C4/Auth_with_ldap.pm

   1 package C4::Auth_with_ldap;
   2
   3 # Copyright 2000-2002 Katipo Communications
   4 #
   5 # This file is part of Koha.
   6 #
   7 # Koha is free software; you can redistribute it and/or modify it under the
   8 # terms of the GNU General Public License as published by the Free Software
   9 # Foundation; either version 2 of the License, or (at your option) any later
  10 # version.
  11 #
  12 # Koha is distributed in the hope that it will be useful, but WITHOUT ANY
  13 # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  14 # A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License along
  17 # with Koha; if not, write to the Free Software Foundation, Inc.,
  18 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19
  20 use strict;
  21 #use warnings; FIXME - Bug 2505
  22 use Carp;
  23
  24 use C4::Debug;
  25 use C4::Context;
  26 use C4::Members qw(AddMember changepassword);
  27 use C4::Members::Attributes;
  28 use C4::Members::AttributeTypes;
  29 use C4::Members::Messaging;
  30 use C4::Auth qw(checkpw_internal);
  31 use Koha::AuthUtils qw(hash_password);
  32 use List::MoreUtils qw( any );
  33 use Net::LDAP;
  34 use Net::LDAP::Filter;
  35
  36 use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $debug);
  37
  38 BEGIN {
  39         require Exporter;
  40     $VERSION = 3.07.00.049;     # set the version for version checking
  41         @ISA    = qw(Exporter);
  42         @EXPORT = qw( checkpw_ldap );
  43 }
  44
  45 # Redefine checkpw_ldap:
  46 # connect to LDAP (named or anonymous)
  47 # ~ retrieves $userid from KOHA_CONF mapping
  48 # ~ then compares $password with userPassword
  49 # ~ then gets the LDAP entry
  50 # ~ and calls the memberadd if necessary
  51
  52 sub ldapserver_error {
  53         return sprintf('No ldapserver "%s" defined in KOHA_CONF: ' . $ENV{KOHA_CONF}, shift);
  54 }
  55
  56 use vars qw($mapping @ldaphosts $base $ldapname $ldappassword);
  57 my $context = C4::Context->new()        or die 'C4::Context->new failed';
  58 my $ldap = C4::Context->config("ldapserver") or die 'No "ldapserver" in server hash from KOHA_CONF: ' . $ENV{KOHA_CONF};
  59 my $prefhost  = $ldap->{hostname}       or die ldapserver_error('hostname');
  60 my $base      = $ldap->{base}           or die ldapserver_error('base');
  61 $ldapname     = $ldap->{user}           ;
  62 $ldappassword = $ldap->{pass}           ;
  63 our %mapping  = %{$ldap->{mapping}}; # FIXME dpavlin -- don't die because of || (); from 6eaf8511c70eb82d797c941ef528f4310a15e9f9
  64 my @mapkeys = keys %mapping;
  65 $debug and print STDERR "Got ", scalar(@mapkeys), " ldap mapkeys (  total  ): ", join ' ', @mapkeys, "\n";
  66 @mapkeys = grep {defined $mapping{$_}->{is}} @mapkeys;
  67 $debug and print STDERR "Got ", scalar(@mapkeys), " ldap mapkeys (populated): ", join ' ', @mapkeys, "\n";
  68
  69 my %config = (
  70         anonymous => ($ldapname and $ldappassword) ? 0 : 1,
  71     replicate => defined($ldap->{replicate}) ? $ldap->{replicate} : 1,  #    add from LDAP to Koha database for new user
  72        update => defined($ldap->{update}   ) ? $ldap->{update}    : 1,  # update from LDAP to Koha database for existing user
  73 );
  74
  75 sub description {
  76         my $result = shift or return;
  77         return "LDAP error #" . $result->code
  78                         . ": " . $result->error_name . "\n"
  79                         . "# " . $result->error_text . "\n";
  80 }
  81
  82 sub search_method {
  83     my $db     = shift or return;
  84     my $userid = shift or return;
  85         my $uid_field = $mapping{userid}->{is} or die ldapserver_error("mapping for 'userid'");
  86         my $filter = Net::LDAP::Filter->new("$uid_field=$userid") or die "Failed to create new Net::LDAP::Filter";
  87         my $search = $db->search(
  88                   base => $base,
  89                 filter => $filter,
  90                 # attrs => ['*'],
  91         ) or die "LDAP search failed to return object.";
  92         my $count = $search->count;
  93         if ($search->code > 0) {
