[Patches] [PATCH] Bug 6800: Handle X-Forwarded-For headers
koha-patchbot at kohaaloha.com
koha-patchbot at kohaaloha.com
Wed Dec 21 11:00:03 NZDT 2011
From: Jared Camins-Esakov <jcamins at cpbibliography.com>
Date: Sat, 27 Aug 2011 12:10:24 -0400
Subject: [PATCH] Bug 6800: Handle X-Forwarded-For headers
Previously Koha always used the remote address for its sessions. This is a
problem where a sizable percentage of sessions are being routed through the
same proxy (for example, in the case of load balancers or reverse proxies,
or even a corporate proxy). This commit adds support for pulling the
client's IP address out of the X-Forwarded-For HTTP header, so that sessions
will be keyed to the client and not the proxy.
Although X-Forwarded-For can be spoofed, in situations where all clients
would have the same immediate REMOTE_ADDRESS (e.g. load balancing, reverse
proxy, corporate firewall), using X-Forwarded-For seems the lesser of two
evils (if you're running the proxy, you can guarantee that the most recent
entry in X-Forwarded-For is accurate, hence the behavior when the syspref is
set to require a routable IP).
=== SYSPREFS ===
This commit adds the syspref HandleXForwardedFor with the following options:
* Always use the address of the machine connecting to Koha as the client IP
for authenticated sessions. This is appropriate for configurations with
no reverse proxy or load balancer, and is exactly the same as the
previous behavior.
* Always use the address of the machine with the web browser as the client
IP for authenticated sessions. This is appropriate for configurations
that are contained entirely within a LAN, and therefore non-routable IPs
can be mapped to specific computers.
* Use the first routable address or the address of the last hop before the
proxy as the client IP for authenticated sessions. This is appropriate
for configurations that include a reverse proxy or load balancer exposed
via the public Internet. Anyone connecting through an additional proxy
will have their session linked to that proxy's IP.
=== API CHANGES ===
This commit adds the get_clientip method to C4::Auth to handle
identification of the client IP:
my $clientip = get_clientip($remote_addr, $forwarded_for, $require_routable);
Parses the remote IP address (passed to the function in $remote_addr), the
X-Forwarded-For header (passed to the function in $forwarded_for), and
retrieves the IP address of the client, returning a string representation of
the IP address. If $require_routable is set to "first", this function will
always return the most-distant IP address. If $require_routable is set to
"routable", this function will choose the first routable IP address in the
list of relays, or the address immediately before the closest proxy. If
$require_routable is set to "ignore", this function will always return the
most recent hop (i.e. the remote address). "Ignore" is the default, if
$require_routable is not set.
=== TESTING INSTRUCTIONS ===
The problem with the current configuration in Koha can be seen by
configuring Koha to listen on 127.0.0.1 and setting up a Squid proxy with
the following configuration options on the same server:
# BEGIN SQUID CONFIGURATION
# The next two lines must go at the top of the squid configuration file:
http_port ${PUBLIC_IP}:80 accel defaultsite=${YOUR_DOMAIN} vhost
cache_peer 127.0.0.1 parent 80 0 no-query originserver name=myAccel
# The next four lines must go AFTER the line "acl CONNECT method CONNECT
acl our_sites dstdomain .${YOUR_DOMAIN}
http_access allow our_sites
cache_peer_access myAccel allow our_sites
cache_peer_access myAccel deny all
# END SQUID CONFIGURATION
If you view the session log after connecting via ${PUBLIC_IP}:80, you will
see an entry for 127.0.0.1. This is the default behavior after this patch is
applied as well, but by changing the syspref HandleXForwardedFor to "Always
use the address of the originating machine," you can ensure that the IP that
shows up will always be the IP address of the machine with the web browser,
or by setting the syspref to "Use the first routable address or address of
last hop before proxy," you can ensure that the IP will always be either the
first routable address or the address of the system connecting to the
reverse proxy. On a LAN, the difference between those two options can be
tested by daisy-chaining a second squid proxy to the first, and connecting
through that.
In addition to these steps for testing, several tests have been added to
confirm that C4::Auth::get_clientip correctly handles valid input.
