WebSockets: json-escape user strings loaded from manifest.xml

libs/surfaces/websockets/manifest.cc

@@ -16,6 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include <iomanip>
 #include <iostream>
 #include <sstream>
 
@@ -76,9 +77,9 @@ SurfaceManifest::to_json ()
 
 	ss << "{"
 		<< "\"path\":\"" << Glib::path_get_basename (_path) << "\""
-		<< ",\"name\":\"" << _name << "\""
-		<< ",\"description\":\"" << _description << "\""
-		<< ",\"version\":\"" << _version << "\""
+		<< ",\"name\":\"" << escape_json (_name) << "\""
+		<< ",\"description\":\"" << escape_json (_description) << "\""
+		<< ",\"version\":\"" << escape_json (_version) << "\""
 		<< "}";
 
 	return ss.str ();
@@ -90,3 +91,20 @@ SurfaceManifest::exists_at_path (std::string path)
 	std::string xml_path = Glib::build_filename (path, manifest_filename);
 	return Glib::file_test (xml_path, Glib::FILE_TEST_EXISTS);
 }
+
+/* adapted from https://stackoverflow.com/questions/10789740/passing-stdstring-by-value-or-reference
+   CC BY-SA 4.0 license */
+std::string
+SurfaceManifest::escape_json (const std::string &s) {
+    std::ostringstream o;
+
+    for (std::string::const_iterator it = s.begin(); it != s.end(); ++it) {
+        if (*it == '"' || *it == '\\' || ('\x00' <= *it && *it <= '\x1f')) {
+            o << "\\u" << std::hex << std::setw (4) << std::setfill ('0') << static_cast<int>(*it);
+        } else {
+            o << *it;
+        }
+    }
+    
+    return o.str ();
+}

libs/surfaces/websockets/manifest.h

@@ -37,6 +37,7 @@ public:
 	std::string to_json ();
 
 	static bool exists_at_path (std::string);
+	static std::string escape_json (const std::string&);
 
 private:
 	bool _valid;