# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
-# You should have received a copy of the GNU General Public License along with
-# Koha; if not, write to the Free Software Foundation, Inc., 59 Temple Place,
-# Suite 330, Boston, MA 02111-1307 USA
+# You should have received a copy of the GNU General Public License along
+# with Koha; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
use strict;
+#use warnings; FIXME - Bug 2505
use Digest::MD5 qw(md5_base64);
+use C4::Debug;
use C4::Context;
-use C4::Members qw(AddMember );
-
+use C4::Members qw(AddMember changepassword);
+use C4::Members::Attributes;
+use C4::Members::AttributeTypes;
+use C4::Utils qw( :all );
+use List::MoreUtils qw( any );
use Net::LDAP;
use Net::LDAP::Filter;
-# use Net::LDAP qw(:all);
-use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
+use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $debug);
BEGIN {
require Exporter;
- $VERSION = 3.01; # set the version for version checking
- our $debug = $ENV{DEBUG} || 0;
- @ISA = qw(Exporter C4::Auth);
- @EXPORT = qw( checkauth );
+ $VERSION = 3.10; # set the version for version checking
+ @ISA = qw(Exporter);
+ @EXPORT = qw( checkpw_ldap );
}
-=head1 NAME
-
-C4::Auth - Authenticates Koha users
-
-=head1 SYNOPSIS
-
- use C4::Auth_with_ldap;
-
-=head1 LDAP specific
-
- This module is specific to LDAP authentification. It requires Net::LDAP package and one or more
- working LDAP servers.
- To use it :
- * modify the code between LOCAL and /LOCAL to fit your LDAP server parameters & fields.
-
- It is assumed your user records are stored according to the inetOrgPerson schema, RFC#2798.
- Thus the username must match the "uid" field, and the password must match the "userPassword" field.
-
-=cut
-
-# Redefine checkauth:
+# Redefine checkpw_ldap:
# connect to LDAP (named or anonymous)
-# ~ retrieves $userid from "uid"
+# ~ retrieves $userid from KOHA_CONF mapping
# ~ then compares $password with userPassword
# ~ then gets the LDAP entry
# ~ and calls the memberadd if necessary
-my %mapping = (
- firstname => 'givenName',
- surname => 'sn',
- streetaddress => 'l',
- branchcode => 'branch',
- emailaddress => 'mail',
- categorycode => 'employeeType',
- city => 'null',
- phone => 'telephoneNumber',
-);
+sub ldapserver_error ($) {
+ return sprintf('No ldapserver "%s" defined in KOHA_CONF: ' . $ENV{KOHA_CONF}, shift);
+}
-my (@ldaphosts) = (qw(localhost)); # potentially multiple LDAP hosts!
-my $base = "dc=metavore,dc=com";
-my $ldapname = "cn=Manager,$base"; # The LDAP user.
-my $ldappassword = 'metavore';
+use vars qw($mapping @ldaphosts $base $ldapname $ldappassword);
+my $context = C4::Context->new() or die 'C4::Context->new failed';
+my $ldap = C4::Context->config("ldapserver") or die 'No "ldapserver" in server hash from KOHA_CONF: ' . $ENV{KOHA_CONF};
+my $prefhost = $ldap->{hostname} or die ldapserver_error('hostname');
+my $base = $ldap->{base} or die ldapserver_error('base');
+$ldapname = $ldap->{user} ;
+$ldappassword = $ldap->{pass} ;
+our %mapping = %{$ldap->{mapping}}; # FIXME dpavlin -- don't die because of || (); from 6eaf8511c70eb82d797c941ef528f4310a15e9f9
+my @mapkeys = keys %mapping;
+$debug and print STDERR "Got ", scalar(@mapkeys), " ldap mapkeys ( total ): ", join ' ', @mapkeys, "\n";
+@mapkeys = grep {defined $mapping{$_}->{is}} @mapkeys;
+$debug and print STDERR "Got ", scalar(@mapkeys), " ldap mapkeys (populated): ", join ' ', @mapkeys, "\n";
my %config = (
anonymous => ($ldapname and $ldappassword) ? 0 : 1,
- replicate => 1, # add from LDAP to Koha database for new user
- update => 1, # update from LDAP to Koha database for existing user
+ replicate => defined($ldap->{replicate}) ? $ldap->{replicate} : 1, # add from LDAP to Koha database for new user
+ update => defined($ldap->{update} ) ? $ldap->{update} : 1, # update from LDAP to Koha database for existing user
);
sub description ($) {
. "# " . $result->error_text . "\n";
}
-sub checkauth {
- my ($dbh, $userid, $password) = @_;
- if ( $userid eq C4::Context->config('user')
- && $password eq C4::Context->config('pass') )
- {
- return 2; # Koha superuser account
- }
- my $db = Net::LDAP->new(\@ldaphosts);
- #$debug and $db->debug(5);
- my $filter = Net::LDAP::Filter->new("uid=$userid") or die "Failed to create new Net::LDAP::Filter";
+sub search_method {
+ my $db = shift or return;
+ my $userid = shift or return;
+ my $uid_field = $mapping{userid}->{is} or die ldapserver_error("mapping for 'userid'");
+ my $filter = Net::LDAP::Filter->new("$uid_field=$userid") or die "Failed to create new Net::LDAP::Filter";
my $res = ($config{anonymous}) ? $db->bind : $db->bind($ldapname, password=>$ldappassword);
if ($res->code) { # connection refused
- warn "LDAP bind failed as $ldapname: " . description($res);
+ warn "LDAP bind failed as ldapuser " . ($ldapname || '[ANONYMOUS]') . ": " . description($res);
return 0;
}
my $search = $db->search(
warn sprintf("LDAP Auth rejected : %s gets %d hits\n", $filter->as_string, $count);
return 0;
}
+ return $search;
+}
+
+sub checkpw_ldap {
+ my ($dbh, $userid, $password) = @_;
+ my @hosts = split(',', $prefhost);
+ my $db = Net::LDAP->new(\@hosts);
+ #$debug and $db->debug(5);
+ my $userldapentry;
+ if ( $ldap->{auth_by_bind} ) {
+ my $principal_name = $ldap->{principal_name};
+ if ($principal_name and $principal_name =~ /\%/) {
+ $principal_name = sprintf($principal_name,$userid);
+ } else {
+ $principal_name = $userid;
+ }
+ my $res = $db->bind( $principal_name, password => $password );
+ if ( $res->code ) {
+ $debug and warn "LDAP bind failed as kohauser $principal_name: ". description($res);
+ return 0;
+ }
+
+ # FIXME dpavlin -- we really need $userldapentry leater on even if using auth_by_bind!
+ my $search = search_method($db, $userid) or return 0; # warnings are in the sub
+ $userldapentry = $search->shift_entry;
- my $userldapentry = $search->shift_entry;
- my $cmpmesg = $db->compare( $userldapentry, attr=>'userPassword', value => $password );
- if($cmpmesg->code != 6) {
- warn "LDAP Auth rejected : invalid password for user '$userid'. " . description($cmpmesg);
- return 0;
- }
- unless($config{update} or $config{replicate}) {
- return 1;
- }
- my %borrower = ldap_entry_2_hash($userldapentry,$userid);
- if (exists_local($userid)) {
- ($config{update} ) and &update_local($userid,$password,%borrower);
} else {
- ($config{replicate}) and AddMember(%borrower);
+ my $search = search_method($db, $userid) or return 0; # warnings are in the sub
+ $userldapentry = $search->shift_entry;
+ my $cmpmesg = $db->compare( $userldapentry, attr=>'userpassword', value => $password );
+ if ($cmpmesg->code != 6) {
+ warn "LDAP Auth rejected : invalid password for user '$userid'. " . description($cmpmesg);
+ return 0;
+ }
}
- return 1;
+
+ # To get here, LDAP has accepted our user's login attempt.
