diff options
Diffstat (limited to 'client')
| -rw-r--r-- | client/src/leap/soledad/client/__init__.py | 3 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/adbapi.py | 77 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/mp_safe_db.py | 2 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/pragmas.py | 349 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/sqlcipher.py | 565 |
5 files changed, 538 insertions, 458 deletions
diff --git a/client/src/leap/soledad/client/__init__.py b/client/src/leap/soledad/client/__init__.py index 0750dfbe..50fcff2c 100644 --- a/client/src/leap/soledad/client/__init__.py +++ b/client/src/leap/soledad/client/__init__.py @@ -374,7 +374,8 @@ class Soledad(object): include_deleted=include_deleted) def get_all_docs(self, include_deleted=False): - """Get the JSON content for all documents in the database. + """ + Get the JSON content for all documents in the database. :param include_deleted: If set to True, deleted documents will be returned with empty content. Otherwise deleted diff --git a/client/src/leap/soledad/client/adbapi.py b/client/src/leap/soledad/client/adbapi.py new file mode 100644 index 00000000..730999a3 --- /dev/null +++ b/client/src/leap/soledad/client/adbapi.py @@ -0,0 +1,77 @@ +# -*- coding: utf-8 -*- +# sqlcipher.py +# Copyright (C) 2013, 2014 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/>. +""" +An asyncrhonous interface to soledad using sqlcipher backend. +It uses twisted.enterprise.adbapi. + +""" +import os +import sys + +from twisted.enterprise import adbapi +from twisted.python import log + +DEBUG_SQL = os.environ.get("LEAP_DEBUG_SQL") +if DEBUG_SQL: + log.startLogging(sys.stdout) + + +def getConnectionPool(db=None, key=None): + return SQLCipherConnectionPool( + "pysqlcipher.dbapi2", database=db, key=key, check_same_thread=False) + + +class SQLCipherConnectionPool(adbapi.ConnectionPool): + + key = None + + def connect(self): + """ + Return a database connection when one becomes available. + + This method blocks and should be run in a thread from the internal + threadpool. Don't call this method directly from non-threaded code. + Using this method outside the external threadpool may exceed the + maximum number of connections in the pool. + + :return: a database connection from the pool. + """ + self.noisy = DEBUG_SQL + + tid = self.threadID() + conn = self.connections.get(tid) + + if self.key is None: + self.key = self.connkw.pop('key', None) + + if conn is None: + if self.noisy: + log.msg('adbapi connecting: %s %s%s' % (self.dbapiName, + self.connargs or '', + self.connkw or '')) + conn = self.dbapi.connect(*self.connargs, **self.connkw) + + # XXX we should hook here all OUR SOLEDAD pragmas ----- + conn.cursor().execute("PRAGMA key=%s" % self.key) + conn.commit() + # ----------------------------------------------------- + # XXX profit of openfun isntead??? + + if self.openfun is not None: + self.openfun(conn) + self.connections[tid] = conn + return conn diff --git a/client/src/leap/soledad/client/mp_safe_db.py b/client/src/leap/soledad/client/mp_safe_db.py index 780b7153..9ed0bef4 100644 --- a/client/src/leap/soledad/client/mp_safe_db.py +++ b/client/src/leap/soledad/client/mp_safe_db.py @@ -88,7 +88,7 @@ class MPSafeSQLiteDB(Thread): res = Queue() self.execute(req, arg, res) while True: - rec=res.get() + rec = res.get() if rec == self.NO_MORE: break yield rec diff --git a/client/src/leap/soledad/client/pragmas.py b/client/src/leap/soledad/client/pragmas.py new file mode 100644 index 00000000..a21e68a8 --- /dev/null +++ b/client/src/leap/soledad/client/pragmas.py @@ -0,0 +1,349 @@ +# -*- coding: utf-8 -*- +# pragmas.py +# Copyright (C) 2013, 2014 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/>. +""" +Different pragmas used in the SQLCIPHER database. +""" +# TODO --------------------------------------------------------------- +# Work In Progress. +# We need to reduce the impedance mismatch between the current soledad +# implementation and the eventually asynchronous api. +# So... how to plug it in, allowing for an optional sync / async coexistence? +# One of the first things is to isolate all the pragmas work that has to be +# done during initialization. +# And, instead of having all of them passed the db_handle and executing that, +# we could have just a string returned, that can be chained to a deferred. +# --------------------------------------------------------------------- +import logging +import string + +logger = logging.getLogger(__name__) + + +def set_crypto_pragmas(db_handle, sqlcipher_opts): + """ + Set cryptographic params (key, cipher, KDF number of iterations and + cipher page size). + + :param db_handle: + :type db_handle: + :param sqlcipher_opts: options for the SQLCipherDatabase + :type sqlcipher_opts: SQLCipherOpts instance + """ + # XXX assert CryptoOptions + opts = sqlcipher_opts + _set_key(db_handle, opts.key, opts.is_raw_key) + _set_cipher(db_handle, opts.cipher) + _set_kdf_iter(db_handle, opts.kdf_iter) + _set_cipher_page_size(db_handle, opts.cipher_page_size) + + +def _set_key(db_handle, key, is_raw_key): + """ + Set the C{key} for use with the database. + + The process of creating a new, encrypted database is called 'keying' + the database. SQLCipher uses just-in-time key derivation at the point + it is first needed for an operation. This means that the key (and any + options) must be set before the first operation on the database. As + soon as the database is touched (e.g. SELECT, CREATE TABLE, UPDATE, + etc.) and pages need to be read or written, the key is prepared for + use. + + Implementation Notes: + + * PRAGMA key should generally be called as the first operation on a + database. + + :param key: The key for use with the database. + :type key: str + :param is_raw_key: Whether C{key} is a raw 64-char hex string or a + passphrase that should be hashed to obtain the + encyrption key. + :type is_raw_key: bool + """ + if is_raw_key: + _set_key_raw(db_handle, key) + else: + _set_key_passphrase(db_handle, key) + + +def _set_key_passphrase(cls, db_handle, passphrase): + """ + Set a passphrase for encryption key derivation. + + The key itself can be a passphrase, which is converted to a key using + PBKDF2 key derivation. The result is used as the encryption key for + the database. By using this method, there is no way to alter the KDF; + if you want to do so you should use a raw key instead and derive the + key using your own KDF. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param passphrase: The passphrase used to derive the encryption key. + :type passphrase: str + """ + db_handle.cursor().execute("PRAGMA key = '%s'" % passphrase) + + +def _set_key_raw(db_handle, key): + """ + Set a raw hexadecimal encryption key. + + It is possible to specify an exact byte sequence using a blob literal. + With this method, it is the calling application's responsibility to + ensure that the data provided is a 64 character hex string, which will + be converted directly to 32 bytes (256 bits) of key data. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param key: A 64 character hex string. + :type key: str + """ + if not all(c in string.hexdigits for c in key): + raise NotAnHexString(key) + db_handle.cursor().execute('PRAGMA key = "x\'%s"' % key) + + +def _set_cipher(db_handle, cipher='aes-256-cbc'): + """ + Set the cipher and mode to use for symmetric encryption. + + SQLCipher uses aes-256-cbc as the default cipher and mode of + operation. It is possible to change this, though not generally + recommended, using PRAGMA cipher. + + SQLCipher makes direct use of libssl, so all cipher options available + to libssl are also available for use with SQLCipher. See `man enc` for + OpenSSL's supported ciphers. + + Implementation Notes: + + * PRAGMA cipher must be called after PRAGMA key and before the first + actual database operation or it will have no effect. + + * If a non-default value is used PRAGMA cipher to create a database, + it must also be called every time that database is opened. + + * SQLCipher does not implement its own encryption. Instead it uses the + widely available and peer-reviewed OpenSSL libcrypto for all + cryptographic functions. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param cipher: The cipher and mode to use. + :type cipher: str + """ + db_handle.cursor().execute("PRAGMA cipher = '%s'" % cipher) + + +def _set_kdf_iter(db_handle, kdf_iter=4000): + """ + Set the number of iterations for the key derivation function. + + SQLCipher uses PBKDF2 key derivation to strengthen the key and make it + resistent to brute force and dictionary attacks. The default + configuration uses 4000 PBKDF2 iterations (effectively 16,000 SHA1 + operations). PRAGMA kdf_iter can be used to increase or decrease the + number of iterations used. + + Implementation Notes: + + * PRAGMA kdf_iter must be called after PRAGMA key and before the first + actual database operation or it will have no effect. + + * If a non-default value is used PRAGMA kdf_iter to create a database, + it must also be called every time that database is opened. + + * It is not recommended to reduce the number of iterations if a + passphrase is in use. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param kdf_iter: The number of iterations to use. + :type kdf_iter: int + """ + db_handle.cursor().execute("PRAGMA kdf_iter = '%d'" % kdf_iter) + + +def _set_cipher_page_size(db_handle, cipher_page_size=1024): + """ + Set the page size of the encrypted database. + + SQLCipher 2 introduced the new PRAGMA cipher_page_size that can be + used to adjust the page size for the encrypted database. The default + page size is 1024 bytes, but it can be desirable for some applications + to use a larger page size for increased performance. For instance, + some recent testing shows that increasing the page size can noticeably + improve performance (5-30%) for certain queries that manipulate a + large number of pages (e.g. selects without an index, large inserts in + a transaction, big deletes). + + To adjust the page size, call the pragma immediately after setting the + key for the first time and each subsequent time that you open the + database. + + Implementation Notes: + + * PRAGMA cipher_page_size must be called after PRAGMA key and before + the first actual database operation or it will have no effect. + + * If a non-default value is used PRAGMA cipher_page_size to create a + database, it must also be called every time that database is opened. