magic-wormhole/src/wormhole/_interfaces.py

460 lines
14 KiB
Python

from zope.interface import Interface
# These interfaces are private: we use them as markers to detect
# swapped argument bugs in the various .wire() calls
class IWormhole(Interface):
"""Internal: this contains the methods invoked 'from below'."""
def got_welcome(welcome):
pass
def got_code(code):
pass
def got_key(key):
pass
def got_verifier(verifier):
pass
def got_versions(versions):
pass
def received(plaintext):
pass
def closed(result):
pass
class IBoss(Interface):
pass
class INameplate(Interface):
pass
class IMailbox(Interface):
pass
class ISend(Interface):
pass
class IOrder(Interface):
pass
class IKey(Interface):
pass
class IReceive(Interface):
pass
class IRendezvousConnector(Interface):
pass
class ILister(Interface):
pass
class ICode(Interface):
pass
class IInput(Interface):
pass
class IAllocator(Interface):
pass
class ITerminator(Interface):
pass
class ITiming(Interface):
pass
class ITorManager(Interface):
pass
class IWordlist(Interface):
def choose_words(length):
"""Randomly select LENGTH words, join them with hyphens, return the
result."""
def get_completions(prefix):
"""Return a list of all suffixes that could complete the given
prefix."""
# These interfaces are public, and are re-exported by __init__.py
class IDeferredWormhole(Interface):
def get_welcome():
"""
Wait for the 'welcome message' dictionary, sent by the server upon
first connection.
:rtype: ``Deferred[dict]``
:return: the welcome dictionary, when it arrives from the server
"""
def allocate_code(code_length=2):
"""
Ask the wormhole to allocate a nameplate and generate a random code.
When the code is ready, any Deferreds returned by ``get_code()`` will
be fired. Only one of generate_code/set_code/input_code may be used.
:param int code_length: the number of random words to use. More
words means the code is harder to guess. Defaults to 2.
:return: None
~mod.class
"""
def set_code(code):
"""
Tell the wormhole to use a specific code, either copied from a
wormhole that used ``allocate_code``, or created out-of-band by
humans (and given to ``set_code`` on both wormholes).
Any Deferreds returned by ``get_code()`` will be fired as soon as
this is called. Only one of generate_code/set_code/input_code may be
used.
:return: None
"""
def input_code():
"""
Ask the wormhole to perform interactive entry of the code, with
completion on the nameplate and/or words.
This does not actually interact with the user, but instead returns a
'code-entry helper' object. The application is responsible for doing
the IO: the helper is used to get completion lists and to submit the
finished code. See ``input_with_completion`` for a wrapper function
that uses ``readline`` to do CLI-style input completion.
Any Deferreds returned by ``get_code()`` will be fired when the final
code is submitted to the helper. Only one of
generate_code/set_code/input_code may be used.
:return: a code-entry helper instance
:rtype: IHelper
"""
def get_code():
"""
Wait for the wormhole code to be established, then return the code.
This is really only useful on the initiating side, which needs to
deliver the code to the user (so the user can dictate it to the other
user, who can deliver it to their application with ``set_code`` or
``input_code``). On the receiving side, merely submitting the code
is sufficient.
The wormhole code is always unicode (so ``str`` on py3, ``unicode``
on py2).
For ``allocate_code``, this must wait for the server to allocate a
nameplate. For ``input_code``, it waits for the final code to be
submitted to the helper. For ``set_code``, it fires immediately.
:return: the wormhole code
:rtype: ``Deferred[str]``
"""
def get_unverified_key():
"""
Wait for key-exchange to occur, then return the raw unverified SPAKE2
key. When this fires, we have not seen any evidence that anyone else
shares this key (nor have we seen evidence of a failed attack: e.g. a
payload encrypted with a different key).
This is only useful for testing, and for noticing a significant delay
between the key-agreement message and the subsequent key-verification
("versions") message.
:return: the raw unverified SPAKE2 key
:rtype: ``Deferred[bytes]``
"""
def get_verifier():
"""
Wait for key verification to occur, then return the verifier string.
When this fires, we have seen at least one validly-encrypted message
from our peer, indicating that we have established a shared secret
key with some party who knows (or correctly guessed) the wormhole
code.
The verifier string (bytes) can be displayed to the user (perhaps as
hex), who can manually compare it with the peer's verifier, to obtain
more confidence in the secrecy of the established key.
If we receive an invalid encrypted message (such as what would happen
if an attacker tried and failed to guess the wormhole code), this
will instead errback with a ``WrongPasswordError``.
:return: the verifier string, after a valid encrypted message has
arrived
:rtype: ``Deferred[bytes]``
"""
def get_versions():
"""
Wait for a valid VERSION message to arrive, then return the peer's
"versions" dictionary. This dictionary comes from the ``versions=``
argument to the peer's ``wormhole()`` constructor, and is meant to
assist with capability-negotiation between the two peers. In
particular, the ``versions`` dictionary is delivered before either
side has called ``send_message()``, so it can influence the first
message sent to a peer that is too old to use that first message for
negotiation purposes.
If we receive any invalid encrypted message (such as what would
happen if an attacker tried and failed to guess the wormhole code),
this will instead errback with a ``WrongPasswordError``.
:return: the verisions dictionary
:rtype: ``Deferred[dict]``
"""
def derive_key(purpose, length):
"""
Derive a purpose-specific key.
This combines the master SPAKE2 key with the given purpose string and
deterministically derives a new key of the requested length. Any two
connected Wormhole objects which call ``derive_key`` with the same
purpose and length will get the same key. This can be used to
encrypt or sign other messages, or exchanged for verification
purposes. The master key will remain secret even if you reveal a
derivative key.