Signed-off-by: Chris Cormack <chrisc at catalyst.net.nz>
---
C4/Auth.pm | 85 ++++++++++++++++----
installer/data/mysql/sysprefs.sql | 2 +-
installer/data/mysql/updatedatabase.pl | 9 ++-
.../prog/en/modules/admin/preferences/admin.pref | 8 ++
t/Auth.t | 17 ++++
5 files changed, 104 insertions(+), 17 deletions(-)
create mode 100644 t/Auth.t
diff --git a/C4/Auth.pm b/C4/Auth.pm
index e360e10..977985c 100755
--- a/C4/Auth.pm
+++ b/C4/Auth.pm
@@ -646,6 +646,7 @@ sub checkauth {
$timeout = $1 * 86400;
};
$timeout = 600 unless $timeout;
+ my $clientip = get_clientip($ENV{'REMOTE_ADDR'}, $ENV{'HTTP_X_FORWARDED_FOR'}, C4::Context->preference('HandleXForwardedFor'));
_version_check($type,$query);
# state variables
@@ -720,10 +721,10 @@ sub checkauth {
$userid = undef;
$sessionID = undef;
}
- elsif ( $ip ne $ENV{'REMOTE_ADDR'} ) {
+ elsif ($ip ne $clientip) {
# Different ip than originally logged in from
$info{'oldip'} = $ip;
- $info{'newip'} = $ENV{'REMOTE_ADDR'};
+ $info{'newip'} = $clientip;
$info{'different_ip'} = 1;
$session->delete();
C4::Context->_unset_userenv($sessionID);
@@ -765,7 +766,7 @@ sub checkauth {
$userid = $retuserid if ($retuserid ne '');
}
if ($return) {
- _session_log(sprintf "%20s from %16s logged in at %30s.\n", $userid,$ENV{'REMOTE_ADDR'},(strftime '%c', localtime));
+ _session_log(sprintf "%20s from %16s logged in at %30s.\n", $userid,$clientip,(strftime '%c', localtime));
if ( $flags = haspermission( $userid, $flagsrequired ) ) {
$loggedin = 1;
}
@@ -813,7 +814,6 @@ sub checkauth {
# launch a sequence to check if we have a ip for the branch, i
# if we have one we replace the branchcode of the userenv by the branch bound in the ip.
- my $ip = $ENV{'REMOTE_ADDR'};
# if they specify at login, use that
if ($query->param('branch')) {
$branchcode = $query->param('branch');
@@ -823,7 +823,7 @@ sub checkauth {
if (C4::Context->boolean_preference('IndependantBranches') && C4::Context->boolean_preference('Autolocation')){
# we have to check they are coming from the right ip range
my $domain = $branches->{$branchcode}->{'branchip'};
- if ($ip !~ /^$domain/){
+ if ($clientip !~ /^$domain/){
$loggedin=0;
$info{'wrongip'} = 1;
}
@@ -833,7 +833,7 @@ sub checkauth {
foreach my $br ( keys %$branches ) {
# now we work with the treatment of ip
my $domain = $branches->{$br}->{'branchip'};
- if ( $domain && $ip =~ /^$domain/ ) {
+ if ( $domain && $clientip =~ /^$domain/ ) {
$branchcode = $branches->{$br}->{'branchcode'};
# new op dev : add the branchprinter and branchname in the cookie
@@ -850,7 +850,7 @@ sub checkauth {
$session->param('branchname',$branchname);
$session->param('flags',$userflags);
$session->param('emailaddress',$emailaddress);
- $session->param('ip',$session->remote_addr());
+ $session->param('ip',$clientip);
$session->param('lasttime',time());
$debug and printf STDERR "AUTH_4: (%s)\t%s %s - %s\n", map {$session->param($_)} qw(cardnumber firstname surname branch) ;
}
@@ -866,7 +866,7 @@ sub checkauth {
$session->param('branchname','NO_LIBRARY_SET');
$session->param('flags',1);
$session->param('emailaddress', C4::Context->preference('KohaAdminEmailAddress'));
- $session->param('ip',$session->remote_addr());
+ $session->param('ip',$clientip);
$session->param('lasttime',time());
}
C4::Context::set_userenv(
@@ -917,7 +917,7 @@ sub checkauth {
C4::Context::set_shelves_userenv('tot',$total);
