Linux Network Administrator's Guide, Second Edition

Controlling Access to UUCP Features

UUCP is quite a flexible system. With that flexibility comes a need to carefully control access to its features to prevent abuse, whether it be intentional or accidental. The primary features of concern to the UUCP administrator are remote command execution, file transfer, and forwarding. Taylor UUCP provides a means of limiting the freedom that remote UUCP hosts have in exercising each of these features. With careful selection of permissions, the UUCP administrator can ensure that the host’s security is preserved.

Command Execution

UUCP’s task is to copy files from one system to another and to request execution of certain commands on remote hosts. Of course, you as an administrator would want to control what rights you grant other systems—allowing them to execute any command they choose on your system is definitely not a good idea.

By default, the only commands Taylor UUCP allows other systems to execute on your machine are rmail and rnews, which are commonly used to exchange email and Usenet News over UUCP. To change the set of commands for a particular system, you can use the commands keyword in the sys file. Similarly, you may want to limit the search path to just those directories containing the allowed commands. You can change the search path allowed for a remote host with the command-path statement. For instance, you may want to allow system pablo to execute the bsmtp command in addition to rmail and rnews:^[99]

system pablo ... ...