  94                 warn sprintf("LDAP Auth rejected : %s gets %d hits\n", $filter->as_string, $count) . description($search);
  95                 return 0;
  96         }
  97         if ($count != 1) {
  98                 warn sprintf("LDAP Auth rejected : %s gets %d hits\n", $filter->as_string, $count);
  99                 return 0;
 100         }
 101     return $search;
 102 }
 103
 104 sub checkpw_ldap {
 105     my ($dbh, $userid, $password) = @_;
 106     my @hosts = split(',', $prefhost);
 107     my $db = Net::LDAP->new(\@hosts);
 108     unless ( $db ) {
 109         warn "LDAP connexion failed";
 110         return 0;
 111     }
 112
 113         #$debug and $db->debug(5);
 114     my $userldapentry;
 115
 116     if ( $ldap->{auth_by_bind} ) {
 117         my $principal_name;
 118         if ( $ldap->{anonymous_bind} ) {
 119
 120             # Perform an anonymous bind
 121             my $res = $db->bind;
 122             if ( $res->code ) {
 123                 warn "Anonymous LDAP bind failed: " . description($res);
 124                 return 0;
 125             }
 126
 127             # Perform a LDAP search for the given username
 128             my $search = search_method( $db, $userid )
 129               or return 0;    # warnings are in the sub
 130             $userldapentry = $search->shift_entry;
 131             $principal_name = $userldapentry->dn;
 132         }
 133         else {
 134             $principal_name = $ldap->{principal_name};
 135             if ( $principal_name and $principal_name =~ /\%/ ) {
 136                 $principal_name = sprintf( $principal_name, $userid );
 137             }
 138             else {
 139                 $principal_name = $userid;
 140             }
 141         }
 142
 143         # Perform a LDAP bind for the given username using the matched DN
 144         my $res = $db->bind( $principal_name, password => $password );
 145         if ( $res->code ) {
 146             warn "LDAP bind failed as kohauser $userid: " . description($res);
 147             return 0;
 148         }
 149         if ( !defined($userldapentry)
 150             && ( $config{update} or $config{replicate} ) )
 151         {
 152             my $search = search_method( $db, $userid ) or return 0;
 153             $userldapentry = $search->shift_entry;
 154         }
 155     } else {
 156                 my $res = ($config{anonymous}) ? $db->bind : $db->bind($ldapname, password=>$ldappassword);
 157                 if ($res->code) {               # connection refused
 158                         warn "LDAP bind failed as ldapuser " . ($ldapname || '[ANONYMOUS]') . ": " . description($res);
 159                         return 0;
 160                 }
 161         my $search = search_method($db, $userid) or return 0;   # warnings are in the sub
 162         $userldapentry = $search->shift_entry;
 163                 my $cmpmesg = $db->compare( $userldapentry, attr=>'userpassword', value => $password );
 164                 if ($cmpmesg->code != 6) {
 165                         warn "LDAP Auth rejected : invalid password for user '$userid'. " . description($cmpmesg);
 166                         return 0;
 167                 }
 168         }
 169
 170     # To get here, LDAP has accepted our user's login attempt.
 171     # But we still have work to do.  See perldoc below for detailed breakdown.
 172
 173     my (%borrower);
 174         my ($borrowernumber,$cardnumber,$local_userid,$savedpw) = exists_local($userid);
 175
 176     if (( $borrowernumber and $config{update}   ) or
 177         (!$borrowernumber and $config{replicate})   ) {
 178         %borrower = ldap_entry_2_hash($userldapentry,$userid);
 179         $debug and print STDERR "checkpw_ldap received \%borrower w/ " . keys(%borrower), " keys: ", join(' ', keys %borrower), "\n";
 180     }
 181
 182     if ($borrowernumber) {
 183         if ($config{update}) { # A1, B1
 184             my $c2 = &update_local($local_userid,$password,$borrowernumber,\%borrower) || '';
 185             ($cardnumber eq $c2) or warn "update_local returned cardnumber '$c2' instead of '$cardnumber'";
 186         } else { # C1, D1
 187             # maybe update just the password?
