1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
Origin: backport, commit:27cd872e6e36a81d0bb6f5b8765a1705fecfc253
Description: Added ALLOWED_HOSTS setting for HTTP host header validation.
Bug-Debian: http://bugs.debian.org/701186
--- a/django/conf/global_settings.py
+++ b/django/conf/global_settings.py
@@ -29,6 +29,10 @@ ADMINS = ()
# * Receive x-headers
INTERNAL_IPS = ()
+# Hosts/domain names that are valid for this site.
+# "*" matches anything, ".example.com" matches example.com and all subdomains
+ALLOWED_HOSTS = ['*']
+
# Local time zone for this installation. All choices can be found here:
# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name (although not all
# systems may support all possibilities).
--- a/django/conf/project_template/settings.py
+++ b/django/conf/project_template/settings.py
@@ -20,6 +20,10 @@ DATABASES = {
}
}
+# Hosts/domain names that are valid for this site; required if DEBUG is False
+# See https://docs.djangoproject.com/en/{{ docs_version }}/ref/settings/#allowed-hosts
+ALLOWED_HOSTS = []
+
# Local time zone for this installation. Choices can be found here:
# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
# although not all choices may be available on all operating systems.
--- a/django/http/__init__.py
+++ b/django/http/__init__.py
@@ -60,11 +60,15 @@ class HttpRequest(object):
if server_port != (self.is_secure() and '443' or '80'):
host = '%s:%s' % (host, server_port)
- # Disallow potentially poisoned hostnames.
- if not host_validation_re.match(host.lower()):
- raise SuspiciousOperation('Invalid HTTP_HOST header: %s' % host)
-
- return host
+ if settings.DEBUG:
+ allowed_hosts = ['*']
+ else:
+ allowed_hosts = settings.ALLOWED_HOSTS
+ if validate_host(host, allowed_hosts):
+ return host
+ else:
+ raise SuspiciousOperation(
+ "Invalid HTTP_HOST header (you may need to set ALLOWED_HOSTS): %s" % host)
def get_full_path(self):
return ''
@@ -505,3 +509,43 @@ def str_to_unicode(s, encoding):
else:
return s
+def validate_host(host, allowed_hosts):
+ """
+ Validate the given host header value for this site.
+
+ Check that the host looks valid and matches a host or host pattern in the
+ given list of ``allowed_hosts``. Any pattern beginning with a period
+ matches a domain and all its subdomains (e.g. ``.example.com`` matches
+ ``example.com`` and any subdomain), ``*`` matches anything, and anything
+ else must match exactly.
+
+ Return ``True`` for a valid host, ``False`` otherwise.
+
+ """
+ # All validation is case-insensitive
+ host = host.lower()
+
+ # Basic sanity check
+ if not host_validation_re.match(host):
+ return False
+
+ # Validate only the domain part.
+ if host[-1] == ']':
+ # It's an IPv6 address without a port.
+ domain = host
+ else:
+ domain = host.rsplit(':', 1)[0]
+
+ for pattern in allowed_hosts:
+ pattern = pattern.lower()
+ match = (
+ pattern == '*' or
+ pattern.startswith('.') and (
+ domain.endswith(pattern) or domain == pattern[1:]
+ ) or
+ pattern == domain
+ )
+ if match:
+ return True
+
+ return False
--- a/django/test/utils.py
+++ b/django/test/utils.py
@@ -62,6 +62,9 @@ def setup_test_environment():
mail.original_email_backend = settings.EMAIL_BACKEND
settings.EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'
+ settings._original_allowed_hosts = settings.ALLOWED_HOSTS
+ settings.ALLOWED_HOSTS = ['*']
+
mail.outbox = []
deactivate()
@@ -82,6 +85,9 @@ def teardown_test_environment():
settings.EMAIL_BACKEND = mail.original_email_backend
del mail.original_email_backend
+ settings.ALLOWED_HOSTS = settings._original_allowed_hosts
+ del settings._original_allowed_hosts
+
del mail.outbox
def get_runner(settings):
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
@@ -74,6 +74,42 @@ of (Full name, e-mail address). Example:
Note that Django will e-mail *all* of these people whenever an error happens.
See :doc:`/howto/error-reporting` for more information.
+.. setting:: ALLOWED_HOSTS
+
+ALLOWED_HOSTS
+-------------
+
+Default: ``['*']``
+
+A list of strings representing the host/domain names that this Django site can
+serve. This is a security measure to prevent an attacker from poisoning caches
+and password reset emails with links to malicious hosts by submitting requests
+with a fake HTTP ``Host`` header, which is possible even under many
+seemingly-safe webserver configurations.
+
+Values in this list can be fully qualified names (e.g. ``'www.example.com'``),
+in which case they will be matched against the request's ``Host`` header
+exactly (case-insensitive, not including port). A value beginning with a period
+can be used as a subdomain wildcard: ``'.example.com'`` will match
+``example.com``, ``www.example.com``, and any other subdomain of
+``example.com``. A value of ``'*'`` will match anything; in this case you are
+responsible to provide your own validation of the ``Host`` header (perhaps in a
+middleware; if so this middleware must be listed first in
+:setting:`MIDDLEWARE_CLASSES`).
+
+If the ``Host`` header (or ``X-Forwarded-Host`` if
+:setting:`USE_X_FORWARDED_HOST` is enabled) does not match any value in this
+list, the :meth:`django.http.HttpRequest.get_host()` method will raise
+:exc:`~django.core.exceptions.SuspiciousOperation`.
+
+When :setting:`DEBUG` is ``True`` or when running tests, host validation is
+disabled; any host will be accepted. Thus it's usually only necessary to set it
+in production.
+
+This validation only applies via :meth:`~django.http.HttpRequest.get_host()`;
+if your code accesses the ``Host`` header directly from ``request.META`` you
+are bypassing this security protection.
+
.. setting:: ALLOWED_INCLUDE_ROOTS
ALLOWED_INCLUDE_ROOTS
|
