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#!/usr/bin/perl |
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# Copyright vanoudt@gmail.com 2014 |
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# Based on persona code from chris@bigballofwax.co.nz 2013 |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it |
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# under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Koha is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Koha; if not, see <http://www.gnu.org/licenses>. |
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# |
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# |
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# Basic OAuth2/OpenID Connect authentication for google goes like this |
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# First: |
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# get your clientid, clientsecret from google. At this stage, tell |
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# google that your redirect url is /cgi-bin/koha/svc/oauthlogin |
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# |
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# The first thing that happens when this script is called is |
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# that one gets redirected to an authentication url from google |
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# |
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# If successful, that then redirects back to this script, setting |
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# a CODE parameter which we use to look up a json authentication |
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# token. This token includes an encrypted json id_token, which we |
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# round-trip back to google to decrypt. Finally, we can extract |
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# the email address from this. |
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# |
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# There is some room for improvement here. In particular, Google |
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# recommends verifying and decrypting the id_token locally, which |
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# means caching some information and updating it daily. But that |
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# would make things a lot faster |
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|
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use Modern::Perl; |
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use CGI qw ( -utf8 escape ); |
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use C4::Auth qw{ checkauth get_session get_template_and_user }; |
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use C4::Context; |
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use C4::Output; |
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|
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use LWP::UserAgent; |
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use HTTP::Request::Common qw{ POST }; |
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use JSON; |
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use MIME::Base64 qw{ decode_base64url }; |
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|
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my $discoveryDocURL = |
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'https://accounts.google.com/.well-known/openid-configuration'; |
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my $authendpoint = ''; |
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my $tokenendpoint = ''; |
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my $scope = 'openid email profile'; |
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my $host = C4::Context->preference('OPACBaseURL') // q{}; |
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my $restricttodomain = C4::Context->preference('GoogleOpenIDConnectDomain') |
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// q{}; |
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# protocol is assumed in OPACBaseURL see bug 5010. |
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my $redirecturl = $host . '/cgi-bin/koha/svc/auth/googleopenidconnect'; |
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my $issuer = 'accounts.google.com'; |
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my $clientid = C4::Context->preference('GoogleOAuth2ClientID'); |
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my $clientsecret = C4::Context->preference('GoogleOAuth2ClientSecret'); |
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|
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my $ua = LWP::UserAgent->new(); |
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my $response = $ua->get($discoveryDocURL); |
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if ( $response->is_success ) { |
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my $json = decode_json( $response->decoded_content ); |
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if ( exists( $json->{'authorization_endpoint'} ) ) { |
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$authendpoint = $json->{'authorization_endpoint'}; |
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} |
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if ( exists( $json->{'token_endpoint'} ) ) { |
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$tokenendpoint = $json->{'token_endpoint'}; |
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} |
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} |
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my $query = CGI->new; |
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|
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sub loginfailed { |
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my $cgi_query = shift; |
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my $reason = shift; |
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$cgi_query->delete('code'); |
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$cgi_query->param( 'OpenIDConnectFailed' => $reason ); |
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my ( $template, $borrowernumber, $cookie ) = get_template_and_user( |
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{ |
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template_name => 'opac-user.tt', |
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query => $cgi_query, |
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type => 'opac', |
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authnotrequired => 0, |
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} |
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); |
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$template->param( 'invalidGoogleOpenIDConnectLogin' => $reason ); |
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$template->param( 'loginprompt' => 1 ); |
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output_html_with_http_headers $cgi_query, $cookie, $template->output; |
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return; |
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} |
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if ( defined $query->param('error') ) { |
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loginfailed( $query, |
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'An authentication error occurred. (Error:' |
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. $query->param('error') |
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. ')' ); |
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} |
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elsif ( defined $query->param('code') ) { |
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my $stateclaim = $query->param('state'); |
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my $session = get_session( $query->cookie('CGISESSID') ); |
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if ( $session->param('google-openid-state') ne $stateclaim ) { |
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$session->clear( ["google-openid-state"] ); |
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$session->flush(); |
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loginfailed( $query, |
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'Authentication failed. Your session has an unexpected state.' ); |
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} |
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$session->clear( ["google-openid-state"] ); |
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$session->flush(); |
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|
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my $code = $query->param('code'); |
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my $ua = LWP::UserAgent->new(); |
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if ( $tokenendpoint eq q{} ) { |
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loginfailed( $query, 'Unable to discover token endpoint.' ); |
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} |
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my $request = POST( |
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$tokenendpoint, |
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[ |
