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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import base64
import calendar
import datetime
import json
import os
import time
import iso8601
import pytest
import six
from cryptography.fernet import Fernet, InvalidToken, MultiFernet
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.backends.interfaces import CipherBackend, HMACBackend
from cryptography.hazmat.primitives.ciphers import algorithms, modes
import cryptography_vectors
def json_parametrize(keys, filename):
vector_file = cryptography_vectors.open_vector_file(
os.path.join('fernet', filename), "r"
)
with vector_file:
data = json.load(vector_file)
return pytest.mark.parametrize(keys, [
tuple([entry[k] for k in keys])
for entry in data
])
def test_default_backend():
f = Fernet(Fernet.generate_key())
assert f._backend is default_backend()
@pytest.mark.requires_backend_interface(interface=CipherBackend)
@pytest.mark.requires_backend_interface(interface=HMACBackend)
@pytest.mark.supported(
only_if=lambda backend: backend.cipher_supported(
algorithms.AES(b"\x00" * 32), modes.CBC(b"\x00" * 16)
),
skip_message="Does not support AES CBC",
)
class TestFernet(object):
@json_parametrize(
("secret", "now", "iv", "src", "token"), "generate.json",
)
def test_generate(self, secret, now, iv, src, token, backend):
f = Fernet(secret.encode("ascii"), backend=backend)
actual_token = f._encrypt_from_parts(
src.encode("ascii"),
calendar.timegm(iso8601.parse_date(now).utctimetuple()),
b"".join(map(six.int2byte, iv))
)
assert actual_token == token.encode("ascii")
@json_parametrize(
("secret", "now", "src", "ttl_sec", "token"), "verify.json",
)
def test_verify(self, secret, now, src, ttl_sec, token, backend,
monkeypatch):
f = Fernet(secret.encode("ascii"), backend=backend)
current_time = calendar.timegm(iso8601.parse_date(now).utctimetuple())
monkeypatch.setattr(time, "time", lambda: current_time)
payload = f.decrypt(token.encode("ascii"), ttl=ttl_sec)
assert payload == src.encode("ascii")
@json_parametrize(("secret", "token", "now", "ttl_sec"), "invalid.json")
def test_invalid(self, secret, token, now, ttl_sec, backend, monkeypatch):
f = Fernet(secret.encode("ascii"), backend=backend)
current_time = calendar.timegm(iso8601.parse_date(now).utctimetuple())
monkeypatch.setattr(time, "time", lambda: current_time)
with pytest.raises(InvalidToken):
f.decrypt(token.encode("ascii"), ttl=ttl_sec)
def test_invalid_start_byte(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(InvalidToken):
f.decrypt(base64.urlsafe_b64encode(b"\x81"))
def test_timestamp_too_short(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(InvalidToken):
f.decrypt(base64.urlsafe_b64encode(b"\x80abc"))
def test_non_base64_token(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(InvalidToken):
f.decrypt(b"\x00")
def test_unicode(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(TypeError):
f.encrypt(u"")
with pytest.raises(TypeError):
f.decrypt(u"")
def test_timestamp_ignored_no_ttl(self, monkeypatch, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
pt = b"encrypt me"
token = f.encrypt(pt)
ts = "1985-10-26T01:20:01-07:00"
current_time = calendar.timegm(iso8601.parse_date(ts).utctimetuple())
monkeypatch.setattr(time, "time", lambda: current_time)
assert f.decrypt(token, ttl=None) == pt
@pytest.mark.parametrize("message", [b"", b"Abc!", b"\x00\xFF\x00\x80"])
def test_roundtrips(self, message, backend):
f = Fernet(Fernet.generate_key(), backend=backend)
assert f.decrypt(f.encrypt(message)) == message
def test_bad_key(self, backend):
with pytest.raises(ValueError):
Fernet(base64.urlsafe_b64encode(b"abc"), backend=backend)
def test_extract_timestamp(self, monkeypatch, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
current_time = 1526138327
monkeypatch.setattr(time, "time", lambda: current_time)
token = f.encrypt(b'encrypt me')
assert f.extract_timestamp(token) == current_time
with pytest.raises(InvalidToken):
f.extract_timestamp(b"nonsensetoken")
@pytest.mark.requires_backend_interface(interface=CipherBackend)
@pytest.mark.requires_backend_interface(interface=HMACBackend)
@pytest.mark.supported(
only_if=lambda backend: backend.cipher_supported(
algorithms.AES(b"\x00" * 32), modes.CBC(b"\x00" * 16)
),
skip_message="Does not support AES CBC",
)
class TestMultiFernet(object):
def test_encrypt(self, backend):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
f = MultiFernet([f1, f2])
assert f1.decrypt(f.encrypt(b"abc")) == b"abc"
def test_decrypt(self, backend):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
f = MultiFernet([f1, f2])
assert f.decrypt(f1.encrypt(b"abc")) == b"abc"
assert f.decrypt(f2.encrypt(b"abc")) == b"abc"
with pytest.raises(InvalidToken):
f.decrypt(b"\x00" * 16)
def test_no_fernets(self, backend):
with pytest.raises(ValueError):
MultiFernet([])
def test_non_iterable_argument(self, backend):
with pytest.raises(TypeError):
MultiFernet(None)
def test_rotate(self, backend):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
mf1 = MultiFernet([f1])
mf2 = MultiFernet([f2, f1])
plaintext = b"abc"
mf1_ciphertext = mf1.encrypt(plaintext)
assert mf2.decrypt(mf1_ciphertext) == plaintext
rotated = mf2.rotate(mf1_ciphertext)
assert rotated != mf1_ciphertext
assert mf2.decrypt(rotated) == plaintext
with pytest.raises(InvalidToken):
mf1.decrypt(rotated)
def test_rotate_preserves_timestamp(self, backend, monkeypatch):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
mf1 = MultiFernet([f1])
mf2 = MultiFernet([f2, f1])
plaintext = b"abc"
mf1_ciphertext = mf1.encrypt(plaintext)
later = datetime.datetime.now() + datetime.timedelta(minutes=5)
later_time = time.mktime(later.timetuple())
monkeypatch.setattr(time, "time", lambda: later_time)
original_time, _ = Fernet._get_unverified_token_data(mf1_ciphertext)
rotated_time, _ = Fernet._get_unverified_token_data(
mf2.rotate(mf1_ciphertext)
)
assert later_time != rotated_time
assert original_time == rotated_time
def test_rotate_decrypt_no_shared_keys(self, backend):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
mf1 = MultiFernet([f1])
mf2 = MultiFernet([f2])
with pytest.raises(InvalidToken):
mf2.rotate(mf1.encrypt(b"abc"))
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