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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Soenke Huster <soenke.huster@eknoes.de>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.17 014/343] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt
Date:   Tue, 12 Apr 2022 08:27:12 +0200
Message-Id: <20220412062951.516538389@linuxfoundation.org>
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From: Soenke Huster <soenke.huster@eknoes.de>

[ 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 <soenke.huster@eknoes.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 a105b7317560..519f5906ee98 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);
-- 
2.35.1