diff options
| -rw-r--r-- | docs/features/passthrough.rst | 4 | ||||
| -rw-r--r-- | libmproxy/protocol/__init__.py | 4 | ||||
| -rw-r--r-- | libmproxy/protocol/tls.py | 126 | ||||
| -rw-r--r-- | libmproxy/proxy/root_context.py | 22 |
4 files changed, 98 insertions, 58 deletions
diff --git a/docs/features/passthrough.rst b/docs/features/passthrough.rst index 80521393..b7b5df84 100644 --- a/docs/features/passthrough.rst +++ b/docs/features/passthrough.rst @@ -31,9 +31,9 @@ mitmproxy allows you to specify a regex which is matched against a ``host:port`` There are two important quirks to consider: -- **In transparent mode, the ignore pattern is matched against the IP.** While we usually infer the +- **In transparent mode, the ignore pattern is matched against the IP and ClientHello SNI host.** While we usually infer the hostname from the Host header if the :option:`--host` argument is passed to mitmproxy, we do not - have access to this information before the SSL handshake. + have access to this information before the SSL handshake. If the client uses SNI however, then we treat the SNI host as an ignore target. - In regular mode, explicit HTTP requests are never ignored. [#explicithttp]_ The ignore pattern is applied on CONNECT requests, which initiate HTTPS or clear-text WebSocket connections. diff --git a/libmproxy/protocol/__init__.py b/libmproxy/protocol/__init__.py index 0d624fd7..d8ebd4f0 100644 --- a/libmproxy/protocol/__init__.py +++ b/libmproxy/protocol/__init__.py @@ -28,12 +28,12 @@ as late as possible; this makes server replay without any outgoing connections p from __future__ import (absolute_import, print_function, division) from .base import Layer, ServerConnectionMixin, Kill from .http import Http1Layer, UpstreamConnectLayer, Http2Layer -from .tls import TlsLayer, is_tls_record_magic +from .tls import TlsLayer, is_tls_record_magic, TlsClientHello from .rawtcp import RawTCPLayer __all__ = [ "Layer", "ServerConnectionMixin", "Kill", "Http1Layer", "UpstreamConnectLayer", "Http2Layer", - "TlsLayer", "is_tls_record_magic", + "TlsLayer", "is_tls_record_magic", "TlsClientHello" "RawTCPLayer" ] diff --git a/libmproxy/protocol/tls.py b/libmproxy/protocol/tls.py index ed747643..6d4cac85 100644 --- a/libmproxy/protocol/tls.py +++ b/libmproxy/protocol/tls.py @@ -221,6 +221,80 @@ def is_tls_record_magic(d): d[2] in ('\x00', '\x01', '\x02', '\x03') ) +def get_client_hello(client_conn): + """ + Peek into the socket and read all records that contain the initial client hello message. + + client_conn: + The :py:class:`client connection <libmproxy.models.ClientConnection>`. + + Returns: + The raw handshake packet bytes, without TLS record header(s). + """ + client_hello = "" + client_hello_size = 1 + offset = 0 + while len(client_hello) < client_hello_size: + record_header = client_conn.rfile.peek(offset + 5)[offset:] + if not is_tls_record_magic(record_header) or len(record_header) != 5: + raise TlsProtocolException('Expected TLS record, got "%s" instead.' % record_header) + record_size = struct.unpack("!H", record_header[3:])[0] + 5 + record_body = client_conn.rfile.peek(offset + record_size)[offset + 5:] + if len(record_body) != record_size - 5: + raise TlsProtocolException("Unexpected EOF in TLS handshake: %s" % record_body) + client_hello += record_body + offset += record_size + client_hello_size = struct.unpack("!I", '\x00' + client_hello[1:4])[0] + 4 + return client_hello + +class TlsClientHello(object): + def __init__(self, raw_client_hello): + self._client_hello = ClientHello.parse(raw_client_hello) + + def raw(self): + return self._client_hello + + @property + def client_cipher_suites(self): + return self._client_hello.cipher_suites.cipher_suites + + @property + def client_sni(self): + for extension in self._client_hello.extensions: + if (extension.type == 0x00 and len(extension.server_names) == 1 + and extension.server_names[0].type == 0): + return extension.server_names[0].name + + @property + def client_alpn_protocols(self): + for extension in self._client_hello.extensions: + if extension.type == 0x10: + return list(extension.alpn_protocols) + + @classmethod + def from_client_conn(cls, client_conn): + """ + Peek into the connection, read the initial client hello and parse it to obtain ALPN values. + client_conn: + The :py:class:`client connection <libmproxy.models.ClientConnection>`. + Returns: + :py:class:`client hello <libmproxy.protocol.tls.TlsClientHello>`. + """ + try: + raw_client_hello = get_client_hello(client_conn)[4:] # exclude handshake header. + except ProtocolException as e: + raise TlsProtocolException('Cannot read raw Client Hello: %s' % repr(e)) + + try: + return