[sans-io] tls: various improvements

This commit is contained in:
Maximilian Hils 2019-11-24 00:16:38 +01:00
parent 09b6257de0
commit 6cf0bec912
7 changed files with 100 additions and 40 deletions

View File

@ -78,6 +78,8 @@ class TlsConfig:
tls_start.ssl_conn.set_app_data({
"server_alpn": tls_start.context.server.alpn
})
tls_start.ssl_conn.set_accept_state()
def create_proxy_server_ssl_conn(self, tls_start: tls.StartHookData) -> None:
client = tls_start.context.client
@ -126,6 +128,7 @@ class TlsConfig:
**args
)
tls_start.ssl_conn = SSL.Connection(ssl_ctx)
tls_start.ssl_conn.set_connect_state()
def configure(self, updated):
if not any(x in updated for x in ["confdir", "certs"]):

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@ -1,6 +1,7 @@
from enum import Flag, auto
from typing import List, Optional, Sequence, Union
from mitmproxy import certs
from mitmproxy.options import Options
@ -19,6 +20,7 @@ class Connection:
state: ConnectionState
tls: bool = False
tls_established: bool = False
certificate_chain: Optional[Sequence[certs.Cert]] = None
alpn: Optional[bytes] = None
alpn_offers: Sequence[bytes] = ()
cipher_list: Sequence[bytes] = ()