 188                 return(1, $cardnumber, $local_userid);
 189         }
 190     } elsif ($config{replicate}) { # A2, C2
 191         $borrowernumber = AddMember(%borrower) or die "AddMember failed";
 192         C4::Members::Messaging::SetMessagingPreferencesFromDefaults( { borrowernumber => $borrowernumber, categorycode => $borrower{'categorycode'} } );
 193    } else {
 194         return 0;   # B2, D2
 195     }
 196     if (C4::Context->preference('ExtendedPatronAttributes') && $borrowernumber && ($config{update} ||$config{replicate})) {
 197         my @extended_patron_attributes;
 198         foreach my $attribute_type ( C4::Members::AttributeTypes::GetAttributeTypes() ) {
 199             my $code = $attribute_type->{code};
 200             if ( exists($borrower{$code}) && $borrower{$code} !~ m/^\s*$/ ) { # skip empty values
 201                 push @extended_patron_attributes, { code => $code, value => $borrower{$code} };
 202             }
 203         }
 204         #Check before add
 205         my @unique_attr;
 206         foreach my $attr ( @extended_patron_attributes ) {
 207             if (C4::Members::Attributes::CheckUniqueness($attr->{code}, $attr->{value}, $borrowernumber)) {
 208                 push @unique_attr, $attr;
 209             } else {
 210                 warn "ERROR_extended_unique_id_failed $attr->{code} $attr->{value}";
 211             }
 212         }
 213         C4::Members::Attributes::SetBorrowerAttributes($borrowernumber, \@unique_attr);
 214     }
 215 return(1, $cardnumber, $userid);
 216 }
 217
 218 # Pass LDAP entry object and local cardnumber (userid).
 219 # Returns borrower hash.
 220 # Edit KOHA_CONF so $memberhash{'xxx'} fits your ldap structure.
 221 # Ensure that mandatory fields are correctly filled!
 222 #
 223 sub ldap_entry_2_hash {
 224         my $userldapentry = shift;
 225         my %borrower = ( cardnumber => shift );
 226         my %memberhash;
 227         $userldapentry->exists('uid');  # This is bad, but required!  By side-effect, this initializes the attrs hash.
 228         if ($debug) {
 229                 foreach (keys %$userldapentry) {
 230                         print STDERR "\n\nLDAP key: $_\t", sprintf('(%s)', ref $userldapentry->{$_}), "\n";
 231                 }
 232         }
 233         my $x = $userldapentry->{attrs} or return;
 234         foreach (keys %$x) {
 235                 $memberhash{$_} = join ' ', @{$x->{$_}};
 236                 $debug and print STDERR sprintf("building \$memberhash{%s} = ", $_, join(' ', @{$x->{$_}})), "\n";
 237         }
 238         $debug and print STDERR "Finsihed \%memberhash has ", scalar(keys %memberhash), " keys\n",
 239                                         "Referencing \%mapping with ", scalar(keys %mapping), " keys\n";
 240         foreach my $key (keys %mapping) {
 241                 my  $data = $memberhash{ lc($mapping{$key}->{is}) }; # Net::LDAP returns all names in lowercase
 242                 $debug and printf STDERR "mapping %20s ==> %-20s (%s)\n", $key, $mapping{$key}->{is}, $data;
 243                 unless (defined $data) {
 244                         $data = $mapping{$key}->{content} || '';        # default or failsafe ''
 245                 }
 246                 $borrower{$key} = ($data ne '') ? $data : ' ' ;
 247         }
 248         $borrower{initials} = $memberhash{initials} ||
 249                 ( substr($borrower{'firstname'},0,1)
 250                 . substr($borrower{ 'surname' },0,1)
 251                 . " ");
 252
 253         # check if categorycode exists, if not, fallback to default from koha-conf.xml
 254         my $dbh = C4::Context->dbh;
 255         my $sth = $dbh->prepare("SELECT categorycode FROM categories WHERE categorycode = ?");
 256         $sth->execute( uc($borrower{'categorycode'}) );
 257         unless ( my $row = $sth->fetchrow_hashref ) {
 258                 my $default = $mapping{'categorycode'}->{content};
 259                 $debug && warn "Can't find ", $borrower{'categorycode'}, " default to: $default for ", $borrower{userid};
 260                 $borrower{'categorycode'} = $default
 261         }
 262
 263         return %borrower;
 264 }
 265
 266 sub exists_local {
 267         my $arg = shift;
 268         my $dbh = C4::Context->dbh;
 269         my $select = "SELECT borrowernumber,cardnumber,userid,password FROM borrowers ";
 270
 271         my $sth = $dbh->prepare("$select WHERE userid=?");      # was cardnumber=?
 272         $sth->execute($arg);
 273         $debug and printf STDERR "Userid '$arg' exists_local? %s\n", $sth->rows;
 274         ($sth->rows == 1) and return $sth->fetchrow;
 275
 276         $sth = $dbh->prepare("$select WHERE cardnumber=?");
 277         $sth->execute($arg);
 278         $debug and printf STDERR "Cardnumber '$arg' exists_local? %s\n", $sth->rows;
 279         ($sth->rows == 1) and return $sth->fetchrow;
 280         return 0;
 281 }
 282
 283 sub _do_changepassword {
 284     my ($userid, $borrowerid, $password) = @_;
 285
 286     my $digest = hash_password($password);
 287
 288     $debug and print STDERR "changing local password for borrowernumber=$borrowerid to '$digest'\n";
 289     changepassword($userid, $borrowerid, $digest);
 290
 291     my ($ok, $cardnum) = checkpw_internal(C4::Context->dbh, $userid, $password);
 292     return $cardnum if $ok;
 293
 294     warn "Password mismatch after update to borrowernumber=$borrowerid";
 295     return;
 296 }
 297
 298 sub update_local {
 299     my $userid     = shift or croak "No userid";
 300     my $password   = shift or croak "No password";
 301     my $borrowerid = shift or croak "No borrowerid";
 302     my $borrower   = shift or croak "No borrower record";
 303
 304     my @keys = keys %$borrower;
 305     my $dbh = C4::Context->dbh;
 306     my $query = "UPDATE  borrowers\nSET     " .
 307         join(',', map {"$_=?"} @keys) .
 308         "\nWHERE   borrowernumber=? ";
 309     my $sth = $dbh->prepare($query);
 310     if ($debug) {
 311         print STDERR $query, "\n",
 312             join "\n", map {"$_ = '" . $borrower->{$_} . "'"} @keys;
 313         print STDERR "\nuserid = $userid\n";
 314     }
 315     $sth->execute(
 316         ((map {$borrower->{$_}} @keys), $borrowerid)
 317     );
 318
 319     # MODIFY PASSWORD/LOGIN
 320     _do_changepassword($userid, $borrowerid, $password);
 321 }
 322
 323 1;
 324 __END__
 325
 326 =head1 NAME
 327
 328 C4::Auth - Authenticates Koha users
 329
 330 =head1 SYNOPSIS
 331
 332   use C4::Auth_with_ldap;
 333
 334 =head1 LDAP Configuration
 335
 336     This module is specific to LDAP authentification. It requires Net::LDAP package and one or more
 337         working LDAP servers.
 338         To use it :
 339            * Modify ldapserver element in KOHA_CONF
 340            * Establish field mapping in <mapping> element.
 341
 342         For example, if your user records are stored according to the inetOrgPerson schema, RFC#2798,
 343         the username would match the "uid" field, and the password should match the "userpassword" field.
