The rmid Command (original) (raw)

default

The default or unspecified value execPolicy allows the rmid command to execute commands with specific command-line options only when the rmid command was granted permission to execute those commands and options in the security policy file that the rmid command uses. Only the default activation group implementation can be used with the default execution policy.

The rmid command starts a JVM for an activation group with the information in the group's registered activation group descriptor, ActivationGroupDesc. The group descriptor specifies an optional ActivationGroupDesc.CommandEnvironment that includes the command to execute to start the activation group and any command-line options to be added to the command line. By default, the rmid command uses the java command found in java.home. The group descriptor also contains properties overrides that are added to the command line as options defined as: -Dproperty=value. The com.sun.rmi.rmid.ExecPermission permission grants the rmid command permission to execute a command that's specified in the group descriptor's CommandEnvironment to start an activation group. The com.sun.rmi.rmid.ExecOptionPermission permission enables the rmid command to use command-line options, specified as properties overrides in the group descriptor or as options in the CommandEnvironment when starting the activation group. When granting the rmid command permission to execute various commands and options, the permissions ExecPermission and ExecOptionPermission must be granted to all code sources.

ExecPermission class: Represents permission for the rmid command to execute a specific command to start an activation group.

ExecPermission syntax: The name of ExecPermission is the path name of a command to grant the rmid command permission to execute.

A path name that ends in a slash (/) and an asterisk (*) indicates that all of the files are contained in that directory where the slash is the file-separator character, File.separatorChar.

A path name that ends in a slash (/) and a minus sign (-) indicates that all files and subdirectories are contained in that directory (recursively).

A path name that consists of the special token <<ALL FILES>> matches any file.

A path name that consists of an asterisk (*) indicates that all the files are in the current directory.

A path name that consists of a minus sign (-) indicates that all the files are in the current directory and (recursively) all files and subdirectories are contained in the current directory.

ExecOptionPermission class: Represents permission for the rmid command to use a specific command-line option when starting an activation group. The name of ExecOptionPermission is the value of a command-line option.

ExecOptionPermission syntax: Options support a limited wild card scheme. An asterisk signifies a wild card match, and it can appear as the option name itself (matches any option), or an asterisk (*) can appear at the end of the option name only when the asterisk (*) follows a dot (.) or an equals sign (=).

For example: * or -Dmydir.* or -Da.b.c=* is valid, but *mydir or -Da*b or ab* isn't valid.

Policy file for rmid

When you grant the rmid command permission to execute various commands and options, the permissions ExecPermission and ExecOptionPermission must be granted to all code sources (universally). It is safe to grant these permissions universally because only the rmid command checks these permissions.

An example policy file that grants various execute permissions to the rmid command is:

Linux:

grant {  
    permission com.sun.rmi.rmid.ExecPermission  
        "/files/apps/java/jdk1.7.0/linux/bin/java";  
    permission com.sun.rmi.rmid.ExecPermission  
        "/files/apps/rmidcmds/*";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Djava.security.policy=/files/policies/group.policy";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Djava.security.debug=*";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Dsun.rmi.*";  
};

Windows:

grant {  
    permission com.sun.rmi.rmid.ExecPermission  
        "c:\\files\\apps\\java\\jdk1.7.0\\win\\bin\\java";  
    permission com.sun.rmi.rmid.ExecPermission  
        "c:\\files\\apps\\rmidcmds\\*";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Djava.security.policy=c:\\files\\policies\\group.policy";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Djava.security.debug=*";  
    permission com.sun.rmi.rmid.ExecOptionPermission  
        "-Dsun.rmi.*";  
};

The first permission granted allows the rmid command to execute the 1.7.0 release of the java command, specified by its explicit path name. By default, the version of the java command found in java.home is used (the same one that the rmid command uses), and doesn't need to be specified in the policy file. The second permission allows the rmid command to execute any command in either the directory /files/apps/rmidcmds (Linux and macOS) or the directory c:\files\apps\rmidcmds\ (Windows).

The third permission granted, ExecOptionPermission, allows the rmid command to start an activation group that defines the security policy file to be either /files/policies/group.policy (Linux) or c:\files\policies\group.policy (Windows). The next permission allows the java.security.debug property to be used by an activation group. The last permission allows any property in the sun.rmi property name hierarchy to be used by activation groups.

To start the rmid command with a policy file, the java.security.policy property needs to be specified on the rmid command line, for example:

rmid -J-Djava.security.policy=rmid.policy.

policyClassName

If the default behavior isn't flexible enough, then an administrator can provide, when starting the rmid command, the name of a class whose checkExecCommand method is executed to check commands to be executed by the rmid command.

The policyClassName specifies a public class with a public, no-argument constructor and an implementation of the following checkExecCommand method:

 public void checkExecCommand(ActivationGroupDesc desc, String[] command)
        throws SecurityException;

Before starting an activation group, the rmid command calls the policy's checkExecCommand method and passes to it the activation group descriptor and an array that contains the complete command to start the activation group. If the checkExecCommand throws a SecurityException, then the rmid command doesn't start the activation group and an ActivationException is thrown to the caller attempting to activate the object.