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# -*- coding: utf-8 -*-
# http_target.py
# Copyright (C) 2015 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
A U1DB backend for encrypting data before sending to server and decrypting
after receiving.
"""
import json
import base64
import logging
from uuid import uuid4
from twisted.internet import defer
from twisted.web.error import Error
from u1db import errors
from u1db import SyncTarget
from u1db.remote import utils
from leap.common.http import HTTPClient
from leap.soledad.common.document import SoledadDocument
from leap.soledad.common.errors import InvalidAuthTokenError
from leap.soledad.client.crypto import is_symmetrically_encrypted
from leap.soledad.client.crypto import encrypt_doc
from leap.soledad.client.crypto import decrypt_doc
from leap.soledad.client.events import SOLEDAD_SYNC_SEND_STATUS
from leap.soledad.client.events import SOLEDAD_SYNC_RECEIVE_STATUS
from leap.soledad.client.events import emit
from leap.soledad.client.encdecpool import SyncDecrypterPool
logger = logging.getLogger(__name__)
class SoledadHTTPSyncTarget(SyncTarget):
"""
A SyncTarget that encrypts data before sending and decrypts data after
receiving.
Normally encryption will have been written to the sync database upon
document modification. The sync database is also used to write temporarily
the parsed documents that the remote send us, before being decrypted and
written to the main database.
"""
def __init__(self, url, source_replica_uid, creds, crypto, cert_file,
sync_db=None, sync_enc_pool=None):
"""
Initialize the sync target.
:param url: The server sync url.
:type url: str
:param source_replica_uid: The source replica uid which we use when
deferring decryption.
:type source_replica_uid: str
:param creds: A dictionary containing the uuid and token.
:type creds: creds
:param crypto: An instance of SoledadCrypto so we can encrypt/decrypt
document contents when syncing.
:type crypto: soledad.crypto.SoledadCrypto
:param cert_file: Path to the certificate of the ca used to validate
the SSL certificate used by the remote soledad
server.
:type cert_file: str
:param sync_db: Optional. handler for the db with the symmetric
encryption of the syncing documents. If
None, encryption will be done in-place,
instead of retreiving it from the dedicated
database.
:type sync_db: Sqlite handler
:param verify_ssl: Whether we should perform SSL server certificate
verification.
:type verify_ssl: bool
"""
if url.endswith("/"):
url = url[:-1]
self._url = str(url) + "/sync-from/" + str(source_replica_uid)
self.source_replica_uid = source_replica_uid
self._auth_header = None
self.set_creds(creds)
self._crypto = crypto
self._sync_db = sync_db
self._sync_enc_pool = sync_enc_pool
self._insert_doc_cb = None
# asynchronous encryption/decryption attributes
self._decryption_callback = None
self._sync_decr_pool = None
self._http = HTTPClient(cert_file)
def close(self):
self._http.close()
def set_creds(self, creds):
"""
Update credentials.
:param creds: A dictionary containing the uuid and token.
:type creds: dict
"""
uuid = creds['token']['uuid']
token = creds['token']['token']
auth = '%s:%s' % (uuid, token)
b64_token = base64.b64encode(auth)
self._auth_header = {'Authorization': ['Token %s' % b64_token]}
@property
def _defer_encryption(self):
return self._sync_enc_pool is not None
#
# SyncTarget API
#
@defer.inlineCallbacks
def get_sync_info(self, source_replica_uid):
"""
Return information about known state of remote database.
Return the replica_uid and the current database generation of the
remote database, and its last-seen database generation for the client
replica.
:param source_replica_uid: The client-size replica uid.
:type source_replica_uid: str
:return: A deferred which fires with (target_replica_uid,
target_replica_generation, target_trans_id,
source_replica_last_known_generation,
source_replica_last_known_transaction_id)
:rtype: twisted.internet.defer.Deferred
"""
raw = yield self._http_request(self._url, headers=self._auth_header)
res = json.loads(raw)
defer.returnValue([
res['target_replica_uid'],
res['target_replica_generation'],
res['target_replica_transaction_id'],
res['source_replica_generation'],
res['source_transaction_id']
])
def record_sync_info(
self, source_replica_uid, source_replica_generation,
source_replica_transaction_id):
"""
Record tip information for another replica.
