mitmproxy/libmproxy/protocol/http_wrappers.py
2015-07-30 13:53:17 +02:00

830 lines
26 KiB
Python

from __future__ import absolute_import
import Cookie
import copy
import threading
import time
import urllib
import urlparse
from email.utils import parsedate_tz, formatdate, mktime_tz
import netlib
from netlib import http, tcp, odict, utils
from netlib.http import cookies, semantics, http1
from .tcp import TCPHandler
from .primitives import KILL, ProtocolHandler, Flow, Error
from ..proxy.connection import ServerConnection
from .. import encoding, utils, controller, stateobject, proxy
HDR_FORM_URLENCODED = "application/x-www-form-urlencoded"
HDR_FORM_MULTIPART = "multipart/form-data"
CONTENT_MISSING = 0
class decoded(object):
"""
A context manager that decodes a request or response, and then
re-encodes it with the same encoding after execution of the block.
Example:
with decoded(request):
request.content = request.content.replace("foo", "bar")
"""
def __init__(self, o):
self.o = o
ce = o.headers.get_first("content-encoding")
if ce in encoding.ENCODINGS:
self.ce = ce
else:
self.ce = None
def __enter__(self):
if self.ce:
self.o.decode()
def __exit__(self, type, value, tb):
if self.ce:
self.o.encode(self.ce)
class MessageMixin(stateobject.StateObject):
_stateobject_attributes = dict(
httpversion=tuple,
headers=odict.ODictCaseless,
body=str,
timestamp_start=float,
timestamp_end=float
)
_stateobject_long_attributes = {"body"}
def get_state(self, short=False):
ret = super(MessageMixin, self).get_state(short)
if short:
if self.body:
ret["contentLength"] = len(self.body)
elif self.body == CONTENT_MISSING:
ret["contentLength"] = None
else:
ret["contentLength"] = 0
return ret
def get_decoded_content(self):
"""
Returns the decoded content based on the current Content-Encoding
header.
Doesn't change the message iteself or its headers.
"""
ce = self.headers.get_first("content-encoding")
if not self.body or ce not in encoding.ENCODINGS:
return self.body
return encoding.decode(ce, self.body)
def decode(self):
"""
Decodes body based on the current Content-Encoding header, then
removes the header. If there is no Content-Encoding header, no
action is taken.
Returns True if decoding succeeded, False otherwise.
"""
ce = self.headers.get_first("content-encoding")
if not self.body or ce not in encoding.ENCODINGS:
return False
data = encoding.decode(ce, self.body)
if data is None:
return False
self.body = data
del self.headers["content-encoding"]
return True
def encode(self, e):
"""
Encodes body with the encoding e, where e is "gzip", "deflate"
or "identity".
"""
# FIXME: Error if there's an existing encoding header?
self.body = encoding.encode(e, self.body)
self.headers["content-encoding"] = [e]
def size(self, **kwargs):
"""
Size in bytes of a fully rendered message, including headers and
HTTP lead-in.
"""
hl = len(self._assemble_head(**kwargs))
if self.body:
return hl + len(self.body)
else:
return hl
def copy(self):
c = copy.copy(self)
c.headers = self.headers.copy()
return c
def replace(self, pattern, repl, *args, **kwargs):
"""
Replaces a regular expression pattern with repl in both the headers
and the body of the message. Encoded body will be decoded
before replacement, and re-encoded afterwards.
Returns the number of replacements made.
"""
with decoded(self):
self.body, c = utils.safe_subn(
pattern, repl, self.body, *args, **kwargs
)
c += self.headers.replace(pattern, repl, *args, **kwargs)
return c
def _assemble_first_line(self):
"""
Returns the assembled request/response line
"""
raise NotImplementedError() # pragma: nocover
def _assemble_headers(self):
"""
Returns the assembled headers
"""
raise NotImplementedError() # pragma: nocover
def _assemble_head(self):
"""
Returns the assembled request/response line plus headers
"""
raise NotImplementedError() # pragma: nocover
def assemble(self):
"""
Returns the assembled request/response
"""
raise NotImplementedError() # pragma: nocover
class HTTPRequest(MessageMixin, semantics.Request):
"""
An HTTP request.
Exposes the following attributes:
method: HTTP method
scheme: URL scheme (http/https)
host: Target hostname of the request. This is not neccessarily the
directy upstream server (which could be another proxy), but it's always
the target server we want to reach at the end. This attribute is either
inferred from the request itself (absolute-form, authority-form) or from
the connection metadata (e.g. the host in reverse proxy mode).
port: Destination port
path: Path portion of the URL (not present in authority-form)
httpversion: HTTP version tuple, e.g. (1,1)
headers: odict.ODictCaseless object
content: Content of the request, None, or CONTENT_MISSING if there
is content associated, but not present. CONTENT_MISSING evaluates
to False to make checking for the presence of content natural.
form_in: The request form which mitmproxy has received. The following
values are possible:
- relative (GET /index.html, OPTIONS *) (covers origin form and
asterisk form)
- absolute (GET http://example.com:80/index.html)
- authority-form (CONNECT example.com:443)
Details: http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-25#section-5.3
form_out: The request form which mitmproxy will send out to the
destination
timestamp_start: Timestamp indicating when request transmission started
timestamp_end: Timestamp indicating when request transmission ended
"""
def __init__(
self,
form_in,
method,
scheme,
host,
port,
path,
httpversion,
headers,
body,
timestamp_start=None,
timestamp_end=None,
form_out=None,
):
semantics.Request.__init__(
self,
form_in,
method,
scheme,
host,
port,
path,
httpversion,
headers,
body,
timestamp_start,
timestamp_end,
)
self.form_out = form_out or form_in
# Have this request's cookies been modified by sticky cookies or auth?
self.stickycookie = False
self.stickyauth = False
# Is this request replayed?
self.is_replay = False
_stateobject_attributes = MessageMixin._stateobject_attributes.copy()
_stateobject_attributes.update(
form_in=str,
method=str,
scheme=str,
host=str,
port=int,
path=str,
form_out=str,
is_replay=bool
)
# This list is adopted legacy code.
# We probably don't need to strip off keep-alive.
_headers_to_strip_off = ['Proxy-Connection',
'Keep-Alive',
'Connection',
'Transfer-Encoding',
'Upgrade']
@classmethod
def from_state(cls, state):
f = cls(
None,
None,
None,
None,
None,
None,
None,
None,
None,
None,
None)
f.load_state(state)
return f
def __repr__(self):
return "<HTTPRequest: {0}>".format(
self._assemble_first_line(self.form_in)[:-9]
)
@classmethod
def from_protocol(
self,
protocol,
include_body=True,
body_size_limit=None,
):
req = protocol.read_request(
include_body = include_body,
body_size_limit = body_size_limit,
)
return HTTPRequest(
req.form_in,
req.method,
req.scheme,
req.host,
req.port,
req.path,
req.httpversion,
req.headers,
req.body,
req.timestamp_start,
req.timestamp_end,
)
def _assemble_first_line(self, form=None):
form = form or self.form_out
if form == "relative":
request_line = '%s %s HTTP/%s.%s' % (
self.method, self.path, self.httpversion[0], self.httpversion[1]
)
elif form == "authority":
request_line = '%s %s:%s HTTP/%s.%s' % (
self.method, self.host, self.port, self.httpversion[0],
self.httpversion[1]
)
elif form == "absolute":
request_line = '%s %s://%s:%s%s HTTP/%s.%s' % (
self.method, self.scheme, self.host,
self.port, self.path, self.httpversion[0],
self.httpversion[1]
)
else:
raise http.HttpError(400, "Invalid request form")
return request_line
def _assemble_headers(self):
headers = self.headers.copy()
for k in self._headers_to_strip_off:
del headers[k]
if 'host' not in headers and self.scheme and self.host and self.port:
headers["Host"] = [utils.hostport(self.scheme,
self.host,
self.port)]
# If content is defined (i.e. not None or CONTENT_MISSING), we always
# add a content-length header.
if self.body or self.body == "":
headers["Content-Length"] = [str(len(self.body))]
return headers.format()
def _assemble_head(self, form=None):
return "%s\r\n%s\r\n" % (
self._assemble_first_line(form), self._assemble_headers()
)
def assemble(self, form=None):
"""
Assembles the request for transmission to the server. We make some
modifications to make sure interception works properly.
