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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
"""
X-Forwarded-For Proxy Fix
=========================
This module provides a middleware that adjusts the WSGI environ based on
``X-Forwarded-`` headers that proxies in front of an application may
set.
When an application is running behind a proxy server, WSGI may see the
request as coming from that server rather than the real client. Proxies
set various headers to track where the request actually came from.
This middleware should only be used if the application is actually
behind such a proxy, and should be configured with the number of proxies
that are chained in front of it. Not all proxies set all the headers.
Since incoming headers can be faked, you must set how many proxies are
setting each header so the middleware knows what to trust.
.. autoclass:: ProxyFix
:copyright: 2007 Pallets
:license: BSD-3-Clause
"""
import typing as t
from ..http import parse_list_header
if t.TYPE_CHECKING:
from _typeshed.wsgi import StartResponse
from _typeshed.wsgi import WSGIApplication
from _typeshed.wsgi import WSGIEnvironment
class ProxyFix:
"""Adjust the WSGI environ based on ``X-Forwarded-`` that proxies in
front of the application may set.
- ``X-Forwarded-For`` sets ``REMOTE_ADDR``.
- ``X-Forwarded-Proto`` sets ``wsgi.url_scheme``.
- ``X-Forwarded-Host`` sets ``HTTP_HOST``, ``SERVER_NAME``, and
``SERVER_PORT``.
- ``X-Forwarded-Port`` sets ``HTTP_HOST`` and ``SERVER_PORT``.
- ``X-Forwarded-Prefix`` sets ``SCRIPT_NAME``.
You must tell the middleware how many proxies set each header so it
knows what values to trust. It is a security issue to trust values
that came from the client rather than a proxy.
The original values of the headers are stored in the WSGI
environ as ``werkzeug.proxy_fix.orig``, a dict.
:param app: The WSGI application to wrap.
:param x_for: Number of values to trust for ``X-Forwarded-For``.
:param x_proto: Number of values to trust for ``X-Forwarded-Proto``.
:param x_host: Number of values to trust for ``X-Forwarded-Host``.
:param x_port: Number of values to trust for ``X-Forwarded-Port``.
:param x_prefix: Number of values to trust for
``X-Forwarded-Prefix``.
.. code-block:: python
from werkzeug.middleware.proxy_fix import ProxyFix
# App is behind one proxy that sets the -For and -Host headers.
app = ProxyFix(app, x_for=1, x_host=1)
.. versionchanged:: 1.0
Deprecated code has been removed:
* The ``num_proxies`` argument and attribute.
* The ``get_remote_addr`` method.
* The environ keys ``orig_remote_addr``,
``orig_wsgi_url_scheme``, and ``orig_http_host``.
.. versionchanged:: 0.15
All headers support multiple values. The ``num_proxies``
argument is deprecated. Each header is configured with a
separate number of trusted proxies.
.. versionchanged:: 0.15
Original WSGI environ values are stored in the
``werkzeug.proxy_fix.orig`` dict. ``orig_remote_addr``,
``orig_wsgi_url_scheme``, and ``orig_http_host`` are deprecated
and will be removed in 1.0.
.. versionchanged:: 0.15
Support ``X-Forwarded-Port`` and ``X-Forwarded-Prefix``.
.. versionchanged:: 0.15
``X-Forwarded-Host`` and ``X-Forwarded-Port`` modify
``SERVER_NAME`` and ``SERVER_PORT``.
"""
def __init__(
self,
app: "WSGIApplication",
x_for: int = 1,
x_proto: int = 1,
x_host: int = 0,
x_port: int = 0,
x_prefix: int = 0,
) -> None:
self.app = app
self.x_for = x_for
self.x_proto = x_proto
self.x_host = x_host
self.x_port = x_port
self.x_prefix = x_prefix
def _get_real_value(self, trusted: int, value: t.Optional[str]) -> t.Optional[str]:
"""Get the real value from a list header based on the configured
number of trusted proxies.
:param trusted: Number of values to trust in the header.
:param value: Comma separated list header value to parse.
:return: The real value, or ``None`` if there are fewer values
than the number of trusted proxies.
.. versionchanged:: 1.0
Renamed from ``_get_trusted_comma``.
.. versionadded:: 0.15
"""
if not (trusted and value):
return None
values = parse_list_header(value)
if len(values) >= trusted:
return values[-trusted]
return None
def __call__(
self, environ: "WSGIEnvironment", start_response: "StartResponse"
) -> t.Iterable[bytes]:
"""Modify the WSGI environ based on the various ``Forwarded``
headers before calling the wrapped application. Store the
original environ values in ``werkzeug.proxy_fix.orig_{key}``.
"""
environ_get = environ.get
orig_remote_addr = environ_get("REMOTE_ADDR")
orig_wsgi_url_scheme = environ_get("wsgi.url_scheme")
orig_http_host = environ_get("HTTP_HOST")
environ.update(
{
"werkzeug.proxy_fix.orig": {
"REMOTE_ADDR": orig_remote_addr,
"wsgi.url_scheme": orig_wsgi_url_scheme,
"HTTP_HOST": orig_http_host,
"SERVER_NAME": environ_get("SERVER_NAME"),
"SERVER_PORT": environ_get("SERVER_PORT"),
"SCRIPT_NAME": environ_get("SCRIPT_NAME"),
}
}
)
x_for = self._get_real_value(self.x_for, environ_get("HTTP_X_FORWARDED_FOR"))
if x_for:
environ["REMOTE_ADDR"] = x_for
x_proto = self._get_real_value(
self.x_proto, environ_get("HTTP_X_FORWARDED_PROTO")
)
if x_proto:
environ["wsgi.url_scheme"] = x_proto
x_host = self._get_real_value(self.x_host, environ_get("HTTP_X_FORWARDED_HOST"))
if x_host:
environ["HTTP_HOST"] = environ["SERVER_NAME"] = x_host
# "]" to check for IPv6 address without port
if ":" in x_host and not x_host.endswith("]"):
environ["SERVER_NAME"], environ["SERVER_PORT"] = x_host.rsplit(":", 1)
x_port = self._get_real_value(self.x_port, environ_get("HTTP_X_FORWARDED_PORT"))
if x_port:
host = environ.get("HTTP_HOST")
if host:
# "]" to check for IPv6 address without port
if ":" in host and not host.endswith("]"):
host = host.rsplit(":", 1)[0]
environ["HTTP_HOST"] = f"{host}:{x_port}"
environ["SERVER_PORT"] = x_port
x_prefix = self._get_real_value(
self.x_prefix, environ_get("HTTP_X_FORWARDED_PREFIX")
)
if x_prefix:
environ["SCRIPT_NAME"] = x_prefix
return self.app(environ, start_response)
|
