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  1. JDK
  2. JDK-8037938

Socket connect requires crossdomain.xml

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    • Icon: Bug Bug
    • Resolution: Not an Issue
    • Icon: P3 P3
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      FULL PRODUCT VERSION :
      1.8.0

      ADDITIONAL OS VERSION INFORMATION :
      Ubuntu 13.10, Windows 8

      A DESCRIPTION OF THE PROBLEM :
      An applet connects back to codebasehost on port 7777. It is denied access with a java.net.SocketPermission. Adding

      permission java.net.SocketPermission "10.0.101.9:7777", "connect,resolve";

      ...to policy file resolves the problem, but this should not be necessary. Setting up a sniffer indicates that Java behind the curtains actually does connect to the port but thinks it is a web server and asks for crossdomain.xml which is not hosted on that port.

      REGRESSION. Last worked in version 7u51

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Compile, jar and sign the following:

      import javax.swing.JApplet;
      import java.net.Socket;

      public class Test extends JApplet {
          private int getParameter(String name, int def) {
              try {
                  def = Integer.parseInt(getParameter(name));
              } catch (Exception e) {
              }
              return def;
          }
          public void init() {
              String host = getCodeBase().getHost();
              try {
                  Socket s = new Socket(host, getParameter("PORT", 7777));
                  s.getOutputStream().write("Hello from client".getBytes("ascii"));
                  byte b[] = new byte[1024];
                  int bytesRead = s.getInputStream().read(b);

                  System.out.write(b, 0, bytesRead);
                  System.out.flush();
                  s.close();
              } catch (Exception e) {
                  System.out.println(e);
              }
          }
      }


      ...with this manifest file:

      Permissions: sandbox
      Caller-Allowable-Codebase: *
      Codebase: *
      Application-Name: Test


      Put on webserver with this index.html:
      <html>
          <body>
              <applet archive="test.jar" code="Test" width="0" height="0">
                  <param name="PORT" value="7777"/>
              </applet>
          </body>
      </html>

      Run a server on web server host like this:

      $ echo "Hello from server" | nc -l 7777

      Run appletviewer from machine with Java 1.8.0:

      $ appletviewer http://webserver/index.html

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      On the server you should receive the string "Hello from client" on the console, and in the client you should get "Hello from server" in java console.


      ACTUAL -
      Server receives web request, client gets SocketPermission exception.

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import javax.swing.JApplet;
      import java.net.Socket;

      public class Test extends JApplet {
          private int getParameter(String name, int def) {
              try {
                  def = Integer.parseInt(getParameter(name));
              } catch (Exception e) {
              }
              return def;
          }
          public void init() {
              String host = getCodeBase().getHost();
              try {
                  Socket s = new Socket(host, getParameter("PORT", 7777));
                  s.getOutputStream().write("Hello from client".getBytes("ascii"));
                  byte b[] = new byte[1024];
                  int bytesRead = s.getInputStream().read(b);

                  System.out.write(b, 0, bytesRead);
                  System.out.flush();
                  s.close();
              } catch (Exception e) {
                  System.out.println(e);
              }
          }
      }

      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Ask for permissions in client policy file:

      permission java.net.SocketPermission "10.0.101.9:7777", "connect,resolve";

            ngthomas Thomas Ng (Inactive)
            webbuggrp Webbug Group
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              Created:
              Updated:
              Resolved: