| Message ID | 20240324140444.119584-1-duoming@zju.edu.cn (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger | expand |
On 3/24/24 07:04, Duoming Zhou wrote: > 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 <duoming@zju.edu.cn> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > 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 688b112e712..9f279c0e13a 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_shutdown_sync(&cpu5wdt_device.timer); > } > > misc_deregister(&cpu5wdt_misc);
diff --git a/drivers/watchdog/cpu5wdt.c b/drivers/watchdog/cpu5wdt.c index 688b112e712..9f279c0e13a 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_shutdown_sync(&cpu5wdt_device.timer); } misc_deregister(&cpu5wdt_misc);
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 <duoming@zju.edu.cn> --- drivers/watchdog/cpu5wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)