diff options
Diffstat (limited to 'libmproxy/protocol/tls.py')
| -rw-r--r-- | libmproxy/protocol/tls.py | 137 |
1 files changed, 86 insertions, 51 deletions
diff --git a/libmproxy/protocol/tls.py b/libmproxy/protocol/tls.py index ed747643..28f8c177 100644 --- a/libmproxy/protocol/tls.py +++ b/libmproxy/protocol/tls.py @@ -5,14 +5,14 @@ import sys from construct import ConstructError import six -from netlib.exceptions import InvalidCertificateException, TcpException, TlsException +from netlib.exceptions import InvalidCertificateException +from netlib.exceptions import TlsException from ..contrib.tls._constructs import ClientHello from ..exceptions import ProtocolException, TlsProtocolException, ClientHandshakeException from .base import Layer - # taken from https://testssl.sh/openssl-rfc.mappping.html CIPHER_ID_NAME_MAP = { 0x00: 'NULL-MD5', @@ -222,7 +222,85 @@ def is_tls_record_magic(d): ) +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): self.client_sni = None self.client_alpn_protocols = None @@ -281,60 +359,17 @@ 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: + 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") - return - - try: - client_hello = ClientHello.parse(raw_client_hello) - except ConstructError 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: @@ -435,7 +470,7 @@ class TlsLayer(Layer): alpn = [x for x in self.client_alpn_protocols if not deprecated_http2_variant(x)] else: alpn = None - if alpn and "h2" in alpn and not self.config.http2 : + if alpn and "h2" in alpn and not self.config.http2: alpn.remove("h2") ciphers_server = self.config.ciphers_server |