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@ -4,10 +4,12 @@ from typing import Any, Dict, Generator, Iterator, Optional, Tuple
from OpenSSL import SSL
from mitmproxy import certs
from mitmproxy.net import tls as net_tls
from mitmproxy.proxy2 import commands, events, layer
from mitmproxy.proxy2 import context
from mitmproxy.proxy2.utils import expect
from mitmproxy.utils import human
def is_tls_handshake_record(d: bytes) -> bool:
@ -142,6 +144,17 @@ class _TLSLayer(layer.Layer):
state = ", ".join(conn_states)
return f"{type(self).__name__}({state})"
def start_tls(self, conn: context.Connection, initial_data: bytes = b""):
assert conn not in self.tls
assert conn.connected
conn.tls = True
tls_start = StartHookData(conn, self.context)
yield commands.Hook("tls_start", tls_start)
self.tls[conn] = tls_start.ssl_conn
yield from self.negotiate(conn, initial_data)
def tls_interact(self, conn: context.Connection) -> commands.TCommandGenerator:
while True:
try:
@ -163,17 +176,37 @@ class _TLSLayer(layer.Layer):
yield from self.tls_interact(conn)
return False, None
except SSL.Error as e:
return False, repr(e)
# provide more detailed information for some errors.
last_err = e.args[0][-1]
if last_err == ('SSL routines', 'tls_process_server_certificate', 'certificate verify failed'):
verify_result = SSL._lib.SSL_get_verify_result(self.tls[conn]._ssl)
error = SSL._ffi.string(SSL._lib.X509_verify_cert_error_string(verify_result)).decode()
return False, f"Certificate verify failed: {error}"
elif last_err == ('SSL routines', 'ssl3_read_bytes', 'tlsv1 alert unknown ca'):
return False, "TLS Alert: Unknown CA"
else:
return False, repr(e)
else:
# Get all peer certificates.
# https://www.openssl.org/docs/man1.1.1/man3/SSL_get_peer_cert_chain.html
# If called on the client side, the stack also contains the peer's certificate; if called on the server
# side, the peer's certificate must be obtained separately using SSL_get_peer_certificate(3).
all_certs = self.tls[conn].get_peer_cert_chain() or []
if conn == self.context.client:
cert = self.tls[conn].get_peer_certificate()
if cert:
all_certs.insert(0, cert)
conn.tls_established = True
conn.sni = self.tls[conn].get_servername()
conn.alpn = self.tls[conn].get_alpn_proto_negotiated()
conn.certificate_chain = [certs.Cert(x) for x in all_certs]
conn.cipher_list = self.tls[conn].get_cipher_list()
conn.tls_version = self.tls[conn].get_protocol_version_name()
conn.timestamp_tls_setup = time.time()
yield commands.Log(f"TLS established: {conn}")
yield from self.receive(conn, b"")
# TODO: Set all other connection attributes here
return True, None
def receive(self, conn: context.Connection, data: bytes):
@ -250,22 +283,10 @@ class ServerTLSLayer(_TLSLayer):
for command in super().event_to_child(event):
if isinstance(command, EstablishServerTLS):
self.command_to_reply_to[command.connection] = command
yield from self.start_server_tls(command.connection)
yield from self.start_tls(command.connection)
else:
yield command
def start_server_tls(self, conn: context.Server):
assert conn not in self.tls
assert conn.connected
conn.tls = True
tls_start = StartHookData(conn, self.context)
yield commands.Hook("tls_start", tls_start)
self.tls[conn] = tls_start.ssl_conn
self.tls[conn].set_connect_state()
yield from self.negotiate(conn, b"")
class ClientTLSLayer(_TLSLayer):
"""
@ -320,13 +341,12 @@ class ClientTLSLayer(_TLSLayer):
yield commands.Log("Unable to establish TLS connection with server. "
"Trying to establish TLS with client anyway.")
yield from self.start_client_tls()
yield from self.start_tls(client, bytes(self.recv_buffer))
self.recv_buffer.clear()
self._handle_event = super()._handle_event
# In any case, we now have enough information to start server TLS if needed.
yield from self.event_to_child(events.Start())
elif isinstance(event, events.ConnectionClosed) and event.connection == client:
self.recv_buffer.clear()
else:
yield from self.event_to_child(event)
@ -351,29 +371,17 @@ class ClientTLSLayer(_TLSLayer):
)
return err
def start_client_tls(self) -> commands.TCommandGenerator:
client = self.context.client
tls_start = StartHookData(client, self.context)
yield commands.Hook("tls_start", tls_start)
self.tls[client] = tls_start.ssl_conn
self.tls[client].set_accept_state()
yield from self.negotiate(client, bytes(self.recv_buffer))
self.recv_buffer.clear()
def negotiate(self, conn: context.Connection, data: bytes) -> Generator[commands.Command, Any, bool]:
done, err = yield from super().negotiate(conn, data)
if err:
if self.context.client.sni:
# TODO: Also use other sources than SNI
dest = " for " + self.context.client.sni.decode("idna")
dest = self.context.client.sni.decode("idna")
else:
dest = ""
dest = human.format_address(self.context.server.address)
yield commands.Log(
f"Client TLS Handshake failed. "
f"The client may not trust the proxy's certificate{dest} ({err}).",
f"The client may not trust the proxy's certificate for {dest} ({err}).",
level="warn"
)
yield commands.CloseConnection(self.context.client)
return done

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@ -16,11 +16,16 @@ import traceback
import typing
from contextlib import contextmanager
from OpenSSL import SSL
from mitmproxy import http, options as moptions
from mitmproxy.addons import tlsconfig
from mitmproxy.proxy.protocol.http import HTTPMode
from mitmproxy.proxy2 import commands, events, layer, layers
from mitmproxy.proxy2.context import Client, Connection, ConnectionState, Context
from mitmproxy.proxy2.layers import tls
from mitmproxy.utils import human
from test.mitmproxy.proxy2.layers.test_tls import tlsdata
class StreamIO(typing.NamedTuple):
@ -270,9 +275,29 @@ if __name__ == "__main__":
if "redirect" in flow.request.path:
flow.request.host = "httpbin.org"
def tls_start(tls_start: tls.StartHookData):
# INSECURE
ssl_context = SSL.Context(SSL.SSLv23_METHOD)
if tls_start.conn == tls_start.context.client:
ssl_context.use_privatekey_file(
tlsdata.path("../../data/verificationcerts/trusted-leaf.key")
)
ssl_context.use_certificate_chain_file(
tlsdata.path("../../data/verificationcerts/trusted-leaf.crt")
)
tls_start.ssl_conn = SSL.Connection(ssl_context)
if tls_start.conn == tls_start.context.client:
tls_start.ssl_conn.set_accept_state()
else:
tls_start.ssl_conn.set_connect_state()
tls_start.ssl_conn.set_tlsext_host_name(tls_start.context.client.sni)
await SimpleConnectionHandler(reader, writer, opts, {
"next_layer": next_layer,
"request": request
"request": request,
"tls_start": tls_start,
}).handle_client()

