mitmproxy/netlib/http/http1/protocol.py
2015-07-22 15:30:51 +02:00

485 lines
15 KiB
Python

from __future__ import (absolute_import, print_function, division)
import binascii
import collections
import string
import sys
import urlparse
from netlib import odict, utils, tcp, http
from .. import status_codes
from ..exceptions import *
class HTTP1Protocol(object):
def __init__(self, tcp_handler):
self.tcp_handler = tcp_handler
def get_request_line(self):
"""
Get a line, possibly preceded by a blank.
"""
line = self.tcp_handler.rfile.readline()
if line == "\r\n" or line == "\n":
# Possible leftover from previous message
line = self.tcp_handler.rfile.readline()
return line
def read_headers(self):
"""
Read a set of headers.
Stop once a blank line is reached.
Return a ODictCaseless object, or None if headers are invalid.
"""
ret = []
name = ''
while True:
line = self.tcp_handler.rfile.readline()
if not line or line == '\r\n' or line == '\n':
break
if line[0] in ' \t':
if not ret:
return None
# continued header
ret[-1][1] = ret[-1][1] + '\r\n ' + line.strip()
else:
i = line.find(':')
# We're being liberal in what we accept, here.
if i > 0:
name = line[:i]
value = line[i + 1:].strip()
ret.append([name, value])
else:
return None
return odict.ODictCaseless(ret)
def read_chunked(self, limit, is_request):
"""
Read a chunked HTTP body.
May raise HttpError.
"""
# FIXME: Should check if chunked is the final encoding in the headers
# http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-16#section-3.3
# 3.3 2.
total = 0
code = 400 if is_request else 502
while True:
line = self.tcp_handler.rfile.readline(128)
if line == "":
raise HttpErrorConnClosed(code, "Connection closed prematurely")
if line != '\r\n' and line != '\n':
try:
length = int(line, 16)
except ValueError:
raise HttpError(
code,
"Invalid chunked encoding length: %s" % line
)
total += length
if limit is not None and total > limit:
msg = "HTTP Body too large. Limit is %s," \
" chunked content longer than %s" % (limit, total)
raise HttpError(code, msg)
chunk = self.tcp_handler.rfile.read(length)
suffix = self.tcp_handler.rfile.readline(5)
if suffix != '\r\n':
raise HttpError(code, "Malformed chunked body")
yield line, chunk, '\r\n'
if length == 0:
return
@classmethod
def has_chunked_encoding(self, headers):
return "chunked" in [
i.lower() for i in http.get_header_tokens(headers, "transfer-encoding")
]
@classmethod
def parse_http_protocol(self, line):
"""
Parse an HTTP protocol declaration.
Returns a (major, minor) tuple, or None.
"""
if not line.startswith("HTTP/"):
return None
_, version = line.split('/', 1)
if "." not in version:
return None
major, minor = version.split('.', 1)
try:
major = int(major)
minor = int(minor)
except ValueError:
return None
return major, minor
@classmethod
def parse_init(self, line):
try:
method, url, protocol = string.split(line)
except ValueError:
return None
httpversion = self.parse_http_protocol(protocol)
if not httpversion:
return None
if not utils.isascii(method):
return None
return method, url, httpversion
@classmethod
def parse_init_connect(self, line):
"""
Returns (host, port, httpversion) if line is a valid CONNECT line.
http://tools.ietf.org/html/draft-luotonen-web-proxy-tunneling-01 section 3.1
"""
v = self.parse_init(line)
if not v:
return None
method, url, httpversion = v
if method.upper() != 'CONNECT':
return None
try:
host, port = url.split(":")
except ValueError:
return None
try:
port = int(port)
except ValueError:
return None
if not http.is_valid_port(port):
return None
if not http.is_valid_host(host):
return None
return host, port, httpversion
@classmethod
def parse_init_proxy(self, line):
v = self.parse_init(line)
if not v:
return None
method, url, httpversion = v
parts = http.parse_url(url)
if not parts:
return None
scheme, host, port, path = parts
return method, scheme, host, port, path, httpversion
@classmethod
def parse_init_http(self, line):
"""
Returns (method, url, httpversion)
"""
v = self.parse_init(line)
if not v:
return None
method, url, httpversion = v
if not utils.isascii(url):
return None
if not (url.startswith("/") or url == "*"):
return None
return method, url, httpversion
@classmethod
def connection_close(self, httpversion, headers):
"""
Checks the message to see if the client connection should be closed
according to RFC 2616 Section 8.1 Note that a connection should be
closed as well if the response has been read until end of the stream.
"""
# At first, check if we have an explicit Connection header.
if "connection" in headers:
toks = http.get_header_tokens(headers, "connection")
if "close" in toks:
return True
elif "keep-alive" in toks:
return False
# If we don't have a Connection header, HTTP 1.1 connections are assumed to
# be persistent
return httpversion != (1, 1)
@classmethod
def parse_response_line(self, line):
parts = line.strip().split(" ", 2)
if len(parts) == 2: # handle missing message gracefully
parts.append("")
if len(parts) != 3:
return None
proto, code, msg = parts
try:
code = int(code)
except ValueError:
return None
return (proto, code, msg)
def read_http_body(self, *args, **kwargs):
return "".join(
content for _, content, _ in self.read_http_body_chunked(*args, **kwargs)
)
def read_http_body_chunked(
self,
headers,
limit,
request_method,
response_code,
is_request,
max_chunk_size=None
):
"""
Read an HTTP message body:
headers: An ODictCaseless object
limit: Size limit.
