shell bypass 403
#
# Copyright 2009 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""HTTP utility code shared by clients and servers.
This module also defines the `HTTPServerRequest` class which is exposed
via `tornado.web.RequestHandler.request`.
"""
from __future__ import absolute_import, division, print_function, with_statement
import calendar
import collections
import copy
import datetime
import email.utils
import numbers
import re
import time
from tornado.escape import native_str, parse_qs_bytes, utf8
from tornado.log import gen_log
from tornado.util import ObjectDict, PY3
if PY3:
import http.cookies as Cookie
from http.client import responses
from urllib.parse import urlencode
else:
import Cookie
from httplib import responses
from urllib import urlencode
# responses is unused in this file, but we re-export it to other files.
# Reference it so pyflakes doesn't complain.
responses
try:
from ssl import SSLError
except ImportError:
# ssl is unavailable on app engine.
class _SSLError(Exception):
pass
# Hack around a mypy limitation. We can't simply put "type: ignore"
# on the class definition itself; must go through an assignment.
SSLError = _SSLError # type: ignore
try:
import typing
except ImportError:
pass
# RFC 7230 section 3.5: a recipient MAY recognize a single LF as a line
# terminator and ignore any preceding CR.
_CRLF_RE = re.compile(r'\r?\n')
class _NormalizedHeaderCache(dict):
"""Dynamic cached mapping of header names to Http-Header-Case.
Implemented as a dict subclass so that cache hits are as fast as a
normal dict lookup, without the overhead of a python function
call.
>>> normalized_headers = _NormalizedHeaderCache(10)
>>> normalized_headers["coNtent-TYPE"]
'Content-Type'
"""
def __init__(self, size):
super(_NormalizedHeaderCache, self).__init__()
self.size = size
self.queue = collections.deque()
def __missing__(self, key):
normalized = "-".join([w.capitalize() for w in key.split("-")])
self[key] = normalized
self.queue.append(key)
if len(self.queue) > self.size:
# Limit the size of the cache. LRU would be better, but this
# simpler approach should be fine. In Python 2.7+ we could
# use OrderedDict (or in 3.2+, @functools.lru_cache).
old_key = self.queue.popleft()
del self[old_key]
return normalized
_normalized_headers = _NormalizedHeaderCache(1000)
class HTTPHeaders(collections.MutableMapping):
"""A dictionary that maintains ``Http-Header-Case`` for all keys.
Supports multiple values per key via a pair of new methods,
`add()` and `get_list()`. The regular dictionary interface
returns a single value per key, with multiple values joined by a
comma.
>>> h = HTTPHeaders({"content-type": "text/html"})
>>> list(h.keys())
['Content-Type']
>>> h["Content-Type"]
'text/html'
>>> h.add("Set-Cookie", "A=B")
>>> h.add("Set-Cookie", "C=D")
>>> h["set-cookie"]
'A=B,C=D'
>>> h.get_list("set-cookie")
['A=B', 'C=D']
>>> for (k,v) in sorted(h.get_all()):
... print('%s: %s' % (k,v))
...
Content-Type: text/html
Set-Cookie: A=B
Set-Cookie: C=D
"""
def __init__(self, *args, **kwargs):
self._dict = {} # type: typing.Dict[str, str]
self._as_list = {} # type: typing.Dict[str, typing.List[str]]
self._last_key = None
if (len(args) == 1 and len(kwargs) == 0 and
isinstance(args[0], HTTPHeaders)):
# Copy constructor
for k, v in args[0].get_all():
self.add(k, v)
else:
# Dict-style initialization
self.update(*args, **kwargs)
# new public methods
def add(self, name, value):
# type: (str, str) -> None
"""Adds a new value for the given key."""
norm_name = _normalized_headers[name]
self._last_key = norm_name
if norm_name in self:
self._dict[norm_name] = (native_str(self[norm_name]) + ',' +
native_str(value))
self._as_list[norm_name].append(value)
else:
self[norm_name] = value
def get_list(self, name):
"""Returns all values for the given header as a list."""
norm_name = _normalized_headers[name]
return self._as_list.get(norm_name, [])
def get_all(self):
# type: () -> typing.Iterable[typing.Tuple[str, str]]
"""Returns an iterable of all (name, value) pairs.