 344
 345         Make sure that ALL required fields are populated by your LDAP database (and mapped in KOHA_CONF).
 346         What are the required fields?  Well, in mysql you can check the database table "borrowers" like this:
 347
 348         mysql> show COLUMNS from borrowers;
 349                 +---------------------+--------------+------+-----+---------+----------------+
 350                 | Field               | Type         | Null | Key | Default | Extra          |
 351                 +---------------------+--------------+------+-----+---------+----------------+
 352                 | borrowernumber      | int(11)      | NO   | PRI | NULL    | auto_increment |
 353                 | cardnumber          | varchar(16)  | YES  | UNI | NULL    |                |
 354                 | surname             | mediumtext   | NO   |     | NULL    |                |
 355                 | firstname           | text         | YES  |     | NULL    |                |
 356                 | title               | mediumtext   | YES  |     | NULL    |                |
 357                 | othernames          | mediumtext   | YES  |     | NULL    |                |
 358                 | initials            | text         | YES  |     | NULL    |                |
 359                 | streetnumber        | varchar(10)  | YES  |     | NULL    |                |
 360                 | streettype          | varchar(50)  | YES  |     | NULL    |                |
 361                 | address             | mediumtext   | NO   |     | NULL    |                |
 362                 | address2            | text         | YES  |     | NULL    |                |
 363                 | city                | mediumtext   | NO   |     | NULL    |                |
 364                 | state               | mediumtext   | YES  |     | NULL    |                |
 365                 | zipcode             | varchar(25)  | YES  |     | NULL    |                |
 366                 | country             | text         | YES  |     | NULL    |                |
 367                 | email               | mediumtext   | YES  |     | NULL    |                |
 368                 | phone               | text         | YES  |     | NULL    |                |
 369                 | mobile              | varchar(50)  | YES  |     | NULL    |                |
 370                 | fax                 | mediumtext   | YES  |     | NULL    |                |
 371                 | emailpro            | text         | YES  |     | NULL    |                |
 372                 | phonepro            | text         | YES  |     | NULL    |                |
 373                 | B_streetnumber      | varchar(10)  | YES  |     | NULL    |                |
 374                 | B_streettype        | varchar(50)  | YES  |     | NULL    |                |
 375                 | B_address           | varchar(100) | YES  |     | NULL    |                |
 376                 | B_address2          | text         | YES  |     | NULL    |                |
 377                 | B_city              | mediumtext   | YES  |     | NULL    |                |
 378                 | B_state             | mediumtext   | YES  |     | NULL    |                |
 379                 | B_zipcode           | varchar(25)  | YES  |     | NULL    |                |
 380                 | B_country           | text         | YES  |     | NULL    |                |
 381                 | B_email             | text         | YES  |     | NULL    |                |
 382                 | B_phone             | mediumtext   | YES  |     | NULL    |                |
 383                 | dateofbirth         | date         | YES  |     | NULL    |                |
 384                 | branchcode          | varchar(10)  | NO   | MUL |         |                |
 385                 | categorycode        | varchar(10)  | NO   | MUL |         |                |
 386                 | dateenrolled        | date         | YES  |     | NULL    |                |
 387                 | dateexpiry          | date         | YES  |     | NULL    |                |
 388                 | gonenoaddress       | tinyint(1)   | YES  |     | NULL    |                |
 389                 | lost                | tinyint(1)   | YES  |     | NULL    |                |
 390                 | debarred            | date         | YES  |     | NULL    |                |
 391                 | debarredcomment     | varchar(255) | YES  |     | NULL    |                |
 392                 | contactname         | mediumtext   | YES  |     | NULL    |                |
 393                 | contactfirstname    | text         | YES  |     | NULL    |                |
 394                 | contacttitle        | text         | YES  |     | NULL    |                |
 395                 | guarantorid         | int(11)      | YES  | MUL | NULL    |                |