+ # But we still have work to do. See perldoc below for detailed breakdown.
+
+ my (%borrower);
+ my ($borrowernumber,$cardnumber,$local_userid,$savedpw) = exists_local($userid);
+
+ if (( $borrowernumber and $config{update} ) or
+ (!$borrowernumber and $config{replicate}) ) {
+ %borrower = ldap_entry_2_hash($userldapentry,$userid);
+ $debug and print STDERR "checkpw_ldap received \%borrower w/ " . keys(%borrower), " keys: ", join(' ', keys %borrower), "\n";
+ }
+
+ if ($borrowernumber) {
+ if ($config{update}) { # A1, B1
+ my $c2 = &update_local($local_userid,$password,$borrowernumber,\%borrower) || '';
+ ($cardnumber eq $c2) or warn "update_local returned cardnumber '$c2' instead of '$cardnumber'";
+ } else { # C1, D1
+ # maybe update just the password?
+ return(1, $cardnumber); # FIXME dpavlin -- don't destroy ExtendedPatronAttributes
+ }
+ } elsif ($config{replicate}) { # A2, C2
+ $borrowernumber = AddMember(%borrower) or die "AddMember failed";
+ } else {
+ return 0; # B2, D2
+ }
+ if (C4::Context->preference('ExtendedPatronAttributes') && $borrowernumber && ($config{update} ||$config{replicate})) {
+ my @types = C4::Members::AttributeTypes::GetAttributeTypes();
+ my @attributes = grep{my $key=$_; any{$_ eq $key}@types;} keys %borrower;
+ my $extended_patron_attributes = map{{code=>$_,value=>$borrower{$_}}}@attributes;
+ my $extended_patron_attributes = [] unless $extended_patron_attributes;
+ my @errors;
+ #Check before add
+ for (my $i; $i< scalar(@$extended_patron_attributes)-1;$i++) {
+ my $attr=$extended_patron_attributes->[$i];
+ unless (C4::Members::Attributes::CheckUniqueness($attr->{code}, $attr->{value}, $borrowernumber)) {
+ unshift @errors, $i;
+ warn "ERROR_extended_unique_id_failed $attr->{code} $attr->{value}";
+ }
+ }
+ #Removing erroneous attributes
+ foreach my $index (@errors){
+ @$extended_patron_attributes=splice(@$extended_patron_attributes,$index,1);
+ }
+ C4::Members::Attributes::SetBorrowerAttributes($borrowernumber, $extended_patron_attributes);
+ }
+return(1, $cardnumber);
}
# Pass LDAP entry object and local cardnumber (userid).
# Returns borrower hash.
-# Edit %mapping so $memberhash{'xxx'} fits your ldap structure.
+# Edit KOHA_CONF so $memberhash{'xxx'} fits your ldap structure.
# Ensure that mandatory fields are correctly filled!
#
sub ldap_entry_2_hash ($$) {
my $userldapentry = shift;
my %borrower = ( cardnumber => shift );
my %memberhash;
- my $x = $userldapentry->{asn}{attributes} or return undef;
- my $key;
- foreach my $k (@$x) {
- foreach my $k2 ( keys %$k ) {
- if ($k2 eq 'type') {
- $key = $$k{$k2};
- } else {
- $memberhash{$key} .= map {$_ . " "} @$k{$k2};
- }
+ $userldapentry->exists('uid'); # This is bad, but required! By side-effect, this initializes the attrs hash.
