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OpenRADIUS LDAP module


Description:
The RadLDAP module can perform arbitrary LDAP searches based on the requests you send from OpenRADIUS: the base DN, search filter and optionally the bind credentials can all be specified by A/V pairs.
 
Usage:
The module is to be run from OpenRADIUS using an interface definition like this:
interface(name = "...",
	  prog = "radldap [options] ldaphost",
	  flags = Binary,
	  sendattr = "str",
	  sendattr = "User-Name",
	  sendattr = "User-Password",
	  ...),

The 'Binary' flag is required for any interface that uses this module.

The module only uses the 'str' attribute and optionally the 'User-Name' and 'User-Password' attributes from requests sent to it; the sendattr ACL is specified for efficiency only. You don't need to specify a recvattr ACL; you can control which attributes are returned from the directory using the LDAP-to-RADIUS mapping file that is described below.
 

Options:
The following command line options are provided:

-m mapfile
Specify an attribute mapping file name other than the default (which can be set by changing RADLDAP_MAPFILE in Make.conf).
 
-b binddn
A DN to bind to upon startup. If this option is specified, the module will ignore any User-Name / User-Password attributes sent to it. If left out, the module will re-bind each time a request comes in, using User-Name as the bind DN and User-Password as the password.
 
-s password
A bind password to for the DN specified with '-b'. If '-b' is specified without '-s', the module will do an anonymous LDAP bind when starting (and ignore User-Name and User-Password attributes in requests).
 
-p port
Port to contact LDAP on, if other than the default LDAP_PORT (389).
 
-u
Causes the module to unbind from the LDAP after each request. This may be especially useful for pre-v3 servers if you want to authenticate users by binding; multiple binds during the same session are only specified since version 3.

You can also try this as a workaround for buggy LDAP libraries or servers if the module or LDAP server seems to leak memory. It negatively affects performance though, because LDAP's TCP connection is shut down as well if you unbind.
 

-d
Increase debugging level. Debugging messages are output on standard error (fd 2, which can be redirected by OpenRADIUS using '-o'). With one '-d', all operations will be shown, but without bind passwords. Two '-d's cause the passwords to be included as well.
 
Attribute mapping:
The LDAP attributes returned by your searches are mapped to RADIUS attributes using a configurable mapping file, which consists of lines formatted like this:
ldapAttributeName		spcnr	vndnr	atrnr
The default mapping file shown below is most useful if you can model your LDAP schema according to RADIUS data types, i.e. if you can store integers and IP addresses as 32-bit network-order binary values.

If this is inconvenient, you'll want to define some additional string-type attributes in dict.internal and use them in the mapping file instead of the ones listed here. You can then easily convert them to their real RADIUS counterparts using the behaviour language's standard conversion operators.

These are the contents of the default 'radldap.attrmap' that is installed along with the executable in the modules directory:

#
# LDAP attribute name		Space	Vendor	Attr
#			(RAD-ATR = 2;		
#			INTERNAL = 100)	

radAuthType			100	0	40
radClearPassword		100	0	41
radMd5HexPassword		100	0	42
radTrustedProxy			100	0	43
radStripRealm			100	0	44

# 'str', written as host:port,secret
radProxyTarget			100	0	4	

#
# Standard RADIUS attributes
#

radServiceType			2	0	6
radFramedProtocol		2	0	7
radFramedIpAddress		2	0	8
radFramedIpNetmask		2	0	9
radFilterId			2	0	11
radLoginIpHost			2	0	14
radLoginService			2	0	15
radLoginTcpPort			2	0	16
radReplyMessage			2	0	18
radFramedRoute			2	0	22
radSessionTimeout		2	0	27
radIdleTimeout			2	0	28
radPortLimit			2	0	62

# Testing only - return each cn as a 'str' 
cn				100	0	4	
Operation:
This module has two modes of operation, depending on its command line arguments:

if you specify a bind DN and password, the module will perform an LDAP bind at startup, using those credentials. It will use the resulting authenticated connection for each subsequent search operation (unless you specify '-u', see below).

If you don't include the credentials on the command line, the module will do its bind operation each time it gets a request, taking the DN from the last 'User-Name' attribute and using the last 'User-Password' as the password. It will still keep its connection to the LDAP host open (unless '-u' is used).

The latter mode can only be used with PAP, but provides the easiest way to make authentication work the same way as when using an LDAP client.

In either case, the module performs a subtree search for each request, using the first 'str' as the base DN and the second 'str' as the search filter.

It then translates each LDAP attribute that is present in each of the objects returned by the search, to the OpenRADIUS space/vendor/attribute combination that is listed in the mapping file for that attribute. The mapping file can be specified on the command line, otherwise a compiled-in default filename is used.

It sets the last instance of the 'int' attribute in its response to the number of objects returned by the search.

If you specify the '-u' command line switch, the module will unbind() from the directory after each request, to work around buggy and leaking LDAP implementations. This may useful especially if you use the '(re-)bind using User-Name / User-Password' mode. LDAPv3 implementations should support multiple binds during the same session fine though.
 

Distribution:
This standard module is included with the server and installed by default.
 

Generated on Sun Mar 25 00:43:53 2007 by decorate.pl / menuize.pl