If a header has multiple values, multiple pairs will be
returned with the same name.
"""
for name, values in self._as_list.items():
for value in values:
yield (name, value)
def parse_line(self, line):
"""Updates the dictionary with a single header line.
>>> h = HTTPHeaders()
>>> h.parse_line("Content-Type: text/html")
>>> h.get('content-type')
'text/html'
"""
if line[0].isspace():
# continuation of a multi-line header
new_part = ' ' + line.lstrip()
self._as_list[self._last_key][-1] += new_part
self._dict[self._last_key] += new_part
else:
name, value = line.split(":", 1)
self.add(name, value.strip())
@classmethod
def parse(cls, headers):
"""Returns a dictionary from HTTP header text.
>>> h = HTTPHeaders.parse("Content-Type: text/html\\r\\nContent-Length: 42\\r\\n")
>>> sorted(h.items())
[('Content-Length', '42'), ('Content-Type', 'text/html')]
"""
h = cls()
for line in _CRLF_RE.split(headers):
if line:
h.parse_line(line)
return h
# MutableMapping abstract method implementations.
def __setitem__(self, name, value):
norm_name = _normalized_headers[name]
self._dict[norm_name] = value
self._as_list[norm_name] = [value]
def __getitem__(self, name):
# type: (str) -> str
return self._dict[_normalized_headers[name]]
def __delitem__(self, name):
norm_name = _normalized_headers[name]
del self._dict[norm_name]
del self._as_list[norm_name]
def __len__(self):
return len(self._dict)
def __iter__(self):
return iter(self._dict)
def copy(self):
# defined in dict but not in MutableMapping.
return HTTPHeaders(self)
# Use our overridden copy method for the copy.copy module.
# This makes shallow copies one level deeper, but preserves
# the appearance that HTTPHeaders is a single container.
__copy__ = copy
def __str__(self):
lines = []
for name, value in self.get_all():
lines.append("%s: %s\n" % (name, value))
return "".join(lines)
__unicode__ = __str__
class HTTPServerRequest(object):
"""A single HTTP request.
All attributes are type `str` unless otherwise noted.
.. attribute:: method
HTTP request method, e.g. "GET" or "POST"
.. attribute:: uri
The requested uri.
.. attribute:: path
The path portion of `uri`
.. attribute:: query
The query portion of `uri`
.. attribute:: version
HTTP version specified in request, e.g. "HTTP/1.1"
.. attribute:: headers
`.HTTPHeaders` dictionary-like object for request headers. Acts like
a case-insensitive dictionary with additional methods for repeated
headers.
.. attribute:: body
Request body, if present, as a byte string.
.. attribute:: remote_ip
Client's IP address as a string. If ``HTTPServer.xheaders`` is set,
will pass along the real IP address provided by a load balancer
in the ``X-Real-Ip`` or ``X-Forwarded-For`` header.
.. versionchanged:: 3.1
The list format of ``X-Forwarded-For`` is now supported.
.. attribute:: protocol
The protocol used, either "http" or "https". If ``HTTPServer.xheaders``
is set, will pass along the protocol used by a load balancer if
reported via an ``X-Scheme`` header.
.. attribute:: host
The requested hostname, usually taken from the ``Host`` header.
.. attribute:: arguments
GET/POST arguments are available in the arguments property, which
maps arguments names to lists of values (to support multiple values
for individual names). Names are of type `str`, while arguments
are byte strings. Note that this is different from
`.RequestHandler.get_argument`, which returns argument values as
unicode strings.
.. attribute:: query_arguments
Same format as ``arguments``, but contains only arguments extracted
from the query string.
.. versionadded:: 3.2
.. attribute:: body_arguments
Same format as ``arguments``, but contains only arguments extracted
from the request body.
.. versionadded:: 3.2
.. attribute:: files
File uploads are available in the files property, which maps file
names to lists of `.HTTPFile`.
.. attribute:: connection
An HTTP request is attached to a single HTTP connection, which can
be accessed through the "connection" attribute. Since connections
are typically kept open in HTTP/1.1, multiple requests can be handled
sequentially on a single connection.