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param cipher_page_size: The page size. + :type cipher_page_size: int + """ + db_handle.cursor().execute( + "PRAGMA cipher_page_size = '%d'" % cipher_page_size) + + +# XXX UNUSED ? +def set_rekey(db_handle, new_key, is_raw_key): + """ + Change the key of an existing encrypted database. + + To change the key on an existing encrypted database, it must first be + unlocked with the current encryption key. Once the database is + readable and writeable, PRAGMA rekey can be used to re-encrypt every + page in the database with a new key. + + * PRAGMA rekey must be called after PRAGMA key. It can be called at any + time once the database is readable. + + * PRAGMA rekey can not be used to encrypted a standard SQLite + database! It is only useful for changing the key on an existing + database. + + * Previous versions of SQLCipher provided a PRAGMA rekey_cipher and + code>PRAGMA rekey_kdf_iter. These are deprecated and should not be + used. Instead, use sqlcipher_export(). + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param new_key: The new key. + :type new_key: str + :param is_raw_key: Whether C{password} is a raw 64-char hex string or a + passphrase that should be hashed to obtain the encyrption + key. + :type is_raw_key: bool + """ + if is_raw_key: + _set_rekey_raw(db_handle, new_key) + else: + _set_rekey_passphrase(db_handle, new_key) + + +def _set_rekey_passphrase(db_handle, passphrase): + """ + Change the passphrase for encryption key derivation. + + The key itself can be a passphrase, which is converted to a key using + PBKDF2 key derivation. The result is used as the encryption key for + the database. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param passphrase: The passphrase used to derive the encryption key. + :type passphrase: str + """ + db_handle.cursor().execute("PRAGMA rekey = '%s'" % passphrase) + + +def _set_rekey_raw(cls, db_handle, key): + """ + Change the raw hexadecimal encryption key. + + It is possible to specify an exact byte sequence using a blob literal. + With this method, it is the calling application's responsibility to + ensure that the data provided is a 64 character hex string, which will + be converted directly to 32 bytes (256 bits) of key data. + + :param db_handle: A handle to the SQLCipher database. + :type db_handle: pysqlcipher.Connection + :param key: A 64 character hex string. + :type key: str + """ + if not all(c in string.hexdigits for c in key): + raise NotAnHexString(key) + db_handle.cursor().execute('PRAGMA rekey = "x\'%s"' % key) + + +def set_synchronous_off(db_handle): + """ + Change the setting of the "synchronous" flag to OFF. + """ + logger.debug("SQLCIPHER: SETTING SYNCHRONOUS OFF") + db_handle.cursor().execute('PRAGMA synchronous=OFF') + + +def set_synchronous_normal(db_handle): + """ + Change the setting of the "synchronous" flag to NORMAL. + """ + logger.debug("SQLCIPHER: SETTING SYNCHRONOUS NORMAL") + db_handle.cursor().execute('PRAGMA synchronous=NORMAL') + + +def set_mem_temp_store(cls, db_handle): + """ + Use a in-memory store for temporary tables. + """ + logger.debug("SQLCIPHER: SETTING TEMP_STORE MEMORY") + db_handle.cursor().execute('PRAGMA temp_store=MEMORY') + + +def set_write_ahead_logging(cls, db_handle): + """ + Enable write-ahead logging, and set the autocheckpoint to 50 pages. + + Setting the autocheckpoint to a small value, we make the reads not + suffer too much performance degradation. + + From the sqlite docs: + + "There is a tradeoff between average read performance and average write + performance. To maximize the read performance, one wants to keep the + WAL as small as possible and hence run checkpoints frequently, perhaps + as often as every COMMIT. To maximize write performance, one wants to + amortize the cost of each checkpoint over as many writes as possible, + meaning that one wants to run checkpoints infrequently and let the WAL + grow as large as possible before each checkpoint. The decision of how + often to run checkpoints may therefore vary from one application to + another depending on the relative read and write performance + requirements of the application. The default strategy is to run a + checkpoint once the WAL reaches 1000 pages" + """ + logger.debug("SQLCIPHER: SETTING WRITE-AHEAD LOGGING") + db_handle.cursor().execute('PRAGMA journal_mode=WAL') + # The optimum value can still use a little bit of tuning, but we favor + # small sizes of the WAL file to get fast reads, since we assume that + # the writes will be quick enough to not block too much. + + # TODO + # As a