cls(raw_client_hello) + except ConstructError as e: + raise TlsProtocolException('Cannot parse Client Hello: %s, Raw Client Hello: %s' % \ + (repr(e), raw_client_hello.encode("hex"))) + + def __repr__(self): + return "TlsClientHello( sni: %s alpn_protocols: %s, cipher_suites: %s)" % \ + (self.client_sni, self.client_alpn_protocols, self.client_cipher_suites) + class TlsLayer(Layer): def __init__(self, ctx, client_tls, server_tls): @@ -281,60 +355,18 @@ class TlsLayer(Layer): else: return "TlsLayer(inactive)" - def _get_client_hello(self): - """ - Peek into the socket and read all records that contain the initial client hello message. - - Returns: - The raw handshake packet bytes, without TLS record header(s). - """ - client_hello = "" - client_hello_size = 1 - offset = 0 - while len(client_hello) < client_hello_size: - record_header = self.client_conn.rfile.peek(offset + 5)[offset:] - if not is_tls_record_magic(record_header) or len(record_header) != 5: - raise TlsProtocolException('Expected TLS record, got "%s" instead.' % record_header) - record_size = struct.unpack("!H", record_header[3:])[0] + 5 - record_body = self.client_conn.rfile.peek(offset + record_size)[offset + 5:] - if len(record_body) != record_size - 5: - raise TlsProtocolException("Unexpected EOF in TLS handshake: %s" % record_body) - client_hello += record_body - offset += record_size - client_hello_size = struct.unpack("!I", '\x00' + client_hello[1:4])[0] + 4 - return client_hello def _parse_client_hello(self): """ Peek into the connection, read the initial client hello and parse it to obtain ALPN values. """ try: - raw_client_hello = self._get_client_hello()[4:] # exclude handshake header. - except ProtocolException as e: - self.log("Cannot parse Client Hello: %s" % repr(e), "error") - return - - try: - client_hello = ClientHello.parse(raw_client_hello) - except ConstructError as e: + parsed = TlsClientHello.from_client_conn(self.client_conn) + self.client_sni = parsed.client_sni + self.client_alpn_protocols = parsed.client_alpn_protocols + self.client_ciphers = parsed.client_cipher_suites + except TlsProtocolException as e: self.log("Cannot parse Client Hello: %s" % repr(e), "error") - self.log("Raw Client Hello: %s" % raw_client_hello.encode("hex"), "debug") - return - - self.client_ciphers = client_hello.cipher_suites.cipher_suites - - for extension in client_hello.extensions: - if extension.type == 0x00: - if len(extension.server_names) != 1 or extension.server_names[0].type != 0: - self.log("Unknown Server Name Indication: %s" % extension.server_names, "error") - self.client_sni = extension.server_names[0].name - elif extension.type == 0x10: - self.client_alpn_protocols = list(extension.alpn_protocols) - - self.log( - "Parsed Client Hello: sni=%s, alpn=%s" % (self.client_sni, self.client_alpn_protocols), - "debug" - ) def connect(self): if not self.server_conn: diff --git a/libmproxy/proxy/root_context.py b/libmproxy/proxy/root_context.py index f62b0c8e..d70fc299 100644 --- a/libmproxy/proxy/root_context.py +++ b/libmproxy/proxy/root_context.py @@ -4,15 +4,14 @@ import sys import six -from libmproxy.exceptions import ProtocolException +from libmproxy.exceptions import ProtocolException, TlsProtocolException from netlib.exceptions import TcpException from ..protocol import ( RawTCPLayer, TlsLayer, Http1Layer, Http2Layer, is_tls_record_magic, ServerConnectionMixin, - UpstreamConnectLayer + UpstreamConnectLayer, TlsClientHello ) from .modes import HttpProxy, HttpUpstreamProxy, ReverseProxy - class RootContext(object): """ The outermost context provided to the root layer. @@ -48,16 +47,25 @@ class RootContext(object): return self.channel.ask("next_layer", layer) def _next_layer(self, top_layer): - # 1. Check for --ignore. - if self.config.check_ignore(top_layer.server_conn.address): - return RawTCPLayer(top_layer, logging=False) - try: d = top_layer.client_conn.rfile.peek(3) except TcpException as e: six.reraise(ProtocolException, ProtocolException(str(e)), sys.exc_info()[2]) client_tls = is_tls_record_magic(d) + # 1. check for --ignore + if self.config.check_ignore: + ignore = self.config.check_ignore(top_layer.server_conn.address) + if not ignore and client_tls: + try: + client_hello = TlsClientHello.from_client_conn(self.client_conn) + except TlsProtocolException as e: + self.log("Cannot parse Client Hello: %s" % repr(e), "error") + else: + ignore = self.config.check_ignore((client_hello.client_sni, 443)) + if ignore: + return RawTCPLayer(top_layer, logging=False) + # 2. Always insert a TLS layer, even if there's neither client nor server tls. # An inline script may upgrade from http to https, # in which case we need some form of TLS layer. |