+ if ($debug) {
+ print STDERR "\nkeys(\%\$userldapentry) = " . join(', ', keys %$userldapentry), "\n", $userldapentry->dump();
+ foreach (keys %$userldapentry) {
+ print STDERR "\n\nLDAP key: $_\t", sprintf('(%s)', ref $userldapentry->{$_}), "\n";
+ hashdump("LDAP key: ",$userldapentry->{$_});
}
}
- foreach my $key (%mapping) {
- my $data = $memberhash{$mapping{$key}};
- defined $data or $data = ' ';
+ my $x = $userldapentry->{attrs} or return undef;
+ foreach (keys %$x) {
+ $memberhash{$_} = join ' ', @{$x->{$_}};
+ $debug and print STDERR sprintf("building \$memberhash{%s} = ", $_, join(' ', @{$x->{$_}})), "\n";
+ }
+ $debug and print STDERR "Finsihed \%memberhash has ", scalar(keys %memberhash), " keys\n",
+ "Referencing \%mapping with ", scalar(keys %mapping), " keys\n";
+ foreach my $key (keys %mapping) {
+ my $data = $memberhash{$mapping{$key}->{is}};
+ $debug and printf STDERR "mapping %20s ==> %-20s (%s)\n", $key, $mapping{$key}->{is}, $data;
+ unless (defined $data) {
+ $data = $mapping{$key}->{content} || ''; # default or failsafe ''
+ }
$borrower{$key} = ($data ne '') ? $data : ' ' ;
}
$borrower{initials} = $memberhash{initials} ||
( substr($borrower{'firstname'},0,1)
. substr($borrower{ 'surname' },0,1)
- . " ");
+ . " ");
return %borrower;
}
sub exists_local($) {
- my $sth = C4::Context->dbh->prepare("SELECT password from borrowers WHERE cardnumber=?");
- $sth->execute(shift);
- return ($sth->rows) ? 1 : 0 ;
+ my $arg = shift;
+ my $dbh = C4::Context->dbh;
+ my $select = "SELECT borrowernumber,cardnumber,userid,password FROM borrowers ";
+
+ my $sth = $dbh->prepare("$select WHERE userid=?"); # was cardnumber=?
+ $sth->execute($arg);
+ $debug and printf STDERR "Userid '$arg' exists_local? %s\n", $sth->rows;
+ ($sth->rows == 1) and return $sth->fetchrow;
+
+ $sth = $dbh->prepare("$select WHERE cardnumber=?");
+ $sth->execute($arg);
+ $debug and printf STDERR "Cardnumber '$arg' exists_local? %s\n", $sth->rows;
+ ($sth->rows == 1) and return $sth->fetchrow;
+ return 0;
+}
+
+sub _do_changepassword {
+ my ($userid, $borrowerid, $digest) = @_;
+ $debug and print STDERR "changing local password for borrowernumber=$borrowerid to '$digest'\n";
+ changepassword($userid, $borrowerid, $digest);
+
+ # Confirm changes
+ my $sth = C4::Context->dbh->prepare("SELECT password,cardnumber FROM borrowers WHERE borrowernumber=? ");
+ $sth->execute($borrowerid);
+ if ($sth->rows) {
+ my ($md5password, $cardnum) = $sth->fetchrow;
+ ($digest eq $md5password) and return $cardnum;
+ warn "Password mismatch after update to cardnumber=$cardnum (borrowernumber=$borrowerid)";
+ return undef;
+ }
+ die "Unexpected error after password update to userid/borrowernumber: $userid / $borrowerid.";
}
-sub update_local($$%) {
- # warn "MODIFY borrower";
- my $userid = shift or return undef;
- my $digest = md5_base64(shift) or return undef;
- my %borrower = shift or return undef;
+sub update_local($$$$) {
+ my $userid = shift or return undef;
+ my $digest = md5_base64(shift) or return undef;
+ my $borrowerid = shift or return undef;
+ my $borrower = shift or return undef;
+ my @keys = keys %$borrower;
my $dbh = C4::Context->dbh;
- my $sth = $dbh->prepare("
-UPDATE borrowers
-SET firstname=?,surname=?,initials=?,streetaddress=?,city=?,phone=?, categorycode=?,branchcode=?,emailaddress=?,sort1=?
-WHERE cardnumber=?
- ");
+ my $query = "UPDATE borrowers\nSET " .
+ join(',', map {"$_=?"} @keys) .
