[1.4.X] Fixed a security issue in get_host.

Full disclosure and new release forthcoming.

Author: apollo13

django/http/__init__.py

@@ -126,6 +126,8 @@ def __init__(self, *args, **kwargs):
 RESERVED_CHARS="!*'();:@&=+$,/?%#[]"
 
 absolute_http_url_re = re.compile(r"^https?://", re.I)
+host_validation_re = re.compile(r"^([a-z0-9.-]+|\[[a-f0-9]*:[a-f0-9:]+\])(:\d+)?$")
+
 
 class Http404(Exception):
  pass
@@ -214,7 +216,7 @@ def get_host(self):
  host = '%s:%s' % (host, server_port)
 
  # Disallow potentially poisoned hostnames.
- if set(';/?@&=+$,').intersection(host):
+ if not host_validation_re.match(host.lower()):
  raise SuspiciousOperation('Invalid HTTP_HOST header: %s' % host)
 
  return host

docs/topics/security.txt

@@ -167,6 +167,33 @@ recommend you ensure your Web server is configured such that:
 Additionally, as of 1.3.1, Django requires you to explicitly enable support for
 the ``X-Forwarded-Host`` header if your configuration requires it.
 
+Configuration for Apache
+------------------------
+
+The easiest way to get the described behavior in Apache is as follows. Create
+a `virtual host`_ using the ServerName_ and ServerAlias_ directives to restrict
+the domains Apache reacts to. Please keep in mind that while the directives do
+support ports the match is only performed against the hostname. This means that
+the ``Host`` header could still contain a port pointing to another webserver on
+the same machine. The next step is to make sure that your newly created virtual
+host is not also the default virtual host. Apache uses the first virtual host
+found in the configuration file as default virtual host. As such you have to
+ensure that you have another virtual host which will act as catch-all virtual
+host. Just add one if you do not have one already, there is nothing special
+about it aside from ensuring it is the first virtual host in the configuration
+file. Debian/Ubuntu users usually don't have to take any action, since Apache
+ships with a default virtual host in ``sites-available`` which is linked into
+``sites-enabled`` as ``000-default`` and included from ``apache2.conf``. Just
+make sure not to name your site ``000-abc``, since files are included in
+alphabetical order.
+
+.. _virtual host: http://httpd.apache.org/docs/2.2/vhosts/
+.. _ServerName: http://httpd.apache.org/docs/2.2/mod/core.html#servername
+.. _ServerAlias: http://httpd.apache.org/docs/2.2/mod/core.html#serveralias
+
+
+
+
 Additional security topics
 ==========================
 

tests/regressiontests/requests/tests.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 from __future__ import with_statement
 
 import time
@@ -154,13 +155,15 @@ def test_http_get_host(self):
  '12.34.56.78:443',
  '[2001:19f0:feee::dead:beef:cafe]',
  '[2001:19f0:feee::dead:beef:cafe]:8080',
+ 'xn--4ca9at.com', # Punnycode for öäü.com
  ]
 
  poisoned_hosts = [
  'example.com@evil.tld',
  'example.com:dr.frankenstein@evil.tld',
- 'example.com:someone@somestie.com:80',
- 'example.com:80/badpath'
+ 'example.com:dr.frankenstein@evil.tld:80',
+ 'example.com:80/badpath',
+ 'example.com: recovermypassword.com',
  ]
 
  for host in legit_hosts:
@@ -230,13 +233,15 @@ def test_http_get_host_with_x_forwarded_host(self):
  '12.34.56.78:443',
  '[2001:19f0:feee::dead:beef:cafe]',
  '[2001:19f0:feee::dead:beef:cafe]:8080',
+ 'xn--4ca9at.com', # Punnycode for öäü.com
  ]
 
  poisoned_hosts = [
  'example.com@evil.tld',
  'example.com:dr.frankenstein@evil.tld',
  'example.com:dr.frankenstein@evil.tld:80',
- 'example.com:80/badpath'
+ 'example.com:80/badpath',
+ 'example.com: recovermypassword.com',
  ]
 
  for host in legit_hosts: