Use in Mosel Restricted Mode

When Mosel is run in restricted mode, the JVM will be started with a security manager that will try to match the Mosel security model. For example, if the Mosel WDOnly restriction is present, you will be prevented from reading from or writing to any files outside of the Mosel instance's working directory. If you set a classpath using the jvmclasspath parameter, this must contain only jars and directories that are readable under any active Mosel security restrictions (e.g. in the work directory or a directly specified in MOSEL_ROPATH or MOSEL_RWPATH if WDOnly restriction is active).

The JVM will always be able to read from the Java installation directory, and any configured Java extension directories, regardless of the Mosel restrictions level.

When the NoExec restriction is present, the use of Java is subject to several additional restrictions:

• Other processes may not be started from Java.
• Native libraries may not be loaded by the Java Virtual Machine, except for those installed within the Java installation directory.
• The JVM's classpath shall only be read from the environment variable MOSJVM_CLASSPATH or the paramter jvmclasspath.
• The environment variable MOSJVM_ALLOW must contain a whitespace-separated list of the classes that can be called using a jvmcall<type> function, or '*' if you wish to allow any class to be called.
• Arbitrary JVM arguments may not be specified using jvmsetcreationargs.

When any Mosel security restriction is present (i.e. MOSEL_RESTR is non-zero), the JVM will additionally be restricted as follows:

• The JVM may not open any GUI windows.
• System.setSecurityManager may not be called.
• Direct access to file descriptors is disabled.
• Access to the printing API is disabled.
• Access to the audio API is disabled.
• Access to the reflection API is disabled.
• Access to the preferences backing store is disabled.
• Code may not add additional classes with package names starting java. or sun.
• Java code may not set cookie handlers, proxy selectors, response caches or change the default authenticator.
• Java code may not set SSL hostname verifiers or change the default SSL context.
• Creation of sockets is disabled.
• Access to private credentials is disabled.
• Access to Kerberos delegation is disabled.

The above list is not intended to be exhaustive; the permissions required to perform Java operations are sometimes non-obvious. When building a solution that will use mosjvm in an environment where Mosel security restrictions are in place, it is recommended that the developer performs testing with the required Mosel security restrictions as early as possible.