Bluetooth: HCI: Use skb_pull_data to parse Inquiry Result with RSSI event

This uses skb_pull_data to check the Inquiry Result with RSSI events
received have the minimum required length.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci.h

@@ -2194,7 +2194,7 @@ struct hci_ev_pscan_rep_mode {
 } __packed;
 
 #define HCI_EV_INQUIRY_RESULT_WITH_RSSI	0x22
-struct inquiry_info_with_rssi {
+struct inquiry_info_rssi {
 	bdaddr_t bdaddr;
 	__u8     pscan_rep_mode;
 	__u8     pscan_period_mode;
@@ -2202,7 +2202,7 @@ struct inquiry_info_with_rssi {
 	__le16   clock_offset;
 	__s8     rssi;
 } __packed;
-struct inquiry_info_with_rssi_and_pscan_mode {
+struct inquiry_info_rssi_pscan {
 	bdaddr_t bdaddr;
 	__u8     pscan_rep_mode;
 	__u8     pscan_period_mode;
@@ -2211,6 +2211,14 @@ struct inquiry_info_with_rssi_and_pscan_mode {
 	__le16   clock_offset;
 	__s8     rssi;
 } __packed;
+struct hci_ev_inquiry_result_rssi {
+	__u8     num;
+	struct inquiry_info_rssi info[];
+} __packed;
+struct hci_ev_inquiry_result_rssi_pscan {
+	__u8     num;
+	struct inquiry_info_rssi_pscan info[];
+} __packed;
 
 #define HCI_EV_REMOTE_EXT_FEATURES	0x23
 struct hci_ev_remote_ext_features {

net/bluetooth/hci_event.c

@@ -4921,12 +4921,21 @@ static void hci_pscan_rep_mode_evt(struct hci_dev *hdev, struct sk_buff *skb)
 static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					     struct sk_buff *skb)
 {
+	union {
+		struct hci_ev_inquiry_result_rssi *res1;
+		struct hci_ev_inquiry_result_rssi_pscan *res2;
+	} *ev;
 	struct inquiry_data data;
-	int num_rsp = *((__u8 *) skb->data);
+	int i;
 
-	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_INQUIRY_RESULT_WITH_RSSI,
+			     sizeof(*ev));
+	if (!ev)
+		return;
+
+	BT_DBG("%s num_rsp %d", hdev->name, ev->res1->num);
 
-	if (!num_rsp)
+	if (!ev->res1->num)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
@@ -4934,16 +4943,13 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 
 	hci_dev_lock(hdev);
 
-	if ((skb->len - 1) / num_rsp != sizeof(struct inquiry_info_with_rssi)) {
-		struct inquiry_info_with_rssi_and_pscan_mode *info;
-		info = (void *) (skb->data + 1);
+	if (skb->len == flex_array_size(ev, res2->info, ev->res2->num)) {
+		struct inquiry_info_rssi_pscan *info;
 
-		if (skb->len < num_rsp * sizeof(*info) + 1)
-			goto unlock;
-
-		for (; num_rsp; num_rsp--, info++) {
+		for (i = 0; i < ev->res2->num; i++) {
 			u32 flags;
 
+			info = &ev->res2->info[i];
 			bacpy(&data.bdaddr, &info->bdaddr);
 			data.pscan_rep_mode	= info->pscan_rep_mode;
 			data.pscan_period_mode	= info->pscan_period_mode;
@@ -4959,15 +4965,13 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					  info->dev_class, info->rssi,
 					  flags, NULL, 0, NULL, 0);
 		}
-	} else {
-		struct inquiry_info_with_rssi *info = (void *) (skb->data + 1);
+	} else if (skb->len == flex_array_size(ev, res1->info, ev->res1->num)) {
+		struct inquiry_info_rssi *info;
 
-		if (skb->len < num_rsp * sizeof(*info) + 1)
-			goto unlock;
-
-		for (; num_rsp; num_rsp--, info++) {
+		for (i = 0; i < ev->res1->num; i++) {
 			u32 flags;
 
+			info = &ev->res1->info[i];
 			bacpy(&data.bdaddr, &info->bdaddr);
 			data.pscan_rep_mode	= info->pscan_rep_mode;
 			data.pscan_period_mode	= info->pscan_period_mode;
@@ -4983,9 +4987,11 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					  info->dev_class, info->rssi,
 					  flags, NULL, 0, NULL, 0);
 		}
+	} else {
+		bt_dev_err(hdev, "Malformed HCI Event: 0x%2.2x",
+			   HCI_EV_INQUIRY_RESULT_WITH_RSSI);
 	}
 
-unlock:
 	hci_dev_unlock(hdev);
 }