further improvement, we might want to set autocheckpoint to 0 + # here and do the checkpoints manually in a separate thread, to avoid + # any blocks in the main thread (we should run a loopingcall from here) + db_handle.cursor().execute('PRAGMA wal_autocheckpoint=50') + + +class NotAnHexString(Exception): + """ + Raised when trying to (raw) key the database with a non-hex string. + """ + pass diff --git a/client/src/leap/soledad/client/sqlcipher.py b/client/src/leap/soledad/client/sqlcipher.py index 45629045..613903f7 100644 --- a/client/src/leap/soledad/client/sqlcipher.py +++ b/client/src/leap/soledad/client/sqlcipher.py @@ -44,7 +44,6 @@ handled by Soledad should be created by SQLCipher >= 2.0. import logging import multiprocessing import os -import string import threading import time import json @@ -64,6 +63,7 @@ from leap.soledad.client.target import SoledadSyncTarget from leap.soledad.client.target import PendingReceivedDocsSyncError from leap.soledad.client.sync import SoledadSynchronizer from leap.soledad.client.mp_safe_db import MPSafeSQLiteDB +from leap.soledad.client import pragmas from leap.soledad.common import soledad_assert from leap.soledad.common.document import SoledadDocument @@ -91,6 +91,55 @@ SQLITE_CHECK_SAME_THREAD = False SQLITE_ISOLATION_LEVEL = None +class SQLCipherOptions(object): + def __init__(self, path, key, create=True, is_raw_key=False, + cipher='aes-256-cbc', kdf_iter=4000, cipher_page_size=1024, + document_factory=None, defer_encryption=False, + sync_db_key=None): + """ + Options for the initialization of an SQLCipher database. + + :param path: The filesystem path for the database to open. + :type path: str + :param create: + True/False, should the database be created if it doesn't + already exist? + :param create: bool + :param document_factory: + A function that will be called with the same parameters as + Document.__init__. + :type document_factory: callable + :param crypto: An instance of SoledadCrypto so we can encrypt/decrypt + document contents when syncing. + :type crypto: soledad.crypto.SoledadCrypto + :param is_raw_key: + Whether ``password`` is a raw 64-char hex string or a passphrase + that should be hashed to obtain the encyrption key. + :type raw_key: bool + :param cipher: The cipher and mode to use. + :type cipher: str + :param kdf_iter: The number of iterations to use. + :type kdf_iter: int + :param cipher_page_size: The page size. + :type cipher_page_size: int + :param defer_encryption: + Whether to defer encryption/decryption of documents, or do it + inline while syncing. + :type defer_encryption: bool + """ + self.path = path + self.key = key + self.is_raw_key = is_raw_key + self.create = create + self.cipher = cipher + self.kdf_iter = kdf_iter + self.cipher_page_size = cipher_page_size + self.defer_encryption = defer_encryption + self.sync_db_key = sync_db_key + self.document_factory = None + + +# XXX Use SQLCIpherOptions instead def open(path, password, create=True, document_factory=None, crypto=None, raw_key=False, cipher='aes-256-cbc', kdf_iter=4000, cipher_page_size=1024, defer_encryption=False, sync_db_key=None): @@ -108,56 +157,22 @@ def open(path, password, create=True, document_factory=None, crypto=None, Will raise u1db.errors.DatabaseDoesNotExist if create=False and the database does not already exist. - :param path: The filesystem path for the database to open. - :type path: str - :param create: True/False, should the database be created if it doesn't - already exist? - :param create: bool - :param document_factory: A function that will be called with the same - parameters as Document.__init__. - :type document_factory: callable - :param crypto: An instance of SoledadCrypto so we can encrypt/decrypt - document contents when syncing. - :type crypto: soledad.crypto.SoledadCrypto - :param raw_key: Whether C{password} is a raw 64-char hex string or a - passphrase that should be hashed to obtain the encyrption key. - :type raw_key: bool - :param cipher: The cipher and mode to use. - :type cipher: str - :param kdf_iter: The number of iterations to use. - :type kdf_iter: int - :param cipher_page_size: The page size. - :type cipher_page_size: int - :param defer_encryption: Whether to defer encryption/decryption of - documents, or do it inline while syncing. - :type defer_encryption: bool - :return: An instance of Database. :rtype SQLCipherDatabase """ - return SQLCipherDatabase.open_database( - path, password, create=create, document_factory=document_factory, - crypto=crypto, raw_key=raw_key, cipher=cipher, kdf_iter=kdf_iter, - cipher_page_size=cipher_page_size, defer_encryption=defer_encryption, - sync_db_key=sync_db_key) - - -# -# Exceptions -# - -class DatabaseIsNotEncrypted(Exception): - """ - Exception raised when trying to open non-encrypted databases. - """ - pass - - -class NotAnHexString(Exception): - """ - Raised when trying to (raw) key the database with a non-hex string. - """ - pass + args = (path, password) + kwargs = { + 'create': create, + 'document_factory': document_factory, + 'crypto': crypto, + 'raw_key': raw_key, + 'cipher': cipher, + 'kdf_iter': kdf_iter, + 'cipher_page_size': cipher_page_size, + 'defer_encryption': defer_encryption, + 'sync_db_key': sync_db_key} + # XXX pass only a CryptoOptions object around + return SQLCipherDatabase.open_database(*args, **kwargs) # @@ -200,6 +215,7 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): same database replica. """ + # XXX Use SQLCIpherOptions instead def __init__(self, sqlcipher_file, password, document_factory=None, crypto=None, raw_key=False, cipher='aes-256-cbc', kdf_iter=4000, cipher_page_size=1024, sync_db_key=None): @@ -214,30 +230,10 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): experience several kinds of leakages. *** IMPORTANT *** - - :param sqlcipher_file: The path for the SQLCipher file. - :type sqlcipher_file: str - :param password: The password that protects the SQLCipher db. - :type password: str - :param document_factory: A function that will be called with the same - parameters as Document.__init__. - :type document_factory: callable - :param crypto: An instance of SoledadCrypto so we can encrypt/decrypt - document contents when syncing. - :type crypto: soledad.crypto.SoledadCrypto - :param raw_key: Whether password is a raw 64-char hex string or a - passphrase that should be hashed to obtain the - encyrption key. - :type raw_key: bool - :param cipher: The cipher and mode to use. - :type cipher: str - :param kdf_iter: The number of iterations to use. - :type kdf_iter: int - :param cipher_page_size: The page size. - :type cipher_page_size: int """ # ensure the db is encrypted if the file already exists if os.path.exists(sqlcipher_file): + # XXX pass only a CryptoOptions object around self.assert_db_is_encrypted( sqlcipher_file, password, raw_key, cipher, kdf_iter, cipher_page_size) @@ -249,16 +245,19 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): isolation_level=SQLITE_ISOLATION_LEVEL, check_same_thread=SQLITE_CHECK_SAME_THREAD) # set SQLCipher cryptographic parameters - self._set_crypto_pragmas( + + # XXX allow optiona deferredChain here ? + pragmas.set_crypto_pragmas( self._db_handle, password, raw_key, cipher, kdf_iter, cipher_page_size) if os.environ.get('LEAP_SQLITE_NOSYNC'): - self._pragma_synchronous_off(self._db_handle) + pragmas.set_synchronous_off(self._db_handle) else: - self._pragma_synchronous_normal(self._db_handle) + pragmas.set_synchronous_normal(self._db_handle) if os.environ.get('LEAP_SQLITE_MEMSTORE'): - self._pragma_mem_temp_store(self._db_handle) - self._pragma_write_ahead_logging(self._db_handle) + pragmas.set_mem_temp_store(self._db_handle) + pragmas.set_write_ahead_logging(self._db_handle) + self._real_replica_uid = None self._ensure_schema() self._crypto = crypto @@ -296,6 +295,7 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): self._syncers = {} @classmethod + # XXX Use SQLCIpherOptions instead def _open_database(cls, sqlcipher_file, password, document_factory=None, crypto=None, raw_key=False, cipher='aes-256-cbc', kdf_iter=4000, cipher_page_size=1024, @@ -303,29 +303,6 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): """ Open a SQLCipher database. - :param sqlcipher_file: The path for the SQLCipher file. - :type sqlcipher_file: str - :param password: The password that protects the SQLCipher db. - :type password: str - :param document_factory: A function that will be called with the same - parameters as Document.__init__. - :type document_factory: callable - :param crypto: An instance of SoledadCrypto so we can encrypt/decrypt - document contents when syncing. - :type crypto: soledad.crypto.SoledadCrypto - :param raw_key: Whether C{password} is a raw 64-char hex string or a - passphrase that should be hashed to obtain the encyrption key. - :type raw_key: bool - :param cipher: The cipher and mode to use. - :type cipher: str - :param kdf_iter: The number of iterations to use. - :type kdf_iter: int - :param cipher_page_size: The page size. - :type cipher_page_size: int - :param defer_encryption: Whether to defer encryption/decryption of - documents, or do it inline while syncing. - :type defer_encryption: bool - :return: The database object. :rtype: SQLCipherDatabase """ @@ -346,7 +323,9 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): try: # set cryptographic params - cls._set_crypto_pragmas( + + # XXX pass only a CryptoOptions object around + pragmas.set_crypto_pragmas( db_handle, password, raw_key, cipher, kdf_iter, cipher_page_size) c = db_handle.cursor() @@ -372,11 +351,12 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): cipher_page_size=cipher_page_size, sync_db_key=sync_db_key) @classmethod - def open_database(cls, sqlcipher_file, password, create, backend_cls=None, + def open_database(cls, sqlcipher_file, password, create, document_factory=None, crypto=None, raw_key=False, cipher='aes-256-cbc', kdf_iter=4000, cipher_page_size=1024, defer_encryption=False, sync_db_key=None): + # XXX pass only a CryptoOptions object around """ Open a SQLCipher database. @@ -388,67 +368,29 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): *** IMPORTANT *** - :param sqlcipher_file: The path for the SQLCipher file. - :type sqlcipher_file: str - - :param password: The password that protects the SQLCipher db. - :type password: str - - :param create: Should the datbase be created if it does not already - exist? - :type create: bool - - :param backend_cls: A class to use as backend. - :type backend_cls: type - - :param document_factory: A function that will be called with the same - parameters as Document.