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. (Or your ikiwiki CGI wrapper, I guess, but don't do that.) 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_requiressl`: defaults to 1, can be 0
  13 * `sslcookie`: needs to be 1 if `unixauth_requiressl` 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 `unixauth` tests for the presence of the `HTTPS` environment variable. `Wrapper.pm` needs to be tweaked to pass it through; without that, the plugin fails closed.
  18
  19 [[!toggle id="diff" text="Wrapper.pm.diff"]]
  20
  21 [[!toggleable id="diff" text="""
  22
  23     --- Wrapper.pm.orig 2008-07-29 00:09:10.000000000 -0400
  24     +++ Wrapper.pm
  25     @@ -28,7 +28,7 @@ sub gen_wrapper () { #{{{
  26         my @envsave;
  27         push @envsave, qw{REMOTE_ADDR QUERY_STRING REQUEST_METHOD REQUEST_URI
  28                        CONTENT_TYPE CONTENT_LENGTH GATEWAY_INTERFACE
  29     -                  HTTP_COOKIE REMOTE_USER} if $config{cgi};
  30     +                  HTTP_COOKIE REMOTE_USER HTTPS} if $config{cgi};
  31         my $envsave="";
  32         foreach my $var (@envsave) {
  33                 $envsave.=<<"EOF"
  34
  35 """]]
  36
  37 [[!toggle id="code" text="unixauth.pm"]]
  38
  39 [[!toggleable id="code" text="""
  40
  41     #!/usr/bin/perl
  42     # Ikiwiki unixauth authentication.
  43     package IkiWiki::Plugin::unixauth;
  44
  45     use warnings;
  46     use strict;
  47     use IkiWiki 2.00;
  48
  49     sub import { #{{{
  50             hook(type => "formbuilder_setup", id => "unixauth",
  51                 call => \&formbuilder_setup);
  52             hook(type => "formbuilder", id => "unixauth",
  53                 call => \&formbuilder);
  54         hook(type => "sessioncgi", id => "unixauth", call => \&sessioncgi);
  55     } # }}}
  56
  57     # Checks if a string matches a user's password, and returns true or false.
  58     sub checkpassword ($$;$) { #{{{
  59         my $user=shift;
  60         my $password=shift;
  61         my $field=shift || "password";
  62
  63         # It's very important that the user not be allowed to log in with
  64         # an empty password!
  65         if (! length $password) {
  66                 return 0;
  67         }
  68
  69         my $ret=0;
  70         if (! exists $config{unixauth_type}) {
  71                 # admin needs to carefully think over his configuration
  72                 return 0;
  73         }
  74         elsif ($config{unixauth_type} eq "checkpassword") {
  75                 open UNIXAUTH, "|$config{unixauth_command} true 3<&0" or die("Could not run $config{unixauth_type}");
  76                 print UNIXAUTH "$user\0$password\0Y123456\0";
  77                 close UNIXAUTH;
  78                 $ret=!($?>>8);
  79         }
  80         elsif ($config{unixauth_type} eq "pwauth") {
  81                 open UNIXAUTH, "|$config{unixauth_command}" or die("Could not run $config{unixauth_type}");
  82                 print UNIXAUTH "$user\n$password\n";
  83                 close UNIXAUTH;
  84                 $ret=!($?>>8);
  85         }
  86         else {
  87                 # no such authentication type
  88                 return 0;
  89         }
  90
  91         if ($ret) {
  92             my $userinfo=IkiWiki::userinfo_retrieve();
  93             if (! length $user || ! defined $userinfo ||
  94                 ! exists $userinfo->{$user} || ! ref $userinfo->{$user}) {
  95                     IkiWiki::userinfo_setall($user, {
  96                         'email' => '',
  97                         'regdate' => time,
  98                     });
  99             }
 100         }
 101
 102         return $ret;
 103     } #}}}
 104
 105     sub formbuilder_setup (@) { #{{{
 106         my %params=@_;
 107
 108         my $form=$params{form};
 109         my $session=$params{session};
 110         my $cgi=$params{cgi};
 111
 112         # if not under SSL, die before even showing a login form,
 113         # unless the admin explicitly says it's fine
 114         if (! exists $config{unixauth_requiressl}) {
 115                 $config{unixauth_requiressl} = 1;
 116         }
 117         if ($config{unixauth_requiressl}) {
 118             if ((! $config{sslcookie}) || (! exists $ENV{'HTTPS'})) {
 119                 die("SSL required to login. Contact your administrator.<br>");
 120             }
 121         }
 122
 123         if ($form->title eq "signin") {
 124                 $form->field(name => "name", required => 0);
 125                 $form->field(name => "password", type => "password", required => 0);
 126
 127                 if ($form->submitted) {
 128                         my $submittype=$form->submitted;
 129                         # Set required fields based on how form was submitted.
 130                         my %required=(
 131                                 "Login" => [qw(name password)],
 132                         );
 133                         foreach my $opt (@{$required{$submittype}}) {
 134                                 $form->field(name => $opt, required => 1);
 135                         }
 136
 137                         # Validate password against name for Login.
 138                         if ($submittype eq "Login") {
 139                                 $form->field(
 140                                         name => "password",
 141                                         validate => sub {
 142                                                 checkpassword($form->field("name"), shift);
 143                                         },
 144                                 );
 145                         }
 146
 147                         # XXX is this reachable? looks like no
 148                         elsif ($submittype eq "Login") {
 149                                 $form->field(
 150                                         name => "name",
 151                                         validate => sub {
 152                                                 my $name=shift;
 153                                                 length $name &&
 154                                                 IkiWiki::userinfo_get($name, "regdate");
 155                                         },
 156                                 );
 157                         }
 158                 }
 159                 else {
 160                         # First time settings.
 161                         $form->field(name => "name");
 162                         if ($session->param("name")) {
 163                                 $form->field(name => "name", value => $session->param("name"));
 164                         }
 165                 }
 166         }
 167         elsif ($form->title eq "preferences") {
 168                 $form->field(name => "name", disabled => 1,
 169                         value => $session->param("name"), force => 1,
 170                         fieldset => "login");
 171                 $form->field(name => "password", disabled => 1, type => "password",
 172                         fieldset => "login"),
 173         }
 174     }
 175
 176     sub formbuilder (@) { #{{{
 177         my %params=@_;
 178
 179         my $form=$params{form};
 180         my $session=$params{session};
 181         my $cgi=$params{cgi};
 182         my $buttons=$params{buttons};
 183
 184         if ($form->title eq "signin") {
 185                 if ($form->submitted && $form->validate) {
 186                         if ($form->submitted eq 'Login') {
 187                                 $session->param("name", $form->field("name"));
 188                                 IkiWiki::cgi_postsignin($cgi, $session);
 189                         }
 190                 }
 191         }
 192         elsif ($form->title eq "preferences") {
 193                 if ($form->submitted eq "Save Preferences" && $form->validate) {
 194                         my $user_name=$form->field('name');
 195                 }
 196         }
 197     } #}}}
 198
 199     sub sessioncgi ($$) { #{{{
 200         my $q=shift;
 201         my $session=shift;
 202     } #}}}
 203
 204     1
 205
 206 """]]