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code => $code, |
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client_id => $clientid, |
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client_secret => $clientsecret, |
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redirect_uri => $redirecturl, |
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grant_type => 'authorization_code', |
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$scope => $scope |
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] |
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); |
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my $response = $ua->request($request)->decoded_content; |
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my $json = decode_json($response); |
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if ( exists( $json->{'id_token'} ) ) { |
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if ( lc( $json->{'token_type'} ) ne 'bearer' ) { |
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loginfailed( $query, |
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'Authentication failed. Incorrect token type.' ); |
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} |
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my $idtoken = $json->{'id_token'}; |
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# Normally we'd have to validate the token - but google says not to worry here (Avoids another library!) |
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# See https://developers.google.com/identity/protocols/OpenIDConnect#obtainuserinfo for rationale |
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my @segments = split( '\.', $idtoken ); |
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unless ( scalar(@segments) == 3 ) { |
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loginfailed( $query, |
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'Login token broken: either too many or too few segments.' ); |
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} |
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my ( $header, $claims, $validation ) = @segments; |
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$claims = decode_base64url($claims); |
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my $claims_json = decode_json($claims); |
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if ( ( $claims_json->{'iss'} ne ( 'https://' . $issuer ) ) |
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&& ( $claims_json->{'iss'} ne $issuer ) ) |
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{ |
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loginfailed( $query, |
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"Authentication failed. Issuer of authentication isn't Google." |
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); |
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} |
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if ( ref( $claims_json->{'aud'} ) eq 'ARRAY' ) { |
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warn "Audience is an array of size: " |
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. scalar( @$claims_json->{'aud'} ); |
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if ( scalar( @$claims_json->{'aud'} ) > 1 ) |
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{ # We don't want any other audiences |
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loginfailed( $query, |
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"Authentication failed. Unexpected audience provided." ); |
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} |
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} |
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if ( ( $claims_json->{'aud'} ne $clientid ) |
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|| ( $claims_json->{'azp'} ne $clientid ) ) |
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{ |
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loginfailed( $query, |
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"Authentication failed. Unexpected audience." ); |
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} |
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if ( $claims_json->{'exp'} < time() ) { |
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loginfailed( $query, 'Sorry, your authentication has timed out.' ); |
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} |
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if ( exists( $claims_json->{'email'} ) ) { |
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my $email = $claims_json->{'email'}; |
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if ( ( $restricttodomain ne q{} ) |
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&& ( index( $email, $restricttodomain ) < 0 ) ) |
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{ |
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loginfailed( $query, |
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'The email you have used is not valid for this library. Email addresses should conclude with ' |
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. $restricttodomain |
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. ' .' ); |
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} |
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else { |
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my ( $userid, $cookie, $session_id ) = |
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checkauth( $query, 1, {}, 'opac', $email ); |
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if ($userid) { # A user with this email is registered in koha |
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print $query->redirect( |
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-uri => '/cgi-bin/koha/opac-user.pl', |
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-cookie => $cookie |
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); |
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} |
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else { |
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loginfailed( $query, |
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'The email address you are trying to use is not associated with a borrower at this library.' |
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); |
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} |
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} |
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} |
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else { |
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loginfailed( $query, |
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'Unexpectedly, no email seems to be associated with that acccount.' |
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); |
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} |
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} |
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else { |
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loginfailed( $query, 'Failed to get proper credentials from Google.' ); |
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} |
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} |
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else { |
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my $session = get_session( $query->cookie('CGISESSID') ); |
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my $openidstate = 'auth_'; |
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$openidstate .= sprintf( "%x", rand 16 ) for 1 .. 32; |
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$session->param( 'google-openid-state', $openidstate ); |
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$session->flush(); |
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my $prompt = $query->param('reauthenticate') // q{}; |
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if ( $authendpoint eq q{} ) { |
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loginfailed( $query, 'Unable to discover authorisation endpoint.' ); |
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} |
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my $authorisationurl = |
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$authendpoint . '?' |
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. 'response_type=code&' |
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. 'redirect_uri=' |
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. escape($redirecturl) . q{&} |
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. 'client_id=' |
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. escape($clientid) . q{&} |
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. 'scope=' |
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. escape($scope) . q{&} |
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. 'state=' |
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. escape($openidstate); |
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if ( $prompt || ( defined $prompt && length $prompt > 0 ) ) { |
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$authorisationurl .= '&prompt=' . escape($prompt); |
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} |
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print $query->redirect($authorisationurl); |
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} |