Raises an Exception if the request cannot be assembled.
"""
if self.body == CONTENT_MISSING:
raise proxy.ProxyError(
502,
"Cannot assemble flow with CONTENT_MISSING"
)
head = self._assemble_head(form)
if self.body:
return head + self.body
else:
return head
def __hash__(self):
return id(self)
def anticache(self):
"""
Modifies this request to remove headers that might produce a cached
response. That is, we remove ETags and If-Modified-Since headers.
"""
delheaders = [
"if-modified-since",
"if-none-match",
]
for i in delheaders:
del self.headers[i]
def anticomp(self):
"""
Modifies this request to remove headers that will compress the
resource's data.
"""
self.headers["accept-encoding"] = ["identity"]
def constrain_encoding(self):
"""
Limits the permissible Accept-Encoding values, based on what we can
decode appropriately.
"""
if self.headers["accept-encoding"]:
self.headers["accept-encoding"] = [
', '.join(
e for e in encoding.ENCODINGS if e in self.headers["accept-encoding"][0])]
def update_host_header(self):
"""
Update the host header to reflect the current target.
"""
self.headers["Host"] = [self.host]
def get_form(self):
"""
Retrieves the URL-encoded or multipart form data, returning an ODict object.
Returns an empty ODict if there is no data or the content-type
indicates non-form data.
"""
if self.body:
if self.headers.in_any("content-type", HDR_FORM_URLENCODED, True):
return self.get_form_urlencoded()
elif self.headers.in_any("content-type", HDR_FORM_MULTIPART, True):
return self.get_form_multipart()
return odict.ODict([])
def get_form_urlencoded(self):
"""
Retrieves the URL-encoded form data, returning an ODict object.
Returns an empty ODict if there is no data or the content-type
indicates non-form data.
"""
if self.body and self.headers.in_any(
"content-type",
HDR_FORM_URLENCODED,
True):
return odict.ODict(utils.urldecode(self.body))
return odict.ODict([])
def get_form_multipart(self):
if self.body and self.headers.in_any(
"content-type",
HDR_FORM_MULTIPART,
True):
return odict.ODict(
utils.multipartdecode(
self.headers,
self.body))
return odict.ODict([])
def set_form_urlencoded(self, odict):
"""
Sets the body to the URL-encoded form data, and adds the
appropriate content-type header. Note that this will destory the
existing body if there is one.
"""
# FIXME: If there's an existing content-type header indicating a
# url-encoded form, leave it alone.
self.headers["Content-Type"] = [HDR_FORM_URLENCODED]
self.body = utils.urlencode(odict.lst)
def get_path_components(self):
"""
Returns the path components of the URL as a list of strings.
Components are unquoted.
"""
_, _, path, _, _, _ = urlparse.urlparse(self.url)
return [urllib.unquote(i) for i in path.split("/") if i]
def set_path_components(self, lst):
"""
Takes a list of strings, and sets the path component of the URL.
Components are quoted.
"""
lst = [urllib.quote(i, safe="") for i in lst]
path = "/" + "/".join(lst)
scheme, netloc, _, params, query, fragment = urlparse.urlparse(self.url)
self.url = urlparse.urlunparse(
[scheme, netloc, path, params, query, fragment]
)
def get_query(self):
"""
Gets the request query string. Returns an ODict object.
"""
_, _, _, _, query, _ = urlparse.urlparse(self.url)
if query:
return odict.ODict(utils.urldecode(query))
return odict.ODict([])
def set_query(self, odict):
"""
Takes an ODict object, and sets the request query string.
