Apache-AuthCookie

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lib/Apache/AuthCookie.pm  view on Meta::CPAN

package Apache::AuthCookie;
$Apache::AuthCookie::VERSION = '3.32';
# ABSTRACT: Perl Authentication and Authorization via cookies

use strict;

use Carp;
use mod_perl qw(1.07 StackedHandlers MethodHandlers Authen Authz);
use Apache::Constants qw(:common M_GET FORBIDDEN OK REDIRECT);
use Apache::AuthCookie::Params;
use Apache::AuthCookie::Util qw(is_blank is_local_destination);
use Apache::Util qw(escape_uri);
use Apache::URI;
use Encode ();


sub recognize_user ($$) {
    my ($self, $r) = @_;

    # only check if user is not already set
    return DECLINED unless is_blank($r->connection->user);

    my $debug = $r->dir_config("AuthCookieDebug") || 0;
    my ($auth_type, $auth_name) = ($r->auth_type, $r->auth_name);

    return DECLINED if is_blank($auth_type) or is_blank($auth_name);

    return DECLINED if is_blank($r->header_in('Cookie'));

    my $cookie_name = $self->cookie_name($r);

    my ($cookie) = $r->header_in('Cookie') =~ /$cookie_name=([^;]+)/;
    $r->log_error("cookie $cookie_name is $cookie") if $debug >= 2;
    return DECLINED unless $cookie;

    my ($user, @args) = $auth_type->authen_ses_key($r, $cookie);
    if (!is_blank($user) and scalar @args == 0) {
        $r->log_error("user is $user") if $debug >= 2;

        # if SessionTimeout is on, send new cookie with new Expires.
        if (my $expires = $r->dir_config("${auth_name}SessionTimeout")) {
            $self->send_cookie($cookie, { expires => $expires });
        }

        $r->connection->user( $self->_encode($r, $user) );
    }
    elsif (scalar @args > 0 and $auth_type->can('custom_errors')) {
        return $auth_type->custom_errors($r, $user, @args);
    }

    return is_blank($user) ? DECLINED : OK;
}

sub cookie_name {
    my ($self, $r) = @_;

    my $auth_type = $r->auth_type;
    my $auth_name = $r->auth_name;

    my $cookie_name = $r->dir_config("${auth_name}CookieName")
        || "${auth_type}_${auth_name}";

    return $cookie_name;
}


sub encoding {
    my ($self, $r) = @_;

    my $auth_name = $r->auth_name;

    return $r->dir_config("${auth_name}Encoding");

lib/Apache/AuthCookie.pm  view on Meta::CPAN

    return $reqs;
}


sub handle_cache {
    my $self = shift;

    my $r = Apache->request;

    my $auth_name = $r->auth_name;
    return unless $auth_name;

    unless ($r->dir_config("${auth_name}Cache")) {
        $r->no_cache(1);
        $r->err_header_out(Pragma => 'no-cache');
    }
}


sub remove_cookie {
    my $self = shift;

    my $r = Apache->request;

    my $debug = $r->dir_config("AuthCookieDebug") || 0;

    my $cookie_name = $self->cookie_name($r);

    my $str = $self->cookie_string(
        request => $r,
        key     => $cookie_name,
        value   => '',
        expires => 'Mon, 21-May-1971 00:00:00 GMT'
    );

    $r->err_headers_out->add("Set-Cookie" => "$str");

    $r->log_error("removed cookie $cookie_name") if $debug >= 2;
}

# convert current request to GET
sub _convert_to_get {
    my ($self, $r) = @_;

    return unless $r->method eq 'POST';

    my $debug = $r->dir_config("AuthCookieDebug") || 0;

    $r->log_error("Converting POST -> GET") if $debug >= 2;

    my $args = $self->params($r);

    my @pairs = ();

    for my $name ($args->param) {
        # we dont want to copy login data, only extra data
        next if $name eq 'destination'
             or $name =~ /^credential_\d+$/;

        for my $v ($args->param($name)) {
            push @pairs, escape_uri($name) . '=' . escape_uri($v);
        }
    }

    $r->args(join '&', @pairs) if scalar(@pairs) > 0;

    $r->method('GET');
    $r->method_number(M_GET);
    $r->headers_in->unset('Content-Length');
}


sub params {
    my ($self, $r) = @_;

    return Apache::AuthCookie::Params->new($r);
}


sub login ($$) {
    my ($self, $r) = @_;
    my $debug = $r->dir_config("AuthCookieDebug") || 0;

    my ($auth_type, $auth_name) = ($r->auth_type, $r->auth_name);

    my $params = $self->params($r);

    $self->_convert_to_get($r) if $r->method eq 'POST';

    my $destination         = $params->param('destination');
    my $default_destination = $r->dir_config("${auth_name}DefaultDestination");

    if (is_blank($destination)) {
        if (!is_blank($default_destination)) {
            $destination = $default_destination;
            $r->log_error("destination set to $destination");
        }
        else {
            $r->log_error("No key 'destination' found in form data");
            $r->subprocess_env('AuthCookieReason', 'no_cookie');
            return $auth_type->login_form;
        }
    }

    if ($r->dir_config("${auth_name}EnforceLocalDestination")) {
        my $current_url = Apache::URI->parse($r)->unparse;
        unless (is_local_destination($destination, $current_url)) {
            $r->log_error("non-local destination $destination detected for uri ",$r->uri);

            if (is_local_destination($default_destination, $current_url)) {
                $destination = $default_destination;
                $r->log_error("destination changed to $destination");
            }
            else {
                $r->log_error("Returning login form: non local destination: $destination");
                $r->subprocess_env('AuthCookieReason', 'no_cookie');
                return $auth_type->login_form($r);
            }
        }
    }

    # Get the credentials from the data posted by the client
    my @credentials;
    for (my $i = 0 ; defined $params->param("credential_$i") ; $i++) {
        my $key = "credential_$i";
        my $val = $params->param("credential_$i");
        $r->log_error("$key $val") if $debug >= 2;
        push @credentials, $val;
    }

    # save creds in pnotes in case login form script wants to use them.
    $r->pnotes("${auth_name}Creds", \@credentials);

    # Exchange the credentials for a session key.
    my $ses_key = $self->authen_cred($r, @credentials);
    unless ($ses_key) {
        $r->log_error("Bad credentials") if $debug >= 2;
        $r->subprocess_env('AuthCookieReason', 'bad_credentials');
        $r->uri($self->untaint_destination($destination));
        return $auth_type->login_form;
    }

    if ($debug >= 2) {
        if (defined $ses_key) {
            $r->log_error("ses_key $ses_key");
        }
        else {
            $r->log_error("ses_key undefined");
        }
    }

    $self->send_cookie($ses_key);

    $self->handle_cache;

    $r->header_out(Location => $self->untaint_destination($destination));

    return REDIRECT;
}


sub untaint_destination {
    my ($self, $dest) = @_;

    return Apache::AuthCookie::Util::escape_destination($dest);
}


sub logout($$) {
    my ($self, $r) = @_;
    my $debug = $r->dir_config("AuthCookieDebug") || 0;

    $self->remove_cookie;

    $self->handle_cache;

    #my %args = $r->args;
    #if (exists $args{'redirect'}) {
    #  $r->err_header_out("Location" => $args{'redirect'});
    #  return REDIRECT;
    #} else {
    #  $r->status(200);
    #  return OK;
    #}
}


sub authenticate ($$) {
    my ($auth_type, $r) = @_;
    my $auth_user;
    my $debug = $r->dir_config("AuthCookieDebug") || 0;

    $r->log_error("auth_type " . $auth_type) if ($debug >= 3);

    unless ($r->is_initial_req) {
        if (defined $r->prev) {
            # we are in a subrequest.  Just copy user from previous request.
            # encoding would have been handled in prev req, so do not encode here.
            $r->connection->user($r->prev->connection->user);
        }
        return OK;
    }

    if ($r->auth_type ne $auth_type) {
        # This location requires authentication because we are being called,
        # but we don't handle this AuthType.
        $r->log_error("AuthType mismatch: $auth_type =/= " . $r->auth_type)
            if $debug >= 3;
        return DECLINED;
    }

    # Ok, the AuthType is $auth_type which we handle, what's the authentication
    # realm's name?
    my $auth_name = $r->auth_name;
    $r->log_error("auth_name " . $auth_name) if $debug >= 2;
    unless ($auth_name) {
        $r->log_reason("AuthName not set, AuthType=$auth_type", $r->uri);
        return SERVER_ERROR;
    }

    # Get the Cookie header. If there is a session key for this realm, strip
    # off everything but the value of the cookie.
    my $cookie_name = $auth_type->cookie_name($r);
    my ($ses_key_cookie) =
        ($r->header_in("Cookie") || "") =~ /$cookie_name=([^;]+)/;

lib/Apache/AuthCookie.pm  view on Meta::CPAN

    $r->custom_response($CODE, $msg) if $msg;
    return($CODE);
  }

  where CODE is a valid code from Apache::Constants

=head2 recognize_user($r)

If the user has provided a valid session key but the document isn't
protected, this method will set C<$r-E<gt>connection-E<gt>user>
anyway.  Use it as a PerlFixupHandler, unless you have a better idea.

=head2 encoding($r): string

Return the ${auth_name}Encoding setting that is in effect for this request.

=head2 requires_encoding($r): string

Return the ${auth_name}RequiresEncoding setting that is in effect for this request.

=head2 decoded_user($r): string

If you have set ${auth_name}Encoding, then this will return the decoded value of
C<< $r->connection->user >>.

=head2 decoded_requires($r): arrayref

This method returns the C<< $r->requires >> array, with the C<requirement>
values decoded if C<${auth_name}RequiresEncoding> is in effect for this
request.

=head2 handle_cache(): void

If C<${auth_name}Cache> is defined, this sets up the response so that the
client will not cache the result.  This sents C<no_cache> in the apache request
object and sends the appropriate headers so that the client will not cache the
response.

=head2 remove_cookie(): void

Adds a C<Set-Cookie> header that instructs the client to delete the cookie
immediately.

=head2 params($r): Apache::AuthCookie::Params

Get the params object for this request.

=head2 login($r)

This method handles the submission of the login form.  It will call
the C<authen_cred()> method, passing it C<$r> and all the submitted
data with names like C<"credential_#">, where # is a number.  These will
be passed in a simple array, so the prototype is
C<$self-E<gt>authen_cred($r, @credentials)>.  After calling
C<authen_cred()>, we set the user's cookie and redirect to the
URL contained in the C<"destination"> submitted form field.

=head2 untaint_destination($uri)

This method returns a modified version of the destination parameter
before embedding it into the response header. Per default it escapes
CR, LF and TAB characters of the uri to avoid certain types of
security attacks. You can override it to more limit the allowed
destinations, e.g., only allow relative uris, only special hosts or
only limited set of characters.

=head2 logout($r)

This is simply a convenience method that unsets the session key for
you.  You can call it in your logout scripts.  Usually this looks like
C<$r-E<gt>auth_type-E<gt>logout($r);>.

=head2 authenticate($r)

This method is one you'll use in a server config file (httpd.conf,
.htaccess, ...) as a PerlAuthenHandler.  If the user provided a
session key in a cookie, the C<authen_ses_key()> method will get
called to check whether the key is valid.  If not, or if there is no
key provided, we redirect to the login form.

=head2 login_form()

This method is responsible for displaying the login form. The default
implementation will make an internal redirect and display the URL you
specified with the C<PerlSetVar WhatEverLoginScript> configuration
directive. You can overwrite this method to provide your own
mechanism.

=head2 login_form_status($r)

This method returns the HTTP status code that will be returned with the login
form response.  The default behaviour is to return FORBIDDEN, except for some
known browsers which ignore HTML content for FORBIDDEN responses (e.g.:
SymbianOS).  You can override this method to return custom codes.

Note that FORBIDDEN is the most correct code to return as the given request was
not authorized to view the requested page.  You should only change this if
FORBIDDEN does not work.

=head2 get_satisfy(): string

Get the C<Satisfy> value for the current request, or C<all> if it is not
configured.

