Assigning Privileges

You, in your capacity as system administrator, are responsible for assigning privileges. Typically, you assign the privilege to a command in a rights profile. The rights profile is then assigned to a role or to a user. The Solaris Management Console provides the graphical user interface (GUI) to assign privileges. Privileges can also be assigned by using commands such as smuser and smrole. For more information on how to use the GUI to assign privileges, see Chapter 9, Using Role-Based Access Control (Tasks).

Privileges can also be assigned directly to a user. If you trust a subset of users to use a privilege responsibly throughout their sessions, you can assign the privilege directly. Good candidates for direct assignment are privileges that have a limited effect, such as proc_clock_highres. Poor candidates for direct assignment are privileges that have far-reaching effects, such as file_dac_write.

Privileges can also be denied to a user or to a system. Care must be taken when removing privileges from the initial inheritable set or the limit set of a user or a system.

Expanding a User or Role's Privileges

Users and roles have an inheritable set of privileges, and a limit set of privileges. The limit set cannot be expanded, since the limit set is initially all privileges. The initial inheritable set can be expanded for users, roles, and systems. A privilege that is not in the inheritable set can also be assigned to a process.

The assignment of privileges per process is the most precise way to add privileges. You can expand the number of privileged operations that a user can perform by enabling the user to assume a role. The role would be assigned profiles that include commands with added privileges. When the user assumes the role, the user gets the role's profile shell. By typing in the role's shell, the commands in the role's profiles execute with the added privileges.

You can also assign a profile to the user rather than to a role that the user assumes. The profile would include commands with added privileges. When the user opens a profile shell, such as pfksh, the user can execute the commands in the user's profile with privilege. In a regular shell, the commands do not execute with privilege. The privileged process can only execute in a privileged shell.

To expand the initial inheritable set of privileges for users, roles, or systems is a riskier way to assign privileges. All privileges in the inheritable set are in the permitted and effective sets. All commands that the user or role types in a shell can use the directly assigned privileges. Directly assigned privileges enable a user or role to easily perform operations that can be outside the bounds of their administrative responsiblities.

When you add to the initial inheritable set of privileges on a system, all users who log on to the system have a larger set of basic privileges. Such direct assignment enables all users of the system to easily perform operations that are probably outside the bounds of ordinary users.

Restricting a User or Role's Privileges

By removing privileges, you can prevent users and roles from performing particular tasks. You can remove privileges from the initial inheritable set, and from the limit set. You should carefully test removal of privileges before you distribute an initial inheritable set or a limit set that is smaller than the default set. By removing privileges from the initial inheritable set, you might prevent users from logging in. When privileges are removed from the limit set, a legacy setuid program might fail because the program requires a privilege that was removed.

Assigning Privileges to a Script

Scripts are executables, like commands. Therefore, in a rights profile, you can add privileges to a script just as you can add privileges to a command. The script runs with the added privileges when a user or role who has been assigned the profile executes the script in a profile shell. If the script contains commands that require privileges, the commands with added privileges should also be in the profile.

Privilege-aware programs can restrict privileges per process. Your job with a privilege-aware program is to assign the executable just the privileges that the program needs. You then test the program to see that the program succeeds in performing its tasks. You also check that the program does not abuse its use of privileges.