ification of the
timer function." So timer_delete_sync is enough for this case.]
Signed-off-by: He Zhe <[email protected]>
---
drivers/watchdog/cpu5wdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/watchdog/cpu5wdt.c b/drivers/watchdog/cpu5wdt.c
index 9867a3a936df..91adfb55c972 100644
--- a/drivers/watchdog/cpu5wdt.c
+++ b/drivers/watchdog/cpu5wdt.c
@@ -252,7 +252,7 @@ static void cpu5wdt_exit(void)
if (cpu5wdt_device.queue) {
cpu5wdt_device.queue = 0;
wait_for_completion(&cpu5wdt_device.stop);
- del_timer(&cpu5wdt_device.timer);
+ timer_delete_sync(&cpu5wdt_device.timer);
}
misc_deregister(&cpu5wdt_misc);
--
2.25.1
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