 396                 | borrowernotes       | mediumtext   | YES  |     | NULL    |                |
 397                 | relationship        | varchar(100) | YES  |     | NULL    |                |
 398                 | ethnicity           | varchar(50)  | YES  |     | NULL    |                |
 399                 | ethnotes            | varchar(255) | YES  |     | NULL    |                |
 400                 | sex                 | varchar(1)   | YES  |     | NULL    |                |
 401                 | password            | varchar(30)  | YES  |     | NULL    |                |
 402                 | flags               | int(11)      | YES  |     | NULL    |                |
 403                 | userid              | varchar(30)  | YES  | MUL | NULL    |                |
 404                 | opacnote            | mediumtext   | YES  |     | NULL    |                |
 405                 | contactnote         | varchar(255) | YES  |     | NULL    |                |
 406                 | sort1               | varchar(80)  | YES  |     | NULL    |                |
 407                 | sort2               | varchar(80)  | YES  |     | NULL    |                |
 408                 | altcontactfirstname | varchar(255) | YES  |     | NULL    |                |
 409                 | altcontactsurname   | varchar(255) | YES  |     | NULL    |                |
 410                 | altcontactaddress1  | varchar(255) | YES  |     | NULL    |                |
 411                 | altcontactaddress2  | varchar(255) | YES  |     | NULL    |                |
 412                 | altcontactaddress3  | varchar(255) | YES  |     | NULL    |                |
 413                 | altcontactstate     | mediumtext   | YES  |     | NULL    |                |
 414                 | altcontactzipcode   | varchar(50)  | YES  |     | NULL    |                |
 415                 | altcontactcountry   | text         | YES  |     | NULL    |                |
 416                 | altcontactphone     | varchar(50)  | YES  |     | NULL    |                |
 417                 | smsalertnumber      | varchar(50)  | YES  |     | NULL    |                |
 418                 | privacy             | int(11)      | NO   |     | 1       |                |
 419                 +---------------------+--------------+------+-----+---------+----------------+
 420                 66 rows in set (0.00 sec)
 421                 Where Null="NO", the field is required.
 422
 423 =head1 KOHA_CONF and field mapping
 424
 425 Example XML stanza for LDAP configuration in KOHA_CONF.
 426
 427  <config>
 428   ...
 429   <useldapserver>1</useldapserver>
 430   <!-- LDAP SERVER (optional) -->
 431   <ldapserver id="ldapserver">
 432     <hostname>localhost</hostname>
 433     <base>dc=metavore,dc=com</base>
 434     <user>cn=Manager,dc=metavore,dc=com</user>             <!-- DN, if not anonymous -->
 435     <pass>metavore</pass>          <!-- password, if not anonymous -->
 436     <replicate>1</replicate>       <!-- add new users from LDAP to Koha database -->
 437     <update>1</update>             <!-- update existing users in Koha database -->
 438     <auth_by_bind>0</auth_by_bind> <!-- set to 1 to authenticate by binding instead of
 439                                         password comparison, e.g., to use Active Directory -->
 440     <anonymous_bind>0</anonymous_bind> <!-- set to 1 if users should be searched using
 441                                             an anonymous bind, even when auth_by_bind is on -->
 442     <principal_name>%s@my_domain.com</principal_name>
 443                                    <!-- optional, for auth_by_bind: a printf format to make userPrincipalName from koha userid.
 444                                         Not used with anonymous_bind. -->
 445
 446     <mapping>                  <!-- match koha SQL field names to your LDAP record field names -->
 447       <firstname    is="givenname"      ></firstname>
 448       <surname      is="sn"             ></surname>
 449       <address      is="postaladdress"  ></address>
 450       <city         is="l"              >Athens, OH</city>
 451       <zipcode      is="postalcode"     ></zipcode>
 452       <branchcode   is="branch"         >MAIN</branchcode>
 453       <userid       is="uid"            ></userid>
 454       <password     is="userpassword"   ></password>
 455       <email        is="mail"           ></email>
 456       <categorycode is="employeetype"   >PT</categorycode>
 457       <phone        is="telephonenumber"></phone>
 458     </mapping>
 459   </ldapserver>
 460  </config>
 461
 462 The <mapping> subelements establish the relationship between mysql fields and LDAP attributes. The element name
 463 is the column in mysql, with the "is" characteristic set to the LDAP attribute name.  Optionally, any content
 464 between the element tags is taken as the default value.  In this example, the default categorycode is "PT" (for
 465 patron).
