linux-kernel - [PATCH next] Bluetooth: L2CAP: Fix NULL dereference in l2cap_recv

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Message-ID: <f9975604-6a65-4bcc-b532-15fcaa6da0e5@stanley.mountain>
Date: Wed, 12 Feb 2025 19:40:30 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Luiz Augusto von Dentz <luiz.von.dentz@...el.com>
Cc: Marcel Holtmann <marcel@...tmann.org>,
	Johan Hedberg <johan.hedberg@...il.com>,
	Luiz Augusto von Dentz <luiz.dentz@...il.com>,
	linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH next] Bluetooth: L2CAP: Fix NULL dereference in
 l2cap_recv_acldata()

The "conn" pointer is NULL so this "goto drop;" will lead to a NULL
dereference when we call mutex_unlock(&conn->lock). Free the skb and
return directly instead.

Fixes: dd6367916d2d ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
 net/bluetooth/l2cap_core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 6cdc1dc3a7f9..fec11e576f31 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -7456,8 +7456,10 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 
 	hci_dev_unlock(hcon->hdev);
 
-	if (!conn)
-		goto drop;
+	if (!conn) {
+		kfree_skb(skb);
+		return;
+	}
 
 	BT_DBG("conn %p len %u flags 0x%x", conn, skb->len, flags);
 
-- 
2.47.2