imap-vpop: virtual user interface for UW-imap server

	drh.net
David Harris, dharris@

Posted January 11, 2000.
Updated January 11, 2000.

Quick Summary
This is a patch to the UW-IMAP server which allows it to authenticate virtual users and system users in the same IMAP daemon. A C interface is provided for hooking in an authentication routine for the virtual users. Hopefully others will develop and contribute interfaces for reading virtual users from databases, flat files, and an external program.

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Important Note: This software is not supported by David Harris.
I simply don't have the time right now. Rather, I'm posting my work and hoping that others will add to it and contribute their improvements. A little open-source community devoted to single-uid uwimap solutions will hopefully develop here. Read more about this in the "description" section below.

1. Description

What is this?

This software provides a way to create virtual e-mail users which are authenticated out of some kind of backend database for UW-IMAP. On large mail servers it is far from ideal to create a unix login account for each e-mail user. This patch allows you to run all of your e-mail users, if you wish, under a single userid. This is sometimes called a single-uid e-mail setup.

Right now, this is not a "for the newbies" solution -- you can't apply the patches and follow the install document. I have created the ties into UW-IMAP for authenticating virtual users and defined a C interface for authenticating those virtual users. But you need to create a C function that can authenticate a virtual user. From this C function you do whatever you want such as querying a database.

Hopefully people will contribute various backend C functions for various databases.

Why don't you support this? What does that mean?

I can not support this software simply because I don't have the time. I am 100% all-full-up with running a startup web hosting company, drh.net.

The patch I developed had an authentication backend function which is very specific for my web hosting setup. To make this of general use to the average user, there need to be some example C backend authentication functions. That's where the Bazaar style open source project kicks in -- i'm posting what i have right now, hoping that people who have the knowledge and the need to extend this will. And that they will contribute back what they have developed. Then, we will have something useful to the general user.

Okay, how can I help?

First, subscribe to the development list. Then, download the patch as I have it and develop your own C backend and post that to the list. It will be archived on this website, and I'll link to it from the home page if it is of substantial value. Then, stay on the list and support people that try to use your patch.

Perhaps someday I'll be able to step back in and gather everything together into a nice easy-to-use package with clean documentation and install instructions. Or perhaps someone who has contributed will step up to be the maintainer of this.. and I'll give them control over this website.

2. The Development List-serv

Here is the development list-serv. Expect that traffic will be very light at first. This is an ezmlm list.

Send posts to:

imapvpop @ davideous.com

To subscribe and unsubscribe, respectively, send e-mail to:

Here are the archives:

3. The Actual Stuff

This section of the web page will be a summary of the project. Mostly links to important emails in the archive and downloadable patches.

My original work

imap-4.6-vpop-1.01.patch - the actual patch. This contains a backend vpop__userauthen function that has site specific authenticate logic in it. It's gonna be useless for anyone but me, but it gives you an idea of how to write your own vpop__userauthen function.
brief general description of patch - description of the patch
description of vpop__userauthen interface - description of vpop__userauthen interface. This is a MUST READ for anyone developing their own vpop__userauthen function.

Why getpwnam replacements don't work, IMO.

explanation of the potential security hole
someone else verifying my suspicions
explanation of the sysInbox problem - other people have created single-uid solutions for uwimap by linking in their own getpwnam function. These three e-mails show the problems than this can cause if you do not understand and properly patch the rest of the UW-IMAP login code.

Other people's work

When this appears, I'll link to it here.

Related work

imap-4.6-replace_syslog.patch - a patch to make the server log to STDOUT instead of syslog. If you are running any kind of high-volume sight, I recomend that you use tcpserver (instead of inetd) and cyclog along with this patch.
Maildir driver for UW-imap

4. Change log

Here is a changelog of the updates to this page and these patches:

January 11, 2000

First posting.

5. Disclaimer


THIS SOFTWARE IS PROVIDED BY DAVID R. HARRIS "AS IS" AND ANY EXPRESSED
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL DAVID R. HARRIS OR HIS CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.