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 _XXX hang on, looks like we don't have the huge CGI environment so testing for ${HTTPS} always fails; need another way to be sure_
  18
  19 [[!toggle id="code" text="unixauth.pm"]]
  20
  21 [[!toggleable id="code" text="""
  22
  23     #!/usr/bin/perl
  24     # Ikiwiki unixauth authentication.
  25     package IkiWiki::Plugin::unixauth;
  26
  27     use warnings;
  28     use strict;
  29     use IkiWiki 2.00;
  30
  31     sub import { #{{{
  32             hook(type => "formbuilder_setup", id => "unixauth",
  33                 call => \&formbuilder_setup);
  34             hook(type => "formbuilder", id => "unixauth",
  35                 call => \&formbuilder);
  36         hook(type => "sessioncgi", id => "unixauth", call => \&sessioncgi);
  37     } # }}}
  38
  39     # Checks if a string matches a user's password, and returns true or false.
  40     sub checkpassword ($$;$) { #{{{
  41         my $user=shift;
  42         my $password=shift;
  43         my $field=shift || "password";
  44
  45         # It's very important that the user not be allowed to log in with
  46         # an empty password!
  47         if (! length $password) {
  48                 return 0;
  49         }
  50
  51         my $ret=0;
  52         if (! exists $config{unixauth_type}) {
  53                 # admin needs to carefully think over his configuration
  54                 return 0;
  55         }
  56         elsif ($config{unixauth_type} eq "checkpassword") {
  57                 open UNIXAUTH, "|$config{unixauth_command} true 3<&0" or die("Could not run $config{unixauth_type}");
  58                 print UNIXAUTH "$user\0$password\0Y123456\0";
  59                 close UNIXAUTH;
  60                 $ret=!($?>>8);
  61         }
  62         elsif ($config{unixauth_type} eq "pwauth") {
  63                 open UNIXAUTH, "|$config{unixauth_command}" or die("Could not run $config{unixauth_type}");
  64                 print UNIXAUTH "$user\n$password\n";
  65                 close UNIXAUTH;
  66                 $ret=!($?>>8);
  67         }
  68         else {
  69                 # no such authentication type
  70                 return 0;
  71         }
  72
  73         if ($ret) {
  74             my $userinfo=IkiWiki::userinfo_retrieve();
  75             if (! length $user || ! defined $userinfo ||
  76                 ! exists $userinfo->{$user} || ! ref $userinfo->{$user}) {
  77                     IkiWiki::userinfo_setall($user, {
  78                         'email' => '',
  79                         'regdate' => time,
  80                     });
  81             }
  82         }
  83
  84         return $ret;
  85     } #}}}
  86
  87     sub formbuilder_setup (@) { #{{{
  88         my %params=@_;
  89
  90         my $form=$params{form};
  91         my $session=$params{session};
  92         my $cgi=$params{cgi};
  93
  94         # if not under SSL, die before even showing a login form,
  95         # unless the admin explicitly says it's fine
  96         if (! exists $config{unixauth_requiressl}) {
  97                 $config{unixauth_requiressl} = 1;
  98         }
  99         if ($config{unixauth_requiressl} && \
 100             (! $config{sslcookie} || ! exists $ENV{'HTTPS'})) {
 101                 die("SSL required to login. Contact your administrator.");
 102         }
 103
 104         if ($form->title eq "signin") {
 105                 $form->field(name => "name", required => 0);
 106                 $form->field(name => "password", type => "password", required => 0);
 107
 108                 if ($form->submitted) {
 109                         my $submittype=$form->submitted;
 110                         # Set required fields based on how form was submitted.
 111                         my %required=(
 112                                 "Login" => [qw(name password)],
 113                         );
 114                         foreach my $opt (@{$required{$submittype}}) {
 115                                 $form->field(name => $opt, required => 1);
 116                         }
 117
 118                         # Validate password against name for Login.
 119                         if ($submittype eq "Login") {
 120                                 $form->field(
 121                                         name => "password",
 122                                         validate => sub {
 123                                                 checkpassword($form->field("name"), shift);
 124                                         },
 125                                 );
 126                         }
 127
 128                         # XXX is this reachable? looks like no
 129                         elsif ($submittype eq "Login") {
 130                                 $form->field(
 131                                         name => "name",
 132                                         validate => sub {
 133                                                 my $name=shift;
 134                                                 length $name &&
 135                                                 IkiWiki::userinfo_get($name, "regdate");
 136                                         },
 137                                 );
 138                         }
 139                 }
 140                 else {
 141                         # First time settings.
 142                         $form->field(name => "name");
 143                         if ($session->param("name")) {
 144                                 $form->field(name => "name", value => $session->param("name"));
 145                         }
 146                 }
 147         }
 148         elsif ($form->title eq "preferences") {
 149                 $form->field(name => "name", disabled => 1,
 150                         value => $session->param("name"), force => 1,
 151                         fieldset => "login");
 152                 $form->field(name => "password", disabled => 1, type => "password",
 153                         fieldset => "login"),
 154         }
 155     }
 156
 157     sub formbuilder (@) { #{{{
 158         my %params=@_;
 159
 160         my $form=$params{form};
 161         my $session=$params{session};
 162         my $cgi=$params{cgi};
 163         my $buttons=$params{buttons};
 164
 165         if ($form->title eq "signin") {
 166                 if ($form->submitted && $form->validate) {
 167                         if ($form->submitted eq 'Login') {
 168                                 $session->param("name", $form->field("name"));
 169                                 IkiWiki::cgi_postsignin($cgi, $session);
 170                         }
 171                 }
 172         }
 173         elsif ($form->title eq "preferences") {
 174                 if ($form->submitted eq "Save Preferences" && $form->validate) {
 175                         my $user_name=$form->field('name');
 176                 }
 177         }
 178     } #}}}
 179
 180     sub sessioncgi ($$) { #{{{
 181         my $q=shift;
 182         my $session=shift;
 183     } #}}}
 184
 185     1
 186
 187 """]]