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authordrebs <drebs@leap.se>2013-06-03 16:19:13 -0300
committerdrebs <drebs@leap.se>2013-06-05 12:21:41 -0300
commit3462abf72b9057855fe7e1b92b12f04bdbd67537 (patch)
treeda5a6ac0fea9bd8f25b4704773a79ded9fb01113 /src
parentebca23cd426690453cf5581f32a44121ae1219ce (diff)
Move symmetric encryption/decryption code from leap.common to leap.soledad.
Diffstat (limited to 'src')
-rw-r--r--src/leap/soledad/backends/leap_backend.py8
-rw-r--r--src/leap/soledad/crypto.py57
-rw-r--r--src/leap/soledad/tests/test_crypto.py217
3 files changed, 143 insertions, 139 deletions
diff --git a/src/leap/soledad/backends/leap_backend.py b/src/leap/soledad/backends/leap_backend.py
index d92025db..18c64f97 100644
--- a/src/leap/soledad/backends/leap_backend.py
+++ b/src/leap/soledad/backends/leap_backend.py
@@ -33,11 +33,9 @@ from u1db.errors import BrokenSyncStream
from u1db.remote.http_target import HTTPSyncTarget
-from leap.common.crypto import (
+from leap.soledad.crypto import (
EncryptionMethods,
UnknownEncryptionMethod,
- encrypt_sym,
- decrypt_sym,
)
from leap.common.check import leap_assert
from leap.soledad.auth import TokenBasedAuth
@@ -169,7 +167,7 @@ def encrypt_doc(crypto, doc):
"""
leap_assert(doc.is_tombstone() is False)
# encrypt content using AES-256 CTR mode
- iv, ciphertext = encrypt_sym(
+ iv, ciphertext = crypto.encrypt_sym(
doc.get_json(),
crypto.doc_passphrase(doc.doc_id),
method=EncryptionMethods.AES_256_CTR)
@@ -242,7 +240,7 @@ def decrypt_doc(crypto, doc):
enc_method = doc.content[ENC_METHOD_KEY]
if enc_method == EncryptionMethods.AES_256_CTR:
leap_assert(ENC_IV_KEY in doc.content)
- plainjson = decrypt_sym(
+ plainjson = crypto.decrypt_sym(
ciphertext,
crypto.doc_passphrase(doc.doc_id),
method=enc_method,
diff --git a/src/leap/soledad/crypto.py b/src/leap/soledad/crypto.py
index e020eee6..e3d2c30c 100644
--- a/src/leap/soledad/crypto.py
+++ b/src/leap/soledad/crypto.py
@@ -21,11 +21,29 @@ Cryptographic utilities for Soledad.
"""
+import os
+import binascii
import hmac
import hashlib
+from Crypto.Cipher import AES
+from Crypto.Util import Counter
+from leap.common.check import leap_assert, leap_assert_type
-from leap.common import crypto
+
+class EncryptionMethods(object):
+ """
+ Representation of encryption methods that can be used.
+ """
+
+ AES_256_CTR = 'aes-256-ctr'
+
+
+class UnknownEncryptionMethod(Exception):
+ """
+ Raised when trying to encrypt/decrypt with unknown method.
+ """
+ pass
class NoSymmetricSecret(Exception):
@@ -51,7 +69,7 @@ class SoledadCrypto(object):
self._soledad = soledad
def encrypt_sym(self, data, key,
- method=crypto.EncryptionMethods.AES_256_CTR):
+ method=EncryptionMethods.AES_256_CTR):
"""
Encrypt C{data} using a {password}.
@@ -67,10 +85,23 @@ class SoledadCrypto(object):
@return: A tuple with the initial value and the encrypted data.
@rtype: (long, str)
"""
- return crypto.encrypt_sym(data, key, method)
+ leap_assert_type(key, str)
+
+ # AES-256 in CTR mode
+ if method == EncryptionMethods.AES_256_CTR:
+ leap_assert(
+ len(key) == 32, # 32 x 8 = 256 bits.
+ 'Wrong key size: %s bits (must be 256 bits long).' % (len(key)*8))
+ iv = os.urandom(8)
+ ctr = Counter.new(64, prefix=iv)
+ cipher = AES.new(key=key, mode=AES.MODE_CTR, counter=ctr)
+ return binascii.b2a_base64(iv), cipher.encrypt(data)
+
+ # raise if method is unknown
+ raise UnknownEncryptionMethod('Unkwnown method: %s' % method)
def decrypt_sym(self, data, key,
- method=crypto.EncryptionMethods.AES_256_CTR, **kwargs):
+ method=EncryptionMethods.AES_256_CTR, **kwargs):
"""
Decrypt data using symmetric secret.
@@ -88,7 +119,23 @@ class SoledadCrypto(object):
@return: The decrypted data.
@rtype: str
"""
- return crypto.decrypt_sym(data, key, method, **kwargs)
+ leap_assert_type(key, str)
+
+ # AES-256 in CTR mode
+ if method == EncryptionMethods.AES_256_CTR:
+ # assert params
+ leap_assert(
+ len(key) == 32, # 32 x 8 = 256 bits.
+ 'Wrong key size: %s (must be 256 bits long).' % len(key))
+ leap_assert(
+ 'iv' in kwargs,
+ 'AES-256-CTR needs an initial value given as.')
+ ctr = Counter.new(64, prefix=binascii.a2b_base64(kwargs['iv']))
+ cipher = AES.new(key=key, mode=AES.MODE_CTR, counter=ctr)
+ return cipher.decrypt(data)
+
+ # raise if method is unknown
+ raise UnknownEncryptionMethod('Unkwnown method: %s' % method)
def doc_passphrase(self, doc_id):
"""
diff --git a/src/leap/soledad/tests/test_crypto.py b/src/leap/soledad/tests/test_crypto.py
index ae84dad3..59d20fa7 100644
--- a/src/leap/soledad/tests/test_crypto.py
+++ b/src/leap/soledad/tests/test_crypto.py
@@ -25,27 +25,20 @@ import shutil
import tempfile
import simplejson as json
import hashlib
+import binascii
-from leap.soledad.backends.leap_backend import (
- LeapDocument,
- encrypt_doc,
- decrypt_doc,
- EncryptionSchemes,
- LeapSyncTarget,
- ENC_JSON_KEY,
- ENC_SCHEME_KEY,
- MAC_METHOD_KEY,
- MAC_KEY,
- UnknownMacMethod,
- WrongMac,
-)
-from leap.soledad.backends.couch import CouchDatabase
+from leap.common.testing.basetest import BaseLeapTest
+from Crypto import Random
+
+
+from leap.common.testing.basetest import BaseLeapTest
from leap.soledad import Soledad
-from leap.soledad.crypto import SoledadCrypto
-from leap.soledad.tests import BaseSoledadTest
-from leap.soledad.tests.test_couch import CouchDBTestCase
+from leap.soledad import crypto
+from leap.soledad.backends import leap_backend
+from leap.soledad.backends.couch import CouchDatabase
from leap.soledad.tests import (
+ BaseSoledadTest,
KEY_FINGERPRINT,
PRIVATE_KEY,
)
@@ -54,8 +47,12 @@ from leap.soledad.tests.u1db_tests import (
nested_doc,
TestCaseWithServer,
)
-from leap.soledad.tests.test_leap_backend import make_leap_document_for_test
-from leap.soledad.backends.couch import CouchServerState
+
+
+# These will be used in the future for EncryptedCouchSyncTestCase
+#from leap.soledad.tests.test_couch import CouchDBTestCase
+#from leap.soledad.tests.test_leap_backend import make_leap_document_for_test
+#from leap.soledad.backends.couch import CouchServerState
class EncryptedSyncTestCase(BaseSoledadTest):
@@ -68,112 +65,22 @@ class EncryptedSyncTestCase(BaseSoledadTest):
Test encrypting and decrypting documents.
