Add bounds checking for Scrypt parameters. (#3130)

* Add bounds checking for Scrypt parameters.

* Pep8.

* More PEP8.

* Change wording.

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/hazmat/primitives/test_scrypt.py b/tests/hazmat/primitives/test_scrypt.py
index de4100e3..49b304e0 100644
--- a/tests/hazmat/primitives/test_scrypt.py
+++ b/tests/hazmat/primitives/test_scrypt.py
@@ -117,3 +117,20 @@ class TestScrypt(object):
         scrypt.derive(password)
         with pytest.raises(AlreadyFinalized):
             scrypt.derive(password)
+
+    def test_invalid_n(self, backend):
+        # n is less than 2
+        with pytest.raises(ValueError):
+            Scrypt(b"NaCl", 64, 1, 8, 16, backend)
+
+        # n is not a power of 2
+        with pytest.raises(ValueError):
+            Scrypt(b"NaCl", 64, 3, 8, 16, backend)
+
+    def test_invalid_r(self, backend):
+        with pytest.raises(ValueError):
+            Scrypt(b"NaCl", 64, 2, 0, 16, backend)
+
+    def test_invalid_p(self, backend):
+        with pytest.raises(ValueError):
+            Scrypt(b"NaCl", 64, 2, 8, 0, backend)