Fixed a security issue in get_host.

Full disclosure and new release forthcoming.

django/http/request.py

@@ -25,6 +25,7 @@ from django.utils.encoding import force_bytes, force_text, force_str, iri_to_uri
 
 RAISE_ERROR = object()
 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 UnreadablePostError(IOError):
@@ -64,7 +65,7 @@ class HttpRequest(object):
                 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

@@ -185,6 +185,31 @@ 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:
 
 Additional security topics

tests/regressiontests/requests/tests.py

@@ -116,13 +116,15 @@ class RequestsTests(unittest.TestCase):
             '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:dr.frankenstein@evil.tld:80',
-            'example.com:80/badpath'
+            'example.com:80/badpath',
+            'example.com: recovermypassword.com',
         ]
 
         for host in legit_hosts:
@@ -186,13 +188,15 @@ class RequestsTests(unittest.TestCase):
             '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: