proxy.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This proxies connections for a Carrier Infinity system.
# It reads the data being transferred and logs it to an influxdb server
import gzip
import httplib
import json
import os
import re
import select
import socket
import ssl
import sys
import threading
import time
import urlparse
import zlib
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
from cStringIO import StringIO
from HTMLParser import HTMLParser
from SocketServer import ThreadingMixIn
from subprocess import PIPE, Popen


def with_color(c, s):
    return "\x1b[%dm%s\x1b[0m" % (c, s)


class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
    address_family = socket.AF_INET6
    daemon_threads = True

    def handle_error(self, request, client_address):
        # surpress socket/ssl related errors
        cls, e = sys.exc_info()[:2]
        if cls is socket.error or cls is ssl.SSLError:
            pass
        else:
            return HTTPServer.handle_error(self, request, client_address)


class ProxyRequestHandler(BaseHTTPRequestHandler):
    cakey = "ca.key"
    cacert = "ca.crt"
    certkey = "cert.key"
    certdir = "certs/"
    timeout = 5
    lock = threading.Lock()

    def __init__(self, *args, **kwargs):
        self.tls = threading.local()
        self.tls.conns = {}

        BaseHTTPRequestHandler.__init__(self, *args, **kwargs)

    def log_error(self, format, *args):
        # surpress "Request timed out: timeout('timed out',)"
        if isinstance(args[0], socket.timeout):
            return

        self.log_message(format, *args)

    def do_CONNECT(self):
        if (
            os.path.isfile(self.cakey)
            and os.path.isfile(self.cacert)
            and os.path.isfile(self.certkey)
            and os.path.isdir(self.certdir)
        ):
            self.connect_intercept()
        else:
            self.connect_relay()

    def connect_intercept(self):
        hostname = self.path.split(":")[0]
        certpath = "%s/%s.crt" % (self.certdir.rstrip("/"), hostname)

        with self.lock:
            if not os.path.isfile(certpath):
                epoch = "%d" % (time.time() * 1000)
                p1 = Popen(
                    [
                        "openssl",
                        "req",
                        "-new",
                        "-key",
                        self.certkey,
                        "-subj",
                        "/CN=%s" % hostname,
                    ],
                    stdout=PIPE,
                )
                p2 = Popen(
                    [
                        "openssl",
                        "x509",
                        "-req",
                        "-days",
                        "3650",
                        "-CA",
                        self.cacert,
                        "-CAkey",
                        self.cakey,
                        "-set_serial",
                        epoch,
                        "-out",
                        certpath,
                    ],
                    stdin=p1.stdout,
                    stderr=PIPE,
                )
                p2.communicate()

        self.wfile.write(
            "%s %d %s\r\n" % (self.protocol_version, 200, "Connection Established")
        )
        self.end_headers()

        self.connection = ssl.wrap_socket(
            self.connection, keyfile=self.certkey, certfile=certpath, server_side=True
        )
        self.rfile = self.connection.makefile("rb", self.rbufsize)
        self.wfile = self.connection.makefile("wb", self.wbufsize)

        conntype = self.headers.get("Proxy-Connection", "")
        if conntype.lower() == "close":
            self.close_connection = 1
        elif conntype.lower() == "keep-alive" and self.protocol_version >= "HTTP/1.1":
            self.close_connection = 0

    def connect_relay(self):
        address = self.path.split(":", 1)
        address[1] = int(address[1]) or 443
        try:
            s = socket.create_connection(address, timeout=self.timeout)
        except Exception:
            self.send_error(502)
            return
        self.send_response(200, "Connection Established")
        self.end_headers()

        conns = [self.connection, s]
        self.close_connection = 0
        while not self.close_connection:
            rlist, wlist, xlist = select.select(conns, [], conns, self.timeout)
            if xlist or not rlist:
                break
            for r in rlist:
                other = conns[1] if r is conns[0] else conns[0]
                data = r.recv(8192)
                if not data:
                    self.close_connection = 1
                    break
                other.sendall(data)

    def do_GET(self):
        if self.path == "http://proxy2.test/":
            self.send_cacert()
            return

        req = self
        content_length = int(req.headers.get("Content-Length", 0))
        req_body = self.rfile.read(content_length) if content_length else None