.. versionchanged:: 4.0
Moved from ``tornado.httpserver.HTTPRequest``.
"""
def __init__(self, method=None, uri=None, version="HTTP/1.0", headers=None,
body=None, host=None, files=None, connection=None,
start_line=None):
if start_line is not None:
method, uri, version = start_line
self.method = method
self.uri = uri
self.version = version
self.headers = headers or HTTPHeaders()
self.body = body or b""
# set remote IP and protocol
context = getattr(connection, 'context', None)
self.remote_ip = getattr(context, 'remote_ip', None)
self.protocol = getattr(context, 'protocol', "http")
self.host = host or self.headers.get("Host") or "127.0.0.1"
self.files = files or {}
self.connection = connection
self._start_time = time.time()
self._finish_time = None
self.path, sep, self.query = uri.partition('?')
self.arguments = parse_qs_bytes(self.query, keep_blank_values=True)
self.query_arguments = copy.deepcopy(self.arguments)
self.body_arguments = {}
def supports_http_1_1(self):
"""Returns True if this request supports HTTP/1.1 semantics.
.. deprecated:: 4.0
Applications are less likely to need this information with the
introduction of `.HTTPConnection`. If you still need it, access
the ``version`` attribute directly.
"""
return self.version == "HTTP/1.1"
@property
def cookies(self):
"""A dictionary of Cookie.Morsel objects."""
if not hasattr(self, "_cookies"):
self._cookies = Cookie.SimpleCookie()
if "Cookie" in self.headers:
try:
self._cookies.load(
native_str(self.headers["Cookie"]))
except Exception:
self._cookies = {}
return self._cookies
def write(self, chunk, callback=None):
"""Writes the given chunk to the response stream.
.. deprecated:: 4.0
Use ``request.connection`` and the `.HTTPConnection` methods
to write the response.
"""
assert isinstance(chunk, bytes)
assert self.version.startswith("HTTP/1."), \
"deprecated interface only supported in HTTP/1.x"
self.connection.write(chunk, callback=callback)
def finish(self):
"""Finishes this HTTP request on the open connection.
.. deprecated:: 4.0
Use ``request.connection`` and the `.HTTPConnection` methods
to write the response.
"""
self.connection.finish()
self._finish_time = time.time()
def full_url(self):
"""Reconstructs the full URL for this request."""
return self.protocol + "://" + self.host + self.uri
def request_time(self):
"""Returns the amount of time it took for this request to execute."""
if self._finish_time is None:
return time.time() - self._start_time
else:
return self._finish_time - self._start_time
def get_ssl_certificate(self, binary_form=False):
"""Returns the client's SSL certificate, if any.
To use client certificates, the HTTPServer's
`ssl.SSLContext.verify_mode` field must be set, e.g.::
ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
ssl_ctx.load_cert_chain("foo.crt", "foo.key")
ssl_ctx.load_verify_locations("cacerts.pem")
ssl_ctx.verify_mode = ssl.CERT_REQUIRED
server = HTTPServer(app, ssl_options=ssl_ctx)
By default, the return value is a dictionary (or None, if no
client certificate is present). If ``binary_form`` is true, a
DER-encoded form of the certificate is returned instead. See
SSLSocket.getpeercert() in the standard library for more
details.
http://docs.python.org/library/ssl.html#sslsocket-objects
"""
try:
return self.connection.stream.socket.getpeercert(
binary_form=binary_form)
except SSLError:
return None
def _parse_body(self):
parse_body_arguments(
self.headers.get("Content-Type", ""), self.body,
self.body_arguments, self.files,
self.headers)
for k, v in self.body_arguments.items():
self.arguments.setdefault(k, []).extend(v)
def __repr__(self):
attrs = ("protocol", "host", "method", "uri", "version", "remote_ip")
args = ", ".join(["%s=%r" % (n, getattr(self, n)) for n in attrs])
return "%s(%s, headers=%s)" % (
self.__class__.__name__, args, dict(self.headers))
class HTTPInputError(Exception):
"""Exception class for malformed HTTP requests or responses
from remote sources.
.. versionadded:: 4.0
"""
pass
class HTTPOutputError(Exception):
"""Exception class for errors in HTTP output.