"""
simpledoc = {'key': 'val'}
- doc1 = LeapDocument(doc_id='id')
+ doc1 = leap_backend.LeapDocument(doc_id='id')
doc1.content = simpledoc
# encrypt doc
- doc1.set_json(encrypt_doc(self._soledad._crypto, doc1))
+ doc1.set_json(leap_backend.encrypt_doc(self._soledad._crypto, doc1))
# assert content is different and includes keys
self.assertNotEqual(
simpledoc, doc1.content,
'incorrect document encryption')
- self.assertTrue(ENC_JSON_KEY in doc1.content)
- self.assertTrue(ENC_SCHEME_KEY in doc1.content)
+ self.assertTrue(leap_backend.ENC_JSON_KEY in doc1.content)
+ self.assertTrue(leap_backend.ENC_SCHEME_KEY in doc1.content)
# decrypt doc
- doc1.set_json(decrypt_doc(self._soledad._crypto, doc1))
+ doc1.set_json(leap_backend.decrypt_doc(self._soledad._crypto, doc1))
self.assertEqual(
simpledoc, doc1.content, 'incorrect document encryption')
-#from leap.soledad.server import SoledadApp, SoledadAuthMiddleware
-#
-#
-#def make_token_leap_app(test, state):
-# app = SoledadApp(state)
-# application = SoledadAuthMiddleware(app, prefix='/soledad/')
-# return application
-#
-#
-#def leap_sync_target(test, path):
-# return LeapSyncTarget(test.getURL(path))
-#
-#
-#def token_leap_sync_target(test, path):
-# st = leap_sync_target(test, 'soledad/' + path)
-# st.set_token_credentials('any_user', 'any_token')
-# return st
-#
-#
-#class EncryptedCouchSyncTest(CouchDBTestCase, TestCaseWithServer):
-#
-# make_app_with_state = make_token_leap_app
-#
-# make_document_for_test = make_leap_document_for_test
-#
-# sync_target = token_leap_sync_target
-#
-# def make_app(self):
-# # potential hook point
-# self.request_state = CouchServerState(self._couch_url)
-# return self.make_app_with_state(self.request_state)
-#
-# def _soledad_instance(self, user='leap@leap.se', prefix='',
-# bootstrap=False, gnupg_home='/gnupg',
-# secrets_path='/secret.gpg',
-# local_db_path='/soledad.u1db'):
-# return Soledad(
-# user,
-# '123',
-# gnupg_home=self.tempdir+prefix+gnupg_home,
-# secrets_path=self.tempdir+prefix+secrets_path,
-# local_db_path=self.tempdir+prefix+local_db_path,
-# bootstrap=bootstrap)
-#
-# def setUp(self):
-# CouchDBTestCase.setUp(self)
-# TestCaseWithServer.setUp(self)
-# self.tempdir = tempfile.mkdtemp(suffix='.couch.test')
-# # initialize soledad by hand so we can control keys
-# self._soledad = self._soledad_instance('leap@leap.se')
-# self._soledad._init_dirs()
-# self._soledad._crypto = SoledadCrypto(self._soledad)
-# if not self._soledad._has_get_storage_secret()():
-# self._soledad._gen_get_storage_secret()()
-# self._soledad._load_get_storage_secret()()
-# self._soledad._init_db()
-#
-# def tearDown(self):
-# shutil.rmtree(self.tempdir)
-#
-# def test_encrypted_sym_sync(self):
-# # get direct access to couchdb
-# import ipdb; ipdb.set_trace()
-# self._couch_url = 'http://localhost:' + str(self.wrapper.port)
-# db = CouchDatabase(self._couch_url, 'testdb')
-# # create and encrypt a doc to insert directly in couchdb
-# doc = LeapDocument('doc-id')
-# doc.set_json(
-# encrypt_doc(
-# self._soledad._crypto, 'doc-id', json.dumps(simple_doc)))
-# db.put_doc(doc)
-# # setup credentials for access to soledad server
-# creds = {
-# 'token': {
-# 'uuid': 'leap@leap.se',
-# 'token': '1234',
-# }
-# }
-# # sync local soledad db with server
-# self.assertTrue(self._soledad.get_doc('doc-id') is None)
-# self.startServer()
-# # TODO fix sync for test.
-# #self._soledad.sync(self.getURL('soledad/testdb'), creds)
-# # get and check doc
-# doc = self._soledad.get_doc('doc-id')
-# # TODO: fix below.
-# #self.assertTrue(doc is not None)
-# #self.assertTrue(doc.content == simple_doc)
-
-
class RecoveryDocumentTestCase(BaseSoledadTest):
def test_export_recovery_document_raw(self):
@@ -199,7 +106,7 @@ class RecoveryDocumentTestCase(BaseSoledadTest):
'Failed settinng secret for symmetric encryption.')
-class CryptoMethodsTestCase(BaseSoledadTest):
+class SoledadSecretsTestCase(BaseSoledadTest):
def test__gen_secret(self):
# instantiate and save secret_id
@@ -254,33 +161,85 @@ class MacAuthTestCase(BaseSoledadTest):
Trying to decrypt a document with wrong MAC should raise.