is_request: True if the body to read belongs to a request, False
otherwise
"""
if max_chunk_size is None:
max_chunk_size = limit or sys.maxsize
expected_size = self.expected_http_body_size(
headers, is_request, request_method, response_code
)
if expected_size is None:
if self.has_chunked_encoding(headers):
# Python 3: yield from
for x in self.read_chunked(limit, is_request):
yield x
else: # pragma: nocover
raise HttpError(
400 if is_request else 502,
"Content-Length unknown but no chunked encoding"
)
elif expected_size >= 0:
if limit is not None and expected_size > limit:
raise HttpError(
400 if is_request else 509,
"HTTP Body too large. Limit is %s, content-length was %s" % (
limit, expected_size
)
)
bytes_left = expected_size
while bytes_left:
chunk_size = min(bytes_left, max_chunk_size)
yield "", self.tcp_handler.rfile.read(chunk_size), ""
bytes_left -= chunk_size
else:
bytes_left = limit or -1
while bytes_left:
chunk_size = min(bytes_left, max_chunk_size)
content = self.tcp_handler.rfile.read(chunk_size)
if not content:
return
yield "", content, ""
bytes_left -= chunk_size
not_done = self.tcp_handler.rfile.read(1)
if not_done:
raise HttpError(
400 if is_request else 509,
"HTTP Body too large. Limit is %s," % limit
)
@classmethod
def expected_http_body_size(self, headers, is_request, request_method, response_code):
"""
Returns the expected body length:
- a positive integer, if the size is known in advance
- None, if the size in unknown in advance (chunked encoding or invalid
data)
- -1, if all data should be read until end of stream.
May raise HttpError.
"""
# Determine response size according to
# http://tools.ietf.org/html/rfc7230#section-3.3
if request_method:
request_method = request_method.upper()
if (not is_request and (
request_method == "HEAD" or
(request_method == "CONNECT" and response_code == 200) or
response_code in [204, 304] or
100 <= response_code <= 199)):
return 0
if self.has_chunked_encoding(headers):
return None
if "content-length" in headers:
try:
size = int(headers["content-length"][0])
if size < 0:
raise ValueError()
return size
except ValueError:
return None
if is_request:
return 0
return -1
def read_request(self, include_body=True, body_size_limit=None):
"""
Parse an HTTP request from a file stream
Args:
include_body (bool): Read response body as well
body_size_limit (bool): Maximum body size
wfile (file): If specified, HTTP Expect headers are handled
automatically, by writing a HTTP 100 CONTINUE response to the stream.
Returns:
Request: The HTTP request
Raises:
HttpError: If the input is invalid.
"""
httpversion, host, port, scheme, method, path, headers, content = (
None, None, None, None, None, None, None, None)
request_line = self.get_request_line()
if not request_line:
raise tcp.NetLibDisconnect()
request_line_parts = self.parse_init(request_line)
if not request_line_parts:
raise HttpError(
400,
"Bad HTTP request line: %s" % repr(request_line)
)
method, path, httpversion = request_line_parts
if path == '*' or path.startswith("/"):
form_in = "relative"
if not utils.isascii(path):
raise HttpError(
400,
"Bad HTTP request line: %s" % repr(request_line)
)
elif method.upper() == 'CONNECT':
form_in = "authority"
r = self.parse_init_connect(request_line)
if not r:
raise HttpError(
400,
"Bad HTTP request line: %s" % repr(request_line)
)
host, port, _ = r
path = None
else:
form_in = "absolute"
r = self.parse_init_proxy(request_line)
if not r:
raise HttpError(
400,
"Bad HTTP request line: %s" % repr(request_line)
)
_, scheme, host, port, path, _ = r
headers = self.read_headers()
if headers is None:
raise HttpError(400, "Invalid headers")
expect_header = headers.get_first("expect", "").lower()
if expect_header == "100-continue" and httpversion >= (1, 1):
self.tcp_handler.wfile.write(
'HTTP/1.1 100 Continue\r\n'
'\r\n'
)
self.tcp_handler.wfile.flush()
del headers['expect']
if include_body:
content = self.read_http_body(
headers,
body_size_limit,
method,
None,
True
)
return http.Request(
form_in,
method,
scheme,
host,
port,
path,
httpversion,
headers,
content
)
def read_response(self, request_method, body_size_limit, include_body=True):
"""
Returns an http.Response
By default, both response header and body are read.
If include_body=False is specified, content may be one of the
following:
- None, if the response is technically allowed to have a response body
- "", if the response must not have a response body (e.g. it's a
response to a HEAD request)
"""
line = self.tcp_handler.rfile.readline()
# Possible leftover from previous message
if line == "\r\n" or line == "\n":
line = self.tcp_handler.rfile.readline()
if not line:
raise HttpErrorConnClosed(502, "Server disconnect.")
parts = self.parse_response_line(line)
if not parts:
raise HttpError(502, "Invalid server response: %s" % repr(line))
proto, code, msg = parts
httpversion = self.parse_http_protocol(proto)
if httpversion is None:
raise HttpError(502, "Invalid HTTP version in line: %s" % repr(proto))
headers = self.read_headers()
if headers is None:
raise HttpError(502, "Invalid headers.")
if include_body:
content = self.read_http_body(
headers,
body_size_limit,
request_method,
code,
False
)
else:
# if include_body==False then a None content means the body should be
# read separately
content = None
return http.Response(httpversion, code, msg, headers, content)
@classmethod
def request_preamble(self, method, resource, http_major="1", http_minor="1"):
return '%s %s HTTP/%s.%s' % (
method, resource, http_major, http_minor
)
@classmethod
def response_preamble(self, code, message=None, http_major="1", http_minor="1"):
if message is None:
message = status_codes.RESPONSES.get(code)
return 'HTTP/%s.%s %s %s' % (http_major, http_minor, code, message)