.. versionadded:: 4.0
"""
pass
class HTTPServerConnectionDelegate(object):
"""Implement this interface to handle requests from `.HTTPServer`.
.. versionadded:: 4.0
"""
def start_request(self, server_conn, request_conn):
"""This method is called by the server when a new request has started.
:arg server_conn: is an opaque object representing the long-lived
(e.g. tcp-level) connection.
:arg request_conn: is a `.HTTPConnection` object for a single
request/response exchange.
This method should return a `.HTTPMessageDelegate`.
"""
raise NotImplementedError()
def on_close(self, server_conn):
"""This method is called when a connection has been closed.
:arg server_conn: is a server connection that has previously been
passed to ``start_request``.
"""
pass
class HTTPMessageDelegate(object):
"""Implement this interface to handle an HTTP request or response.
.. versionadded:: 4.0
"""
def headers_received(self, start_line, headers):
"""Called when the HTTP headers have been received and parsed.
:arg start_line: a `.RequestStartLine` or `.ResponseStartLine`
depending on whether this is a client or server message.
:arg headers: a `.HTTPHeaders` instance.
Some `.HTTPConnection` methods can only be called during
``headers_received``.
May return a `.Future`; if it does the body will not be read
until it is done.
"""
pass
def data_received(self, chunk):
"""Called when a chunk of data has been received.
May return a `.Future` for flow control.
"""
pass
def finish(self):
"""Called after the last chunk of data has been received."""
pass
def on_connection_close(self):
"""Called if the connection is closed without finishing the request.
If ``headers_received`` is called, either ``finish`` or
``on_connection_close`` will be called, but not both.
"""
pass
class HTTPConnection(object):
"""Applications use this interface to write their responses.
.. versionadded:: 4.0
"""
def write_headers(self, start_line, headers, chunk=None, callback=None):
"""Write an HTTP header block.
:arg start_line: a `.RequestStartLine` or `.ResponseStartLine`.
:arg headers: a `.HTTPHeaders` instance.
:arg chunk: the first (optional) chunk of data. This is an optimization
so that small responses can be written in the same call as their
headers.
:arg callback: a callback to be run when the write is complete.
The ``version`` field of ``start_line`` is ignored.
Returns a `.Future` if no callback is given.
"""
raise NotImplementedError()
def write(self, chunk, callback=None):
"""Writes a chunk of body data.
The callback will be run when the write is complete. If no callback
is given, returns a Future.
"""
raise NotImplementedError()
def finish(self):
"""Indicates that the last body data has been written.
"""
raise NotImplementedError()
def url_concat(url, args):
"""Concatenate url and arguments regardless of whether
url has existing query parameters.
``args`` may be either a dictionary or a list of key-value pairs
(the latter allows for multiple values with the same key.
>>> url_concat("http://example.com/foo", dict(c="d"))
'http://example.com/foo?c=d'
>>> url_concat("http://example.com/foo?a=b", dict(c="d"))
'http://example.com/foo?a=b&c=d'
>>> url_concat("http://example.com/foo?a=b", [("c", "d"), ("c", "d2")])
'http://example.com/foo?a=b&c=d&c=d2'
"""
if not args:
return url
if url[-1] not in ('?', '&'):
url += '&' if ('?' in url) else '?'
return url + urlencode(args)
class HTTPFile(ObjectDict):
"""Represents a file uploaded via a form.
For backwards compatibility, its instance attributes are also
accessible as dictionary keys.
* ``filename``
* ``body``
* ``content_type``
"""
pass
def _parse_request_range(range_header):
"""Parses a Range header.
Returns either ``None`` or tuple ``(start, end)``.
Note that while the HTTP headers use inclusive byte positions,
this method returns indexes suitable for use in slices.
>>> start, end = _parse_request_range("bytes=1-2")
>>> start, end
(1, 3)
>>> [0, 1, 2, 3, 4][start:end]
[1, 2]
>>> _parse_request_range("bytes=6-")
(6, None)
>>> _parse_request_range("bytes=-6")
(-6, None)
>>> _parse_request_range("bytes=-0")
(None, 0)
>>> _parse_request_range("bytes=")
(None, None)
>>> _parse_request_range("foo=42")
>>> _parse_request_range("bytes=1-2,6-10")
Note: only supports one range (ex, ``bytes=1-2,6-10`` is not allowed).