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@ -39,6 +39,7 @@ def sign(cert: str, subject: str):
f"-extfile \"openssl-{cert}.conf\" "
f"-out {cert}.crt"
)
os.remove(f"openssl-{cert}.conf")
def mkcert(cert, subject):
@ -63,7 +64,7 @@ h = do("openssl x509 -hash -noout -in trusted-root.crt").decode("ascii").strip()
shutil.copyfile("trusted-root.crt", "{}.0".format(h))
# create trusted leaf cert.
mkcert("trusted-leaf", f'DNS:{SUBJECT}' )
mkcert("trusted-leaf", f'DNS:{SUBJECT}')
# create self-signed cert
genrsa("self-signed")
@ -72,4 +73,4 @@ do("openssl req -x509 -new -nodes -batch "
f'-addext "subjectAltName = DNS:{SUBJECT}" '
"-days 7300 "
"-out self-signed.crt"
)
)

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@ -155,7 +155,10 @@ def reply_tls_start(alpn: typing.Optional[bytes] = None, *args, **kwargs) -> tut
tls_start.ssl_conn = SSL.Connection(ssl_context)
if tls_start.conn != tls_start.context.client:
if tls_start.conn == tls_start.context.client:
tls_start.ssl_conn.set_accept_state()
else:
tls_start.ssl_conn.set_connect_state()
# Set SNI
tls_start.ssl_conn.set_tlsext_host_name(tls_start.conn.sni)
@ -233,6 +236,16 @@ class TestServerTLS:
# Echo
_test_echo(playbook, tssl, tctx.server)
with pytest.raises(ssl.SSLWantReadError):
tssl.obj.unwrap()
assert (
playbook
>> events.DataReceived(tctx.server, tssl.out.read())
<< commands.CloseConnection(tctx.server)
>> events.ConnectionClosed(tctx.server)
<< None
)
def test_untrusted_cert(self, tctx):
"""If the certificate is not trusted, we should fail."""
layer = tls.ServerTLSLayer(tctx)
@ -263,8 +276,7 @@ class TestServerTLS:
assert (
playbook
>> events.DataReceived(tctx.server, tssl.out.read())
<< commands.SendData(tctx.client,
b"server-tls-failed: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])")
<< commands.SendData(tctx.client, b"server-tls-failed: Certificate verify failed: Hostname mismatch")
)
assert not tctx.server.tls_established

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@ -189,7 +189,14 @@ class Playbook:
if not self.logs:
for offset, cmd in enumerate(cmds):
pos = i + 1 + offset
if isinstance(cmd, commands.Log) and not isinstance(self.expected[pos], commands.Log):
need_to_emulate_log = (
isinstance(cmd, commands.Log) and
(
pos >= len(self.expected)
or not isinstance(self.expected[pos], commands.Log)
)
)
if need_to_emulate_log:
self.expected.insert(pos, cmd)
if not self.hooks:
last_cmd = self.actual[-1]
@ -319,6 +326,8 @@ class EchoLayer(Layer):
def _handle_event(self, event: events.Event) -> commands.TCommandGenerator:
if isinstance(event, events.DataReceived):
yield commands.SendData(event.connection, event.data.lower())
if isinstance(event, events.ConnectionClosed):
yield commands.CloseConnection(event.connection)
def reply_next_layer(