[PATCH AUTOSEL 5.4 08/12] Bluetooth: L2CAP: Fix use-after-free

From: Sasha Levin
Date: Sun Jul 23 2023 - 21:47:38 EST


From: Zhengping Jiang <jiangzp@xxxxxxxxxx>

[ Upstream commit f752a0b334bb95fe9b42ecb511e0864e2768046f ]

Fix potential use-after-free in l2cap_le_command_rej.

Signed-off-by: Zhengping Jiang <jiangzp@xxxxxxxxxx>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index e56863587ea2e..61bf489265505 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5723,9 +5723,14 @@ static inline int l2cap_le_command_rej(struct l2cap_conn *conn,
if (!chan)
goto done;

+ chan = l2cap_chan_hold_unless_zero(chan);
+ if (!chan)
+ goto done;
+
l2cap_chan_lock(chan);
l2cap_chan_del(chan, ECONNREFUSED);
l2cap_chan_unlock(chan);
+ l2cap_chan_put(chan);

done:
mutex_unlock(&conn->chan_lock);
--
2.39.2