Subject: [PATCH AUTOSEL 5.17 004/149] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt

From: Sasha Levin <[email-masked]>
Date: Fri, 1 Apr 2022 10:23:11 -0400

From: Soenke Huster <[email-masked]>

[ Upstream commit 3afee2118132e93e5f6fa636dfde86201a860ab3 ]

This event is just specified for SCO and eSCO link types.
On the reception of a HCI_Synchronous_Connection_Complete for a BDADDR
of an existing LE connection, LE link type and a status that triggers the
second case of the packet processing a NULL pointer dereference happens,
as conn->link is NULL.

Signed-off-by: Soenke Huster <[email-masked]>
Signed-off-by: Luiz Augusto von Dentz <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/bluetooth/hci_event.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index fc30f4c03d29..e47cde778b1c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4661,6 +4661,19 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, void *data,
 	struct hci_ev_sync_conn_complete *ev = data;
 	struct hci_conn *conn;
 
+	switch (ev->link_type) {
+	case SCO_LINK:
+	case ESCO_LINK:
+		break;
+	default:
+		/* As per Core 5.3 Vol 4 Part E 7.7.35 (p.2219), Link_Type
+		 * for HCI_Synchronous_Connection_Complete is limited to
+		 * either SCO or eSCO
+		 */
+		bt_dev_err(hdev, "Ignoring connect complete event for invalid link type");
+		return;
+	}
+
 	bt_dev_dbg(hdev, "status 0x%2.2x", ev->status);
 
 	hci_dev_lock(hdev);
-- 
2.34.1