GNU Rush
	Restricted User Shell	Sergey Poznyakoff

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4.8 Interactive Access

Sometimes it may be necessary to allow some group of users limited access to interactive shells. GNU Rush contains provisions for such usage.

Configuration: interactive string

If this statement is present in the configuration file, the invocation of rush without command line arguments (interactive usage) becomes equivalent to rush -c string.

This can be used to catch interactive invocations. Consider the following example:

interactive //shell//

rule login
  command //shell//
  group rshell
  map[^] /etc/rush.shell : ${user} 1 2
  transform[0] ${program} s,^,-r,

rule nologin
  command //shell//
  exit You don't have interactive access to this machine.

The interactive statement supplies a fake command line which will indicate an attempt of interactive usage. It is a common practice to select such a string that cannot be a valid system command. The ‘login’ rule matches this command line if the user is a member of the group ‘rshell’. It uses ‘/etc/rush.shell’ to select a shell to use for that user (see section Map). This map file consists of two fields, separated by a colon. If the shell is found, its base name, prefixed with ‘-r’, is used as ‘argv[0]’ (this indicates a restricted login shell). Otherwise, the trap rule ‘nologin’ is matched, which outputs the given diagnostics message and exits rush.

GNU Rush – a restricted user shell. (split by section):

Section:

Chapter:

Doc:

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