raise ValueError on zero length GCM IV (#4348)
diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst
index 5b60009..e74b4d6 100644
--- a/docs/hazmat/primitives/symmetric-encryption.rst
+++ b/docs/hazmat/primitives/symmetric-encryption.rst
@@ -399,7 +399,8 @@
this is ``16``, meaning tag truncation is not allowed. Allowing tag
truncation is strongly discouraged for most applications.
- :raises ValueError: This is raised if ``len(tag) < min_tag_length``.
+ :raises ValueError: This is raised if ``len(tag) < min_tag_length`` or the
+ ``initialization_vector`` is too short.
:raises NotImplementedError: This is raised if the version of the OpenSSL
backend used is 1.0.1 or earlier.
diff --git a/src/cryptography/hazmat/primitives/ciphers/modes.py b/src/cryptography/hazmat/primitives/ciphers/modes.py
index 543015f..e82c1a8 100644
--- a/src/cryptography/hazmat/primitives/ciphers/modes.py
+++ b/src/cryptography/hazmat/primitives/ciphers/modes.py
@@ -208,6 +208,8 @@
# for it
if not isinstance(initialization_vector, bytes):
raise TypeError("initialization_vector must be bytes")
+ if len(initialization_vector) == 0:
+ raise ValueError("initialization_vector must be at least 1 byte")
self._initialization_vector = initialization_vector
if tag is not None:
if not isinstance(tag, bytes):
diff --git a/tests/hazmat/primitives/test_block.py b/tests/hazmat/primitives/test_block.py
index c053fea..37158f1 100644
--- a/tests/hazmat/primitives/test_block.py
+++ b/tests/hazmat/primitives/test_block.py
@@ -191,6 +191,10 @@
backend,
)
+ def test_gcm(self):
+ with pytest.raises(ValueError):
+ modes.GCM(b"")
+
class TestModesRequireBytes(object):
def test_cbc(self):