[PATCH net v3 2/2] ax25: Change kfree() in ax25_dev_free() to ax25_dev_put()

From: Duoming Zhou
Date: Mon May 06 2024 - 10:09:44 EST


The object "ax25_dev" is managed by reference counting. Thus it should
not be directly released by a kfree() call in ax25_dev_free(). Replace
it with a ax25_dev_put() call instead.

Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
---
Changes in v3:
- Make commit messages more clearer.

net/ax25/ax25_dev.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index fbaaba0351e..8ee028e752f 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -188,16 +188,13 @@ struct net_device *ax25_fwd_dev(struct net_device *dev)
*/
void __exit ax25_dev_free(void)
{
- ax25_dev *s, *ax25_dev;
+ ax25_dev *s, *n;

spin_lock_bh(&ax25_dev_lock);
- ax25_dev = ax25_dev_list;
- while (ax25_dev != NULL) {
- s = ax25_dev;
- netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
- ax25_dev = ax25_dev->next;
- kfree(s);
+ list_for_each_entry_safe(s, n, &ax25_dev_list, list) {
+ netdev_put(s->dev, &s->dev_tracker);
+ list_del(&s->list);
+ ax25_dev_put(s);
}
- ax25_dev_list = NULL;
spin_unlock_bh(&ax25_dev_lock);
}
--
2.17.1