"""
simpledoc = {'key': 'val'}
- doc = LeapDocument(doc_id='id')
+ doc = leap_backend.LeapDocument(doc_id='id')
doc.content = simpledoc
# encrypt doc
- doc.set_json(encrypt_doc(self._soledad._crypto, doc))
- self.assertTrue(MAC_KEY in doc.content)
- self.assertTrue(MAC_METHOD_KEY in doc.content)
+ doc.set_json(leap_backend.encrypt_doc(self._soledad._crypto, doc))
+ self.assertTrue(leap_backend.MAC_KEY in doc.content)
+ self.assertTrue(leap_backend.MAC_METHOD_KEY in doc.content)
# mess with MAC
- doc.content[MAC_KEY] = '1234567890ABCDEF'
+ doc.content[leap_backend.MAC_KEY] = '1234567890ABCDEF'
# try to decrypt doc
self.assertRaises(
- WrongMac,
- decrypt_doc, self._soledad._crypto, doc)
+ leap_backend.WrongMac,
+ leap_backend.decrypt_doc, self._soledad._crypto, doc)
def test_decrypt_with_unknown_mac_method_raises(self):
"""
Trying to decrypt a document with unknown MAC method should raise.
"""
simpledoc = {'key': 'val'}
- doc = LeapDocument(doc_id='id')
+ doc = leap_backend.LeapDocument(doc_id='id')
doc.content = simpledoc
# encrypt doc
- doc.set_json(encrypt_doc(self._soledad._crypto, doc))
- self.assertTrue(MAC_KEY in doc.content)
- self.assertTrue(MAC_METHOD_KEY in doc.content)
+ doc.set_json(leap_backend.encrypt_doc(self._soledad._crypto, doc))
+ self.assertTrue(leap_backend.MAC_KEY in doc.content)
+ self.assertTrue(leap_backend.MAC_METHOD_KEY in doc.content)
# mess with MAC method
- doc.content[MAC_METHOD_KEY] = 'mymac'
+ doc.content[leap_backend.MAC_METHOD_KEY] = 'mymac'
# try to decrypt doc
self.assertRaises(
- UnknownMacMethod,
- decrypt_doc, self._soledad._crypto, doc)
+ leap_backend.UnknownMacMethod,
+ leap_backend.decrypt_doc, self._soledad._crypto, doc)
+
+
+class SoledadCryptoTestCase(BaseSoledadTest):
+
+ def test_encrypt_decrypt_sym(self):
+ # generate 256-bit key
+ key = Random.new().read(32)
+ iv, cyphertext = self._soledad._crypto.encrypt_sym(
+ 'data', key,
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertTrue(cyphertext is not None)
+ self.assertTrue(cyphertext != '')
+ self.assertTrue(cyphertext != 'data')
+ plaintext = self._soledad._crypto.decrypt_sym(
+ cyphertext, key, iv=iv,
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertEqual('data', plaintext)
+
+ def test_decrypt_with_wrong_iv_fails(self):
+ key = Random.new().read(32)
+ iv, cyphertext = self._soledad._crypto.encrypt_sym(
+ 'data', key,
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertTrue(cyphertext is not None)
+ self.assertTrue(cyphertext != '')
+ self.assertTrue(cyphertext != 'data')
+ # get a different iv by changing the first byte
+ rawiv = binascii.a2b_base64(iv)
+ wrongiv = rawiv
+ while wrongiv == rawiv:
+ wrongiv = os.urandom(1) + rawiv[1:]
+ plaintext = self._soledad._crypto.decrypt_sym(
+ cyphertext, key, iv=binascii.b2a_base64(wrongiv),
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertNotEqual('data', plaintext)
+
+ def test_decrypt_with_wrong_key_fails(self):
+ key = Random.new().read(32)
+ iv, cyphertext = self._soledad._crypto.encrypt_sym(
+ 'data', key,
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertTrue(cyphertext is not None)
+ self.assertTrue(cyphertext != '')
+ self.assertTrue(cyphertext != 'data')
+ wrongkey = Random.new().read(32) # 256-bits key
+ # ensure keys are different in case we are extremely lucky
+ while wrongkey == key:
+ wrongkey = Random.new().read(32)
+ plaintext = self._soledad._crypto.decrypt_sym(
+ cyphertext, wrongkey, iv=iv,
+ method=crypto.EncryptionMethods.AES_256_CTR)
+ self.assertNotEqual('data', plaintext)