[PATCH 5.4/5.10/5.15] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt

[PATCH 5.4/5.10/5.15] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt

[Ovidiu Panait]

From: Soenke Huster <soenke.huster@eknoes.de>

commit 3afee2118132e93e5f6fa636dfde86201a860ab3 upstream.

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: Ovidiu Panait <ovidiu.panait@eng.windriver.com>
---
This fixes "BUG: KASAN: use-after-free in sco_chan_del()" issue detected while
fuzzing with syzkaller.

 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 57bf05253e04..685f89516e1e 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4116,6 +4116,19 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
 	struct hci_ev_sync_conn_complete *ev = (void *) skb->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_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
 	hci_dev_lock(hdev);
-- 
2.23.0

Re: [PATCH 5.4/5.10/5.15] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt

[Greg KH]

On Wed, Feb 01, 2023 at 12:24:56PM +0200, Ovidiu Panait wrote:
> From: Soenke Huster <soenke.huster@eknoes.de>
> 
> commit 3afee2118132e93e5f6fa636dfde86201a860ab3 upstream.
> 
> 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: Ovidiu Panait <ovidiu.panait@eng.windriver.com>
> ---
> This fixes "BUG: KASAN: use-after-free in sco_chan_del()" issue detected while
> fuzzing with syzkaller.

Now queued up, thanks.

greg k-h