Add simple TUF role metadata model

tests/test_api.py

@@ -0,0 +1,261 @@
+#!/usr/bin/env python
+
+# Copyright 2020, New York University and the TUF contributors
+# SPDX-License-Identifier: MIT OR Apache-2.0
+""" Unit tests for api/metadata.py
+
+"""
+
+import json
+import sys
+import logging
+import os
+import shutil
+import tempfile
+import unittest
+
+from datetime import datetime, timedelta
+from dateutil.relativedelta import relativedelta
+
+# TODO: Remove case handling when fully dropping support for versions >= 3.6
+IS_PY_VERSION_SUPPORTED = sys.version_info >= (3, 6)
+
+# Use setUpModule to tell unittest runner to skip this test module gracefully.
+def setUpModule():
+    if not IS_PY_VERSION_SUPPORTED:
+        raise unittest.SkipTest('requires Python 3.6 or higher')
+
+# Since setUpModule is called after imports we need to import conditionally.
+if IS_PY_VERSION_SUPPORTED:
+    import tuf.exceptions
+    from tuf.api.metadata import (
+        Metadata,
+        Snapshot,
+        Timestamp,
+        Targets
+    )
+
+    from securesystemslib.interface import (
+        import_ed25519_publickey_from_file,
+        import_ed25519_privatekey_from_file
+    )
+
+logger = logging.getLogger(__name__)
+
+
+class TestMetadata(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        # Create a temporary directory to store the repository, metadata, and
+        # target files.  'temporary_directory' must be deleted in
+        # TearDownClass() so that temporary files are always removed, even when
+        # exceptions occur.
+        cls.temporary_directory = tempfile.mkdtemp(dir=os.getcwd())
+
+        test_repo_data = os.path.join(
+                os.path.dirname(os.path.realpath(__file__)), 'repository_data')
+
+        cls.repo_dir = os.path.join(cls.temporary_directory, 'repository')
+        shutil.copytree(
+                os.path.join(test_repo_data, 'repository'), cls.repo_dir)
+
+        cls.keystore_dir = os.path.join(cls.temporary_directory, 'keystore')
+        shutil.copytree(
+                os.path.join(test_repo_data, 'keystore'), cls.keystore_dir)
+
+        # Load keys into memory
+        cls.keystore = {}
+        for role in ['delegation', 'snapshot', 'targets', 'timestamp']:
+            cls.keystore[role] = {
+                'private': import_ed25519_privatekey_from_file(
+                        os.path.join(cls.keystore_dir, role + '_key'),
+                        password="password"),
+                'public': import_ed25519_publickey_from_file(
+                        os.path.join(cls.keystore_dir, role + '_key.pub'))
+            }
+
+
+    @classmethod
+    def tearDownClass(cls):
+        # Remove the temporary repository directory, which should contain all
+        # the metadata, targets, and key files generated for the test cases.
+        shutil.rmtree(cls.temporary_directory)
+
+
+    def test_generic_read(self):
+        for metadata, inner_metadata_cls in [
+                ('snapshot', Snapshot),
+                ('timestamp', Timestamp),
+                ('targets', Targets)]:
+
+            # Load JSON-formatted metdata of each supported type from file
+            # and from out-of-band read JSON string
+            path = os.path.join(self.repo_dir, 'metadata', metadata + '.json')
+            metadata_obj = Metadata.from_json_file(path)
+            with open(path, 'rb') as f:
+                metadata_str = f.read()
+            metadata_obj2 = Metadata.from_json(metadata_str)
+
+            # Assert that both methods instantiate the right inner class for
+            # each metadata type and ...
+            self.assertTrue(
+                    isinstance(metadata_obj.signed, inner_metadata_cls))
+            self.assertTrue(
+                    isinstance(metadata_obj2.signed, inner_metadata_cls))
+
+            # ... and return the same object (compared by dict representation)
+            self.assertDictEqual(
+                    metadata_obj.to_dict(), metadata_obj2.to_dict())
+
+
+        # Assert that it chokes correctly on an unknown metadata type
+        bad_metadata_path = 'bad-metadata.json'
+        bad_metadata = {'signed': {'_type': 'bad-metadata'}}
+        with open(bad_metadata_path, 'wb') as f:
+            f.write(json.dumps(bad_metadata).encode('utf-8'))
+
+        with self.assertRaises(ValueError):
+            Metadata.from_json_file(bad_metadata_path)
+
+        os.remove(bad_metadata_path)
+
+
+    def test_compact_json(self):
+        path = os.path.join(self.repo_dir, 'metadata', 'targets.json')
+        metadata_obj = Metadata.from_json_file(path)
+        self.assertTrue(
+                len(metadata_obj.to_json(compact=True)) <
+                len(metadata_obj.to_json()))
+
+
+    def test_read_write_read_compare(self):
+        for metadata in ['snapshot', 'timestamp', 'targets']:
+            path = os.path.join(self.repo_dir, 'metadata', metadata + '.json')
+            metadata_obj = Metadata.from_json_file(path)
+
+            path_2 = path + '.tmp'
+            metadata_obj.to_json_file(path_2)
+            metadata_obj_2 = Metadata.from_json_file(path_2)
+
+            self.assertDictEqual(
+                    metadata_obj.to_dict(),
+                    metadata_obj_2.to_dict())
+
+            os.remove(path_2)
+
+
+    def test_sign_verify(self):
+        # Load sample metadata (targets) and assert ...