        if req.path[0] == "/":
            if isinstance(self.connection, ssl.SSLSocket):
                req.path = "https://%s%s" % (req.headers["Host"], req.path)
            else:
                req.path = "http://%s%s" % (req.headers["Host"], req.path)

        req_body_modified = self.request_handler(req, req_body)
        if req_body_modified is False:
            self.send_error(403)
            return
        elif req_body_modified is not None:
            req_body = req_body_modified
            req.headers["Content-length"] = str(len(req_body))

        u = urlparse.urlsplit(req.path)
        scheme, netloc = u.scheme, u.netloc
        path = u.path + "?" + u.query if u.query else u.path
        assert scheme in ("http", "https")
        if netloc:
            req.headers["Host"] = netloc
        req_headers = self.filter_headers(req.headers)

        try:
            origin = (scheme, netloc)
            if origin not in self.tls.conns:
                if scheme == "https":
                    ConnClass = httplib.HTTPSConnection
                    self.tls.conns[origin] = ConnClass(netloc, timeout=self.timeout)
                else:
                    ConnClass = httplib.HTTPConnection
                    self.tls.conns[origin] = ConnClass(netloc, timeout=self.timeout)
            conn = self.tls.conns[origin]
            conn.request(self.command, path, req_body, dict(req_headers))
            res = conn.getresponse()
            res_body = res.read()
        except Exception:
            if origin in self.tls.conns:
                del self.tls.conns[origin]
            self.send_error(502)
            return

        version_table = {10: "HTTP/1.0", 11: "HTTP/1.1"}
        setattr(res, "headers", res.msg)
        setattr(res, "response_version", version_table[res.version])

        content_encoding = res.headers.get("Content-Encoding", "identity")
        res_body_plain = self.decode_content_body(res_body, content_encoding)

        res_body_modified = self.response_handler(req, req_body, res, res_body_plain)
        if res_body_modified is False:
            self.send_error(403)
            return
        elif res_body_modified is not None:
            res_body_plain = res_body_modified
            res_body = self.encode_content_body(res_body_plain, content_encoding)
            res.headers["Content-Length"] = str(len(res_body))

        res_headers = self.filter_headers(res.headers)

        msg_write = "%s %d %s\r\n" % (self.protocol_version, res.status, res.reason)
        self.wfile.write(msg_write)
        for line in res_headers.headers:
            self.wfile.write(line)
        self.end_headers()
        self.wfile.write(res_body)
        self.wfile.flush()

        with self.lock:
            self.save_handler(req, req_body, res, res_body_plain)

    do_HEAD = do_GET
    do_POST = do_GET
    do_OPTIONS = do_GET

    def filter_headers(self, headers):
        # http://tools.ietf.org/html/rfc2616#section-13.5.1
        hop_by_hop = (
            "connection",
            "keep-alive",
            "proxy-authenticate",
            "proxy-authorization",
            "te",
            "trailers",
            "transfer-encoding",
            "upgrade",
        )
        for k in hop_by_hop:
            del headers[k]
        return headers

    def encode_content_body(self, text, encoding):
        if encoding == "identity":
            data = text
        elif encoding in ("gzip", "x-gzip"):
            io = StringIO()
            with gzip.GzipFile(fileobj=io, mode="wb") as f:
                f.write(text)
            data = io.getvalue()
        elif encoding == "deflate":
            data = zlib.compress(text)
        else:
            raise Exception("Unknown Content-Encoding: %s" % encoding)
        return data

    def decode_content_body(self, data, encoding):
        if encoding == "identity":
            text = data
        elif encoding in ("gzip", "x-gzip"):
            io = StringIO(data)
            with gzip.GzipFile(fileobj=io) as f:
                text = f.read()
        elif encoding == "deflate":
            try:
                text = zlib.decompress(data)
            except zlib.error:
                text = zlib.decompress(data, -zlib.MAX_WBITS)
        else:
            raise Exception("Unknown Content-Encoding: %s" % encoding)
        return text

    def send_cacert(self):
        with open(self.cacert, "rb") as f:
            data = f.read()

        self.wfile.write("%s %d %s\r\n" % (self.protocol_version, 200, "OK"))
        self.send_header("Content-Type", "application/x-x509-ca-cert")
        self.send_header("Content-Length", len(data))
        self.send_header("Connection", "close")
        self.end_headers()
        self.wfile.write(data)

