ext_ad_group_acl.exe − Squid external ACL helper to check Windows users group membership.

Version 2.0

ext_ad_group_acl.exe [−D domain ] [−cdGh]

ext_ad_group_acl.exe is an installed binary in Squid for Windows builds.

This helper must be used in with an authentication scheme (typically Basic, NTLM or Negotiate) based on Windows Active Directory domain users.

It reads from the standard input the domain username and a list of groups and tries to match each against the groups membership of the specified username.

Two running mode are available:

− Local mode:

membership is checked against machine’s local groups, cannot be used when running on a Domain Controller.

− Active Directory Global mode:

membership is checked against the whole Active Directory Forest of the machine where Squid is running.

The minimal Windows version needed to run ext_ad_group_acl.exe is a Windows 2000 SP4 member of an Active Directory Domain.

When running in Active Directory Global mode, all types of Active Directory security groups are supported: Domain Global , Domain Local from user’s domain, Universal and Active Directory group nesting is fully supported.

−c

Use case insensitive compare (local mode only).

−d

Write debug info to stderr.

−D domain

Specify the default user’s domain

−G

Start helper in Active Directory Global mode.

−h

Display the binary help and command line syntax info using stderr.

When running in Active Directory Global mode, the AD Group can be specified using the following syntax:

1. Plain NT4 Group Name

2. Full NT4 Group Name

3. Active Directory Canonical name

As Exampled:

1. Proxy-Users

2. MYDOMAINProxy-Users

3. mydomain.local/Groups/Proxy-Users

When using Plain NT4 Group Name, the Group is searched in the user’s domain.

external_acl_type AD_global_group %LOGIN c:/squid/libexec/ext_ad_group_acl.exe -G
external_acl_type NT_local_group %LOGIN c:/squid/libexec/ext_ad_group_acl.exe
acl GProxyUsers external AD_global_group MYDOMAINGProxyUsers
acl LProxyUsers external NT_local_group LProxyUsers
acl password proxy_auth REQUIRED
http_access allow password GProxyUsers
http_access allow password LProxyUsers
http_access deny all

In the previous example all validated AD users member of MYDOMAINGProxyUsers domain group or member of LProxyUsers machine local group are allowed to use the cache.

Groups with spaces in name, for example Domain Users , must be quoted and the acl data ( Domain Users ) must be placed into a separate file included by specifying /path/to/file . The previous example will be:

acl ProxyUsers external NT_global_group

and the DomainUsers files will contain only the following line:

"Domain Users"

NOTE 1: When running in Active Directory Global mode, for better performance, all Domain Controllers of the Active Directory forest should be configured as Global Catalog.

NOTE 2: When running in local mode, the standard group name comparison is case sensitive, so group name must be specified with same case as in the local SAM database. It is possible to enable case insensitive group name comparison ( −c ), but on some non−English locales, the results can be unexpected.

NOTE 3: Native WIN32 NTLM and Basic helpers must be used without the −A and −D switches.

Refer to Squid documentation for more details on squid.conf

I strongly recommend that ext_ad_group_acl.exe is tested prior to being used in a production environment. It may behave differently on different platforms.

To test it, run it from the command line. Enter username and group pairs separated by a space (username must entered with URL-encoded domain%5Cusername syntax). Press ENTER to get an OK or ERR message.

Make sure pressing CTRL+D behaves the same as a carriage return.

Make sure pressing CTRL+C aborts the program.

Test that entering no details does not result in an OK or ERR message.

Make sure pressing CTRL+D behaves the same as a carriage return.

Make sure pressing CTRL+C aborts the program.

Test that entering no details does not result in an OK or ERR message.

Test that entering an invalid username and group results in an ERR message.

Test that entering an valid username and group results in an OK message.

This program was written by Guido Serassio <[email protected]>

Based on prior work in mswin_check_lm_group (ext_lm_group_acl)

This manual was written by Guido Serassio <[email protected]> Amos Jeffries <[email protected]>

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 on the usage of this program can be sent to the Squid Users mailing list <[email protected]>

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 <[email protected]>

Report ideas for new improvements to the Squid Developers mailing list <[email protected]>

squid(8), GPL(7),
The Squid FAQ wiki http://wiki.squid-cache.org/SquidFaq
The Squid Configuration Manual http://www.squid-cache.org/Doc/config/