Ubuntu Manpage: basic_ldap_auth - LDAP authentication helper for Squid

Provided by: squid-openssl_5.7-1ubuntu3_amd64

NAME

       basic_ldap_auth - LDAP authentication helper for Squid

SYNOPSIS

       basic_ldap_auth  -b "  base DN " [-u attribute ] [ options ] [ LDAP server name [: port ]|
       URI ]...
       basic_ldap_auth -b " base DN " -f " LDAP search filter " [ options ] [ LDAP server name [:
       port ]| URI ]...

DESCRIPTION

       basic_ldap_auth  allows Squid to connect to a LDAP directory to validate the user name and
       password of Basic HTTP authentication.  LDAP options are specified as  parameters  on  the
       command  line,  while  the  username(s)  and  password(s)  to  be checked against the LDAP
       directory are specified on subsequent lines of input to the helper, one  username/password
       pair per line separated by a space.

       As  expected  by  the basic authentication construct of Squid, after specifying a username
       and password followed by a new line, this helper will produce either  OK  or  ERR  on  the
       following  line  to  show  if  the specified credentials are correct according to the LDAP
       directory.

       The program has two major modes of operation. In the default mode of operation  the  users
       DN  is  constructed using the base DN and user attribute. In the other mode of operation a
       search filter is used to locate valid user DN's below the base DN.

OPTIONS

-b basedn REQUIRED. Specifies the base DN under which the users are located.

-f filter LDAP search filter to locate the user DN. Required if the users are in a
hierarchy below the base DN, or if the login name is not what builds the user
specific part of the users DN.
The search filter can contain up to 15 occurrences of %s which will be
replaced by the username, as in "uid=%s" for RFC2037 directories. For a
detailed description of LDAP search filter syntax see RFC2254.
Will crash if other % values than %s are used, or if more than 15 %s are used.

-u userattr Specifies the name of the DN attribute that contains the username/login.
Combined with the base DN to construct the users DN when no search filter is
specified ( -f option). Defaults to uid
Note: This can only be done if all your users are located directly under the
same position in the LDAP tree and the login name is used for naming each user
object. If your LDAP tree does not match these criteria or if you want to
filter who are valid users then you need to use a search filter to search for
your users DN ( -f option).

-U passwordattr
Use ldap_compare instead of ldap_simple_bind to verify the users password.
passwordattr is the LDAP attribute storing the users password.

-s base|one|sub
Search scope when performing user DN searches specified by the -f option.
Defaults to sub

base object only,

one level below the base object or

subtree below the base object

-D binddn -w password
The DN and password to bind as while performing searches. Required by the -f
flag if the directory does not allow anonymous searches.
As the password needs to be printed in plain text in your Squid configuration
it is strongly recommended to use a account with minimal associated
privileges. This to limit the damage in case someone could get hold of a copy
of your Squid configuration file.

-D binddn -W secretfile
The DN and the name of a file containing the password to bind as while
performing searches.
Less insecure version of the former parameter pair with two advantages: The
password does not occur in the process listing, and the password is not being
compromised if someone gets the squid configuration file without getting the
secretfile.

-P Use a persistent LDAP connection. Normally the LDAP connection is only open
while validating a username to preserve resources at the LDAP server. This
option causes the LDAP connection to be kept open, allowing it to be reused
for further user validations. Recommended for larger installations.

-O Only bind once per LDAP connection. Some LDAP servers do not allow re-binding
as another user after a successful ldap_bind. The use of this option always
opens a new connection for each login attempt. If combined with the -P option
for persistent LDAP connection then the connection used for searching for the
user DN is kept persistent but a new connection is opened to verify each users
password once the DN is found.

-R Do not follow referrals

-a never|always|search|find
when to dereference aliases. Defaults to never

never dereference aliases (default), always dereference aliases, only during a
search or only to find the base object.

-H ldap_uri Specify the LDAP server to connect to by LDAP URI (requires OpenLDAP
libraries). Servers can also be specified last on the command line.

-h ldap_server
Specify the LDAP server to connect to. Servers can also be specified last on
the command line.

-p ldap_port
Specify an alternate TCP port where the LDAP server is listening if other than
the default LDAP port 389. Can also be specified within the server
specification by using servername:port syntax.

-v 2|3 LDAP protocol version. Defaults to 3 if not specified.

-Z Use TLS encryption

-S certpath Enable LDAP over SSL (requires Netscape LDAP API libraries)

-c connect_timeout
Specify timeout used when connecting to LDAP servers (requires Netscape LDAP
API libraries)

-t search_timeout
Specify time limit on LDAP search operations

-d Debug mode where each step taken will get reported in detail. Useful for
understanding what goes wrong if the results is not what is expected.

CONFIGURATION

       For  directories using the RFC2307 layout with a single domain, all you need to specify is
       usually the base DN under where your users are located and the server name:

              basic_ldap_auth -b ou=people,dc=your,dc=domain ldapserver

       If you have sub-domains then you need to use a search filter approach to locate your  user
       DNs as these can no longer be constructed directly from the base DN and login name alone:

              basic_ldap_auth -b dc=your,dc=domain -f uid=%s ldapserver

       And similarly if you only want to allow access to users having a specific attribute

              basic_ldap_auth   -b   dc=your,dc=domain   -f   (&(uid=%s)(specialattribute=value))
              ldapserver

       Or if the user attribute of the user DN is cn instead of uid and you do not want  to  have
       to search for the users then you could use something like the following example for Active
       Directory:

              basic_ldap_auth -u cn -b cn=Users,dc=your,dc=domain ldapserver

       If you want to search for the user DN and your directory does not allow anonymous searches
       then  you must also use the -D and -w flags to specify a user DN and password to log in as
       to perform the searches, as in the following complex Active Directory example

              basic_ldap_auth -P -R -b dc=your,dc=domain  -D  cn=squid,cn=users,dc=your,dc=domain
              -w     secretsquidpassword     -f     (&(userPrincipalName=%s)(objectClass=Person))
              activedirectoryserver

       NOTE: When constructing search filters it is strongly recommended to test the filter using
       ldapsearch  before  you  attempt  to  use basic_ldap_auth.  This to verify that the filter
       matches what you expect.

AUTHOR

       This program is written by Glenn  Newton  <gnewton@wapiti.cisti.nrc.ca>  Henrik  Nordstrom
       <hno@squid-cache.org> This manual is written by Henrik Nordstrom <hno@squid-cache.org>

COPYRIGHT

        * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
        *
        * Squid software is distributed under GPLv2+ license and includes
        * contributions from numerous individuals and organizations.
        * Please see the COPYING and CONTRIBUTORS files for details.

       This program and documentation is copyright to the authors named above.

       Distributed under the GNU General Public License (GNU GPL) version 2 or later (GPLv2+).

QUESTIONS

       Questions on the usage of this program can be sent to the Squid Users mailing list <squid-
       users@lists.squid-cache.org>

       Or to your favorite LDAP list/friend if the question is more related to LDAP than Squid.

REPORTING BUGS

       Bug    reports    need    to    be    made    in    English.     See    http://wiki.squid-
       cache.org/SquidFaq/BugReporting  for  details  of  what  you need to include with your bug
       report.

       Report bugs or bug fixes using http://bugs.squid-cache.org/

       Report serious security bugs to Squid Bugs <squid-bugs@lists.squid-cache.org>

       Report  ideas  for  new  improvements  to  the  Squid  Developers  mailing  list   <squid-
       dev@lists.squid-cache.org>