From bf9830d354c5230ad7b552583375c0ba53a32ac2 Mon Sep 17 00:00:00 2001
From: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Date: Thu, 21 Sep 2023 12:00:17 +0200
Subject: [PATCH] Bug 34478: op-cud - Trick CGI directly

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
---
 C4/Auth.pm                  | 52 +++++++++++++++++++------------------
 Koha/Exceptions/Token.pm    |  5 ++++
 debian/templates/plack.psgi | 13 ++++++++++
 3 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/C4/Auth.pm b/C4/Auth.pm
index 757e97e33a..23c3562d26 100644
--- a/C4/Auth.pm
+++ b/C4/Auth.pm
@@ -32,6 +32,7 @@ use C4::Context;
 use C4::Templates;    # to get the template
 use C4::Languages;
 use C4::Search::History;
+use C4::Output qw( output_and_exit );
 use Koha;
 use Koha::Logger;
 use Koha::Caches;
@@ -53,6 +54,7 @@ use C4::Log qw( logaction );
 use Koha::CookieManager;
 use Koha::Auth::Permissions;
 use Koha::Token;
+use Koha::Exceptions::Token;
 use Koha::Session;
 
 # use utf8;
@@ -189,6 +191,7 @@ sub get_template_and_user {
             $in->{'type'},
             undef,
             $in->{template_name},
+            { skip_csrf_check => 1 },
         );
     }
 
@@ -631,6 +634,16 @@ sub get_template_and_user {
     $template->param( logged_in_user     => $patron );
     $template->param( sessionID          => $sessionID );
 
+    if ( $in->{query}->param('op-cud') ) {
+        C4::Output::output_and_exit( $in->{query}, $cookie, $template, 'wrong_csrf_token' )
+            unless Koha::Token->new->check_csrf(
+            {
+                session_id => scalar $in->{query}->cookie('CGISESSID'),
+                token      => scalar $in->{query}->param('csrf_token'),
+            }
+            );
+    }
+
     return ( $template, $borrowernumber, $cookie, $flags );
 }
 
@@ -791,7 +804,9 @@ sub checkauth {
     my $type            = shift;
     my $emailaddress    = shift;
     my $template_name   = shift;
-    my $params          = shift || {};    # do_not_print
+    my $params          = shift || {}; # do_not_print, skip_csrf_check
+
+    my $skip_csrf_check = $params->{skip_csrf_check} || 0;
     $type = 'opac' unless $type;
 
     if ( $type eq 'opac' && !C4::Context->preference("OpacPublic") ) {
@@ -1312,7 +1327,6 @@ sub checkauth {
     }
 
     # finished authentification, now respond
-    my $auth_template_name = ( $type eq 'opac' ) ? 'opac-auth.tt' : 'auth.tt';
     if ( $auth_state eq 'completed' || $authnotrequired ) {
         # successful login
         unless (@$cookie) {
@@ -1328,35 +1342,22 @@ sub checkauth {
         my $patron = $userid ? Koha::Patrons->find({ userid => $userid }) : undef;
         $patron->update_lastseen('login') if $patron;
 
-        my $original_op_cud = $query->param('op-cud');
-        if ( $request_method eq 'GET' ) {
-            $query->param('op-cud', undef);
-        } elsif ( $request_method eq 'POST' ) {
-            $query->param('op', undef);
-        }
-
-        if ( defined $original_op_cud ) {
+        if ( $query->param('op-cud') ) {
             die "Cannot use GET for this request"
-                if $request_method ne 'POST';
-
-            print $query->header(
-                {
-                    type              => 'text/html',
-                    charset           => 'utf-8',
-                    cookie            => $cookie,
-                    'X-Frame-Options' => 'SAMEORIGIN',
-                    -sameSite         => 'Lax'
-                }
-            );
+                if $request_method eq 'GET';
 
-            my $template = C4::Templates::gettemplate( $auth_template_name, $type, $query );
-            output_and_exit( $query, $cookie, $template, 'wrong_csrf_token' )
-                unless Koha::Token->new->check_csrf(
+            unless (
+                $skip_csrf_check
+                || Koha::Token->new->check_csrf(
                     {
                         session_id => scalar $query->cookie('CGISESSID'),
                         token      => scalar $query->param('csrf_token'),
                     }
-                );
+                )
+                )
+            {
+                Koha::Exceptions::Token::WrongCSRFToken->throw;
+            }
         }
 
         # In case, that this request was a login attempt, we want to prevent that users can repost the opac login
@@ -1398,6 +1399,7 @@ sub checkauth {
     $LibraryNameTitle =~ s/<(?:[^<>'"]|'(?:[^']*)'|"(?:[^"]*)")*>//sg;
 
     my $auth_error = $query->param('auth_error');
+    my $auth_template_name = ( $type eq 'opac' ) ? 'opac-auth.tt' : 'auth.tt';
     my $template = C4::Templates::gettemplate( $auth_template_name, $type, $query );
     $template->param(
         login                                 => 1,
diff --git a/Koha/Exceptions/Token.pm b/Koha/Exceptions/Token.pm
index c7fe147369..92701ebae8 100644
--- a/Koha/Exceptions/Token.pm
+++ b/Koha/Exceptions/Token.pm
@@ -27,6 +27,11 @@ use Exception::Class (
         isa => 'Koha::Exceptions::Token',
         description => 'Bad pattern for random token generation'
     },
+    'Koha::Exceptions::Token::WrongCSRFToken' => {
+        isa => 'Koha::Exceptions::Token',
+        description => 'Invalid CSRF Token'
+    },
+
 );
 
 =head1 NAME
diff --git a/debian/templates/plack.psgi b/debian/templates/plack.psgi
index 89cd6ef48f..577118148c 100644
--- a/debian/templates/plack.psgi
+++ b/debian/templates/plack.psgi
@@ -47,6 +47,19 @@ use CGI qw(-utf8 ); # we will loose -utf8 under plack, otherwise
         $CGI::PARAM_UTF8 = 1;
         Koha::Caches->flush_L1_caches();
         Koha::Cache::Memory::Lite->flush();
+
+        $original_op_cud = $q->param('op-cud');
+        $request_method  = $q->request_method // q{};
+        if ( $request_method eq 'GET' && defined $original_op_cud ) {
+            warn "Programming error - op-cud must not be passed with GET";
+            $q->param( 'op-cud', undef );
+        } elsif ( $request_method ne 'GET' && defined $q->param('op') ) {
+            warn "Programming error - op can only be passed with GET";
+            $q->param( 'op', undef );
+        } else {
+            $q->param( 'op', $original_op_cud );
+        }
+
         return $q;
     };
 }
-- 
2.39.5