001 package com.croftsoft.core.security.manager;
002
003 import java.io.FileDescriptor;
004 import java.net.InetAddress;
005
006 /*********************************************************************
007 * A generic <I>SecurityManager</I> implementation to host untrusted
008 * code loaded over a network. "Untrusted" code is defined as any
009 * class that was loaded using a <I>ClassLoader</I> instead of being
010 * read in directly from the local <I>classpath</I>.
011 *
012 * <P>
013 *
014 * Implement by including the following as the very first line of the
015 * <I>main ( )</I> method of your application:
016 *
017 * <PRE>
018 * System.setSecurityManager ( new HostSecurityManager ( ) );
019 * </PRE>
020 *
021 * <P>
022 *
023 * Each of the 29 "check" methods of the standard Java 1.1.5 superclass
024 * <I>SecurityManager</I> are overridden to just call the
025 * <A HREF="#reject_untrusted">reject_untrusted ( )</A> method.
026 * This method simply throws a <I>SecurityException</I> if the
027 * superclass method <I>inClassLoader ( )</I> returns true.
028 *
029 * <P>
030 *
031 * To my knowledge, the only four possible "hostile" actions remaining
032 * that untrusted code could still perform on the host when using
033 * this implementation of <I>SecurityManager</I> are
034 *
035 * <UL>
036 * <LI> attempting to read from the standard input <I>System.in</I>,
037 * <LI> writing to the console outputs <I>err</I> and <I>out</I>,
038 * <LI> consuming excessive processor time in its single thread, and
039 * <LI> consuming memory until an <I>OutOfMemoryError</I> occurs.
040 * </UL>
041 *
042 * <P>
043 *
044 * Preventing untrusted code from reading from and writing to the
045 * standard console could be accomplished by replacing the default
046 * IO streams with customized classes that would throw a
047 * <I>SecurityException</I>.
048 *
049 * See <I>System.setErr ( err )</I>, <I>System.setIn ( in )</I>, and
050 * <I>System.setOut ( out )</I>.
051 *
052 * <P>
053 *
054 * If the standard console IO stream blocking were implemented,
055 * untrusted code would have no method of communication except by
056 * calling the methods of other objects within the virtual machine.
057 * Further communication (sockets, etc.) to the outside could then be
058 * optionally permitted by trusted classes. See
059 * <I>SecurityManager.inCheck</I>,
060 * <I>SecurityManager.getInCheck ( )</I>, and
061 * <I>SecurityManager.getSecurityContext ( )</I>.
062 *
063 * @author
064 * <A HREF="http://www.alumni.caltech.edu/~croft">David W. Croft</A>
065 * @version
066 * 1999-02-13
067 *********************************************************************/
068
069 public class UntrustedSecurityManager extends SecurityManager
070 //////////////////////////////////////////////////////////////////////
071 //////////////////////////////////////////////////////////////////////
072 {
073
074 /*********************************************************************
075 * Called by all of the "check" methods to foil untrusted code.
076 * <PRE>
077 * if ( inClassLoader ( ) )
078 * throw new SecurityException ( "untrusted" );
079 * </PRE>
080 *********************************************************************/
081 protected void reject_untrusted ( )
082 //////////////////////////////////////////////////////////////////////
083 {
084 if ( inClassLoader ( ) )
085 throw new SecurityException ( "untrusted" );
086 }
087
088 //////////////////////////////////////////////////////////////////////
089 // Check methods
090 //////////////////////////////////////////////////////////////////////
091
092 public void checkAccept ( String host, int port )
093 { reject_untrusted ( ); }
094
095 public void checkAccess ( Thread t )
096 { reject_untrusted ( ); }
097
098 public void checkAccess ( ThreadGroup g )
099 { reject_untrusted ( ); }
100
101 public void checkAwtEventQueueAccess ( )
102 { reject_untrusted ( ); }
103
104 public void checkConnect ( String host, int port )
105 { reject_untrusted ( ); }
106
107 public void checkConnect ( String host, int port, Object context )
108 { reject_untrusted ( ); }
109
110 public void checkCreateClassLoader ( )
111 { reject_untrusted ( ); }
112
113 public void checkDelete ( String file )
114 { reject_untrusted ( ); }
115
116 public void checkExec ( String cmd )
117 { reject_untrusted ( ); }
118
119 public void checkExit ( int status )
120 { reject_untrusted ( ); }
121
122 public void checkLink ( String libname )
123 { reject_untrusted ( ); }
124
125 public void checkListen ( int port )
126 { reject_untrusted ( ); }
127
128 public void checkMemberAccess ( Class clazz, int which )
129 { reject_untrusted ( ); }
130
131 public void checkMulticast ( InetAddress maddr )
132 { reject_untrusted ( ); }
133
134 public void checkMulticast ( InetAddress maddr, byte ttl )
135 { reject_untrusted ( ); }
136
137 public void checkPackageAccess ( String pkg )
138 { reject_untrusted ( ); }
139
140 public void checkPackageDefinition ( String pkg )
141 { reject_untrusted ( ); }
142
143 public void checkPrintJobAccess ( )
144 { reject_untrusted ( ); }
145
146 public void checkPropertiesAccess ( )
147 { reject_untrusted ( ); }
148
149 public void checkPropertyAccess ( String key )
150 { reject_untrusted ( ); }
151
152 public void checkRead ( FileDescriptor fd )
153 { reject_untrusted ( ); }
154
155 public void checkRead ( String file )
156 { reject_untrusted ( ); }
157
158 public void checkRead ( String file, Object context )
159 { reject_untrusted ( ); }
160
161 public void checkSecurityAccess ( String action )
162 { reject_untrusted ( ); }
163
164 public void checkSetFactory ( )
165 { reject_untrusted ( ); }
166
167 public void checkSystemClipboardAccess ( )
168 { reject_untrusted ( ); }
169
170 public boolean checkTopLevelWindow ( Object window )
171 { reject_untrusted ( ); return true; }
172
173 public void checkWrite ( FileDescriptor fd )
174 { reject_untrusted ( ); }
175
176 public void checkWrite ( String file )
177 { reject_untrusted ( ); }
178
179 //////////////////////////////////////////////////////////////////////
180 //////////////////////////////////////////////////////////////////////
181 }