    def print_info(self, req, req_body, res, res_body):
        def parse_qsl(s):
            return "\n".join(
                "%-20s %s" % (k, v)
                for k, v in urlparse.parse_qsl(s, keep_blank_values=True)
            )

        req_header_text = "%s %s %s\n%s" % (
            req.command,
            req.path,
            req.request_version,
            req.headers,
        )
        res_header_text = "%s %d %s\n%s" % (
            res.response_version,
            res.status,
            res.reason,
            res.headers,
        )

        print(with_color(33, req_header_text))

        u = urlparse.urlsplit(req.path)
        if u.query:
            query_text = parse_qsl(u.query)
            print(with_color(32, "==== QUERY PARAMETERS ====\n%s\n" % query_text))

        cookie = req.headers.get("Cookie", "")
        if cookie:
            cookie = parse_qsl(re.sub(r";\s*", "&", cookie))
            print(with_color(32, "==== COOKIE ====\n%s\n" % cookie))

        auth = req.headers.get("Authorization", "")
        if auth.lower().startswith("basic"):
            token = auth.split()[1].decode("base64")
            print(with_color(31, "==== BASIC AUTH ====\n%s\n" % token))

        if req_body is not None:
            req_body_text = None
            content_type = req.headers.get("Content-Type", "")

            if content_type.startswith("application/x-www-form-urlencoded"):
                req_body_text = parse_qsl(req_body)
            elif content_type.startswith("application/json"):
                try:
                    json_obj = json.loads(req_body)
                    json_str = json.dumps(json_obj, indent=2)
                    if json_str.count("\n") < 50:
                        req_body_text = json_str
                    else:
                        lines = json_str.splitlines()
                        req_body_text = "%s\n(%d lines)" % (
                            "\n".join(lines[:50]),
                            len(lines),
                        )
                except ValueError:
                    req_body_text = req_body
            elif len(req_body) < 1024:
                req_body_text = req_body

            if req_body_text:
                print(with_color(32, "==== REQUEST BODY ====\n%s\n" % req_body_text))

        print(with_color(36, res_header_text))

        cookies = res.headers.getheaders("Set-Cookie")
        if cookies:
            cookies = "\n".join(cookies)
            print(with_color(31, "==== SET-COOKIE ====\n%s\n" % cookies))

        if res_body is not None:
            res_body_text = None
            content_type = res.headers.get("Content-Type", "")

            if content_type.startswith("application/json"):
                try:
                    json_obj = json.loads(res_body)
                    json_str = json.dumps(json_obj, indent=2)
                    if json_str.count("\n") < 50:
                        res_body_text = json_str
                    else:
                        lines = json_str.splitlines()
                        res_body_text = "%s\n(%d lines)" % (
                            "\n".join(lines[:50]),
                            len(lines),
                        )
                except ValueError:
                    res_body_text = res_body
            elif content_type.startswith("text/html"):
                m = re.search(r"<title[^>]*>\s*([^<]+?)\s*</title>", res_body, re.I)
                if m:
                    h = HTMLParser()

                    s = m.group(1).decode("utf-8")
                    s = "==== HTML TITLE ====\n%s\n" % h.unescape(s)
                    print(with_color(32, s))
            elif content_type.startswith("text/") and len(res_body) < 1024:
                res_body_text = res_body
            elif content_type.startswith("application/xml"):
                res_body_text = res_body

            if res_body_text:
                s = "==== RESPONSE BODY ====\n%s\n" % res_body_text
                print(with_color(32, s))

    def request_handler(self, req, req_body):
        pass

    def response_handler(self, req, req_body, res, res_body):
        pass

    def save_handler(self, req, req_body, res, res_body):
        self.print_info(req, req_body, res, res_body)


def test(
    HandlerClass=ProxyRequestHandler,
    ServerClass=ThreadingHTTPServer,
    protocol="HTTP/1.1",
):
    # Set up clean logging to stderr
    server_address = ("", "8080")

    HandlerClass.protocol_version = protocol
    httpd = ServerClass(server_address, HandlerClass)

    sa = httpd.socket.getsockname()
    print("Serving HTTP Proxy on", sa[0], "port", sa[1], "...")
    httpd.serve_forever()


if __name__ == "__main__":
    test()