+ "\nWHERE borrowernumber=? ";
+ my $sth = $dbh->prepare($query);
+ if ($debug) {
+ print STDERR $query, "\n",
+ join "\n", map {"$_ = '" . $borrower->{$_} . "'"} @keys;
+ print STDERR "\nuserid = $userid\n";
+ }
$sth->execute(
- $borrower{firstname}, $borrower{surname},
- $borrower{initials}, $borrower{streetaddress},
- $borrower{city}, $borrower{phone},
- $borrower{categorycode}, $borrower{branchcode},
- $borrower{emailaddress}, $borrower{sort1},
- $userid
+ ((map {$borrower->{$_}} @keys), $borrowerid)
);
# MODIFY PASSWORD/LOGIN
- # search borrowerid
- $sth = $dbh->prepare("SELECT borrowernumber from borrowers WHERE cardnumber=? ");
- $sth->execute($userid);
- my ($borrowerid) = $sth->fetchrow;
- # warn "change local password for $borrowerid setting $password";
- changepassword($userid, $borrowerid, $digest);
-
- # Confirm changes
- my $cardnumber;
- $sth = $dbh->prepare("SELECT password,cardnumber from borrowers WHERE userid=? ");
- $cardnumber = confirmer($sth,$userid,$digest) and return $cardnumber;
- $sth = $dbh->prepare("SELECT password,cardnumber from borrowers WHERE cardnumber=? ");
- $cardnumber = confirmer($sth,$userid,$digest) and return $cardnumber;
- die "Unexpected error after password update to $userid / $cardnumber.";
+ _do_changepassword($userid, $borrowerid, $digest);
}
-sub confirmer($$$) {
- my $sth = shift or return undef;
- my $userid = shift or return undef;
- my $digest = shift or return undef;
- $sth->execute($userid);
- if ($sth->rows) {
- my ($md5password, $othernum) = $sth->fetchrow;
- ($digest eq $md5password) and return $othernum;
- warn "Password mismatch after update to userid=$userid";
- return undef;
- }
- warn "Could not recover record after updating password for userid=$userid";
- return 0;
-}
1;
__END__
-=back
+=head1 NAME
+
+C4::Auth - Authenticates Koha users
+
+=head1 SYNOPSIS
+
+ use C4::Auth_with_ldap;
+
+=head1 LDAP Configuration
+
+ This module is specific to LDAP authentification. It requires Net::LDAP package and one or more
+ working LDAP servers.
+ To use it :
+ * Modify ldapserver element in KOHA_CONF
+ * Establish field mapping in <mapping> element.
+
+ For example, if your user records are stored according to the inetOrgPerson schema, RFC#2798,
+ the username would match the "uid" field, and the password should match the "userpassword" field.
+
+ Make sure that ALL required fields are populated by your LDAP database (and mapped in KOHA_CONF).
