[BlackboxAudit] Only update fuzzer.source when creating a fuzzer (#5252)

The `Fuzzer.source` is the point of contact or owner of a fuzzer. When
the fuzzer is created, the source is the author who uploads the fuzzer.
Currently, when we edit the jobs, configuration, or upload a new version
of the fuzzer, the `Fuzzer.source` updates to the person who is making
that change.

This was fine when the only one maintaining a fuzzer was the current
owner of the fuzzer, but breaks down when making LSC type changes to our
fuzzer suite. This PR changes the behavior to only set the source when
creating a fuzzer and introduces a `last_edited_by` to capture the paper
trail of changes. Now, if we want to change the owner we can do so in
the datastore directly, and small edits to disable/enable a Fuzzer won't
change the source, which is the Fuzzer's owner

The user who is making the edit is also logged as part of the
[fuzzer_update_message](https://github.com/google/clusterfuzz/blob/0b9e68ae390d76ae9f475165b1957ca10689f50b/src/appengine/handlers/fuzzers.py#L221).


Tested this locally by creating and editing a fuzzer.

Author: dylanjew

src/appengine/handlers/fuzzers.py

@@ -186,7 +186,7 @@ def apply_fuzzer_changes(self, fuzzer, upload_info):
 
     fuzzer.jobs = jobs
     fuzzer.revision = fuzzer.revision + 1
-    fuzzer.source = helpers.get_user_email()
+    fuzzer.last_edited_by = helpers.get_user_email()
     fuzzer.timeout = timeout
     fuzzer.max_testcases = max_testcases
     fuzzer.result = None
@@ -254,6 +254,8 @@ def post(self):
     fuzzer.revision = 0
     fuzzer.created_at = datetime.datetime.now(tz=datetime.timezone.utc).replace(
         tzinfo=None)
+    fuzzer.source = helpers.get_user_email()
+
     return self.apply_fuzzer_changes(fuzzer, upload_info)
 
 

src/clusterfuzz/_internal/datastore/data_types.py

@@ -313,6 +313,9 @@ class Fuzzer(Model):
   # Fuzzer's source (for accountability).
   source = ndb.StringProperty()
 
+  # Last person to make changes to the Fuzzer code or configuration.
+  last_edited_by = ndb.StringProperty()
+
   # Testcase timeout.
   timeout = ndb.IntegerProperty()
 

src/clusterfuzz/_internal/tests/appengine/handlers/fuzzers_test.py

@@ -78,6 +78,7 @@ def setUp(self):
         'handlers.fuzzers.CreateHandler.get_upload',
         'handlers.fuzzers.CreateHandler.apply_fuzzer_changes',
     ])
+
     self.mock.has_access.return_value = True
     self.mock.get_current_user().email = 'test@user.com'
     self.mock.get_user_email.return_value = 'test@user.com'
@@ -108,6 +109,7 @@ def test_create_fuzzer(self):
     self.assertEqual(fuzzer.name, fuzzer_name)
     self.assertEqual(fuzzer.revision, 0)
     self.assertEqual(fuzzer.created_at, self.mock_time)
+    self.assertEqual(fuzzer.source, 'test@user.com')
 
 
 @test_utils.with_cloud_emulators('datastore')
@@ -125,8 +127,8 @@ def setUp(self):
         'handlers.fuzzers.EditHandler._get_launcher_script',
     ])
     self.mock.has_access.return_value = True
-    self.mock.get_current_user().email = 'test@user.com'
-    self.mock.get_user_email.return_value = 'test@user.com'
+    self.mock.get_current_user().email = 'editor@example.com'
+    self.mock.get_user_email.return_value = 'editor@example.com'
     self.mock.get_upload.return_value = storage.GcsBlobInfo(
         bucket='test-bucket', object_path='key', filename='file.zip', size=123)
 
@@ -150,6 +152,7 @@ def test_update_fuzzer(self):
         name=fuzzer_name,
         jobs=[],
         revision=1,
+        source='original@example.com',
         timeout=10,
     )
     fuzzer.put()
@@ -177,10 +180,11 @@ def test_update_fuzzer(self):
             'data_bundle_name': 'test_bundle',
             'external_contribution': True,
             'executable_path': 'executable',
+            'last_edited_by': 'editor@example.com',
             'launcher_script': 'launcher',
             'jobs': [],
             'max_testcases': 100,
             'revision': 2,
-            'source': 'test@user.com',
+            'source': 'original@example.com',
             'timeout': 30,
         })

src/clusterfuzz/_internal/tests/core/datastore/data_types_test.py

@@ -38,6 +38,7 @@ def test_get_config_dict(self):
         launcher_script='path/to/launcher',
         revision=3,
         source='author',
+        last_edited_by='editor',
     )
 
     config_dict = fuzzer.get_config_dict()
@@ -54,6 +55,7 @@ def test_get_config_dict(self):
             'launcher_script': 'path/to/launcher',
             'revision': 3,
             'source': 'author',
+            'last_edited_by': 'editor',
         },
         config_dict,
     )