See [0] for the details of the range header.
[0]: http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p5-range-latest.html#byte.ranges
"""
unit, _, value = range_header.partition("=")
unit, value = unit.strip(), value.strip()
if unit != "bytes":
return None
start_b, _, end_b = value.partition("-")
try:
start = _int_or_none(start_b)
end = _int_or_none(end_b)
except ValueError:
return None
if end is not None:
if start is None:
if end != 0:
start = -end
end = None
else:
end += 1
return (start, end)
def _get_content_range(start, end, total):
"""Returns a suitable Content-Range header:
>>> print(_get_content_range(None, 1, 4))
bytes 0-0/4
>>> print(_get_content_range(1, 3, 4))
bytes 1-2/4
>>> print(_get_content_range(None, None, 4))
bytes 0-3/4
"""
start = start or 0
end = (end or total) - 1
return "bytes %s-%s/%s" % (start, end, total)
def _int_or_none(val):
val = val.strip()
if val == "":
return None
return int(val)
def parse_body_arguments(content_type, body, arguments, files, headers=None):
"""Parses a form request body.
Supports ``application/x-www-form-urlencoded`` and
``multipart/form-data``. The ``content_type`` parameter should be
a string and ``body`` should be a byte string. The ``arguments``
and ``files`` parameters are dictionaries that will be updated
with the parsed contents.
"""
if headers and 'Content-Encoding' in headers:
gen_log.warning("Unsupported Content-Encoding: %s",
headers['Content-Encoding'])
return
if content_type.startswith("application/x-www-form-urlencoded"):
try:
uri_arguments = parse_qs_bytes(native_str(body), keep_blank_values=True)
except Exception as e:
gen_log.warning('Invalid x-www-form-urlencoded body: %s', e)
uri_arguments = {}
for name, values in uri_arguments.items():
if values:
arguments.setdefault(name, []).extend(values)
elif content_type.startswith("multipart/form-data"):
try:
fields = content_type.split(";")
for field in fields:
k, sep, v = field.strip().partition("=")
if k == "boundary" and v:
parse_multipart_form_data(utf8(v), body, arguments, files)
break
else:
raise ValueError("multipart boundary not found")
except Exception as e:
gen_log.warning("Invalid multipart/form-data: %s", e)
def parse_multipart_form_data(boundary, data, arguments, files):
"""Parses a ``multipart/form-data`` body.
The ``boundary`` and ``data`` parameters are both byte strings.
The dictionaries given in the arguments and files parameters
will be updated with the contents of the body.
"""
# The standard allows for the boundary to be quoted in the header,
# although it's rare (it happens at least for google app engine
# xmpp). I think we're also supposed to handle backslash-escapes
# here but I'll save that until we see a client that uses them
# in the wild.
if boundary.startswith(b'"') and boundary.endswith(b'"'):
boundary = boundary[1:-1]
final_boundary_index = data.rfind(b"--" + boundary + b"--")
if final_boundary_index == -1:
gen_log.warning("Invalid multipart/form-data: no final boundary")
return
parts = data[:final_boundary_index].split(b"--" + boundary + b"\r\n")
for part in parts:
if not part:
continue
eoh = part.find(b"\r\n\r\n")
if eoh == -1:
gen_log.warning("multipart/form-data missing headers")
continue
headers = HTTPHeaders.parse(part[:eoh].decode("utf-8"))
disp_header = headers.get("Content-Disposition", "")
disposition, disp_params = _parse_header(disp_header)
if disposition != "form-data" or not part.endswith(b"\r\n"):
gen_log.warning("Invalid multipart/form-data")
continue
value = part[eoh + 4:-2]
if not disp_params.get("name"):
gen_log.warning("multipart/form-data value missing name")
continue
name = disp_params["name"]
if disp_params.get("filename"):
ctype = headers.get("Content-Type", "application/unknown")
files.setdefault(name, []).append(HTTPFile( # type: ignore
filename=disp_params["filename"], body=value,
content_type=ctype))
else:
arguments.setdefault(name, []).append(value)
def format_timestamp(ts):
"""Formats a timestamp in the format used by HTTP.
