Escape special characters from SVG text

Ref https://github.com/GNS3/gns3-server/issues/952

gns3server/controller/link.py

@@ -18,6 +18,7 @@
 import os
 import re
 import uuid
+import html
 import asyncio
 import aiohttp
 
@@ -83,7 +84,7 @@ class Link:
                 "x": -10,
                 "y": -10,
                 "rotation": 0,
-                "text": "{}/{}".format(adapter_number, port_number),
+                "text": html.escape("{}/{}".format(adapter_number, port_number)),
                 "style": "font-size: 10; font-style: Verdana"
             }
 

gns3server/controller/node.py

@@ -17,6 +17,7 @@
 
 import aiohttp
 import asyncio
+import html
 import copy
 import uuid
 import os
@@ -229,7 +230,7 @@ class Node:
 
             self._label = {
                 "y": round(self._height / 2 + 10) * -1,
-                "text": self._name,
+                "text": html.escape(self._name),
                 "style": style,
                 "x": None,  # None: mean the client should center it
                 "rotation": 0

gns3server/controller/topology.py

@@ -16,6 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import html
 import json
 import copy
 import uuid
@@ -434,7 +435,7 @@ def _convert_1_3_later(topo, topo_path):
             size=int(font_info[1]),
             weight=weight,
             style=style,
-            text=note["text"]
+            text=html.escape(note["text"])
         )
         new_note = {
             "drawing_id": str(uuid.uuid4()),
@@ -521,7 +522,7 @@ def _convert_label(label):
     """
     style = qt_font_to_style(label.get("font"), label.get("color"))
     return {
-        "text": label["text"],
+        "text": html.escape(label["text"]),
         "rotation": 0,
         "style": style,
         "x": int(label["x"]),