Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/asyncio/sslproto.py: 18%
380 statements
« prev ^ index » next coverage.py v7.0.1, created at 2022-12-25 06:11 +0000
1import collections
2import warnings
3try:
4 import ssl
5except ImportError: # pragma: no cover
6 ssl = None
8from . import base_events
9from . import constants
10from . import protocols
11from . import transports
12from .log import logger
15def _create_transport_context(server_side, server_hostname):
16 if server_side:
17 raise ValueError('Server side SSL needs a valid SSLContext')
19 # Client side may pass ssl=True to use a default
20 # context; in that case the sslcontext passed is None.
21 # The default is secure for client connections.
22 # Python 3.4+: use up-to-date strong settings.
23 sslcontext = ssl.create_default_context()
24 if not server_hostname:
25 sslcontext.check_hostname = False
26 return sslcontext
29# States of an _SSLPipe.
30_UNWRAPPED = "UNWRAPPED"
31_DO_HANDSHAKE = "DO_HANDSHAKE"
32_WRAPPED = "WRAPPED"
33_SHUTDOWN = "SHUTDOWN"
36class _SSLPipe(object):
37 """An SSL "Pipe".
39 An SSL pipe allows you to communicate with an SSL/TLS protocol instance
40 through memory buffers. It can be used to implement a security layer for an
41 existing connection where you don't have access to the connection's file
42 descriptor, or for some reason you don't want to use it.
44 An SSL pipe can be in "wrapped" and "unwrapped" mode. In unwrapped mode,
45 data is passed through untransformed. In wrapped mode, application level
46 data is encrypted to SSL record level data and vice versa. The SSL record
47 level is the lowest level in the SSL protocol suite and is what travels
48 as-is over the wire.
50 An SslPipe initially is in "unwrapped" mode. To start SSL, call
51 do_handshake(). To shutdown SSL again, call unwrap().
52 """
54 max_size = 256 * 1024 # Buffer size passed to read()
56 def __init__(self, context, server_side, server_hostname=None):
57 """
58 The *context* argument specifies the ssl.SSLContext to use.
60 The *server_side* argument indicates whether this is a server side or
61 client side transport.
63 The optional *server_hostname* argument can be used to specify the
64 hostname you are connecting to. You may only specify this parameter if
65 the _ssl module supports Server Name Indication (SNI).
66 """
67 self._context = context
68 self._server_side = server_side
69 self._server_hostname = server_hostname
70 self._state = _UNWRAPPED
71 self._incoming = ssl.MemoryBIO()
72 self._outgoing = ssl.MemoryBIO()
73 self._sslobj = None
74 self._need_ssldata = False
75 self._handshake_cb = None
76 self._shutdown_cb = None
78 @property
79 def context(self):
80 """The SSL context passed to the constructor."""
81 return self._context
83 @property
84 def ssl_object(self):
85 """The internal ssl.SSLObject instance.
87 Return None if the pipe is not wrapped.
88 """
89 return self._sslobj
91 @property
92 def need_ssldata(self):
93 """Whether more record level data is needed to complete a handshake
94 that is currently in progress."""
95 return self._need_ssldata
97 @property
98 def wrapped(self):
99 """
100 Whether a security layer is currently in effect.
102 Return False during handshake.
103 """
104 return self._state == _WRAPPED
106 def do_handshake(self, callback=None):
107 """Start the SSL handshake.
109 Return a list of ssldata. A ssldata element is a list of buffers
111 The optional *callback* argument can be used to install a callback that
112 will be called when the handshake is complete. The callback will be
113 called with None if successful, else an exception instance.
114 """
115 if self._state != _UNWRAPPED:
116 raise RuntimeError('handshake in progress or completed')
117 self._sslobj = self._context.wrap_bio(
118 self._incoming, self._outgoing,
119 server_side=self._server_side,
120 server_hostname=self._server_hostname)
121 self._state = _DO_HANDSHAKE
122 self._handshake_cb = callback
123 ssldata, appdata = self.feed_ssldata(b'', only_handshake=True)
124 assert len(appdata) == 0
125 return ssldata
127 def shutdown(self, callback=None):
128 """Start the SSL shutdown sequence.
130 Return a list of ssldata. A ssldata element is a list of buffers
132 The optional *callback* argument can be used to install a callback that
133 will be called when the shutdown is complete. The callback will be
134 called without arguments.
135 """
136 if self._state == _UNWRAPPED:
137 raise RuntimeError('no security layer present')
138 if self._state == _SHUTDOWN:
139 raise RuntimeError('shutdown in progress')
140 assert self._state in (_WRAPPED, _DO_HANDSHAKE)
141 self._state = _SHUTDOWN
142 self._shutdown_cb = callback
143 ssldata, appdata = self.feed_ssldata(b'')
144 assert appdata == [] or appdata == [b'']
145 return ssldata
147 def feed_eof(self):
148 """Send a potentially "ragged" EOF.
150 This method will raise an SSL_ERROR_EOF exception if the EOF is
151 unexpected.
152 """
153 self._incoming.write_eof()
154 ssldata, appdata = self.feed_ssldata(b'')
155 assert appdata == [] or appdata == [b'']
157 def feed_ssldata(self, data, only_handshake=False):
158 """Feed SSL record level data into the pipe.
160 The data must be a bytes instance. It is OK to send an empty bytes
161 instance. This can be used to get ssldata for a handshake initiated by
162 this endpoint.
164 Return a (ssldata, appdata) tuple. The ssldata element is a list of
165 buffers containing SSL data that needs to be sent to the remote SSL.
167 The appdata element is a list of buffers containing plaintext data that
168 needs to be forwarded to the application. The appdata list may contain
169 an empty buffer indicating an SSL "close_notify" alert. This alert must
170 be acknowledged by calling shutdown().
171 """
172 if self._state == _UNWRAPPED:
173 # If unwrapped, pass plaintext data straight through.
174 if data:
175 appdata = [data]
176 else:
177 appdata = []
178 return ([], appdata)
180 self._need_ssldata = False
181 if data:
182 self._incoming.write(data)
184 ssldata = []
185 appdata = []
186 try:
187 if self._state == _DO_HANDSHAKE:
188 # Call do_handshake() until it doesn't raise anymore.
189 self._sslobj.do_handshake()
190 self._state = _WRAPPED
191 if self._handshake_cb:
192 self._handshake_cb(None)
193 if only_handshake:
194 return (ssldata, appdata)
195 # Handshake done: execute the wrapped block
197 if self._state == _WRAPPED:
198 # Main state: read data from SSL until close_notify
199 while True:
200 chunk = self._sslobj.read(self.max_size)
201 appdata.append(chunk)
202 if not chunk: # close_notify
203 break
205 elif self._state == _SHUTDOWN:
206 # Call shutdown() until it doesn't raise anymore.
207 self._sslobj.unwrap()
208 self._sslobj = None
209 self._state = _UNWRAPPED
210 if self._shutdown_cb:
211 self._shutdown_cb()
213 elif self._state == _UNWRAPPED:
214 # Drain possible plaintext data after close_notify.
215 appdata.append(self._incoming.read())
216 except (ssl.SSLError, ssl.CertificateError) as exc:
217 exc_errno = getattr(exc, 'errno', None)
218 if exc_errno not in (
219 ssl.SSL_ERROR_WANT_READ, ssl.SSL_ERROR_WANT_WRITE,
220 ssl.SSL_ERROR_SYSCALL):
221 if self._state == _DO_HANDSHAKE and self._handshake_cb:
222 self._handshake_cb(exc)
223 raise
224 self._need_ssldata = (exc_errno == ssl.SSL_ERROR_WANT_READ)
226 # Check for record level data that needs to be sent back.
227 # Happens for the initial handshake and renegotiations.
228 if self._outgoing.pending:
229 ssldata.append(self._outgoing.read())
230 return (ssldata, appdata)
232 def feed_appdata(self, data, offset=0):
233 """Feed plaintext data into the pipe.
235 Return an (ssldata, offset) tuple. The ssldata element is a list of
236 buffers containing record level data that needs to be sent to the
237 remote SSL instance. The offset is the number of plaintext bytes that
238 were processed, which may be less than the length of data.
240 NOTE: In case of short writes, this call MUST be retried with the SAME
241 buffer passed into the *data* argument (i.e. the id() must be the
242 same). This is an OpenSSL requirement. A further particularity is that
243 a short write will always have offset == 0, because the _ssl module
244 does not enable partial writes. And even though the offset is zero,
245 there will still be encrypted data in ssldata.
246 """
247 assert 0 <= offset <= len(data)
248 if self._state == _UNWRAPPED:
249 # pass through data in unwrapped mode
250 if offset < len(data):
251 ssldata = [data[offset:]]
252 else:
253 ssldata = []
254 return (ssldata, len(data))
256 ssldata = []
257 view = memoryview(data)
258 while True:
259 self._need_ssldata = False
260 try:
261 if offset < len(view):
262 offset += self._sslobj.write(view[offset:])
263 except ssl.SSLError as exc:
264 # It is not allowed to call write() after unwrap() until the
265 # close_notify is acknowledged. We return the condition to the
266 # caller as a short write.
267 exc_errno = getattr(exc, 'errno', None)
268 if exc.reason == 'PROTOCOL_IS_SHUTDOWN':
269 exc_errno = exc.errno = ssl.SSL_ERROR_WANT_READ
270 if exc_errno not in (ssl.SSL_ERROR_WANT_READ,
271 ssl.SSL_ERROR_WANT_WRITE,
272 ssl.SSL_ERROR_SYSCALL):
273 raise
274 self._need_ssldata = (exc_errno == ssl.SSL_ERROR_WANT_READ)
276 # See if there's any record level data back for us.
277 if self._outgoing.pending:
278 ssldata.append(self._outgoing.read())
279 if offset == len(view) or self._need_ssldata:
280 break
281 return (ssldata, offset)
284class _SSLProtocolTransport(transports._FlowControlMixin,
285 transports.Transport):
287 _sendfile_compatible = constants._SendfileMode.FALLBACK
289 def __init__(self, loop, ssl_protocol):
290 self._loop = loop
291 # SSLProtocol instance
292 self._ssl_protocol = ssl_protocol
293 self._closed = False
295 def get_extra_info(self, name, default=None):
296 """Get optional transport information."""
297 return self._ssl_protocol._get_extra_info(name, default)
299 def set_protocol(self, protocol):
300 self._ssl_protocol._set_app_protocol(protocol)
302 def get_protocol(self):
303 return self._ssl_protocol._app_protocol
305 def is_closing(self):
306 return self._closed
308 def close(self):
309 """Close the transport.
311 Buffered data will be flushed asynchronously. No more data
312 will be received. After all buffered data is flushed, the
313 protocol's connection_lost() method will (eventually) called
314 with None as its argument.
315 """
316 self._closed = True
317 self._ssl_protocol._start_shutdown()
319 def __del__(self, _warn=warnings.warn):
320 if not self._closed:
321 _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
322 self.close()
324 def is_reading(self):
325 tr = self._ssl_protocol._transport
326 if tr is None:
327 raise RuntimeError('SSL transport has not been initialized yet')
328 return tr.is_reading()
330 def pause_reading(self):
331 """Pause the receiving end.
333 No data will be passed to the protocol's data_received()
334 method until resume_reading() is called.
335 """
336 self._ssl_protocol._transport.pause_reading()
338 def resume_reading(self):
339 """Resume the receiving end.
341 Data received will once again be passed to the protocol's
342 data_received() method.
343 """
344 self._ssl_protocol._transport.resume_reading()
346 def set_write_buffer_limits(self, high=None, low=None):
347 """Set the high- and low-water limits for write flow control.
349 These two values control when to call the protocol's
350 pause_writing() and resume_writing() methods. If specified,
351 the low-water limit must be less than or equal to the
352 high-water limit. Neither value can be negative.
354 The defaults are implementation-specific. If only the
355 high-water limit is given, the low-water limit defaults to an
356 implementation-specific value less than or equal to the
357 high-water limit. Setting high to zero forces low to zero as
358 well, and causes pause_writing() to be called whenever the
359 buffer becomes non-empty. Setting low to zero causes
360 resume_writing() to be called only once the buffer is empty.
361 Use of zero for either limit is generally sub-optimal as it
362 reduces opportunities for doing I/O and computation
363 concurrently.
364 """
365 self._ssl_protocol._transport.set_write_buffer_limits(high, low)
367 def get_write_buffer_size(self):
368 """Return the current size of the write buffer."""
369 return self._ssl_protocol._transport.get_write_buffer_size()
371 @property
372 def _protocol_paused(self):
373 # Required for sendfile fallback pause_writing/resume_writing logic
374 return self._ssl_protocol._transport._protocol_paused
376 def write(self, data):
377 """Write some data bytes to the transport.
379 This does not block; it buffers the data and arranges for it
380 to be sent out asynchronously.
381 """
382 if not isinstance(data, (bytes, bytearray, memoryview)):
383 raise TypeError(f"data: expecting a bytes-like instance, "
384 f"got {type(data).__name__}")
385 if not data:
386 return
387 self._ssl_protocol._write_appdata(data)
389 def can_write_eof(self):
390 """Return True if this transport supports write_eof(), False if not."""
391 return False
393 def abort(self):
394 """Close the transport immediately.
396 Buffered data will be lost. No more data will be received.
397 The protocol's connection_lost() method will (eventually) be
398 called with None as its argument.
399 """
400 self._ssl_protocol._abort()
401 self._closed = True
404class SSLProtocol(protocols.Protocol):
405 """SSL protocol.
407 Implementation of SSL on top of a socket using incoming and outgoing
408 buffers which are ssl.MemoryBIO objects.
409 """
411 def __init__(self, loop, app_protocol, sslcontext, waiter,
412 server_side=False, server_hostname=None,
413 call_connection_made=True,
414 ssl_handshake_timeout=None):
415 if ssl is None:
416 raise RuntimeError('stdlib ssl module not available')
418 if ssl_handshake_timeout is None:
419 ssl_handshake_timeout = constants.SSL_HANDSHAKE_TIMEOUT
420 elif ssl_handshake_timeout <= 0:
421 raise ValueError(
422 f"ssl_handshake_timeout should be a positive number, "
423 f"got {ssl_handshake_timeout}")
425 if not sslcontext:
426 sslcontext = _create_transport_context(
427 server_side, server_hostname)
429 self._server_side = server_side
430 if server_hostname and not server_side:
431 self._server_hostname = server_hostname
432 else:
433 self._server_hostname = None
434 self._sslcontext = sslcontext
435 # SSL-specific extra info. More info are set when the handshake
436 # completes.
437 self._extra = dict(sslcontext=sslcontext)
439 # App data write buffering
440 self._write_backlog = collections.deque()
441 self._write_buffer_size = 0
443 self._waiter = waiter
444 self._loop = loop
445 self._set_app_protocol(app_protocol)
446 self._app_transport = _SSLProtocolTransport(self._loop, self)
447 # _SSLPipe instance (None until the connection is made)
448 self._sslpipe = None
449 self._session_established = False
450 self._in_handshake = False
451 self._in_shutdown = False
452 # transport, ex: SelectorSocketTransport
453 self._transport = None
454 self._call_connection_made = call_connection_made
455 self._ssl_handshake_timeout = ssl_handshake_timeout
457 def _set_app_protocol(self, app_protocol):
458 self._app_protocol = app_protocol
459 self._app_protocol_is_buffer = \
460 isinstance(app_protocol, protocols.BufferedProtocol)
462 def _wakeup_waiter(self, exc=None):
463 if self._waiter is None:
464 return
465 if not self._waiter.cancelled():
466 if exc is not None:
467 self._waiter.set_exception(exc)
468 else:
469 self._waiter.set_result(None)
470 self._waiter = None
472 def connection_made(self, transport):
473 """Called when the low-level connection is made.
