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Sub-Identity Toolkit


The Cooperative Computing Laboratory Sub-Identity Toolkit is a set of utilities and a Pluggable Authentication Module that provides users with the ability to create sub-users of themselves. Standard Unix permissions checks prevent these subordinate users from accessing their parent user's files.

The Toolkit comes packaged with a set of five utilities and a pluggable authentication module, The utilities and their purposes are as follows:

  • subuseradd creates a named subuser of the calling user.
  • subuserdel deletes a named subuser of the calling user, optionally deleting all files owned by the subuser.
  • subusersu acts like 'su', invoking the identity of the named subuser.
  • subusersudo acts like 'sudo', running a given command as the named subuser.
  • subuserchown acts like 'chown', changing the ownership of the given files to the named subuser (or to the calling user).

The pluggable authentication module,, allows various programs and services (such as 'su') to check whether the named user is a subuser of the calling user, and implicitly allow such actions. So, if there is a line in /etc/pam.d/su saying auth sufficient, then if alice has a sub-user bob, then alice can 'su bob' without having to enter a password. The module is, however, somewhat incomplete, and suggestions/patches are quite welcome.



The latest release can be downloaded from here: subid-current.tgz.

Relevant publications:

This research was supported by the National Science Foundation under grant CNS05-49087.