This must be called after the key has been established, so after any
of
``get_unverified_key()/get_verifier()/get_versions()/get_message()``
have fired. ``derive_key()`` returns immediately, rather than
returning a ``Deferred``.
:return: a derivative key, of the requested length
:rtype: ``bytes``
"""
def send_message(msg):
"""
Send a message to the connected peer.
This accepts a bytestring, and queues it for encryption and delivery
to the other side, where it will eventually appear in
``get_message()``. Messages are delivered in-order, and complete
(the Wormhole is a record-pipe, not a byte-pipe).
This can be called at any time, even before setting the wormhole
code. The message will be queued for delivery after the master key
is established.
:return: None
"""
def get_message():
"""
Wait for, and return, the next message.
This returns a Deferred that will fire when the next (sequential)
application message has been received and successfully decrypted.
Messages will be delivered in-order and intact (the Wormhole is a
record-pipe, not a byte-pipe).
This can be called at any time, even before setting the wormhole
code. The Deferred will not fire until key-negotiation has completed
and a validly-encrypted message has arrived.
If we receive any invalid encrypted message (such as what would
happen if an attacker tried and failed to guess the wormhole code),
this will instead errback with a ``WrongPasswordError``.
:return: the next decrypted message
:rtype: ``Deferred[bytes]``
"""
def close():
"""
Close the wormhole.
This frees all resources associated with the wormhole (including
server-side queues and any established network connections).
For operational purposes, it informs the server that the wormhole
closed "happy". Less-happy moods may be reported if the connection
closed due to a ``WrongPasswordError`` or because of a timeout.
``close()`` returns a Deferred, which fires after the server has been
informed and the sockets have been shut down. One-shot applications
should delay shutdown until this Deferred has fired, to increase the
chances that server resources will be freed. Long-running
applications can probably ignore the Deferred, as they'll probably
remain running long enough to allow the shutdown to complete.
The Deferred will errback if the wormhole had problems, like a
``WrongPasswordError``.
:return: a Deferred that fires when shutdown is complete
:rtype: ``Deferred``
"""
class IInputHelper(Interface):
def refresh_nameplates():
"""
Refresh the nameplates list.
This asks the server for the set of currently-active nameplates
(either from calls to ``allocate_code()`` or referenced by active
wormhole clients). It updates the set available to
``get_nameplate_completions()``.
:return: None
"""
def get_nameplate_completions(prefix):
"""
Return a list of nameplate completions for the given prefix.
This takes the most-recently-received set of active nameplates from
the rendezvous server, finds the subset that start with the given
prefix, and returns the result. The result strings include the
prefix and the terminating hyphen, in random order.
This returns synchronously: it does not wait for a server response.
If called before getting any response from the server, it will return
an empty set. If user input causes completion, it may be a good idea
to kick off a new ``refresh_nameplates()`` too, in case the user is
bouncing on the TAB key in the hopes of seeing their expected
nameplate appear in the list eventually.
:param str prefix: the nameplate as typed so far
:return: a set of potential completions
:rtype: set[str]
"""
def choose_nameplate(nameplate):
"""
Commit to a nameplate, allowing the word-completion phase to begin.
This may only be called once. Calling it a second time will raise
``AlreadyChoseNameplateError``.
:param str nameplate: the complete nameplate, without a trailing
hyphen
:return: None
"""
def when_wordlist_is_available():
"""
Wait for the wordlist to be available.
This fires when the wordlist is available, which means
``get_word_completions()`` is able to return a non-empty set. This
requires the nameplate be submitted, and may also require some server
interaction (to claim the channel and learn a channel-specific
wordlist, e.g. for i18n language selection).
:return: a ``Deferred`` that fires when the wordlist is available
:rtype: Deferred[None]
"""
def get_word_completions(prefix):
"""
Return a list of word completions for the given prefix.
This takes the claimed channel's wordlist, finds the subset that
start with the given prefix, and returns the result. The result
strings include the prefix and the terminating hyphen, in random
order.
The prefix should not include the nameplate, but should include
whatever words have been selected so far (the default uses separate
odd/even wordlists, which means the completion for a single string
depends upon how many words have been entered so far).
This returns synchronously: it does not wait for a server response.
If called before getting the wordlist, it will return an empty set.
If called before ``choose_nameplate()``, this will raise
``MustChooseNameplateFirstError``. If called after
``choose_words()``, this will raise ``AlreadyChoseWordsError``.
:param str prefix: the words typed so far
:return: a set of potential completions
:rtype: set[str]
"""
def choose_words(words):
"""
Submit the final words.
This should be called when the user is finished typing in the code,
and terminates the code-entry process. It does not return anything,
but will cause the Wormhole's ``w.get_code()`` to fire, and initiates
the wormhole connection process.
It accepts a string like "purple-sausages", without the leading
nameplate (which must have been submitted to ``choose_nameplate()``
earlier) or its hyphen. If ``choose_nameplate()`` was not called
first, this will raise ``MustChooseNameplateFirstError``.
This may only be called once, otherwise ``AlreadyChoseWordsError``
will be raised.
:param str words: the 'words' portion of the wormhole code
:return: None
"""
class IJournal(Interface): # TODO: this needs to be public
pass
class IDilator(Interface):
pass
class IDilationManager(Interface):
pass
class IDilationConnector(Interface):
pass
class ISubChannel(Interface):
pass
class IInbound(Interface):
pass
class IOutbound(Interface):
pass