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=============
django-sshkey
=============

django-sshkey allows you to associate multiple SSH public keys with Django
user accounts.  It provides views to list, add, edit, and delete keys, each of
which is intended for end-user consumption.  It also provides a lookup view
and corresponding lookup commands that are suitable for use with the
``AuthorizedKeysCommand`` feature in OpenSSH_ 6.2 and above.

The Django app
==============

To use django-sshkey in your Django project, simply add ``django_sshkey`` to
``INSTALLED_APPS`` in ``settings.py``, map the URLs into your project, and
provide templates for the views (example templates are provided in the source).

In order to associate an incoming public key with a user you must define
``SSHKEY_AUTHORIZED_KEYS_OPTIONS`` in your project's ``settings.py``.  This
should be a string containing options accepted by sshd, with ``{username}``
being replaced with the username of the user associated with the incoming
public key.

For instance::

  SSHKEY_AUTHORIZED_KEYS_OPTIONS = 'command="my-command {username}",no-pty'

in settings.py will cause keys produced by the below commands to look similar
to::

  command="my-command fred",no-pty ssh-rsa AAAAB3NzaC1yc2E...

assuming the key ``AAAAB3NzaC1yc2E...`` is owned by fred.

URL Configuration
-----------------

This text assumes that your project's ``urls.py`` maps ``django_sshkey.urls``
into the URL namespace as follows::

  import django_sshkey.urls
  urlpatterns = patterns('',
    ...
    url('^sshkey/', include(django_sshkey.urls)),
    ...
  )

You will need to adjust your URLs in the examples below if you use a different
mapping.

.. WARNING::

  The ``/sshkey/lookup`` URL can expose all public keys that have
  been uploaded to your site.  Although they are public keys, it is probably a
  good idea to limit what systems can access this URL via your web server's
  configuration.  Most of the lookup methods below require access to this URL,
  and only the systems that need to run the lookup commands should have access
  to it.

Tying OpenSSH to django-sshkey
==============================

There are multiple methods of connecting OpenSSH to django-sshkey.  All of the
methods listed here require the use of the ``AuthorizedKeysCommand`` directive
in ``sshd_config`` present in OpenSSH 6.2 and above.  Please note that the
command that is referenced by this directive and its ancestor directories must
be owned by root and writable only by owner.

Unless otherwise stated, all of the methods below use the ``SSHKEY_LOOKUP_URL``
environment variable to determine the URL of the ``/sshkey/lookup`` URL.  If
this environment variable is not defined then it will default to
``http://localhost:8000/sshkey/lookup``.  If this environment variable is
defined in the sshd process then it will be inherited by the
``AuthorizedKeysCommand``.

Additionally, all of the methods below use either ``curl`` (preferred) or
``wget``.  Some commands also use ``ssh-keygen``.  These commands must be
present in ``PATH``.

If you would prefer not to use these external commands then there are variants
of the lookup commands implemented purely in Python.  However, they are *much*
slower.  To use the variants, replace ``lookup`` with ``pylookup``.  For
example, use ``django-sshkey-pylookup-all`` instead of
``django-sshkey-lookup-all``.

Using ``django-sshkey-lookup-all``
----------------------------------

``Usage: django-sshkey-lookup-all``

This program prints all SSH public keys that are defined on your site.  sshd
will have to scan through all of them to find the first match, so with many
keys this method will be slow.  However, it does not require a patched OpenSSH
server.

This program:

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* can be used directly with ``AuthorizedKeysCommand`` (the username parameter
  is ignored).
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* does not require a patched OpenSSH server.
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* does not scale well to a large number of user keys.
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Using ``django-sshkey-lookup-by-username``
------------------------------------------

``Usage: django-sshkey-lookup-by-username USERNAME``

This program prints all SSH public keys that are associated with the specified
user.

This program:

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* can be used directly with ``AuthorizedKeysCommand``.
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* does not require a patched OpenSSH server.
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* is ideal if each Django user corresponds to a system user account.
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Using ``django-sshkey-lookup-by-fingerprint``
---------------------------------------------

``Usage: django-sshkey-lookup-by-fingerprint``

This program prints all SSH public keys that match the given fingerprint.  The
fingerprint is determined by the first of the following that is found:

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1. The ``SSH_KEY_FINGERPRINT`` environment variable, which should contain the
   MD5 fingerprint of the key (this is the second field generated by
   ``ssh-keygen -l``).
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2. The ``SSH_KEY`` environment variable, which should contain the key in
   standard openssh format (the same format as ``~/.ssh/id_rsa.pub``), is sent
   to ``ssh-keygen -l`` to determine the fingerprint.
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3. The key in standard openssh format is read from standard input and is sent
   to ``ssh-keygen -l`` to determine the fingerprint.
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This program:

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* can be used directly with ``AuthorizedKeysCommand`` (the username parameter
  is ignored).
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* requires a patched OpenSSH server; compatible patches can be found at one of
  the following locations:
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  - openssh-akcenv_ (this is the preferred patch)
  - openssh-stdinkey_
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* is ideal if you want all Django users to access SSH via a shared system user
  account and be identified by their SSH public key.
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Using ``django-sshkey-lookup``
------------------------------

``Usage: django-sshkey-lookup URL [USERNAME]``

This program is a wrapper around the previous two commands.  The first
parameter is placed in the ``SSHKEY_LOOKUP_URL`` environment variable.  If the
second parameter is present then ``django-sshkey-lookup-by-username`` is
executed; otherwise ``django-sshkey-lookup-by-fingerprint`` is executed.

This command is compatible with the old script ``lookup.sh`` but was renamed
to have a less ambiguous name when installed system-wide. A symlink is left in
its place for backwards compatibility.

.. _OpenSSH: http://www.openssh.com/
.. _openssh-akcenv: https://github.com/ScottDuckworth/openssh-akcenv
.. _openssh-stdinkey: https://github.com/ScottDuckworth/openssh-stdinkey