[PATCH 4.19 71/88] media: rc: do not access device via sysfs after rc_unregister_device()

Greg Kroah-Hartman
2020-09-08T18:31:37Z

From: Sean Young <sean@mess.org>

commit a2e2d73fa28136598e84db9d021091f1b98cbb1a upstream.

Device drivers do not expect to have change_protocol or wakeup
re-programming to be accesed after rc_unregister_device(). This can
cause the device driver to access deallocated resources.

Cc: <stable@vger.kernel.org> # 4.16+
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/rc/rc-main.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -1245,6 +1245,10 @@ static ssize_t store_protocols(struct de
}

mutex_lock(&dev->lock);
+ if (!dev->registered) {
+ mutex_unlock(&dev->lock);
+ return -ENODEV;
+ }

old_protocols = *current_protocols;
new_protocols = old_protocols;
@@ -1383,6 +1387,10 @@ static ssize_t store_filter(struct devic
return -EINVAL;

mutex_lock(&dev->lock);
+ if (!dev->registered) {
+ mutex_unlock(&dev->lock);
+ return -ENODEV;
+ }

new_filter = *filter;
if (fattr->mask)
@@ -1497,6 +1505,10 @@ static ssize_t store_wakeup_protocols(st
int i;

mutex_lock(&dev->lock);
+ if (!dev->registered) {
+ mutex_unlock(&dev->lock);
+ return -ENODEV;
+ }

allowed = dev->allowed_wakeup_protocols;