+ What are the required fields? Well, in mysql you can check the database table "borrowers" like this:
+
+ mysql> show COLUMNS from borrowers;
+ +------------------+--------------+------+-----+---------+----------------+
+ | Field | Type | Null | Key | Default | Extra |
+ +------------------+--------------+------+-----+---------+----------------+
+ | borrowernumber | int(11) | NO | PRI | NULL | auto_increment |
+ | cardnumber | varchar(16) | YES | UNI | NULL | |
+ | surname | mediumtext | NO | | | |
+ | firstname | text | YES | | NULL | |
+ | title | mediumtext | YES | | NULL | |
+ | othernames | mediumtext | YES | | NULL | |
+ | initials | text | YES | | NULL | |
+ | streetnumber | varchar(10) | YES | | NULL | |
+ | streettype | varchar(50) | YES | | NULL | |
+ | address | mediumtext | NO | | | |
+ | address2 | text | YES | | NULL | |
+ | city | mediumtext | NO | | | |
+ | zipcode | varchar(25) | YES | | NULL | |
+ | email | mediumtext | YES | | NULL | |
+ | phone | text | YES | | NULL | |
+ | mobile | varchar(50) | YES | | NULL | |
+ | fax | mediumtext | YES | | NULL | |
+ | emailpro | text | YES | | NULL | |
+ | phonepro | text | YES | | NULL | |
+ | B_streetnumber | varchar(10) | YES | | NULL | |
+ | B_streettype | varchar(50) | YES | | NULL | |
+ | B_address | varchar(100) | YES | | NULL | |
+ | B_city | mediumtext | YES | | NULL | |
+ | B_zipcode | varchar(25) | YES | | NULL | |
+ | B_email | text | YES | | NULL | |
+ | B_phone | mediumtext | YES | | NULL | |
+ | dateofbirth | date | YES | | NULL | |
+ | branchcode | varchar(10) | NO | MUL | | |
+ | categorycode | varchar(10) | NO | MUL | | |
+ | dateenrolled | date | YES | | NULL | |
+ | dateexpiry | date | YES | | NULL | |
+ | gonenoaddress | tinyint(1) | YES | | NULL | |
+ | lost | tinyint(1) | YES | | NULL | |
+ | debarred | tinyint(1) | YES | | NULL | |
+ | contactname | mediumtext | YES | | NULL | |
+ | contactfirstname | text | YES | | NULL | |
+ | contacttitle | text | YES | | NULL | |
+ | guarantorid | int(11) | YES | | NULL | |
+ | borrowernotes | mediumtext | YES | | NULL | |
+ | relationship | varchar(100) | YES | | NULL | |
+ | ethnicity | varchar(50) | YES | | NULL | |
+ | ethnotes | varchar(255) | YES | | NULL | |
+ | sex | varchar(1) | YES | | NULL | |
+ | password | varchar(30) | YES | | NULL | |
+ | flags | int(11) | YES | | NULL | |
+ | userid | varchar(30) | YES | MUL | NULL | | # UNIQUE in next release.
+ | opacnote | mediumtext | YES | | NULL | |
+ | contactnote | varchar(255) | YES | | NULL | |
+ | sort1 | varchar(80) | YES | | NULL | |
+ | sort2 | varchar(80) | YES | | NULL | |
+ +------------------+--------------+------+-----+---------+----------------+
+ 50 rows in set (0.01 sec)
+
+ Where Null="NO", the field is required.
+
+=head1 KOHA_CONF and field mapping
+
+Example XML stanza for LDAP configuration in KOHA_CONF.
+
+ <config>
+ ...
+ <useldapserver>1</useldapserver>
+ <!-- LDAP SERVER (optional) -->
+ <ldapserver id="ldapserver">
+ <hostname>localhost</hostname>
+ <base>dc=metavore,dc=com</base>
+ <user>cn=Manager,dc=metavore,dc=com</user> <!-- DN, if not anonymous -->
+ <pass>metavore</pass> <!-- password, if not anonymous -->
+ <replicate>1</replicate> <!-- add new users from LDAP to Koha database -->
+ <update>1</update> <!-- update existing users in Koha database -->
+ <auth_by_bind>0</auth_by_bind> <!-- set to 1 to authenticate by binding instead of
+ password comparison, e.g., to use Active Directory -->
+ <principal_name>%s@my_domain.com</principal_name>
+ <!-- optional, for auth_by_bind: a printf format to make userPrincipalName from koha userid -->
+ <mapping> <!-- match koha SQL field names to your LDAP record field names -->
+ <firstname is="givenname" ></firstname>
+ <surname is="sn" ></surname>
+ <address is="postaladdress" ></address>
+ <city is="l" >Athens, OH</city>
+ <zipcode is="postalcode" ></zipcode>
+ <branchcode is="branch" >MAIN</branchcode>
+ <userid is="uid" ></userid>
+ <password is="userpassword" ></password>
+ <email is="mail" ></email>
+ <categorycode is="employeetype" >PT</categorycode>
+ <phone is="telephonenumber"></phone>
+ </mapping>
+ </ldapserver>
+ </config>
+
+The <mapping> subelements establish the relationship between mysql fields and LDAP attributes. The element name
+is the column in mysql, with the "is" characteristic set to the LDAP attribute name. Optionally, any content
+between the element tags is taken as the default value. In this example, the default categorycode is "PT" (for
+patron).
