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[[!template id=plugin name=unixauth core=0 author="[[schmonz]]"]]
[[!tag type/auth]]
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.
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/).
Config variables that affect the behavior of `unixauth`:
* `unixauth_type`: defaults to unset, can be "checkpassword" or "pwauth"
* `unixauth_command`: defaults to unset, should contain the full path and any arguments
* `unixauth_requiressl`: defaults to 1, can be 0
* `sslcookie`: needs to be 1 if `unixauth_requiressl` is 1 (perhaps this should be done automatically?)
__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. ;-)
`unixauth` needs the `HTTPS` environment variable, available in ikiwiki 2.67 or later (fixed in #[502047](http://bugs.debian.org/502047)), without which it fails closed.
The plugin has not been tested with newer versions of ikiwiki. [[schmonz]] hopes to have time to polish this plugin soon.
[[!toggle id="code" text="unixauth.pm"]]
[[!toggleable id="code" text="""
#!/usr/bin/perl
# Ikiwiki unixauth authentication.
package IkiWiki::Plugin::unixauth;
use warnings;
use strict;
use IkiWiki 2.00;
sub import {
hook(type => "getsetup", id => "unixauth", call => \&getsetup);
hook(type => "formbuilder_setup", id => "unixauth",
call => \&formbuilder_setup);
hook(type => "formbuilder", id => "unixauth",
call => \&formbuilder);
hook(type => "sessioncgi", id => "unixauth", call => \&sessioncgi);
}
sub getsetup () {
return
unixauth_type => {
type => "string",
example => "checkpassword",
description => "type of authenticator; can be 'checkpassword' or 'pwauth'",
safe => 0,
rebuild => 1,
},
unixauth_command => {
type => "string",
example => "/path/to/checkpassword",
description => "full path and any arguments",
safe => 0,
rebuild => 1,
},
unixauth_requiressl => {
type => "boolean",
example => "1",
description => "require SSL? strongly recommended",
safe => 0,
rebuild => 1,
},
plugin => {
description => "Unix user authentication",
safe => 0,
rebuild => 1,
},
}
# Checks if a string matches a user's password, and returns true or false.
sub checkpassword ($$;$) {
my $user=shift;
my $password=shift;
my $field=shift || "password";
# It's very important that the user not be allowed to log in with
# an empty password!
if (! length $password) {
return 0;
}
my $ret=0;
if (! exists $config{unixauth_type}) {
# admin needs to carefully think over his configuration
return 0;
}
elsif ($config{unixauth_type} eq "checkpassword") {
open UNIXAUTH, "|$config{unixauth_command} true 3<&0" or die("Could not run $config{unixauth_type}");
print UNIXAUTH "$user\0$password\0Y123456\0";
close UNIXAUTH;
$ret=!($?>>8);
}
elsif ($config{unixauth_type} eq "pwauth") {
open UNIXAUTH, "|$config{unixauth_command}" or die("Could not run $config{unixauth_type}");
print UNIXAUTH "$user\n$password\n";
close UNIXAUTH;
$ret=!($?>>8);
}
else {
# no such authentication type
return 0;
}
if ($ret) {
my $userinfo=IkiWiki::userinfo_retrieve();
if (! length $user || ! defined $userinfo ||
! exists $userinfo->{$user} || ! ref $userinfo->{$user}) {
IkiWiki::userinfo_setall($user, {
'email' => '',
'regdate' => time,
});
}
}
return $ret;
}
sub formbuilder_setup (@) {
my %params=@_;
my $form=$params{form};
my $session=$params{session};
my $cgi=$params{cgi};
# if not under SSL, die before even showing a login form,
# unless the admin explicitly says it's fine
if (! exists $config{unixauth_requiressl}) {
$config{unixauth_requiressl} = 1;
}
if ($config{unixauth_requiressl}) {
if ((! $config{sslcookie}) || (! exists $ENV{'HTTPS'})) {
die("SSL required to login. Contact your administrator.<br>");
}
}
if ($form->title eq "signin") {
$form->field(name => "name", required => 0);
$form->field(name => "password", type => "password", required => 0);
if ($form->submitted) {
my $submittype=$form->submitted;
# Set required fields based on how form was submitted.
my %required=(
"Login" => [qw(name password)],
);
foreach my $opt (@{$required{$submittype}}) {
$form->field(name => $opt, required => 1);
}
# Validate password against name for Login.
if ($submittype eq "Login") {
$form->field(
name => "password",
validate => sub {
checkpassword($form->field("name"), shift);
},
);
}
# XXX is this reachable? looks like no
elsif ($submittype eq "Login") {
$form->field(
name => "name",
validate => sub {
my $name=shift;
length $name &&
IkiWiki::userinfo_get($name, "regdate");
},
);
}
}
else {
# First time settings.
$form->field(name => "name");
if ($session->param("name")) {
$form->field(name => "name", value => $session->param("name"));
}
}
}
elsif ($form->title eq "preferences") {
$form->field(name => "name", disabled => 1,
value => $session->param("name"), force => 1,
fieldset => "login");
$form->field(name => "password", disabled => 1, type => "password",
fieldset => "login"),
}
}
sub formbuilder (@) {
my %params=@_;
my $form=$params{form};
my $session=$params{session};
my $cgi=$params{cgi};
my $buttons=$params{buttons};
if ($form->title eq "signin") {
if ($form->submitted && $form->validate) {
if ($form->submitted eq 'Login') {
$session->param("name", $form->field("name"));
IkiWiki::cgi_postsignin($cgi, $session);
}
}
}
elsif ($form->title eq "preferences") {
if ($form->submitted eq "Save Preferences" && $form->validate) {
my $user_name=$form->field('name');
}
}
}
sub sessioncgi ($$) {
my $q=shift;
my $session=shift;
}
1
"""]]
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