Koha/Middleware/RealIP.pm

   1 package Koha::Middleware::RealIP;
   2
   3 # Copyright 2019 ByWater Solutions and the Koha Dev Team
   4 #
   5 # This file is part of Koha.
   6 #
   7 # Koha is free software; you can redistribute it and/or modify it
   8 # under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # Koha is distributed in the hope that it will be useful, but
  13 # WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with Koha; if not, see <http://www.gnu.org/licenses>.
  19
  20 use Modern::Perl;
  21
  22 use parent qw(Plack::Middleware);
  23
  24 use C4::Context;
  25
  26 use Net::Netmask;
  27 use Plack::Util::Accessor qw( trusted_proxy );
  28
  29 =head1 METHODS
  30
  31 =head2 prepare_app
  32
  33 This method generates and stores the list of trusted ip's as Netmask objects
  34 at the time Plack starts up, obviating the need to regerenate them on each request.
  35
  36 =cut
  37
  38 sub prepare_app {
  39     my $self = shift;
  40     $self->trusted_proxy( get_trusted_proxies() );
  41 }
  42
  43 =head2 call
  44
  45 This method is called for each request, and will ensure the correct remote address
  46 is set in the REMOTE_ADDR environment variable.
  47
  48 =cut
  49
  50 sub call {
  51     my $self = shift;
  52     my $env  = shift;
  53
  54     if ( $env->{HTTP_X_FORWARDED_FOR} ) {
  55         my @trusted_proxy = $self->trusted_proxy ? @{ $self->trusted_proxy } : undef;
  56
  57         if (@trusted_proxy) {
  58             my $addr = get_real_ip( $env->{REMOTE_ADDR}, $env->{HTTP_X_FORWARDED_FOR}, \@trusted_proxy );
  59             $ENV{REMOTE_ADDR} = $addr;
  60             $env->{REMOTE_ADDR} = $addr;
  61         }
  62     }
  63
  64     return $self->app->($env);
  65 }
  66
  67 =head2 get_real_ip
  68
  69 my $address = get_real_ip( $remote_addres, $x_forwarded_for_header );
  70
  71 This method takes the current remote address and the x-forwarded-for header string,
  72 determines the correct external ip address, and returns it.
  73
  74 =cut
  75
  76 sub get_real_ip {
  77     my ( $remote_addr, $header ) = @_;
  78
  79     my @forwarded_for = $header =~ /([^,\s]+)/g;
  80     return $remote_addr unless @forwarded_for;
  81
  82     my $trusted_proxies = get_trusted_proxies();
  83
  84     my @unconfirmed = ( @forwarded_for, $remote_addr );
  85
  86     my $real_ip;
  87     while (my $addr = pop @unconfirmed) {
  88         my $has_matched = 0;
  89         foreach my $netmask (@$trusted_proxies) {
  90             $has_matched++, last if $netmask->match($addr);
  91         }
  92         $real_ip = $addr, last unless $has_matched;
  93     }
  94
  95     return $real_ip;
  96 }
  97
  98 =head2 get_trusted_proxies
  99
 100 This method returns an arrayref of Net::Netmask objects for all
 101 the trusted proxies given to Koha.
 102
 103 =cut
 104
 105 sub get_trusted_proxies {
 106     my $proxies_conf = C4::Context->config('koha_trusted_proxies');
 107     return unless $proxies_conf;
 108     my @trusted_proxies_ip = split( / /, $proxies_conf );
 109     my @trusted_proxies = map { Net::Netmask->new($_) } @trusted_proxies_ip;
 110     return \@trusted_proxies;
 111 }
 112
 113
 114 =head1 AUTHORS
 115
 116 Kyle M Hall <kyle@bywatersolutions.com>
 117
 118 =cut
 119
 120 1;