"""
scheme, netloc, path, params, _, fragment = urlparse.urlparse(self.url)
query = utils.urlencode(odict.lst)
self.url = urlparse.urlunparse(
[scheme, netloc, path, params, query, fragment]
)
def pretty_host(self, hostheader):
"""
Heuristic to get the host of the request.
Note that pretty_host() does not always return the TCP destination
of the request, e.g. if an upstream proxy is in place
If hostheader is set to True, the Host: header will be used as
additional (and preferred) data source. This is handy in
transparent mode, where only the IO of the destination is known,
but not the resolved name. This is disabled by default, as an
attacker may spoof the host header to confuse an analyst.
"""
host = None
if hostheader:
host = self.headers.get_first("host")
if not host:
host = self.host
if host:
try:
return host.encode("idna")
except ValueError:
return host
else:
return None
def pretty_url(self, hostheader):
if self.form_out == "authority": # upstream proxy mode
return "%s:%s" % (self.pretty_host(hostheader), self.port)
return utils.unparse_url(self.scheme,
self.pretty_host(hostheader),
self.port,
self.path).encode('ascii')
@property
def url(self):
"""
Returns a URL string, constructed from the Request's URL components.
"""
return utils.unparse_url(
self.scheme,
self.host,
self.port,
self.path
).encode('ascii')
@url.setter
def url(self, url):
"""
Parses a URL specification, and updates the Request's information
accordingly.
Returns False if the URL was invalid, True if the request succeeded.
"""
parts = http.parse_url(url)
if not parts:
raise ValueError("Invalid URL: %s" % url)
self.scheme, self.host, self.port, self.path = parts
def get_cookies(self):
"""
Returns a possibly empty netlib.odict.ODict object.
"""
ret = odict.ODict()
for i in self.headers["cookie"]:
ret.extend(cookies.parse_cookie_header(i))
return ret
def set_cookies(self, odict):
"""
Takes an netlib.odict.ODict object. Over-writes any existing Cookie
headers.
"""
v = cookies.format_cookie_header(odict)
self.headers["Cookie"] = [v]
def replace(self, pattern, repl, *args, **kwargs):
"""
Replaces a regular expression pattern with repl in the headers, the
request path and the body of the request. Encoded content will be
decoded before replacement, and re-encoded afterwards.
Returns the number of replacements made.
"""
c = MessageMixin.replace(self, pattern, repl, *args, **kwargs)
self.path, pc = utils.safe_subn(
pattern, repl, self.path, *args, **kwargs
)
c += pc
return c
class HTTPResponse(MessageMixin, semantics.Response):
"""
An HTTP response.
Exposes the following attributes:
httpversion: HTTP version tuple, e.g. (1, 0), (1, 1), or (2, 0)
status_code: HTTP response status code
msg: HTTP response message
headers: ODict Caseless object
content: Content of the request, None, or CONTENT_MISSING if there
is content associated, but not present. CONTENT_MISSING evaluates
to False to make checking for the presence of content natural.
timestamp_start: Timestamp indicating when request transmission started
timestamp_end: Timestamp indicating when request transmission ended
"""
def __init__(
self,
httpversion,
status_code,
msg,
headers,
body,
timestamp_start=None,
timestamp_end=None,
):
semantics.Response.__init__(
self,
httpversion,
status_code,
msg,
headers,
body,
timestamp_start=timestamp_start,
timestamp_end=timestamp_end,
)
