From: Zhengping Jiang <jiangzp@google.com>
Date: Thu, 25 May 2023 00:04:15 +0000 (-0700)
Subject: Bluetooth: L2CAP: Fix use-after-free
X-Git-Tag: v4.14.324~42
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e76bab1b7afa580cd76362540fc37551ada4359b;p=thirdparty%2Fkernel%2Fstable.git

Bluetooth: L2CAP: Fix use-after-free

[ Upstream commit f752a0b334bb95fe9b42ecb511e0864e2768046f ]

Fix potential use-after-free in l2cap_le_command_rej.

Signed-off-by: Zhengping Jiang <jiangzp@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 25d88b8cfae97..6bae68b5d439c 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5705,9 +5705,14 @@ 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);