Bluetooth: Prevent out-of-bounds read in hci_inquiry_result_with_rssi_evt()

BugLink: https://bugs.launchpad.net/bugs/1892822

commit 629b49c8 upstream.

Check `num_rsp` before using it as for-loop counter. Add `unlock` label.

Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

net/bluetooth/hci_event.c

@@ -3609,6 +3609,9 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 		struct inquiry_info_with_rssi_and_pscan_mode *info;
 		info = (void *) (skb->data + 1);
 
+		if (skb->len < num_rsp * sizeof(*info) + 1)
+			goto unlock;
+
 		for (; num_rsp; num_rsp--, info++) {
 			u32 flags;
 
@@ -3630,6 +3633,9 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 	} else {
 		struct inquiry_info_with_rssi *info = (void *) (skb->data + 1);
 
+		if (skb->len < num_rsp * sizeof(*info) + 1)
+			goto unlock;
+
 		for (; num_rsp; num_rsp--, info++) {
 			u32 flags;
 
@@ -3650,6 +3656,7 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 		}
 	}
 
+unlock:
 	hci_dev_unlock(hdev);
 }