Re: [comp.unix.shell] Help creating a restricted shell

[Zoltan Hidvegi <hzoli@cs.elte.hu>]

Zsh-3.1.1 will have restricted mode similar to bash and ksh.  It is already
ready and working, just waiting for the release.  This is controlled via a
new option, RESTRICTED.  This option is set when the command name used to
invoke zsh starts with the letter 'r' but the option can also be set with
setopt.  Once it is set, it cannot be unset.

The restricted option is only switched on after processing startup files.
In restricted mode, the SHELL, PATH, path, MODULE_PATH, module_path,
{E,}{U,G}ID, HISTSIZE, HISTFILE, USERNAME, LD_{,AOUT}{PRELOAD,LIBRARY_PATH}
parameters cannot be changed.  It is not possible to change the current
directory, to execute binaries with absoulte patchname and to use
redirections writing to a file.

The idea is to prohibit executing any binary code directly specified by the
user and to prevent writing to any file.

Zoltan