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Message-Id: <c1d18fcf1bf6ef65264ba992172ea1636dbf5431.1715065005.git.duoming@zju.edu.cn>
Date: Tue, 7 May 2024 15:03:41 +0800
From: Duoming Zhou <duoming@....edu.cn>
To: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
linux-hams@...r.kernel.org,
pabeni@...hat.com,
kuba@...nel.org,
edumazet@...gle.com,
jreuter@...na.de,
dan.carpenter@...aro.org,
Duoming Zhou <duoming@....edu.cn>
Subject: [PATCH net v5 3/4] ax25: Fix reference count leak issues of net_device
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 <dan.carpenter@...aro.org>
Signed-off-by: Duoming Zhou <duoming@....edu.cn>
---
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 66aa381af0e..c6ab9b0f0be 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -121,15 +121,9 @@ 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
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