The argument may be a numeric timestamp as returned by `time.time`,
a time tuple as returned by `time.gmtime`, or a `datetime.datetime`
object.
>>> format_timestamp(1359312200)
'Sun, 27 Jan 2013 18:43:20 GMT'
"""
if isinstance(ts, numbers.Real):
pass
elif isinstance(ts, (tuple, time.struct_time)):
ts = calendar.timegm(ts)
elif isinstance(ts, datetime.datetime):
ts = calendar.timegm(ts.utctimetuple())
else:
raise TypeError("unknown timestamp type: %r" % ts)
return email.utils.formatdate(ts, usegmt=True)
RequestStartLine = collections.namedtuple(
'RequestStartLine', ['method', 'path', 'version'])
def parse_request_start_line(line):
"""Returns a (method, path, version) tuple for an HTTP 1.x request line.
The response is a `collections.namedtuple`.
>>> parse_request_start_line("GET /foo HTTP/1.1")
RequestStartLine(method='GET', path='/foo', version='HTTP/1.1')
"""
try:
method, path, version = line.split(" ")
except ValueError:
raise HTTPInputError("Malformed HTTP request line")
if not re.match(r"^HTTP/1\.[0-9]$", version):
raise HTTPInputError(
"Malformed HTTP version in HTTP Request-Line: %r" % version)
return RequestStartLine(method, path, version)
ResponseStartLine = collections.namedtuple(
'ResponseStartLine', ['version', 'code', 'reason'])
def parse_response_start_line(line):
"""Returns a (version, code, reason) tuple for an HTTP 1.x response line.
The response is a `collections.namedtuple`.
>>> parse_response_start_line("HTTP/1.1 200 OK")
ResponseStartLine(version='HTTP/1.1', code=200, reason='OK')
"""
line = native_str(line)
match = re.match("(HTTP/1.[0-9]) ([0-9]+) ([^\r]*)", line)
if not match:
raise HTTPInputError("Error parsing response start line")
return ResponseStartLine(match.group(1), int(match.group(2)),
match.group(3))
# _parseparam and _parse_header are copied and modified from python2.7's cgi.py
# The original 2.7 version of this code did not correctly support some
# combinations of semicolons and double quotes.
# It has also been modified to support valueless parameters as seen in
# websocket extension negotiations.
def _parseparam(s):
while s[:1] == ';':
s = s[1:]
end = s.find(';')
while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
end = s.find(';', end + 1)
if end < 0:
end = len(s)
f = s[:end]
yield f.strip()
s = s[end:]
def _parse_header(line):
"""Parse a Content-type like header.
Return the main content-type and a dictionary of options.
"""
parts = _parseparam(';' + line)
key = next(parts)
pdict = {}
for p in parts:
i = p.find('=')
if i >= 0:
name = p[:i].strip().lower()
value = p[i + 1:].strip()
if len(value) >= 2 and value[0] == value[-1] == '"':
value = value[1:-1]
value = value.replace('\\\\', '\\').replace('\\"', '"')
pdict[name] = value
else:
pdict[p] = None
return key, pdict
def _encode_header(key, pdict):
"""Inverse of _parse_header.
>>> _encode_header('permessage-deflate',
... {'client_max_window_bits': 15, 'client_no_context_takeover': None})
'permessage-deflate; client_max_window_bits=15; client_no_context_takeover'
"""
if not pdict:
return key
out = [key]
# Sort the parameters just to make it easy to test.
for k, v in sorted(pdict.items()):
if v is None:
out.append(k)
else:
# TODO: quote if necessary.
out.append('%s=%s' % (k, v))
return '; '.join(out)
def doctests():
import doctest
return doctest.DocTestSuite()
def split_host_and_port(netloc):
"""Returns ``(host, port)`` tuple from ``netloc``.
Returned ``port`` will be ``None`` if not present.
.. versionadded:: 4.1
"""
match = re.match(r'^(.+):(\d+)$', netloc)
if match:
host = match.group(1)
port = int(match.group(2))
else:
host = netloc
port = None
return (host, port)