After sync_exchange has been processed, the caller will have
received new content from this replica. This call allows the
source replica instigating the sync to inform us what their
generation became after applying the documents we returned.
This is used to allow future sync operations to not need to repeat data
that we just talked about. It also means that if this is called at the
wrong time, there can be database records that will never be
synchronized.
:param source_replica_uid: The identifier for the source replica.
:type source_replica_uid: str
:param source_replica_generation: The database generation for the
source replica.
:type source_replica_generation: int
:param source_replica_transaction_id: The transaction id associated
with the source replica
generation.
:type source_replica_transaction_id: str
:return: A deferred which fires with the result of the query.
:rtype: twisted.internet.defer.Deferred
"""
data = json.dumps({
'generation': source_replica_generation,
'transaction_id': source_replica_transaction_id
})
headers = self._auth_header.copy()
headers.update({'content-type': ['application/json']})
return self._http_request(
self._url,
method='PUT',
headers=headers,
body=data)
@defer.inlineCallbacks
def sync_exchange(self, docs_by_generation, source_replica_uid,
last_known_generation, last_known_trans_id,
insert_doc_cb, ensure_callback=None,
defer_decryption=True, sync_id=None):
"""
Find out which documents the remote database does not know about,
encrypt and send them. After that, receive documents from the remote
database.
:param docs_by_generations: A list of (doc_id, generation, trans_id)
of local documents that were changed since
the last local generation the remote
replica knows about.
:type docs_by_generations: list of tuples
:param source_replica_uid: The uid of the source replica.
:type source_replica_uid: str
:param last_known_generation: Target's last known generation.
:type last_known_generation: int
:param last_known_trans_id: Target's last known transaction id.
:type last_known_trans_id: str
:param insert_doc_cb: A callback for inserting received documents from
target. If not overriden, this will call u1db
insert_doc_from_target in synchronizer, which
implements the TAKE OTHER semantics.
:type insert_doc_cb: function
:param ensure_callback: A callback that ensures we know the target
replica uid if the target replica was just
created.
:type ensure_callback: function
:param defer_decryption: Whether to defer the decryption process using
the intermediate database. If False,
decryption will be done inline.
:type defer_decryption: bool
:return: A deferred which fires with the new generation and
transaction id of the target replica.
:rtype: twisted.internet.defer.Deferred
"""
self._ensure_callback = ensure_callback
if sync_id is None:
sync_id = str(uuid4())
self.source_replica_uid = source_replica_uid
# save a reference to the callback so we can use it after decrypting
self._insert_doc_cb = insert_doc_cb
gen_after_send, trans_id_after_send = yield self._send_docs(
docs_by_generation,
last_known_generation,
last_known_trans_id,
sync_id)
cur_target_gen, cur_target_trans_id = yield self._receive_docs(
last_known_generation, last_known_trans_id,
ensure_callback, sync_id,
defer_decryption=defer_decryption)
# update gen and trans id info in case we just sent and did not
# receive docs.
if gen_after_send is not None and gen_after_send > cur_target_gen:
cur_target_gen = gen_after_send
cur_target_trans_id = trans_id_after_send
defer.returnValue([cur_target_gen, cur_target_trans_id])
#
# methods to send docs
#
def _prepare(self, comma, entries, **dic):
entry = comma + '\r\n' + json.dumps(dic)
entries.append(entry)
return len(entry)
@defer.inlineCallbacks
def _send_docs(self, docs_by_generation, last_known_generation,
last_known_trans_id, sync_id):
if not docs_by_generation:
defer.returnValue([None, None])
headers = self._auth_header.copy()
headers.update({'content-type': ['application/x-soledad-sync-put']})
# add remote replica metadata to the request
first_entries = ['[']
self._prepare(
'', first_entries,
last_known_generation=last_known_generation,
last_known_trans_id=last_known_trans_id,
sync_id=sync_id,
ensure=self._ensure_callback is not None)
idx = 0
total = len(docs_by_generation)
for doc, gen, trans_id in docs_by_generation:
idx += 1
result = yield self._send_one_doc(
headers, first_entries, doc,
gen, trans_id, total, idx)
if self._defer_encryption:
self._sync_enc_pool.delete_encrypted_doc(
doc.doc_id, doc.rev)
emit(SOLEDAD_SYNC_SEND_STATUS,
"Soledad sync send status: %d/%d"
% (idx, total))
response_dict = json.loads(result)[0]
gen_after_send = response_dict['new_generation']
trans_id_after_send = response_dict['new_transaction_id']
defer.returnValue([gen_after_send, trans_id_after_send])
@defer.inlineCallbacks
def _send_one_doc(self, headers, first_entries, doc, gen, trans_id,
number_of_docs, doc_idx):
entries = first_entries[:]
# add the document to the request
content = yield self._encrypt_doc(doc)
self._prepare(
',', entries,
id=doc.doc_id, rev=doc.rev, content=content, gen=gen,
trans_id=trans_id, number_of_docs=number_of_docs,
doc_idx=doc_idx)
entries.append('\r\n]')
data = ''.join(entries)
result = yield self._http_request(
self._url,
method='POST',
headers=headers,
body=data)
defer.returnValue(result)
def _encrypt_doc(self, doc):
d = None
if doc.is_tombstone():
d = defer.succeed(None)
elif not self._defer_encryption:
# fallback case, for tests
d = defer.succeed(encrypt_doc(self._crypto, doc))
else:
def _maybe_encrypt_doc_inline(doc_json):
if doc_json is None:
# the document is not marked as tombstone, but we got
# nothing from the sync db. As it is not encrypted
# yet, we force inline encryption.
return encrypt_doc(self._crypto, doc)
return doc_json
d = self._sync_enc_pool.get_encrypted_doc(doc.doc_id, doc.rev)
d.addCallback(_maybe_encrypt_doc_inline)
return d
#
# methods to receive doc
#
@defer.inlineCallbacks
def _receive_docs(self, last_known_generation, last_known_trans_id,
ensure_callback, sync_id, defer_decryption):
self._queue_for_decrypt = defer_decryption \
and self._sync_db is not None
new_generation = last_known_generation
new_transaction_id = last_known_trans_id
if self._queue_for_decrypt:
logger.debug(
"Soledad sync: will queue received docs for decrypting.")
if defer_decryption:
self._setup_sync_decr_pool()
headers = self._auth_header.copy()
headers.update({'content-type': ['application/x-soledad-sync-get']})
# ---------------------------------------------------------------------
# maybe receive the first document
# ---------------------------------------------------------------------
# we fetch the first document before fetching the rest because we need
# to know the total number of documents to be received, and this
# information comes as metadata to each request.
doc = yield self._receive_one_doc(
headers, last_known_generation, last_known_trans_id,
sync_id, 0)
self._received_docs = 0
number_of_changes, ngen, ntrans = self._insert_received_doc(doc, 1, 1)
if defer_decryption:
self._sync_decr_pool.start(number_of_changes)
# ---------------------------------------------------------------------
# maybe receive the rest of the documents
# ---------------------------------------------------------------------
# launch many asynchronous fetches and inserts of received documents
# in the temporary sync db. Will wait for all results before
# continuing.
received = 1
deferreds = []
while received < number_of_changes:
d = self._receive_one_doc(
headers, last_known_generation,
last_known_trans_id, sync_id, received)
d.addCallback(
self._insert_received_doc,
received + 1, # the index of the current received doc
number_of_changes)
deferreds.append(d)
received += 1
results = yield defer.gatherResults(deferreds)
# get generation and transaction id of target after insertions
if deferreds:
_, new_generation, new_transaction_id = results.pop()
# ---------------------------------------------------------------------
# wait for async decryption to finish
# ---------------------------------------------------------------------
if defer_decryption:
yield self._sync_decr_pool.deferred
self._sync_decr_pool.close()
defer.returnValue([new_generation, new_transaction_id])
def _receive_one_doc(self, headers, last_known_generation,
last_known_trans_id, sync_id, received):
entries = ['[']
# add remote replica metadata to the request
self._prepare(
'', entries,
last_known_generation=last_known_generation,
last_known_trans_id=last_known_trans_id,
sync_id=sync_id,
ensure=self._ensure_callback is not None)
# inform server of how many documents have already been received
self._prepare(
',', entries, received=received)
entries.append('\r\n]')
# send headers
return self._http_request(
self._url,
method='POST',
headers=headers,
body=''.join(entries))
def _insert_received_doc(self, response, idx, total):
"""
Insert a received document into the local replica.
