The ax25_dev_device_down() exists reference count leak issues of
the object "net_device". When the ax25 device is shutting down.
The ax25_dev_device_down() drops the reference count of net_device
one or zero times depending on if we goto unlock_put or not, which
will cause memory leak.
In order to solve the above issue, decrease the reference count of
net_device after dev->ax25_ptr is set to null.
Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Suggested-by: Dan Carpenter <[email protected]>
Signed-off-by: Duoming Zhou <[email protected]>
---
Changes in v4:
- Make the fix procedure of net_device as a separate update steps.
net/ax25/ax25_dev.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 6a572fe1046..05e556cdc2b 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -120,15 +120,9 @@ void ax25_dev_device_down(struct net_device *dev)
list_for_each_entry(s, &ax25_dev_list, list) {
if (s == ax25_dev) {
list_del(&s->list);
- goto unlock_put;
+ break;
}
}
- dev->ax25_ptr = NULL;
- spin_unlock_bh(&ax25_dev_lock);
- ax25_dev_put(ax25_dev);
- return;
-
-unlock_put:
dev->ax25_ptr = NULL;
spin_unlock_bh(&ax25_dev_lock);
netdev_put(dev, &ax25_dev->dev_tracker);
--
2.17.1