+        path = os.path.join(self.repo_dir, 'metadata', 'targets.json')
+        metadata_obj = Metadata.from_json_file(path)
+
+        # ... it has a single existing signature,
+        self.assertTrue(len(metadata_obj.signatures) == 1)
+        # ... which is valid for the correct key.
+        self.assertTrue(metadata_obj.verify(
+                self.keystore['targets']['public']))
+
+        # Append a new signature with the unrelated key and assert that ...
+        metadata_obj.sign(self.keystore['snapshot']['private'], append=True)
+        # ... there are now two signatures, and
+        self.assertTrue(len(metadata_obj.signatures) == 2)
+        # ... both are valid for the corresponding keys.
+        self.assertTrue(metadata_obj.verify(
+                self.keystore['targets']['public']))
+        self.assertTrue(metadata_obj.verify(
+                self.keystore['snapshot']['public']))
+
+        # Create and assign (don't append) a new signature and assert that ...
+        metadata_obj.sign(self.keystore['timestamp']['private'], append=False)
+        # ... there now is only one signature,
+        self.assertTrue(len(metadata_obj.signatures) == 1)
+        # ... valid for that key.
+        self.assertTrue(metadata_obj.verify(
+                self.keystore['timestamp']['public']))
+
+        # Assert exception if there are more than one signatures for a key
+        metadata_obj.sign(self.keystore['timestamp']['private'], append=True)
+        with self.assertRaises(tuf.exceptions.Error) as ctx:
+            metadata_obj.verify(self.keystore['timestamp']['public'])
+        self.assertTrue(
+                '2 signatures for key' in str(ctx.exception),
+                str(ctx.exception))
+
+        # Assert exception if there is no signature for a key
+        with self.assertRaises(tuf.exceptions.Error) as ctx:
+            metadata_obj.verify(self.keystore['targets']['public'])
+        self.assertTrue(
+                'no signature for' in str(ctx.exception),
+                str(ctx.exception))
+
+
+    def test_metadata_base(self):
+        # Use of Snapshot is arbitrary, we're just testing the base class features
+        # with real data
+        snapshot_path = os.path.join(
+                self.repo_dir, 'metadata', 'snapshot.json')
+        md = Metadata.from_json_file(snapshot_path)
+
+        self.assertEqual(md.signed.version, 1)
+        md.signed.bump_version()
+        self.assertEqual(md.signed.version, 2)
+        self.assertEqual(md.signed.expires, datetime(2030, 1, 1, 0, 0))
+        md.signed.bump_expiration()
+        self.assertEqual(md.signed.expires, datetime(2030, 1, 2, 0, 0))
+        md.signed.bump_expiration(timedelta(days=365))
+        self.assertEqual(md.signed.expires, datetime(2031, 1, 2, 0, 0))
+
+
+    def test_metadata_snapshot(self):
+        snapshot_path = os.path.join(
+                self.repo_dir, 'metadata', 'snapshot.json')
+        snapshot = Metadata.from_json_file(snapshot_path)
+
+        # Create a dict representing what we expect the updated data to be
+        fileinfo = snapshot.signed.meta
+        hashes = {'sha256': 'c2986576f5fdfd43944e2b19e775453b96748ec4fe2638a6d2f32f1310967095'}
+        fileinfo['role1.json']['version'] = 2
+        fileinfo['role1.json']['hashes'] = hashes
+        fileinfo['role1.json']['length'] = 123
+
+        snapshot.signed.update('role1', 2, 123, hashes)
+        self.assertEqual(snapshot.signed.meta, fileinfo)
+
+
+    def test_metadata_timestamp(self):
+        timestamp_path = os.path.join(
+                self.repo_dir, 'metadata', 'timestamp.json')
+        timestamp = Metadata.from_json_file(timestamp_path)
+
+        self.assertEqual(timestamp.signed.version, 1)
+        timestamp.signed.bump_version()
+        self.assertEqual(timestamp.signed.version, 2)
+
+        self.assertEqual(timestamp.signed.expires, datetime(2030, 1, 1, 0, 0))
+        timestamp.signed.bump_expiration()
+        self.assertEqual(timestamp.signed.expires, datetime(2030, 1, 2, 0, 0))
+        timestamp.signed.bump_expiration(timedelta(days=365))
+        self.assertEqual(timestamp.signed.expires, datetime(2031, 1, 2, 0, 0))
+
+        # Test whether dateutil.relativedelta works, this provides a much
+        # easier to use interface for callers
+        delta = relativedelta(days=1)
+        timestamp.signed.bump_expiration(delta)
+        self.assertEqual(timestamp.signed.expires, datetime(2031, 1, 3, 0, 0))
+        delta = relativedelta(years=5)
+        timestamp.signed.bump_expiration(delta)
+        self.assertEqual(timestamp.signed.expires, datetime(2036, 1, 3, 0, 0))
+
+        hashes = {'sha256': '0ae9664468150a9aa1e7f11feecb32341658eb84292851367fea2da88e8a58dc'}
+        fileinfo = timestamp.signed.meta['snapshot.json']
+        fileinfo['hashes'] = hashes
+        fileinfo['version'] = 2
+        fileinfo['length'] = 520
+        timestamp.signed.update(2, 520, hashes)
+        self.assertEqual(timestamp.signed.meta['snapshot.json'], fileinfo)
+
+
+# Run unit test.
+if __name__ == '__main__':
+    unittest.main()