This is a note to let you know that I've just added the patch titled
ax25: Fix reference count leak issue of net_device
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ax25-fix-reference-count-leak-issue-of-net_device.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0e8a4a77c6290bfc8e86f93df3ef84396b188121
Author: Duoming Zhou <duoming@xxxxxxxxxx>
Date: Thu May 9 17:37:02 2024 +0800
ax25: Fix reference count leak issue of net_device
[ Upstream commit 36e56b1b002bb26440403053f19f9e1a8bc075b2 ]
There is a reference count leak issue of the object "net_device" in
ax25_dev_device_down(). 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 <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/r/7ce3b23a40d9084657ba1125432f0ecc380cbc80.1715247018.git.duoming@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 52ccc37d5687a..c9d55b99a7a57 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -118,15 +118,10 @@ 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);
