GNU userv

Put the security boundary where it ought to be.

userv (pronounced you-serve) is a program which, according to the specification, is

a Unix system facility to allow one program to invoke another when only limited trust exists between them.

It is a tool for system administrators, who often find themselves with a program running as one user which needs to be able to do certain things as another user. For example, my machine's news system needs to scan my users' newsrcs to ensure that the right newsgroups are fetched. Before userv that part of the news system had to run as root, and clumsily use `su'.

It is also a component for application authors. For example, imagine a version of `cron' which didn't need to run as root, so that a security bug in cron would just mean that bad people could get cron jobs to run at the wrong times, rather than everyone on the system being able to break in completely. Imagine being able to do sophisticated mail filtering at delivery time without the mail transfer or delivery agents needing to be root.

Feedback

If you are subscribed to userv-discuss please send bug reports there; otherwise mail them to userv-bugreports@chiark.greenend.org.uk.

Mailinglists

I have set up mailinglists userv-announce and userv-discuss. The announcements list is moderated and will contain only announcements of important bugs, new versions, &c. The bug reports address mentioned above is also a mailing list; feel free to subscribe to it.

There are archives and subscription web pages, or you can subscribe by sending mail containing the word `subscribe' to userv-announce-REQUEST@chiark.greenend.org.uk or userv-discuss-REQUEST@chiark.greenend.org.uk.

Download

Available for download from chiark.greenend.org.uk are:

The current version as a gzipped tarfile.
Debian GNU/Linux source and binary packages are available via anonymous FTP.
All versions distributed so far are also available via anonymous FTP.
The HTML specification, including notes on how and why to use it. The specification is also available as a gzipped PostScript file. (The Debiandoc-SGML source for the spec is in the software distribution.)
The overview diagram as PostScript, or in the original xfig format.
The changelog as a plain text file.
The slides for a talk I gave at the 1998 UKUUG Linux Event in Manchester and earlier at the 1998 Linux Kongress in Cologne.

You can also access the project CVS repositories:

A mirror of my CVS repository is available via rsync from rsync.chiark.greenend.org.uk::ftp/users/ian/cvs-pub/userv (use FTP first to find your way around), or via cvsweb.
This web page is maintained in Savannah, where you can browse the webpage CVS.

userv is also available from the GNU Project FTP servers and their mirrors.

Copyright and licensing

userv is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program and documentation is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with userv, or one should be available above; if not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA, or email userv-maint@chiark.greenend.org.uk.

Ian Jackson / userv-maint@chiark.greenend.org.uk; more free software by me.

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