 466
 467 =head1 CONFIGURATION
 468
 469 Once a user has been accepted by the LDAP server, there are several possibilities for how Koha will behave, depending on
 470 your configuration and the presence of a matching Koha user in your local DB:
 471
 472                          LOCAL_USER
 473  OPTION UPDATE REPLICATE  EXISTS?  RESULT
 474    A1      1       1        1      OK : We're updating them anyway.
 475    A2      1       1        0      OK : We're adding them anyway.
 476    B1      1       0        1      OK : We update them.
 477    B2      1       0        0     FAIL: We cannot add new user.
 478    C1      0       1        1      OK : We do nothing.  (maybe should update password?)
 479    C2      0       1        0      OK : We add the new user.
 480    D1      0       0        1      OK : We do nothing.  (maybe should update password?)
 481    D2      0       0        0     FAIL: We cannot add new user.
 482
 483 Note: failure here just means that Koha will fallback to checking the local DB.  That is, a given user could login with
 484 their LDAP password OR their local one.  If this is a problem, then you should enable update and supply a mapping for
 485 password.  Then the local value will be updated at successful LDAP login and the passwords will be synced.
 486
 487 If you choose NOT to update local users, the borrowers table will not be affected at all.
 488 Note that this means that patron passwords may appear to change if LDAP is ever disabled, because
 489 the local table never contained the LDAP values.
 490
 491 =head2 auth_by_bind
 492
 493 Binds as the user instead of retrieving their record.  Recommended if update disabled.
 494
 495 =head2 principal_name
 496
 497 Provides an optional sprintf-style format for manipulating the userid before the bind.
 498 Even though the userPrincipalName is one intended target, any uniquely identifying
 499 attribute that the server allows to be used for binding could be used.
 500
 501 Currently, principal_name only operates when auth_by_bind is enabled.
 502
 503 =head2 Active Directory
 504
 505 The auth_by_bind and principal_name settings are recommended for Active Directory.
 506
 507 Under default Active Directory rules, we cannot determine the distinguishedName attribute from the Koha userid as reliably as
 508 we would typically under openldap.  Instead of:
 509
 510     distinguishedName: CN=barnes.7,DC=my_company,DC=com
 511
 512 We might get:
 513
 514     distinguishedName: CN=Barnes\, Jim,OU=Test Accounts,OU=User Accounts,DC=my_company,DC=com
 515
 516 Matching that would require us to know more info about the account (firstname, surname) and to include punctuation and whitespace
 517 in Koha userids.  But the userPrincipalName should be consistent, something like:
 518
 519     userPrincipalName: barnes.7@my_company.com
 520
 521 Therefore it is often easier to bind to Active Directory with userPrincipalName, effectively the
 522 canonical email address for that user, or what it would be if email were enabled for them.  If Koha userid values
 523 will match the username portion of the userPrincipalName, and the domain suffix is the same for all users, then use principal_name
 524 like this:
 525     <principal_name>%s@core.my_company.com</principal_name>
 526
 527 The user of the previous example, barnes.7, would then attempt to bind as:
 528     barnes.7@core.my_company.com
 529
 530 =head1 SEE ALSO
 531
 532 CGI(3)
 533
 534 Net::LDAP()
 535
 536 XML::Simple()
 537
 538 Digest::MD5(3)
 539
 540 sprintf()
 541
 542 =cut
 543
 544 # For reference, here's an important difference in the data structure we rely on.
 545 # ========================================
 546 # Using attrs instead of {asn}->attributes
 547 # ========================================
 548 #
 549 #       LDAP key: ->{             cn} = ARRAY w/ 3 members.
 550 #       LDAP key: ->{             cn}->{           sss} = sss
 551 #       LDAP key: ->{             cn}->{   Steve Smith} = Steve Smith
 552 #       LDAP key: ->{             cn}->{Steve S. Smith} = Steve S. Smith
 553 #
 554 #       LDAP key: ->{      givenname} = ARRAY w/ 1 members.
 555 #       LDAP key: ->{      givenname}->{Steve} = Steve
 556 #