:param response: The body and headers of the response.
:type response: tuple(str, dict)
:param idx: The index count of the current operation.
:type idx: int
:param total: The total number of operations.
:type total: int
"""
new_generation, new_transaction_id, number_of_changes, doc_id, \
rev, content, gen, trans_id = \
self._parse_received_doc_response(response)
if doc_id is not None:
# decrypt incoming document and insert into local database
# -------------------------------------------------------------
# symmetric decryption of document's contents
# -------------------------------------------------------------
# If arriving content was symmetrically encrypted, we decrypt it.
# We do it inline if defer_decryption flag is False or no sync_db
# was defined, otherwise we defer it writing it to the received
# docs table.
doc = SoledadDocument(doc_id, rev, content)
if is_symmetrically_encrypted(doc):
if self._queue_for_decrypt:
self._sync_decr_pool.insert_encrypted_received_doc(
doc.doc_id, doc.rev, doc.content, gen, trans_id,
idx)
else:
# defer_decryption is False or no-sync-db fallback
doc.set_json(decrypt_doc(self._crypto, doc))
self._insert_doc_cb(doc, gen, trans_id)
else:
# not symmetrically encrypted doc, insert it directly
# or save it in the decrypted stage.
if self._queue_for_decrypt:
self._sync_decr_pool.insert_received_doc(
doc.doc_id, doc.rev, doc.content, gen, trans_id,
idx)
else:
self._insert_doc_cb(doc, gen, trans_id)
# -------------------------------------------------------------
# end of symmetric decryption
# -------------------------------------------------------------
self._received_docs += 1
msg = "%d/%d" % (self._received_docs, total)
emit(SOLEDAD_SYNC_RECEIVE_STATUS, msg)
logger.debug("Sync receive status: %s" % msg)
return number_of_changes, new_generation, new_transaction_id
def _parse_received_doc_response(self, response):
"""
Parse the response from the server containing the received document.
:param response: The body and headers of the response.
:type response: tuple(str, dict)
:return: (new_gen, new_trans_id, number_of_changes, doc_id, rev,
content, gen, trans_id)
:rtype: tuple
"""
# decode incoming stream
parts = response.splitlines()
if not parts or parts[0] != '[' or parts[-1] != ']':
raise errors.BrokenSyncStream
data = parts[1:-1]
# decode metadata
line, comma = utils.check_and_strip_comma(data[0])
metadata = None
try:
metadata = json.loads(line)
new_generation = metadata['new_generation']
new_transaction_id = metadata['new_transaction_id']
number_of_changes = metadata['number_of_changes']
except (json.JSONDecodeError, KeyError):
raise errors.BrokenSyncStream
# make sure we have replica_uid from fresh new dbs
if self._ensure_callback and 'replica_uid' in metadata:
self._ensure_callback(metadata['replica_uid'])
# parse incoming document info
doc_id = None
rev = None
content = None
gen = None
trans_id = None
if number_of_changes > 0:
try:
entry = json.loads(data[1])
doc_id = entry['id']
rev = entry['rev']
content = entry['content']
gen = entry['gen']
trans_id = entry['trans_id']
except (IndexError, KeyError):
raise errors.BrokenSyncStream
return new_generation, new_transaction_id, number_of_changes, \
doc_id, rev, content, gen, trans_id
def _setup_sync_decr_pool(self):
"""
Set up the SyncDecrypterPool for deferred decryption.
"""
if self._sync_decr_pool is None and self._sync_db is not None:
# initialize syncing queue decryption pool
self._sync_decr_pool = SyncDecrypterPool(
self._crypto,
self._sync_db,
insert_doc_cb=self._insert_doc_cb,
source_replica_uid=self.source_replica_uid)
def _http_request(self, url, method='GET', body=None, headers={}):
d = self._http.request(url, method, body, headers)
d.addErrback(_unauth_to_invalid_token_error)
return d
def _unauth_to_invalid_token_error(failure):
"""
An errback to translate unauthorized errors to our own invalid token
class.
:param failure: The original failure.
:type failure: twisted.python.failure.Failure
:return: Either the original failure or an invalid auth token error.
:rtype: twisted.python.failure.Failure
"""
failure.trap(Error)
if failure.getErrorMessage() == "401 Unauthorized":
raise InvalidAuthTokenError
return failure
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