Lighttpd

TracNav(DocsToc) {{{
#!rst ====================
Using Authentication ====================

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Module: mod_auth
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.. meta::
:keywords: lighttpd, authentication

.. contents:: Table of Contents

Description ===========

Supported Methods
-----------------

lighttpd supports both authentication methods described by
RFC 2617:

basic
`````

The Basic method transfers the username and the password in
cleartext over the network (base64 encoded) and might result
in security problems if not used in conjunction with a crypted
channel between client and server.

digest
``````

The Digest method only transfers a hashed value over the
network which performs a lot of work to harden the
authentication process in insecure networks.

Backends
--------

Depending on the method lighttpd provides various way to store
the credentials used for the authentication.

for basic auth:

- plain_
- htpasswd_
- htdigest_
- ldap_

for digest auth:

- plain_
- htdigest_

plain
`````

A file which contains username and the cleartext password
seperated by a colon. Each entry is terminated by a single
newline.::

e.g.:
  agent007:secret

htpasswd
````````

A file which contains username and the crypt()'ed password
seperated by a colon. Each entry is terminated by a single
newline. ::

e.g.:
  agent007:XWY5JwrAVBXsQ

You can use htpasswd from the apache distribution to manage
those files. ::

$ htpasswd lighttpd.user.htpasswd agent007

Keep in mind that not all versions of htpasswd default to use
Apache's modified MD5 algorithm for passwords, which is
required by lighttpd.

htdigest
````````

A file which contains username, realm and the md5()'ed
password seperated by a colon. Each entry is terminated
by a single newline. ::

e.g.:
  agent007:download area:8364d0044ef57b3defcfa141e8f77b65

You can use htdigest from the apache distribution to manage
those files. ::

$ htdigest lighttpd.user.htdigest 'download area' agent007

Using md5sum can also generate the password-hash: ::

#!/bin/sh
  user=$1
  realm=$2
  pass=$3

hash=`echo -n "$user:$realm:$pass" | md5sum | cut -b -32`

echo "$user:$realm:$hash"

To use it (spaces between arguments!) :

$ htdigest.sh 'agent007' 'download area' 'secret'

agent007:download area:8364d0044ef57b3defcfa141e8f77b65

ldap
````

the ldap backend is performing the following steps
to authenticate a user

1. Init the LDAP connection
2. Set Protocol version to LDAPv3
3. If StartTLS if configured -> Configure CA certificate if supplied
4. If StartTLS if configured -> Activate TLS using StartTLS
5. If Bind DN is included -> Simple bind with Bind-DN and Bind-Password
6. If there is no Bind-DN -> Simple bind anonymously
7. Try up to two times a SUBTREE search of the base-DN with the filter applied.
8. Retrieve the DN of the user matching the filter.
9. Finally, re-init the connection (following the steps above), this time using the DN found using the filter and the password supplied by the user.

if all 9 steps are performed without any error the user is
authenticated

Configuration =============

::

1. debugging

1. 0 for off, 1 for 'auth-ok' messages, 2 for verbose debugging
   auth.debug = 0

1. type of backend

1. plain, htpasswd, ldap or htdigest
   auth.backend = "htpasswd"

1. filename of the password storage for
2. plain
   auth.backend.plain.userfile = "lighttpd-plain.user"

1. for htpasswd
   auth.backend.htpasswd.userfile = "/full/path/to/lighttpd-htpasswd.user"

1. for htdigest
   auth.backend.htdigest.userfile = "lighttpd-htdigest.user"

1. for ldap

1. the $ in auth.backend.ldap.filter is replaced by the
2. 'username' from the login dialog
   auth.backend.ldap.hostname = "localhost"
   auth.backend.ldap.base-dn = "dc=my-domain,dc=com"
   auth.backend.ldap.filter = "(uid=$)"
3. if enabled, startTLS needs a valid (base64-encoded) CA
4. certificate unless the certificate has been stored
5. in a c_hashed directory and referenced in ldap.conf
   auth.backend.ldap.starttls = "enable"
   auth.backend.ldap.ca-file = "/etc/CAcertificate.pem"
6. If you need to use a custom bind to access the server
   auth.backend.ldap.bind-dn = "uid=admin,dc=my-domain,dc=com"
   auth.backend.ldap.bind-pw = "mysecret"
7. If you want to allow empty passwords
8. 0 for requiring passwords, 1 for allowing empty passwords
   auth.backend.ldap.allow-empty-pw = 0

1. restrictions

1. set restrictions: #
2. ( <left-part-of-the-url> =>
3. ( "method" => "htdigest"/"basic",
4. "realm" => <realm>,
5. "require" => "user=<username>" )
6. ) #
7. <realm> is a string to display in the dialog
8. presented to the user and is also used for the
9. digest-algorithm and has to match the realm in the
10. htdigest file (if used) #

auth.require = ( "/download/" => 
                   ( 
           # method must be either basic or digest
             "method"  => "digest",
             "realm"   => "download archiv",
             "require" => "user=agent007|user=agent008" 
           ),
           "/server-info" => 
                   ( 
             "method"  => "digest",
             "realm"   => "download archiv",
             "require" => "valid-user" 
           )
                 )

1. Or, using regular expressions:
   $HTTP["url"] =~ "^/download|^/server-info" {
   auth.require = ( "" => (
   "method" => "digest",
   "realm" => "download archiv",
   "require" => "user=agent007|user=agent008"
   )
   )
   }

Limitations ============

- The implementation of digest method is currently not
completely compliant with the standard as it still allows
a replay attack.

- LDAP authentication only allows alphanumeric uid's that
do not contain punctuations. i.e.) john.doe will come
up as "ldap: invalid character (a-zA-Z0-9 allowed) in username: john.doe"

- There seems to be no reasonable logging of failed login attempts yet

See Also ========
}}}

• [wiki:HowToAuthenticationFromMultipleFiles Authenticate from Multiple Password Files]