# Is this request replayed?
self.is_replay = False
self.stream = False
_stateobject_attributes = MessageMixin._stateobject_attributes.copy()
_stateobject_attributes.update(
code=int,
msg=str
)
_headers_to_strip_off = ['Proxy-Connection',
'Alternate-Protocol',
'Alt-Svc']
@classmethod
def from_state(cls, state):
f = cls(None, None, None, None, None)
f.load_state(state)
return f
def __repr__(self):
if self.body:
size = netlib.utils.pretty_size(len(self.body))
else:
size = "content missing"
return "<HTTPResponse: {status_code} {msg} ({contenttype}, {size})>".format(
status_code=self.status_code,
msg=self.msg,
contenttype=self.headers.get_first(
"content-type", "unknown content type"
),
size=size
)
@classmethod
def from_protocol(
self,
protocol,
request_method,
include_body=True,
body_size_limit=None
):
resp = protocol.read_response(
request_method,
body_size_limit,
include_body=include_body
)
return HTTPResponse(
resp.httpversion,
resp.status_code,
resp.msg,
resp.headers,
resp.body,
resp.timestamp_start,
resp.timestamp_end,
)
def _assemble_first_line(self):
return 'HTTP/%s.%s %s %s' % \
(self.httpversion[0], self.httpversion[1], self.code, self.msg)
def _assemble_headers(self, preserve_transfer_encoding=False):
headers = self.headers.copy()
for k in self._headers_to_strip_off:
del headers[k]
if not preserve_transfer_encoding:
del headers['Transfer-Encoding']
# If body is defined (i.e. not None or CONTENT_MISSING), we always
# add a content-length header.
if self.body or self.body == "":
headers["Content-Length"] = [str(len(self.body))]
return headers.format()
def _assemble_head(self, preserve_transfer_encoding=False):
return '%s\r\n%s\r\n' % (
self._assemble_first_line(),
self._assemble_headers(
preserve_transfer_encoding=preserve_transfer_encoding
)
)
def assemble(self):
"""
Assembles the response for transmission to the client. We make some
modifications to make sure interception works properly.
Raises an Exception if the request cannot be assembled.
"""
if self.body == CONTENT_MISSING:
raise proxy.ProxyError(
502,
"Cannot assemble flow with CONTENT_MISSING"
)
head = self._assemble_head()
if self.body:
return head + self.body
else:
return head
def _refresh_cookie(self, c, delta):
"""
Takes a cookie string c and a time delta in seconds, and returns
a refreshed cookie string.
"""
c = Cookie.SimpleCookie(str(c))
for i in c.values():
if "expires" in i:
d = parsedate_tz(i["expires"])
if d:
d = mktime_tz(d) + delta
i["expires"] = formatdate(d)
else:
# This can happen when the expires tag is invalid.
# reddit.com sends a an expires tag like this: "Thu, 31 Dec
# 2037 23:59:59 GMT", which is valid RFC 1123, but not
# strictly correct according to the cookie spec. Browsers
# appear to parse this tolerantly - maybe we should too.
# For now, we just ignore this.
del i["expires"]
return c.output(header="").strip()
def refresh(self, now=None):
"""
This fairly complex and heuristic function refreshes a server
response for replay.
- It adjusts date, expires and last-modified headers.
- It adjusts cookie expiration.
"""
if not now:
now = time.time()
delta = now - self.timestamp_start
refresh_headers = [
"date",
"expires",
"last-modified",
]
for i in refresh_headers:
if i in self.headers:
d = parsedate_tz(self.headers[i][0])
if d:
new = mktime_tz(d) + delta
self.headers[i] = [formatdate(new)]
c = []
for i in self.headers["set-cookie"]:
c.append(self._refresh_cookie(i, delta))
if c:
self.headers["set-cookie"] = c
def get_cookies(self):
"""
Get the contents of all Set-Cookie headers.
Returns a possibly empty ODict, where keys are cookie name strings,
and values are [value, attr] lists. Value is a string, and attr is
an ODictCaseless containing cookie attributes. Within attrs, unary
attributes (e.g. HTTPOnly) are indicated by a Null value.
"""
ret = []
for header in self.headers["set-cookie"]:
v = http.cookies.parse_set_cookie_header(header)
if v:
name, value, attrs = v
ret.append([name, [value, attrs]])
return odict.ODict(ret)
def set_cookies(self, odict):
"""
Set the Set-Cookie headers on this response, over-writing existing
headers.
Accepts an ODict of the same format as that returned by get_cookies.
"""
values = []
for i in odict.lst:
values.append(
http.cookies.format_set_cookie_header(
i[0],
i[1][0],
i[1][1]
)
)
self.headers["Set-Cookie"] = values