doc/plugins/contrib/unixauth.mdwn

   1 [[!template id=plugin name=unixauth core=0 author="[[schmonz]]"]]
   2 [[!tag type/auth]]
   3
   4 This plugin authenticates users against the Unix user database. It presents a similar UI to [[plugins/passwordauth]], but simpler, as there's no need to be able to register or change one's password.
   5
   6 To authenticate, either [checkpassword](http://cr.yp.to/checkpwd.html) or [pwauth](http://www.unixpapa.com/pwauth/) must be installed and configured. `checkpassword` is strongly preferred. If your web server runs as an unprivileged user -- as it darn well should! -- then `checkpassword` needs to be setuid root. Other checkpassword implementations are available, notably [checkpassword-pam](http://checkpasswd-pam.sourceforge.net/).
   7
   8 Config variables that affect the behavior of `unixauth`:
   9
  10 * `unixauth_type`: defaults to unset, can be "checkpassword" or "pwauth"
  11 * `unixauth_command`: defaults to unset, should contain the full path and any arguments
  12 * `unixauth_sslrequire`: defaults to 1, can be 0
  13 * `sslcookie`: needs to be 1 if `unixauth_sslrequire` is 1 (perhaps this should be done automatically?)
  14
  15 __Security__: [As with passwordauth](/security/#index14h2), be wary of sending usernames and passwords in cleartext. Unlike passwordauth, sniffing `unixauth` credentials can get an attacker much further than mere wiki access. Therefore, this plugin defaults to not even _displaying_ the login form fields unless we're running under SSL. Nobody should be able to do anything remotely dumb until the admin has done at least a little thinking. After that, dumb things are always possible. ;-)
  16
  17 [[!toggle id="code" text="unixauth.pm"]]
  18
  19 [[!toggleable id="code" text="""
  20
  21     #!/usr/bin/perl
  22     # Ikiwiki unixauth authentication.
  23     package IkiWiki::Plugin::unixauth;
  24
  25     use warnings;
  26     use strict;
  27     use IkiWiki 2.00;
  28
  29     sub import { #{{{
  30             hook(type => "formbuilder_setup", id => "unixauth",
  31                 call => \&formbuilder_setup);
  32             hook(type => "formbuilder", id => "unixauth",
  33                 call => \&formbuilder);
  34         hook(type => "sessioncgi", id => "unixauth", call => \&sessioncgi);
  35     } # }}}
  36
  37     # Checks if a string matches a user's password, and returns true or false.
  38     sub checkpassword ($$;$) { #{{{
  39         my $user=shift;
  40         my $password=shift;
  41         my $field=shift || "password";
  42
  43         # It's very important that the user not be allowed to log in with
  44         # an empty password!
  45         if (! length $password) {
  46                 return 0;
  47         }
  48
  49         my $ret=0;
  50         if (! exists $config{unixauth_type}) {
  51                 # admin needs to carefully think over his configuration
  52                 return 0;
  53         }
  54         elsif ($config{unixauth_type} eq "checkpassword") {
  55                 open UNIXAUTH, "|$config{unixauth_command} true 3<&0" or die("Could not run $config{unixauth_type}");
  56                 print UNIXAUTH "$user\0$password\0Y123456\0";
  57                 close UNIXAUTH;
  58                 $ret=!($?>>8);
  59         }
  60         elsif ($config{unixauth_type} eq "pwauth") {
  61                 open UNIXAUTH, "|$config{unixauth_command}" or die("Could not run $config{unixauth_type}");
  62                 print UNIXAUTH "$user\n$password\n";
  63                 close UNIXAUTH;
  64                 $ret=!($?>>8);
  65         }
  66         else {
  67                 # no such authentication type
  68                 return 0;
  69         }
  70
  71         if ($ret) {
  72             my $userinfo=IkiWiki::userinfo_retrieve();
  73             if (! length $user || ! defined $userinfo ||
  74                 ! exists $userinfo->{$user} || ! ref $userinfo->{$user}) {
  75                     IkiWiki::userinfo_setall($user, {
  76                         'email' => '',
  77                         'regdate' => time,
  78                     });
  79             }
  80         }
  81
  82         return $ret;
  83     } #}}}
  84
  85     sub formbuilder_setup (@) { #{{{
  86         my %params=@_;
  87
  88         my $form=$params{form};
  89         my $session=$params{session};
  90         my $cgi=$params{cgi};
  91
  92         # if not under SSL, die before even showing a login form,
  93         # unless the admin explicitly says it's fine
  94         if (! exists $config{unixauth_requiressl}) {
  95                 $config{unixauth_requiressl} = 1;
  96         }
  97         if ($config{unixauth_requiressl} && \
  98             (! $config{sslcookie} || ! exists $ENV{'HTTPS'})) {
  99                 die("SSL required to login. Contact your administrator.");
 100         }
 101
 102         if ($form->title eq "signin") {
 103                 $form->field(name => "name", required => 0);
 104                 $form->field(name => "password", type => "password", required => 0);
 105
 106                 if ($form->submitted) {
 107                         my $submittype=$form->submitted;
 108                         # Set required fields based on how form was submitted.
 109                         my %required=(
 110                                 "Login" => [qw(name password)],
 111                         );
 112                         foreach my $opt (@{$required{$submittype}}) {
 113                                 $form->field(name => $opt, required => 1);
 114                         }
 115
 116                         # Validate password against name for Login.
 117                         if ($submittype eq "Login") {
 118                                 $form->field(
 119                                         name => "password",
 120                                         validate => sub {
 121                                                 checkpassword($form->field("name"), shift);
 122                                         },
 123                                 );
 124                         }
 125
 126                         # XXX is this reachable? looks like no
 127                         elsif ($submittype eq "Login") {
 128                                 $form->field(
 129                                         name => "name",
 130                                         validate => sub {
 131                                                 my $name=shift;
 132                                                 length $name &&
 133                                                 IkiWiki::userinfo_get($name, "regdate");
 134                                         },
 135                                 );
 136                         }
 137                 }
 138                 else {
 139                         # First time settings.
 140                         $form->field(name => "name");
 141                         if ($session->param("name")) {
 142                                 $form->field(name => "name", value => $session->param("name"));
 143                         }
 144                 }
 145         }
 146         elsif ($form->title eq "preferences") {
 147                 $form->field(name => "name", disabled => 1,
 148                         value => $session->param("name"), force => 1,
 149                         fieldset => "login");
 150                 $form->field(name => "password", disabled => 1, type => "password",
 151                         fieldset => "login"),
 152         }
 153     }
 154
 155     sub formbuilder (@) { #{{{
 156         my %params=@_;
 157
 158         my $form=$params{form};
 159         my $session=$params{session};
 160         my $cgi=$params{cgi};
 161         my $buttons=$params{buttons};
 162
 163         if ($form->title eq "signin") {
 164                 if ($form->submitted && $form->validate) {
 165                         if ($form->submitted eq 'Login') {
 166                                 $session->param("name", $form->field("name"));
 167                                 IkiWiki::cgi_postsignin($cgi, $session);
 168                         }
 169                 }
 170         }
 171         elsif ($form->title eq "preferences") {
 172                 if ($form->submitted eq "Save Preferences" && $form->validate) {
 173                         my $user_name=$form->field('name');
 174                 }
 175         }
 176     } #}}}
 177
 178     sub sessioncgi ($$) { #{{{
 179         my $q=shift;
 180         my $session=shift;
 181     } #}}}
 182
 183     1
 184
 185 """]]