From d74ba3298ddd4d3558224af85768e28f4c7f8d0d Mon Sep 17 00:00:00 2001 From: Paul Kehrer Date: Thu, 5 Jan 2017 14:11:17 -0500 Subject: add memory limit check for scrypt (#3328) * add memory limit check for scrypt fixes #3323 * test a pass * move _MEM_LIMIT to the scrypt module --- tests/hazmat/primitives/test_scrypt.py | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'tests/hazmat') diff --git a/tests/hazmat/primitives/test_scrypt.py b/tests/hazmat/primitives/test_scrypt.py index 49b304e0..87aee1f1 100644 --- a/tests/hazmat/primitives/test_scrypt.py +++ b/tests/hazmat/primitives/test_scrypt.py @@ -14,7 +14,7 @@ from cryptography.exceptions import ( AlreadyFinalized, InvalidKey, UnsupportedAlgorithm ) from cryptography.hazmat.backends.interfaces import ScryptBackend -from cryptography.hazmat.primitives.kdf.scrypt import Scrypt +from cryptography.hazmat.primitives.kdf.scrypt import Scrypt, _MEM_LIMIT from tests.utils import load_nist_vectors, load_vectors_from_file @@ -22,10 +22,30 @@ vectors = load_vectors_from_file( os.path.join("KDF", "scrypt.txt"), load_nist_vectors) +def _skip_if_memory_limited(memory_limit, params): + # Memory calc adapted from OpenSSL (URL split over 2 lines, thanks PEP8) + # https://github.com/openssl/openssl/blob/6286757141a8c6e14d647ec733634a + # e0c83d9887/crypto/evp/scrypt.c#L189-L221 + blen = int(params["p"]) * 128 * int(params["r"]) + vlen = 32 * int(params["r"]) * (int(params["n"]) + 2) * 4 + memory_required = blen + vlen + if memory_limit < memory_required: + pytest.skip("Test exceeds Scrypt memory limit. " + "This is likely a 32-bit platform.") + + +def test_memory_limit_skip(): + with pytest.raises(pytest.skip.Exception): + _skip_if_memory_limited(1000, {"p": 16, "r": 64, "n": 1024}) + + _skip_if_memory_limited(2 ** 31, {"p": 16, "r": 64, "n": 1024}) + + @pytest.mark.requires_backend_interface(interface=ScryptBackend) class TestScrypt(object): @pytest.mark.parametrize("params", vectors) def test_derive(self, backend, params): + _skip_if_memory_limited(_MEM_LIMIT, params) password = params["password"] work_factor = int(params["n"]) block_size = int(params["r"]) @@ -77,6 +97,7 @@ class TestScrypt(object): @pytest.mark.parametrize("params", vectors) def test_verify(self, backend, params): + _skip_if_memory_limited(_MEM_LIMIT, params) password = params["password"] work_factor = int(params["n"]) block_size = int(params["r"]) -- cgit v1.2.3