# setting a couple of other session vars...
- $session->param('ip',$session->remote_addr());
+ $session->param('ip',$clientip);
$session->param('lasttime',time());
$session->param('sessiontype','anon');
}
@@ -1088,6 +1088,7 @@ sub check_api_auth {
my $dbh = C4::Context->dbh;
my $timeout = C4::Context->preference('timeout');
$timeout = 600 unless $timeout;
+ my $clientip = get_clientip($ENV{'REMOTE_ADDR'}, $ENV{'HTTP_X_FORWARDED_FOR'}, C4::Context->preference('HandleXForwardedFor'));
unless (C4::Context->preference('Version')) {
# database has not been installed yet
@@ -1139,7 +1140,7 @@ sub check_api_auth {
$userid = undef;
$sessionID = undef;
return ("expired", undef, undef);
- } elsif ( $ip ne $ENV{'REMOTE_ADDR'} ) {
+ } elsif ( $ip ne $clientip ) {
# IP address changed
$session->delete();
C4::Context->_unset_userenv($sessionID);
@@ -1229,7 +1230,6 @@ sub check_api_auth {
}
}
- my $ip = $ENV{'REMOTE_ADDR'};
# if they specify at login, use that
if ($query->param('branch')) {
$branchcode = $query->param('branch');
@@ -1240,7 +1240,7 @@ sub check_api_auth {
foreach my $br ( keys %$branches ) {
# now we work with the treatment of ip
my $domain = $branches->{$br}->{'branchip'};
- if ( $domain && $ip =~ /^$domain/ ) {
+ if ( $domain && $clientip =~ /^$domain/ ) {
$branchcode = $branches->{$br}->{'branchcode'};
# new op dev : add the branchprinter and branchname in the cookie
@@ -1257,7 +1257,7 @@ sub check_api_auth {
$session->param('branchname',$branchname);
$session->param('flags',$userflags);
$session->param('emailaddress',$emailaddress);
- $session->param('ip',$session->remote_addr());
+ $session->param('ip',$clientip);
$session->param('lasttime',time());
} elsif ( $return == 2 ) {
#We suppose the user is the superlibrarian
@@ -1270,7 +1270,7 @@ sub check_api_auth {
$session->param('branchname','NO_LIBRARY_SET');
$session->param('flags',1);
$session->param('emailaddress', C4::Context->preference('KohaAdminEmailAddress'));
- $session->param('ip',$session->remote_addr());
+ $session->param('ip',$clientip);
$session->param('lasttime',time());
}
C4::Context::set_userenv(
@@ -1321,6 +1321,7 @@ sub check_cookie_auth {
my $dbh = C4::Context->dbh;
my $timeout = C4::Context->preference('timeout');
$timeout = 600 unless $timeout;
+ my $clientip = get_clientip($ENV{'REMOTE_ADDR'}, $ENV{'HTTP_X_FORWARDED_FOR'}, C4::Context->preference('HandleXForwardedFor'));
unless (C4::Context->preference('Version')) {
# database has not been installed yet
@@ -1371,7 +1372,7 @@ sub check_cookie_auth {
$userid = undef;
$sessionID = undef;
return ("expired", undef);
- } elsif ( $ip ne $ENV{'REMOTE_ADDR'} ) {
+ } elsif ( $ip ne $clientip ) {
# IP address changed
$session->delete();
C4::Context->_unset_userenv($sessionID);
@@ -1396,6 +1397,60 @@ sub check_cookie_auth {
}
}
+=head2 get_clientip
+
+ my $clientip = get_clientip($remote_addr, $forwarded_for, $require_routable);
+
+Parses the remote IP address (passed to the function in $remote_addr), the
+X-Forwarded-For header (passed to the function in $forwarded_for), and retrieves
+the IP address of the client, returning a string representation of the IP
+address. If $require_routable is set to "first", this function will always
+return the most-distant IP address. If $require_routable is set to "routable",
+this function will choose the first routable IP address in the list of relays,
+or the address immediately before the closest proxy. If $require_routable is set
+to "ignore", this function will always return the most recent hop (i.e. the
+remote address). "Ignore" is the default.
