qcacmn: Fix memory overflow in wmi roam scan filter cmd

The length of buffer used to send wmi roam scan filter cmd is not
properly calculated and thus the length is less than the actual data
to be copied.

Fix it by properly calculating the length of the buffer.

Change-Id: I6a3baa5ca5560d2d04f9bd41a709a37abc1b95a9
CRs-Fixed: 2072057

wmi_unified_tlv.c

@@ -5885,8 +5885,21 @@ static QDF_STATUS send_roam_scan_filter_cmd_tlv(wmi_unified_t wmi_handle,
 	wmi_roam_lca_disallow_config_tlv_param *blist_param;
 
 	len = sizeof(wmi_roam_filter_fixed_param);
+
 	len += WMI_TLV_HDR_SIZE;
-	len += roam_req->len;
+	if (roam_req->num_bssid_black_list)
+		len += roam_req->num_bssid_black_list * sizeof(wmi_mac_addr);
+	len += WMI_TLV_HDR_SIZE;
+	if (roam_req->num_ssid_white_list)
+		len += roam_req->num_ssid_white_list * sizeof(wmi_ssid);
+	len += 2 * WMI_TLV_HDR_SIZE;
+	if (roam_req->num_bssid_preferred_list) {
+		len += roam_req->num_bssid_preferred_list * sizeof(wmi_mac_addr);
+		len += roam_req->num_bssid_preferred_list * sizeof(A_UINT32);
+	}
+	if (roam_req->lca_disallow_config_present)
+		len += WMI_TLV_HDR_SIZE +
+			sizeof(wmi_roam_lca_disallow_config_tlv_param);
 
 	buf = wmi_buf_alloc(wmi_handle, len);
 	if (!buf) {