Replace assertions with real error checks
diff --git a/cryptography/fernet.py b/cryptography/fernet.py
index c0c5631..c5474af 100644
--- a/cryptography/fernet.py
+++ b/cryptography/fernet.py
@@ -38,7 +38,10 @@
backend = default_backend()
key = base64.urlsafe_b64decode(key)
- assert len(key) == 32
+ if len(key) != 32:
+ raise ValueError(
+ "Fernet key must be 32 url-safe base64-encoded bytes"
+ )
self._signing_key = key[:16]
self._encryption_key = key[16:]
@@ -88,7 +91,9 @@
except (TypeError, binascii.Error):
raise InvalidToken
- assert six.indexbytes(data, 0) == 0x80
+ if six.indexbytes(data, 0) != 0x80:
+ raise InvalidToken
+
timestamp = struct.unpack(">Q", data[1:9])[0]
iv = data[9:25]
ciphertext = data[25:-32]
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index 48df867..7766118 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -69,6 +69,11 @@
with pytest.raises(InvalidToken):
f.decrypt(token.encode("ascii"), ttl=ttl_sec)
+ def test_invalid_start_byte(self, backend):
+ f = Fernet(Fernet.generate_key(), backend=backend)
+ with pytest.raises(InvalidToken):
+ f.decrypt(base64.urlsafe_b64encode(b"\x81"))
+
def test_unicode(self, backend):
f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
with pytest.raises(TypeError):
@@ -84,3 +89,7 @@
def test_default_backend(self):
f = Fernet(Fernet.generate_key())
assert f._backend is default_backend()
+
+ def test_bad_key(self, backend):
+ with pytest.raises(ValueError):
+ Fernet(base64.urlsafe_b64encode(b"abc"), backend=backend)