+
+=cut
+
+sub get_clientip {
+ my $remote_addr = shift;
+ my $forwarded_for = shift;
+ my $require_routable = shift;
+ my $clientip;
+
+ $require_routable ||= 'ignore';
+
+ if ($require_routable eq 'ignore' || !length $forwarded_for) {
+ $clientip = $remote_addr;
+ } else {
+ my @ips = split(', ', $forwarded_for);
+ $ips[$#ips + 1] = $remote_addr;
+ if ($require_routable eq 'first') {
+ $clientip = $ips[0];
+ } else { # $require_routable eq 'routable'
+ foreach (@ips) {
+ if ( $_ !~ /^(192\.|10\.|127\.|0\.|169\.254\.|2([345][0-9|2[4-9])\.|172\.(1[6-9]|2[0-9]|3[0-1])\.)/) {
+ $clientip = $_;
+ last;
+ # We've found the client if the IP is not in any of:
+ # * 192.0.0.0/8
+ # * 10.0.0.0/8
+ # * 127.0.0.0/8
+ # * 169.254.0.0/16
+ # * 224.0.0.0/4 or 240.0.0.0/4
+ # * 172.16.0.0/12
+ }
+ }
+ if (!length $clientip) {
+ $clientip = $ips[$#ips - 1];
+ }
+ }
+ }
+
+ return $clientip;
+}
+
=head2 get_session
use CGI::Session;
diff --git a/installer/data/mysql/sysprefs.sql b/installer/data/mysql/sysprefs.sql
index 128c9b2..79e9178 100755
--- a/installer/data/mysql/sysprefs.sql
+++ b/installer/data/mysql/sysprefs.sql
@@ -328,4 +328,4 @@ INSERT INTO systempreferences (variable,value,explanation,options,type) VALUES('
INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES ('OpacKohaUrl','1',"Show 'Powered by Koha' text on OPAC footer.",NULL,NULL);
INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES('EasyAnalyticalRecords','0','If on, display in the catalogue screens tools to easily setup analytical record relationships','','YesNo');
INSERT INTO systempreferences (variable,value,explanation,options,type) VALUES('OpacShowRecentComments',0,'If ON a link to recent comments will appear in the OPAC masthead',NULL,'YesNo');
-
+INSERT INTO systempreferences (variable,value,explanation,options,type) VALUES('HandleXForwardedFor','ignore','Specify how to handle client IPs and the X-Forwarded-For header.','ignore|first|routable','Choice');
diff --git a/installer/data/mysql/updatedatabase.pl b/installer/data/mysql/updatedatabase.pl
index 0063a75..0a16a09 100755
--- a/installer/data/mysql/updatedatabase.pl
+++ b/installer/data/mysql/updatedatabase.pl
@@ -4438,7 +4438,6 @@ if (C4::Context->preference("Version") < TransformToNum($DBversion)) {
SetVersion($DBversion);
}
-
$DBversion = "3.05.00.011";
if (C4::Context->preference("Version") < TransformToNum($DBversion)) {
$dbh->do("INSERT INTO `systempreferences` (variable,value,explanation,options,type) VALUES('OPACResultsSidebar','','Define HTML to be included on the search results page, underneath the facets sidebar','70|10','Textarea')");
@@ -4578,6 +4577,14 @@ if ( C4::Context->preference("Version") < TransformToNum($DBversion) ) {
SetVersion($DBversion);
}
+$DBversion = "3.07.00.XXX";
+if (C4::Context->preference("Version") < TransformToNum($DBversion)) {
+ $dbh->do("INSERT INTO systempreferences (variable,value,explanation,options,type) VALUES('HandleXForwardedFor','ignore','Specify how to handle client IPs and the X-Forwarded-For header.','ignore|first|routable','Choice');");
+ print "Upgrade to $DBversion done (add HandleXForwardedFor syspref- change if you are using a reverse proxy or load balancer)\n";
+ SetVersion($DBversion);
+}
+
+
=head1 FUNCTIONS
=head2 DropAllForeignKeys($table)
diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/admin.pref b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/admin.pref
index f026c7e..3ccc833 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/admin.pref
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/admin.pref
@@ -71,6 +71,14 @@ Administration:
tmp: as temporary files.
memcached: in a memcached server.
-
+ - pref: HandleXForwardedFor
+ default: ignore
+ choices:
+ ignore: Always use the address of the machine connecting to Koha
+ routable: Use the first routable address or address of the last hop before the proxy
+ first: Always use the address of the machine with the web browser
+ - as the client IP for authenticated sessions.
+ -
- pref: IndependantBranches
default: 0
choices:
diff --git a/t/Auth.t b/t/Auth.t
new file mode 100644
index 0000000..d712874
--- /dev/null
+++ b/t/Auth.t
@@ -0,0 +1,17 @@
+#!/usr/bin/perl
+#
+# This Koha test module is a stub!
+# Add more tests here!!!
+
+use strict;
+use warnings;
+
+use Test::More tests => 5;
+
+BEGIN {
+ use_ok('C4::Auth');
+ ok(C4::Auth::get_clientip('192.168.101.2', '192.168.101.3, 192.168.101.4', 'ignore') eq '192.168.101.2', 'get_clientip: Ignore proxies for client IP');
+ ok(C4::Auth::get_clientip('192.168.101.2', '192.168.101.3, 192.168.101.4', 'first') eq '192.168.101.3', 'get_clientip: Always use most remote client IP');
+ ok(C4::Auth::get_clientip('192.168.101.2', '127.0.0.1, 192.168.102.3, 10.0.0.1, 53.42.191.136', 'routable') eq '53.42.191.136', 'get_clientip: Find routable client IP w/reverse proxy');
+ ok(C4::Auth::get_clientip('192.168.101.2', '127.0.0.1, 192.168.102.3, 10.0.0.1', 'routable') eq '10.0.0.1', 'get_clientip: Handle no-routable IPs w/reverse proxy');
+}
--
1.7.5.4
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