Fix a bug with handling of binary data

When checking the length of the data in a request, Barbican assumes
that data is UTF-8 encoded strings.  Barbican then attempts to
decode all data from UTF-8 to byte strings, which results in an
exception when the data does not conform to UTF-8.

This CR also adds the six library as a dependency to add type checking
that is compatible in both Python 2 and 3.

Change-Id: I3e937998c3bd4d5fbe94c89099ba56c26dbb75b7
Closes-Bug: #1315498

barbican/common/validators.py

@@ -6,6 +6,7 @@ import abc
 
 import jsonschema as schema
 from oslo.config import cfg
+import six
 
 from barbican.common import exception
 from barbican.common import utils
@@ -26,7 +27,10 @@ CONF.register_opts(common_opts)
 
 
 def secret_too_big(data):
-    return len(data.encode('utf-8')) > CONF.max_allowed_secret_in_bytes
+    if isinstance(data, six.text_type):
+        return len(data.encode('UTF-8')) > CONF.max_allowed_secret_in_bytes
+    else:
+        return len(data) > CONF.max_allowed_secret_in_bytes
 
 
 def get_invalid_property(validation_error):

barbican/tests/common/test_validators.py

@@ -30,6 +30,33 @@ def suite():
     return suite
 
 
+class WhenTestingValidatorsFunctions(testtools.TestCase):
+
+    def test_secret_too_big_is_false_for_small_secrets(self):
+        data = b'\xb0'
+
+        is_too_big = validators.secret_too_big(data)
+
+        self.assertFalse(is_too_big)
+
+    def test_secret_too_big_is_true_for_big_secrets(self):
+        data = b'\x01' * validators.CONF.max_allowed_secret_in_bytes
+        data += b'\x01'
+
+        is_too_big = validators.secret_too_big(data)
+
+        self.assertTrue(is_too_big)
+
+    def test_secret_too_big_is_true_for_big_unicode_secrets(self):
+        beer = u'\U0001F37A'
+        data = beer * (validators.CONF.max_allowed_secret_in_bytes / 4)
+        data += u'1'
+
+        is_too_big = validators.secret_too_big(data)
+
+        self.assertTrue(is_too_big)
+
+
 class WhenTestingSecretValidator(testtools.TestCase):
 
     def setUp(self):

requirements.txt

@@ -14,6 +14,7 @@ pbr>=0.5.21,<1.0
 pycrypto>=2.6
 pysqlite
 python-keystoneclient>=0.4.1
+six>=1.6.0
 SQLAlchemy>=0.7.8,<=0.9.99
 stevedore>=0.12
 WebOb>=1.2.3,<1.3