__init__. - :type document_factory: callable - - :param crypto: An instance of SoledadCrypto so we can encrypt/decrypt - document contents when syncing. - :type crypto: soledad.crypto.SoledadCrypto - - :param raw_key: Whether C{password} is a raw 64-char hex string or a - passphrase that should be hashed to obtain the - encyrption key. - :type raw_key: bool - - :param cipher: The cipher and mode to use. - :type cipher: str - - :param kdf_iter: The number of iterations to use. - :type kdf_iter: int - - :param cipher_page_size: The page size. - :type cipher_page_size: int - - :param defer_encryption: Whether to defer encryption/decryption of - documents, or do it inline while syncing. - :type defer_encryption: bool - :return: The database object. :rtype: SQLCipherDatabase """ cls.defer_encryption = defer_encryption + args = sqlcipher_file, password + kwargs = { + 'crypto': crypto, + 'raw_key': raw_key, + 'cipher': cipher, + 'kdf_iter': kdf_iter, + 'cipher_page_size': cipher_page_size, + 'defer_encryption': defer_encryption, + 'sync_db_key': sync_db_key, + 'document_factory': document_factory, + } try: - return cls._open_database( - sqlcipher_file, password, document_factory=document_factory, - crypto=crypto, raw_key=raw_key, cipher=cipher, - kdf_iter=kdf_iter, cipher_page_size=cipher_page_size, - defer_encryption=defer_encryption, sync_db_key=sync_db_key) + return cls._open_database(*args, **kwargs) except u1db_errors.DatabaseDoesNotExist: if not create: raise - # TODO: remove backend class from here. - if backend_cls is None: - # default is SQLCipherPartialExpandDatabase - backend_cls = SQLCipherDatabase - return backend_cls( - sqlcipher_file, password, document_factory=document_factory, - crypto=crypto, raw_key=raw_key, cipher=cipher, - kdf_iter=kdf_iter, cipher_page_size=cipher_page_size, - sync_db_key=sync_db_key) + + # XXX here we were missing sync_db_key, intentional? + return SQLCipherDatabase(*args, **kwargs) def sync(self, url, creds=None, autocreate=True, defer_decryption=True): """ @@ -592,7 +534,8 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): self._sync_db = MPSafeSQLiteDB(sync_db_path) # protect the sync db with a password if self._sync_db_key is not None: - self._set_crypto_pragmas( + # XXX pass only a CryptoOptions object around + pragmas.set_crypto_pragmas( self._sync_db, self._sync_db_key, False, 'aes-256-cbc', 4000, 1024) self._sync_db_write_lock = threading.Lock() @@ -712,6 +655,7 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): # SQLCipher API methods # + # XXX Use SQLCIpherOptions instead @classmethod def assert_db_is_encrypted(cls, sqlcipher_file, key, raw_key, cipher, kdf_iter, cipher_page_size): @@ -755,314 +699,12 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): sqlcipher_file, isolation_level=SQLITE_ISOLATION_LEVEL, check_same_thread=SQLITE_CHECK_SAME_THREAD) - cls._set_crypto_pragmas( + pragmas.set_crypto_pragmas( db_handle, key, raw_key, cipher, kdf_iter, cipher_page_size) db_handle.cursor().execute( 'SELECT count(*) FROM sqlite_master') - @classmethod - def _set_crypto_pragmas(cls, db_handle, key, raw_key, cipher, kdf_iter, - cipher_page_size): - """ - Set cryptographic params (key, cipher, KDF number of iterations and - cipher page size). - """ - cls._pragma_key(db_handle, key, raw_key) - cls._pragma_cipher(db_handle, cipher) - cls._pragma_kdf_iter(db_handle, kdf_iter) - cls._pragma_cipher_page_size(db_handle, cipher_page_size) - - @classmethod - def _pragma_key(cls, db_handle, key, raw_key): - """ - Set the C{key} for use with the database. - - The process of creating a new, encrypted database is called 'keying' - the database. SQLCipher uses just-in-time key derivation at the point - it is first needed for an operation. This means that the key (and any - options) must be set before the first operation on the database. As - soon as the database is touched (e.g. SELECT, CREATE TABLE, UPDATE, - etc.) and pages need to be read or written, the key is prepared for - use. - - Implementation Notes: - - * PRAGMA key should generally be called as the first operation on a - database. - - :param key: The key for use with the database. - :type key: str - :param raw_key: Whether C{key} is a raw 64-char hex string or a - passphrase that should be hashed to obtain the encyrption key. - :type raw_key: bool - """ - if raw_key: - cls._pragma_key_raw(db_handle, key) - else: - cls._pragma_key_passphrase(db_handle, key) - - @classmethod - def _pragma_key_passphrase(cls, db_handle, passphrase): - """ - Set a passphrase for encryption key derivation. - - The key itself can be a passphrase, which is converted to a key using - PBKDF2 key derivation. The result is used as the encryption key for - the database. By using this method, there is no way to alter the KDF; - if you want to do so you should use a raw key instead and derive the - key using your own KDF. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param passphrase: The passphrase used to derive the encryption key. - :type passphrase: str - """ - db_handle.cursor().execute("PRAGMA key = '%s'" % passphrase) - - @classmethod - def _pragma_key_raw(cls, db_handle, key): - """ - Set a raw hexadecimal encryption key. - - It is possible to specify an exact byte sequence using a blob literal. - With this method, it is the calling application's responsibility to - ensure that the data provided is a 64 character hex string, which will - be converted directly to 32 bytes (256 bits) of key data. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param key: A 64 character hex string. - :type key: str - """ - if not all(c in string.hexdigits for c in key): - raise NotAnHexString(key) - db_handle.cursor().execute('PRAGMA key = "x\'%s"' % key) - - @classmethod - def _pragma_cipher(cls, db_handle, cipher='aes-256-cbc'): - """ - Set the cipher and mode to use for symmetric encryption. - - SQLCipher uses aes-256-cbc as the default cipher and mode of - operation. It is possible to change this, though not generally - recommended, using PRAGMA cipher. - - SQLCipher makes direct use of libssl, so all cipher options available - to libssl are also available for use with SQLCipher. See `man enc` for - OpenSSL's supported ciphers. - - Implementation Notes: - - * PRAGMA cipher must be called after PRAGMA key and before the first - actual database operation or it will have no effect. - - * If a non-default value is used PRAGMA cipher to create a database, - it must also be called every time that database is opened. - - * SQLCipher does not implement its own encryption. Instead it uses the - widely available and peer-reviewed OpenSSL libcrypto for all - cryptographic functions. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param cipher: The cipher and mode to use. - :type cipher: str - """ - db_handle.cursor().execute("PRAGMA cipher = '%s'" % cipher) - - @classmethod - def _pragma_kdf_iter(cls, db_handle, kdf_iter=4000): - """ - Set the number of iterations for the key derivation function. - - SQLCipher uses PBKDF2 key derivation to strengthen the key and make it - resistent to brute force and dictionary attacks. The default - configuration uses 4000 PBKDF2 iterations (effectively 16,000 SHA1 - operations). PRAGMA kdf_iter can be used to increase or decrease the - number of iterations used. - - Implementation Notes: - - * PRAGMA kdf_iter must be called after PRAGMA key and before the first - actual database operation or it will have no effect. - - * If a non-default value is used PRAGMA kdf_iter to create a database, - it must also be called every time that database is opened. - - * It is not recommended to reduce the number of iterations if a - passphrase is in use. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param kdf_iter: The number of iterations to use. - :type kdf_iter: int - """ - db_handle.cursor().execute("PRAGMA kdf_iter = '%d'" % kdf_iter) - - @classmethod - def _pragma_cipher_page_size(cls, db_handle, cipher_page_size=1024): - """ - Set the page size of the encrypted database. - - SQLCipher 2 introduced the new PRAGMA cipher_page_size that can be - used to adjust the page size for the encrypted database. The default - page size is 1024 bytes, but it can be desirable for some applications - to use a larger page size for increased performance. For instance, - some recent testing shows that increasing the page size can noticeably - improve performance (5-30%) for certain queries that manipulate a - large number of pages (e.g. selects without an index, large inserts in - a transaction, big deletes). - - To adjust the page size, call the pragma immediately after setting the - key for the first time and each subsequent time that you open the - database. - - Implementation Notes: - - * PRAGMA cipher_page_size must be called after PRAGMA key and before - the first actual database operation or it will have no effect. - - * If a non-default value is used PRAGMA cipher_page_size to create a - database, it must also be called every time that database is opened. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param cipher_page_size: The page size. - :type cipher_page_size: int - """ - db_handle.cursor().execute( - "PRAGMA cipher_page_size = '%d'" % cipher_page_size) - - @classmethod - def _pragma_rekey(cls, db_handle, new_key, raw_key): - """ - Change the key of an existing encrypted database. - - To change the key on an existing encrypted database, it must first be - unlocked with the current encryption key. Once the database is - readable and writeable, PRAGMA rekey can be used to re-encrypt every - page in the database with a new key. - - * PRAGMA rekey must be called after PRAGMA key. It can be called at any - time once the database is readable. - - * PRAGMA rekey can not be used to encrypted a standard SQLite - database! It is only useful for changing the key on an existing - database. - - * Previous versions of SQLCipher provided a PRAGMA rekey_cipher and - code>PRAGMA rekey_kdf_iter. These are deprecated and should not be - used. Instead, use sqlcipher_export(). - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param new_key: The new key. - :type new_key: str - :param raw_key: Whether C{password} is a raw 64-char hex string or a - passphrase that should be hashed to obtain the encyrption key. - :type raw_key: bool - """ - # XXX change key param! - if raw_key: - cls._pragma_rekey_raw(db_handle, key) - else: - cls._pragma_rekey_passphrase(db_handle, key) - - @classmethod - def _pragma_rekey_passphrase(cls, db_handle, passphrase): - """ - Change the passphrase for encryption key derivation. - - The key itself can be a passphrase, which is converted to a key using - PBKDF2 key derivation. The result is used as the encryption key for - the database. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param passphrase: The passphrase used to derive the encryption key. - :type passphrase: str - """ - db_handle.cursor().execute("PRAGMA rekey = '%s'" % passphrase) - - @classmethod - def _pragma_rekey_raw(cls, db_handle, key): - """ - Change the raw hexadecimal encryption key. - - It is possible to specify an exact byte sequence using a blob literal. - With this method, it is the calling application's responsibility to - ensure that the data provided is a 64 character hex string, which will - be converted directly to 32 bytes (256 bits) of key data. - - :param db_handle: A handle to the SQLCipher database. - :type db_handle: pysqlcipher.Connection - :param key: A 64 character hex string. - :type key: str - """ - if not all(c in string.hexdigits for c in key): - raise NotAnHexString(key) - # XXX change passphrase param! - db_handle.cursor().execute('PRAGMA rekey = "x\'%s"' % passphrase) - - @classmethod - def _pragma_synchronous_off(cls, db_handle): - """ - Change the setting of the "synchronous" flag to OFF. - """ - logger.debug("SQLCIPHER: SETTING SYNCHRONOUS OFF") - db_handle.cursor().execute('PRAGMA synchronous=OFF') - - @classmethod - def _pragma_synchronous_normal(cls, db_handle): - """ - Change the setting of the "synchronous" flag to NORMAL. - """ - logger.debug("SQLCIPHER: SETTING SYNCHRONOUS NORMAL") - db_handle.cursor().execute('PRAGMA synchronous=NORMAL') - - @classmethod - def _pragma_mem_temp_store(cls, db_handle): - """ - Use a in-memory store for temporary tables. - """ - logger.debug("SQLCIPHER: SETTING TEMP_STORE MEMORY") - db_handle.cursor().execute('PRAGMA temp_store=MEMORY') - - @classmethod - def _pragma_write_ahead_logging(cls, db_handle): - """ - Enable write-ahead logging, and set the autocheckpoint to 50 pages. - - Setting the autocheckpoint to a small value, we make the reads not - suffer too much performance degradation. - - From the sqlite docs: - - "There is a tradeoff between average read performance and average write - performance. To maximize the read performance, one wants to keep the - WAL as small as possible and hence run checkpoints frequently, perhaps - as often as every COMMIT. To maximize write performance, one wants to - amortize the cost of each checkpoint over as many writes as possible, - meaning that one wants to run checkpoints infrequently and let the WAL - grow as large as possible before each checkpoint. The decision of how - often to run checkpoints may therefore vary from one application to - another depending on the relative read and write performance - requirements of the application. The default strategy is to run a - checkpoint once the WAL reaches 1000 pages" - """ - logger.debug("SQLCIPHER: SETTING WRITE-AHEAD LOGGING") - db_handle.cursor().execute('PRAGMA journal_mode=WAL') - # The optimum value can still use a little bit of tuning, but we favor - # small sizes of the WAL file to get fast reads, since we assume that - # the writes will be quick enough to not block too much. - - # TODO - # As a further improvement, we might want to set autocheckpoint to 0 - # here and do the checkpoints manually in a separate thread, to avoid - # any blocks in the main thread (we should run a loopingcall from here) - db_handle.cursor().execute('PRAGMA wal_autocheckpoint=50') - # Extra query methods: extensions to the base sqlite implmentation. def get_count_from_index(self, index_name, *key_values): @@ -1162,5 +804,16 @@ class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase): def replica_uid(self): return self._get_replica_uid() +# +# Exceptions +# + + +class DatabaseIsNotEncrypted(Exception): + """ + Exception raised when trying to open non-encrypted databases. + """ + pass + sqlite_backend.SQLiteDatabase.register_implementation(SQLCipherDatabase) |