Copy data to beginning of buffer, not end. (#2542)

Copy data to beginning of buffer, not end.

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 5.2.2
+  - Bugfix
+    - buffer overrun in tile plugin response handling
+
 # 5.2.0
   Changes form 5.2.0 RC2
    - Bugfixes:

src/server/request_handler.cpp

@@ -105,11 +105,10 @@ void RequestHandler::HandleRequest(const http::request &current_request, http::r
         else
         {
             BOOST_ASSERT(result.is<std::string>());
-            current_reply.content.resize(current_reply.content.size() +
-                                         result.get<std::string>().size());
+            current_reply.content.resize(result.get<std::string>().size());
             std::copy(result.get<std::string>().cbegin(),
                       result.get<std::string>().cend(),
-                      current_reply.content.end());
+                      current_reply.content.begin());
 
             current_reply.headers.emplace_back("Content-Type", "application/x-protobuf");
         }