=head2 authorize($r)

This will step through the C<require> directives you've given for
protected documents and make sure the user passes muster.  The
C<require valid-user> and C<require user joey-jojo> directives are
handled for you.  You can implement custom directives, such as
C<require species hamster>, by defining a method called C<species()>
in your subclass, which will then be called.  The method will be
called as C<$r-E<gt>species($r, $args)>, where C<$args> is everything
on your C<require> line after the word C<species>.  The method should
return OK on success and FORBIDDEN on failure.

=head2 send_cookie($session_key)

By default this method simply sends out the session key you give it.
If you need to change the default behavior (perhaps to update a
timestamp in the key) you can override this method.

lib/Apache/AuthCookie.pm  view on Meta::CPAN

Note that if you don't necessarily trust your users, you can't count
on cookie deletion for logging out.  You'll have to expire some
server-side login information too.  AuthCookie doesn't do this for
you, you have to handle it yourself.

=head1 ENCODING AND CHARACTER SETS

=head2 Encoding

AuthCookie provides support for decoding POST/GET data if you tell it what the
client encoding is.  You do this by setting the C<< ${auth_name}Encoding >>
setting in C<httpd.conf>.  E.g.:

 PerlSetVar WhateEverEncoding UTF-8
 # and you also need to arrange for charset=UTF-8 at the end of the
 # Content-Type header with something like:
 AddDefaultCharset UTF-8

Note that you B<can> use charsets other than C<UTF-8>, however, you need to
arrange for the browser to send the right encoding back to the server.

If you have turned on Encoding support by setting C<< ${auth_name}Encoding >>,
this has the following effects:

=over 4

=item *

The internal pure-perl params processing subclass will be used, even if
libapreq is installed.  libapreq does not handle encoding.

=item *

POST/GET data intercepted by AuthCookie will be decoded to perl's internal
format using L<Encode/decode>.

=item *

The value stored in C<< $r-E<gt>connection-E<gt>user >> will be encoded as
B<bytes>, not characters using the configured encoding name.  This is because
the value stored by mod_perl is a C API string, and not a perl string.  You can
use L</decoded_user()> to get user string encoded using B<character> semantics.

=back

This does has some caveats:

=over 4

=item *

your L</authen_cred()> and L</authen_ses_key()> function is expected to return
a decoded username, either by passing it through L<Encode/decode()>, or, by
turning on the UTF8 flag if appropriate.

=item *

Due to the way HTTP works, cookies cannot contain non-ASCII characters.
Because of this, if you are including the username in your generated session
key, you will need to escape any non-ascii characters in the session key
returned by L</authen_cred()>.

=item *

Similarly, you must reverse this escaping process in L</authen_ses_key()> and
return a L<Encode/decode()> decoded username.  If your L</authen_cred()>
function already only generates ASCII-only session keys then you do not need to
worry about any of this.

=item *

The value stored in C<< $r-E<gt>connection-E<gt>user >> will be encoded using
bytes semantics using the configured B<Encoding>.  If you want the decoded user
value, use L</decoded_user()> instead.

=back

=head2 Requires

You can also specify what the charset is of the Apache C<< $r-E<gt>requires >>
data is by setting C<< ${auth_name}RequiresEncoding >> in httpd.conf.

E.g.:

 PerlSetVar WhatEverRequiresEncoding UTF-8

This will make it so that AuthCookie will decode your C<requires> directives
using the configured character set.  You really only need to do this if you
have used non-ascii characters in any of your C<requires> directives in
httpd.conf.  e.g.:

 requires user programmør

=head1 ABOUT SESSION KEYS

Unlike the sample AuthCookieHandler, you have you verify the user's
login and password in C<authen_cred()>, then you do something
like:

    my $date = localtime;
    my $ses_key = MD5->hexhash(join(';', $date, $PID, $PAC));

save C<$ses_key> along with the user's login, and return C<$ses_key>.

Now C<authen_ses_key()> looks up the C<$ses_key> passed to it and
returns the saved login.  I use Oracle to store the session key and
retrieve it later, see the ToDo section below for some other ideas.

=head2 TO DO

=over 4

=item *

It might be nice if the logout method could accept some parameters
that could make it easy to redirect the user to another URI, or
whatever.  I'd have to think about the options needed before I
implement anything, though.

=back