Device Clean Scripts

Device clean scripts are special scripts that are run when a device is first allocated. Clean scripts address two security concerns:

• Object reuse - The requirement that a device is clean of previous data before being allocated or reallocated.

• Media labeling - The requirement that removable information storage media have a physical label indicating its label. While the ultimate responsibility for putting the labels on the removable media rests with the user, the device clean scripts can prompt the user to do so.

The name of a device clean script for a specific device is stored with that device's entry in the device_allocate(4) file. The operations of each device clean program are specific to each device. The following is a list of tasks that a device clean program performs:

• Eject media - Devices that store information on removable media must be forced to eject that media upon deallocation or reallocation of the device, to prevent passing information to the next user of the device who may be at a different label.

• Reset device state - Devices that keep state information can potentially be used as a covert channel by the users. Thus driver status information must be reset to default values during deallocation of the device.

• Remind user about media labeling - Removable information storage media be labeled with appropriate external media labels. The device user's label is passed to the device clean program when it is invoked (See the device_clean(1M) man page for interface detail.)

Not all allocatable devices require a device clean program. Devices that do not keep states and do not use removable media do not need a device clean program.

Device clean programs for tape, floppy disk, CD-ROM, and audio devices are provided by the Trusted Solaris environment. The configurable nature of the user device allocation mechanism enables an administrator to install new devices and configure device clean programs accordingly.

For more information on device allocation, see Chapter 15, "Managing Devices," in Trusted Solaris Administrator's Procedures.