+
+=head1 CONFIGURATION
+
+Once a user has been accepted by the LDAP server, there are several possibilities for how Koha will behave, depending on
+your configuration and the presence of a matching Koha user in your local DB:
+
+ LOCAL_USER
+ OPTION UPDATE REPLICATE EXISTS? RESULT
+ A1 1 1 1 OK : We're updating them anyway.
+ A2 1 1 0 OK : We're adding them anyway.
+ B1 1 0 1 OK : We update them.
+ B2 1 0 0 FAIL: We cannot add new user.
+ C1 0 1 1 OK : We do nothing. (maybe should update password?)
+ C2 0 1 0 OK : We add the new user.
+ D1 0 0 1 OK : We do nothing. (maybe should update password?)
+ D2 0 0 0 FAIL: We cannot add new user.
+
+Note: failure here just means that Koha will fallback to checking the local DB. That is, a given user could login with
+their LDAP password OR their local one. If this is a problem, then you should enable update and supply a mapping for
+password. Then the local value will be updated at successful LDAP login and the passwords will be synced.
+
+If you choose NOT to update local users, the borrowers table will not be affected at all.
+Note that this means that patron passwords may appear to change if LDAP is ever disabled, because
+the local table never contained the LDAP values.
+
+=head2 auth_by_bind
+
+Binds as the user instead of retrieving their record. Recommended if update disabled.
+
+=head2 principal_name
+
+Provides an optional sprintf-style format for manipulating the userid before the bind.
+Even though the userPrincipalName is one intended target, any uniquely identifying
+attribute that the server allows to be used for binding could be used.
+
+Currently, principal_name only operates when auth_by_bind is enabled.
+
+=head2 Active Directory
+
+The auth_by_bind and principal_name settings are recommended for Active Directory.
+
+Under default Active Directory rules, we cannot determine the distinguishedName attribute from the Koha userid as reliably as
+we would typically under openldap. Instead of:
+
+ distinguishedName: CN=barnes.7,DC=my_company,DC=com
+
+We might get:
+
+ distinguishedName: CN=Barnes\, Jim,OU=Test Accounts,OU=User Accounts,DC=my_company,DC=com
+
+Matching that would require us to know more info about the account (firstname, surname) and to include punctuation and whitespace
+in Koha userids. But the userPrincipalName should be consistent, something like:
+
+ userPrincipalName: barnes.7@my_company.com
+
+Therefore it is often easier to bind to Active Directory with userPrincipalName, effectively the
+canonical email address for that user, or what it would be if email were enabled for them. If Koha userid values
+will match the username portion of the userPrincipalName, and the domain suffix is the same for all users, then use principal_name
+like this:
+ <principal_name>%s@core.my_company.com</principal_name>
+
+The user of the previous example, barnes.7, would then attempt to bind as:
+ barnes.7@core.my_company.com
=head1 SEE ALSO
Net::LDAP()
+XML::Simple()
+
Digest::MD5(3)
+sprintf()
+
=cut
+
+# For reference, here's an important difference in the data structure we rely on.
+# ========================================
+# Using attrs instead of {asn}->attributes
+# ========================================
+#
+# LDAP key: ->{ cn} = ARRAY w/ 3 members.
+# LDAP key: ->{ cn}->{ sss} = sss
+# LDAP key: ->{ cn}->{ Steve Smith} = Steve Smith
+# LDAP key: ->{ cn}->{Steve S. Smith} = Steve S. Smith
+#
+# LDAP key: ->{ givenname} = ARRAY w/ 1 members.
+# LDAP key: ->{ givenname}->{Steve} = Steve
+#