475 Start the SSL handshake.
476 """
477 self._transport = transport
478 self._sslpipe = _SSLPipe(self._sslcontext,
479 self._server_side,
480 self._server_hostname)
481 self._start_handshake()
483 def connection_lost(self, exc):
484 """Called when the low-level connection is lost or closed.
486 The argument is an exception object or None (the latter
487 meaning a regular EOF is received or the connection was
488 aborted or closed).
489 """
490 if self._session_established:
491 self._session_established = False
492 self._loop.call_soon(self._app_protocol.connection_lost, exc)
493 else:
494 # Most likely an exception occurred while in SSL handshake.
495 # Just mark the app transport as closed so that its __del__
496 # doesn't complain.
497 if self._app_transport is not None:
498 self._app_transport._closed = True
499 self._transport = None
500 self._app_transport = None
501 if getattr(self, '_handshake_timeout_handle', None):
502 self._handshake_timeout_handle.cancel()
503 self._wakeup_waiter(exc)
504 self._app_protocol = None
505 self._sslpipe = None
507 def pause_writing(self):
508 """Called when the low-level transport's buffer goes over
509 the high-water mark.
510 """
511 self._app_protocol.pause_writing()
513 def resume_writing(self):
514 """Called when the low-level transport's buffer drains below
515 the low-water mark.
516 """
517 self._app_protocol.resume_writing()
519 def data_received(self, data):
520 """Called when some SSL data is received.
522 The argument is a bytes object.
523 """
524 if self._sslpipe is None:
525 # transport closing, sslpipe is destroyed
526 return
528 try:
529 ssldata, appdata = self._sslpipe.feed_ssldata(data)
530 except (SystemExit, KeyboardInterrupt):
531 raise
532 except BaseException as e:
533 self._fatal_error(e, 'SSL error in data received')
534 return
536 for chunk in ssldata:
537 self._transport.write(chunk)
539 for chunk in appdata:
540 if chunk:
541 try:
542 if self._app_protocol_is_buffer:
543 protocols._feed_data_to_buffered_proto(
544 self._app_protocol, chunk)
545 else:
546 self._app_protocol.data_received(chunk)
547 except (SystemExit, KeyboardInterrupt):
548 raise
549 except BaseException as ex:
550 self._fatal_error(
551 ex, 'application protocol failed to receive SSL data')
552 return
553 else:
554 self._start_shutdown()
555 break
557 def eof_received(self):
558 """Called when the other end of the low-level stream
559 is half-closed.
561 If this returns a false value (including None), the transport
562 will close itself. If it returns a true value, closing the
563 transport is up to the protocol.
564 """
565 try:
566 if self._loop.get_debug():
567 logger.debug("%r received EOF", self)
569 self._wakeup_waiter(ConnectionResetError)
571 if not self._in_handshake:
572 keep_open = self._app_protocol.eof_received()
573 if keep_open:
574 logger.warning('returning true from eof_received() '
575 'has no effect when using ssl')
576 finally:
577 self._transport.close()
579 def _get_extra_info(self, name, default=None):
580 if name in self._extra:
581 return self._extra[name]
582 elif self._transport is not None:
583 return self._transport.get_extra_info(name, default)
584 else:
585 return default
587 def _start_shutdown(self):
588 if self._in_shutdown:
589 return
590 if self._in_handshake:
591 self._abort()
592 else:
593 self._in_shutdown = True
594 self._write_appdata(b'')
596 def _write_appdata(self, data):
597 self._write_backlog.append((data, 0))
598 self._write_buffer_size += len(data)
599 self._process_write_backlog()
601 def _start_handshake(self):
602 if self._loop.get_debug():
603 logger.debug("%r starts SSL handshake", self)
604 self._handshake_start_time = self._loop.time()
605 else:
606 self._handshake_start_time = None
607 self._in_handshake = True
608 # (b'', 1) is a special value in _process_write_backlog() to do
609 # the SSL handshake
