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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.
import base64
import datetime
import json
import os
import time
import pretend
import pytest
import cryptography_vectors
from cryptography.fernet import Fernet, InvalidToken, MultiFernet
from cryptography.hazmat.primitives.ciphers import algorithms, modes
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],
ids=[f"{filename}[{i}]" for i in range(len(data))],
)
@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:
@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"),
int(datetime.datetime.fromisoformat(now).timestamp()),
bytes(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
):
# secret & token are both str
f = Fernet(secret.encode("ascii"), backend=backend)
current_time = int(datetime.datetime.fromisoformat(now).timestamp())
payload = f.decrypt_at_time(
token, # str
ttl=ttl_sec,
current_time=current_time,
)
assert payload == src.encode("ascii")
payload = f.decrypt_at_time(
token.encode("ascii"), # bytes
ttl=ttl_sec,
current_time=current_time,
)
assert payload == src.encode("ascii")
monkeypatch.setattr(time, "time", lambda: current_time)
payload = f.decrypt(token, ttl=ttl_sec) # str
assert payload == src.encode("ascii")
payload = f.decrypt(token.encode("ascii"), ttl=ttl_sec) # bytes
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 = int(datetime.datetime.fromisoformat(now).timestamp())
with pytest.raises(InvalidToken):
f.decrypt_at_time(
token.encode("ascii"),
ttl=ttl_sec,
current_time=current_time,
)
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")
with pytest.raises(InvalidToken):
f.decrypt("nonsensetoken")
def test_invalid_types(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(TypeError):
f.encrypt("") # type: ignore[arg-type]
with pytest.raises(TypeError):
f.decrypt(12345) # type: ignore[arg-type]
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)
monkeypatch.setattr(time, "time", pretend.raiser(ValueError))
assert f.decrypt(token, ttl=None) == pt
def test_ttl_required_in_decrypt_at_time(self, monkeypatch, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
pt = b"encrypt me"
token = f.encrypt(pt)
with pytest.raises(ValueError):
f.decrypt_at_time(
token,
ttl=None, # type: ignore[arg-type]
current_time=int(time.time()),
)
@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
@pytest.mark.parametrize("key", [base64.urlsafe_b64encode(b"abc"), b"abc"])
def test_bad_key(self, backend, key):
with pytest.raises(ValueError):
Fernet(key, backend=backend)
def test_extract_timestamp(self, monkeypatch, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
current_time = 1526138327
token = f.encrypt_at_time(b"encrypt me", current_time)
assert f.extract_timestamp(token) == current_time
assert f.extract_timestamp(token.decode("ascii")) == current_time
with pytest.raises(InvalidToken):
f.extract_timestamp(b"nonsensetoken")
@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:
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])
# token as bytes
assert f.decrypt(f1.encrypt(b"abc")) == b"abc"
assert f.decrypt(f2.encrypt(b"abc")) == b"abc"
# token as str
assert f.decrypt(f1.encrypt(b"abc").decode("ascii")) == b"abc"
assert f.decrypt(f2.encrypt(b"abc").decode("ascii")) == b"abc"
with pytest.raises(InvalidToken):
f.decrypt(b"\x00" * 16)
def test_decrypt_at_time(self, backend):
f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
f = MultiFernet([f1])
pt = b"encrypt me"
token = f.encrypt_at_time(pt, current_time=100)
assert f.decrypt_at_time(token, ttl=1, current_time=100) == pt
with pytest.raises(InvalidToken):
f.decrypt_at_time(token, ttl=1, current_time=102)
with pytest.raises(ValueError):
f.decrypt_at_time(
token, ttl=None, current_time=100 # type: ignore[arg-type]
)
def test_no_fernets(self, backend):
with pytest.raises(ValueError):
MultiFernet([])
def test_non_iterable_argument(self, backend):
with pytest.raises(TypeError):
MultiFernet(None) # type: ignore[arg-type]
def test_rotate_bytes(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_str(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).decode("ascii")
assert mf2.decrypt(mf1_ciphertext) == plaintext
rotated = mf2.rotate(mf1_ciphertext).decode("ascii")
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"
original_time = int(time.time()) - 5 * 60
mf1_ciphertext = mf1.encrypt_at_time(plaintext, original_time)
rotated_time, _ = Fernet._get_unverified_token_data(
mf2.rotate(mf1_ciphertext)
)
assert int(time.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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