split and update upstream status, as per template

 [file]: https://gitlab.torproject.org/tpo/tpa/team/-/issues/new

 [search]: https://gitlab.torproject.org/tpo/tpa/team/-/issues?label_name%5B%5D=LDAP

## Maintainer, users, and upstream

Our [userdir-ldap repository][] is a fork of the [DSA userdir-ldap

repository][]. The codebase is therefore shared with the Debian

project, which uses it more heavily than TPO. According to [GitLab's

analysis](https://salsa.debian.org/dsa-team/mirror/userdir-ldap/-/graphs/master), weasel has contributed the most to the repository (since

2007), followed closely by Joey Schulze, which wrote most of the code

before that, between 1999 and 2007.

[DSA userdir-ldap repository]: https://salsa.debian.org/dsa-team/mirror/userdir-ldap

[userdir-ldap repository]: https://gitweb.torproject.org/admin/userdir-ldap.git/

The service is mostly in maintenance mode, both at DSA and in TPO,

with small, incremental changes being made to the codebase over all

those years. Attempts have been made to rewrite it with a Django

frontend ([ud](https://github.com/Debian/ud), 2013-2014 no change since 2017) or Pylons

([userdir-ldap-pylons](https://salsa.debian.org/dsa-team/mirror/userdir-ldap-pylons), 2011, abandoned), all have been abandoned.

Our fork is primarily maintained by anarcat and weasel. It is used by

*everyone* at Tor.

Our fork tries to follow upstream as closely as possible, but the

Debian project is hardcoded in a lot of places so we (currently) are

forced to keep patches on top of upstream.

### Branching policy

In the [userdir-ldap][userdir-ldap repository] and [userdir-ldap-cgi repository][], we have

tried to follow the [icebreaker branching strategy used at one of

Google's kernel teams](https://lwn.net/Articles/871195/). Briefly, the idea is to have patches

rebased on top of the latest upstream release, with each feature

branch based on top of the tag. Those branches get merged in our

"master" branch which contains our latest source code. When a new

upstream release is done, a new feature branch is created by merging

the previous feature branch and the new release.

This pattern is designed so that it's easier to send patches

upstream. Unfortunately, upstream releases are somewhat irregular so

this somewhat breaks down because we don't have a solid branch point

to base our feature branches off. This is why the branches are named

like `tpo-scrub-0.3.104-pre-dd7f9a3`: the `pre-dd7f9a3` is to indicate

that we are not branched off a real release.

### usedir-ldap-cgi fork status

In the [last sync](https://gitlab.torproject.org/tpo/tpa/team/-/issues/40182), `usedir-ldap-cgi` was brought from 27 patches

down to 16, 10 of which were sent upstream. Our diff there is now:

      22 files changed, 11661 insertions(+), 553 deletions(-)

The large number of inserted lines is because we included the

[styleguide](https://styleguide.torproject.org) `bootstrap.css` which is 11561 lines on its own, so

really, this is the diff stat if we ignore that stylesheet:

      21 files changed, 100 insertions(+), 553 deletions(-)

If the patches get merged upstream, our current delta is:

     21 files changed, 23 insertions(+), 527 deletions(-)

The only way forward here is either to make the "Debian" strings

"variables" in the WML templates or completely remove the

documentation from userdir-ldap-cgi (and move it to the project's

respective wikis).

### userdir-ldap fork status

Our diff in `userdir-ldap` is much smaller:

     6 files changed, 46 insertions(+), 19 deletions(-)

We have 4 patches there, and a handful were merged upstream. The

remaining patches could probably live as configuration files in

Puppet, reducing the diff to nil.

## Monitoring and testing

Nagios checks the `/var/lib/misc/thishost/last_update.trace` timestamp

## Overview

`ud-ldap` is decades old (the `ud-generate` manpage mentions 1999, but

it could be older) and is hard to debug and extend. This section aims

at documenting issues with the software and possible alternatives.

Our [userdir-ldap repository][] is a fork of the [DSA userdir-ldap

repository][]. The codebase is therefore shared with the Debian

project, which uses it more heavily than TPO. According to [GitLab's

analysis](https://salsa.debian.org/dsa-team/mirror/userdir-ldap/-/graphs/master), weasel has contributed the most to the repository (since

2007), followed closely by Joey Schulze, which wrote most of the code

before that, between 1999 and 2007.

[DSA userdir-ldap repository]: https://salsa.debian.org/dsa-team/mirror/userdir-ldap

[userdir-ldap repository]: https://gitweb.torproject.org/admin/userdir-ldap.git/

This section aims at documenting issues with the software and possible

alternatives.

The service is mostly in maintenance mode, both at DSA and in TPO,

with small, incremental changes being made to the codebase over all

those years. Attempts have been made to rewrite it with a Django

frontend ([ud](https://github.com/Debian/ud), 2013-2014 no change since 2017) or Pylons

([userdir-ldap-pylons](https://salsa.debian.org/dsa-team/mirror/userdir-ldap-pylons), 2011, abandoned), all have been abandoned.

### Major issues with userdir-ldap

`ud-ldap` is decades old (the `ud-generate` manpage mentions 1999, but

it could be older) and is hard to maintain, debug and extend.

ud-ldap is old, hard to maintain, and possibly has serious security

issues. it is a liability, in the long term, in particular for those

reasons:

It might have serious security issues. It is a liability, in the long

term, in particular for those reasons:

 * **old cryptographic primitives**: SHA-1 is used to hash `sudo`

   passwords, MD5 is used to hash user passwords, those hashes are