Koha/Token.pm

   1 package Koha::Token;
   2
   3 # Created as wrapper for CSRF tokens, but designed for more general use
   4
   5 # Copyright 2016 Rijksmuseum
   6 #
   7 # This file is part of Koha.
   8 #
   9 # Koha is free software; you can redistribute it and/or modify it under the
  10 # terms of the GNU General Public License as published by the Free Software
  11 # Foundation; either version 3 of the License, or (at your option) any later
  12 # version.
  13 #
  14 # Koha is distributed in the hope that it will be useful, but WITHOUT ANY
  15 # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  16 # A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License along
  19 # with Koha; if not, write to the Free Software Foundation, Inc.,
  20 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21
  22 =head1 NAME
  23
  24 Koha::Token - Tokenizer
  25
  26 =head1 SYNOPSIS
  27
  28     use Koha::Token;
  29     my $tokenizer = Koha::Token->new;
  30     my $token = $tokenizer->generate({ length => 20 });
  31
  32     # safely generate a CSRF token (nonblocking)
  33     my $csrf_token = $tokenizer->generate({
  34         type => 'CSRF', id => $id, secret => $secret,
  35     });
  36
  37     # or check a CSRF token
  38     my $result = $tokenizer->check_csrf({
  39         id => $id, secret => $secret, token => $token,
  40     });
  41
  42 =head1 DESCRIPTION
  43
  44     Designed for providing general tokens.
  45     Created due to the need for a nonblocking call to Bytes::Random::Secure
  46     when generating a CSRF token.
  47
  48 =cut
  49
  50 use Modern::Perl;
  51 use Bytes::Random::Secure ();
  52 use String::Random ();
  53 use WWW::CSRF ();
  54 use base qw(Class::Accessor);
  55 use constant HMAC_SHA1_LENGTH => 20;
  56 use constant CSRF_EXPIRY_HOURS => 8; # 8 hours instead of 7 days..
  57
  58 =head1 METHODS
  59
  60 =head2 new
  61
  62     Create object (via Class::Accessor).
  63
  64 =cut
  65
  66 sub new {
  67     my ( $class ) = @_;
  68     return $class->SUPER::new();
  69 }
  70
  71 =head2 generate
  72
  73     my $token = $tokenizer->generate({ length => 20 });
  74     my $csrf_token = $tokenizer->generate({
  75         type => 'CSRF', id => $id, secret => $secret,
  76     });
  77
  78     Generate several types of tokens. Now includes CSRF.
  79     Room for future extension.
  80
  81 =cut
  82
  83 sub generate {
  84     my ( $self, $params ) = @_;
  85     if( $params->{type} && $params->{type} eq 'CSRF' ) {
  86         $self->{lasttoken} = _gen_csrf( $params );
  87     } else {
  88         $self->{lasttoken} = _gen_rand( $params );
  89     }
  90     return $self->{lasttoken};
  91 }
  92
  93 =head2 generate_csrf
  94
  95     Shortcut for: generate({ type => 'CSRF', ... })
  96
  97 =cut
  98
  99 sub generate_csrf {
 100     my ( $self, $params ) = @_;
 101     return $self->generate({ %$params, type => 'CSRF' });
 102 }
 103
 104 =head2 check
 105
 106     my $result = $tokenizer->check({
 107         type => 'CSRF', id => $id, secret => $secret, token => $token,
 108     });
 109
 110     Check several types of tokens. Now includes CSRF.
 111     Room for future extension.
 112
 113 =cut
 114
 115 sub check {
 116     my ( $self, $params ) = @_;
 117     if( $params->{type} && $params->{type} eq 'CSRF' ) {
 118         return _chk_csrf( $params );
 119     }
 120     return;
 121 }
 122
 123 =head2 check_csrf
 124
 125     Shortcut for: check({ type => 'CSRF', ... })
 126
 127 =cut
 128
 129 sub check_csrf {
 130     my ( $self, $params ) = @_;
 131     return $self->check({ %$params, type => 'CSRF' });
 132 }
 133
 134 # --- Internal routines ---
 135
 136 sub _gen_csrf {
 137
 138 # Since WWW::CSRF::generate_csrf_token does not use the NonBlocking
 139 # parameter of Bytes::Random::Secure, we are passing random bytes from
 140 # a non blocking source to WWW::CSRF via its Random parameter.
 141
 142     my ( $params ) = @_;
 143     return if !$params->{id} || !$params->{secret};
 144
 145
 146     my $randomizer = Bytes::Random::Secure->new( NonBlocking => 1 );
 147         # this is most fundamental: do not use /dev/random since it is
 148         # blocking, but use /dev/urandom !
 149     my $random = $randomizer->bytes( HMAC_SHA1_LENGTH );
 150     my $token = WWW::CSRF::generate_csrf_token(
 151         $params->{id}, $params->{secret}, { Random => $random },
 152     );
 153
 154     return $token;
 155 }
 156
 157 sub _chk_csrf {
 158     my ( $params ) = @_;
 159     return if !$params->{id} || !$params->{secret} || !$params->{token};
 160
 161     my $csrf_status = WWW::CSRF::check_csrf_token(
 162         $params->{id},
 163         $params->{secret},
 164         $params->{token},
 165         { MaxAge => $params->{MaxAge} // ( CSRF_EXPIRY_HOURS * 3600 ) },
 166     );
 167     return $csrf_status == WWW::CSRF::CSRF_OK();
 168 }
 169
 170 sub _gen_rand {
 171     my ( $params ) = @_;
 172     my $length = $params->{length} || 1;
 173     $length = 1 unless $length > 0;
 174
 175     return String::Random::random_string( '.' x $length );
 176 }
 177
 178 =head1 AUTHOR
 179
 180     Marcel de Rooy, Rijksmuseum Amsterdam, The Netherlands
 181
 182 =cut
 183
 184 1;