610 self._write_backlog.append((b'', 1))
611 self._handshake_timeout_handle = \
612 self._loop.call_later(self._ssl_handshake_timeout,
613 self._check_handshake_timeout)
614 self._process_write_backlog()
616 def _check_handshake_timeout(self):
617 if self._in_handshake is True:
618 msg = (
619 f"SSL handshake is taking longer than "
620 f"{self._ssl_handshake_timeout} seconds: "
621 f"aborting the connection"
622 )
623 self._fatal_error(ConnectionAbortedError(msg))
625 def _on_handshake_complete(self, handshake_exc):
626 self._in_handshake = False
627 self._handshake_timeout_handle.cancel()
629 sslobj = self._sslpipe.ssl_object
630 try:
631 if handshake_exc is not None:
632 raise handshake_exc
634 peercert = sslobj.getpeercert()
635 except (SystemExit, KeyboardInterrupt):
636 raise
637 except BaseException as exc:
638 if isinstance(exc, ssl.CertificateError):
639 msg = 'SSL handshake failed on verifying the certificate'
640 else:
641 msg = 'SSL handshake failed'
642 self._fatal_error(exc, msg)
643 return
645 if self._loop.get_debug():
646 dt = self._loop.time() - self._handshake_start_time
647 logger.debug("%r: SSL handshake took %.1f ms", self, dt * 1e3)
649 # Add extra info that becomes available after handshake.
650 self._extra.update(peercert=peercert,
651 cipher=sslobj.cipher(),
652 compression=sslobj.compression(),
653 ssl_object=sslobj,
654 )
655 if self._call_connection_made:
656 self._app_protocol.connection_made(self._app_transport)
657 self._wakeup_waiter()
658 self._session_established = True
659 # In case transport.write() was already called. Don't call
660 # immediately _process_write_backlog(), but schedule it:
661 # _on_handshake_complete() can be called indirectly from
662 # _process_write_backlog(), and _process_write_backlog() is not
663 # reentrant.
664 self._loop.call_soon(self._process_write_backlog)
666 def _process_write_backlog(self):
667 # Try to make progress on the write backlog.
668 if self._transport is None or self._sslpipe is None:
669 return
671 try:
672 for i in range(len(self._write_backlog)):
673 data, offset = self._write_backlog[0]
674 if data:
675 ssldata, offset = self._sslpipe.feed_appdata(data, offset)
676 elif offset:
677 ssldata = self._sslpipe.do_handshake(
678 self._on_handshake_complete)
679 offset = 1
680 else:
681 ssldata = self._sslpipe.shutdown(self._finalize)
682 offset = 1
684 for chunk in ssldata:
685 self._transport.write(chunk)
687 if offset < len(data):
688 self._write_backlog[0] = (data, offset)
689 # A short write means that a write is blocked on a read
690 # We need to enable reading if it is paused!
691 assert self._sslpipe.need_ssldata
692 if self._transport._paused:
693 self._transport.resume_reading()
694 break
696 # An entire chunk from the backlog was processed. We can
697 # delete it and reduce the outstanding buffer size.
698 del self._write_backlog[0]
699 self._write_buffer_size -= len(data)
700 except (SystemExit, KeyboardInterrupt):
701 raise
702 except BaseException as exc:
703 if self._in_handshake:
704 # Exceptions will be re-raised in _on_handshake_complete.
705 self._on_handshake_complete(exc)
706 else:
707 self._fatal_error(exc, 'Fatal error on SSL transport')
709 def _fatal_error(self, exc, message='Fatal error on transport'):
710 if isinstance(exc, OSError):
711 if self._loop.get_debug():
712 logger.debug("%r: %s", self, message, exc_info=True)
713 else:
714 self._loop.call_exception_handler({
715 'message': message,
716 'exception': exc,
717 'transport': self._transport,
718 'protocol': self,
719 })
720 if self._transport:
721 self._transport._force_close(exc)
723 def _finalize(self):
724 self._sslpipe = None
726 if self._transport is not None:
727 self._transport.close()
729 def _abort(self):
730 try:
731 if self._transport is not None:
732 self._transport.abort()
733 finally:
734 self._finalize()