From 6929137715ce4ba1a16362c9b0637af0a03a338b Mon Sep 17 00:00:00 2001
From: DavidKorczynski <david@adalogics.com>
Date: Mon, 15 Aug 2022 12:41:11 +0100
Subject: [PATCH] g-cloud-logging: refine fuzzing set up (#8256)

Add mocking to resources fuzzer and simplify others.
---
 projects/g-cloud-logging-py/Dockerfile        |  1 +
 projects/g-cloud-logging-py/fuzz_entries.py   |  9 ++---
 projects/g-cloud-logging-py/fuzz_helpers.py   | 26 +++++++-------
 projects/g-cloud-logging-py/fuzz_resources.py | 34 ++++++++++++++-----
 4 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/projects/g-cloud-logging-py/Dockerfile b/projects/g-cloud-logging-py/Dockerfile
index 84f466f6c..479b3aaef 100644
--- a/projects/g-cloud-logging-py/Dockerfile
+++ b/projects/g-cloud-logging-py/Dockerfile
@@ -17,6 +17,7 @@
 FROM gcr.io/oss-fuzz-base/base-builder-python
 
 RUN git clone https://github.com/googleapis/python-logging gcloud-logging
+RUN pip3 install --upgrade pip mock
 WORKDIR gcloud-logging
 
 COPY build.sh fuzz_*.py $SRC/
diff --git a/projects/g-cloud-logging-py/fuzz_entries.py b/projects/g-cloud-logging-py/fuzz_entries.py
index 388f3fbb4..d3e8d602d 100644
--- a/projects/g-cloud-logging-py/fuzz_entries.py
+++ b/projects/g-cloud-logging-py/fuzz_entries.py
@@ -15,10 +15,10 @@
 
 import atheris
 import sys
-with atheris.instrument_imports():
-    import google.cloud.logging_v2.entries as entries
-    from google.cloud.logging_v2.client import Client
-    from google.cloud.logging_v2.resource import Resource
+
+import google.cloud.logging_v2.entries as entries
+from google.cloud.logging_v2.client import Client
+from google.cloud.logging_v2.resource import Resource
 
 def create_dummy_log_entry(fdp):
     return entries.LogEntry(
@@ -72,6 +72,7 @@ def TestInput(data):
             raise e
 
 def main():
+    atheris.instrument_all()
     atheris.Setup(sys.argv, TestInput, enable_python_coverage=True)
     atheris.Fuzz()
 
diff --git a/projects/g-cloud-logging-py/fuzz_helpers.py b/projects/g-cloud-logging-py/fuzz_helpers.py
index 4cadac3e9..dec1e3069 100644
--- a/projects/g-cloud-logging-py/fuzz_helpers.py
+++ b/projects/g-cloud-logging-py/fuzz_helpers.py
@@ -15,24 +15,26 @@
 
 import atheris
 import sys
-with atheris.instrument_imports():
-    import google.cloud.logging_v2._helpers as helpers
-    import google.cloud.logging_v2.handlers._helpers as handlers_helpers
+
+import google.cloud.logging_v2._helpers as helpers
+import google.cloud.logging_v2.handlers._helpers as handlers_helpers
+
 
 def TestInput(data):
     fdp = atheris.FuzzedDataProvider(data)
 
-    helpers.retrieve_metadata_server(fdp.ConsumeString(100))
-    helpers._normalize_severity(fdp.ConsumeInt(100))
-    helpers._add_defaults_to_filter(fdp.ConsumeString(100))
-
-    handlers_helpers.get_request_data_from_flask()
-    handlers_helpers.get_request_data_from_django()
-    handlers_helpers._parse_trace_parent(fdp.ConsumeString(100))
-    handlers_helpers._parse_xcloud_trace(fdp.ConsumeString(100))
-    handlers_helpers.get_request_data()
+    op = fdp.ConsumeIntInRange(0, 4)
+    if op == 0:
+        helpers._normalize_severity(fdp.ConsumeInt(sys.maxsize))
+    elif op == 1:
+        helpers._add_defaults_to_filter(fdp.ConsumeUnicodeNoSurrogates(40))
+    elif op == 2:
+        handlers_helpers._parse_trace_parent(fdp.ConsumeUnicodeNoSurrogates(300))
+    else:
+        handlers_helpers._parse_xcloud_trace(fdp.ConsumeUnicodeNoSurrogates(300))
 
 def main():
+    atheris.instrument_all()
     atheris.Setup(sys.argv, TestInput, enable_python_coverage=True)
     atheris.Fuzz()
 
diff --git a/projects/g-cloud-logging-py/fuzz_resources.py b/projects/g-cloud-logging-py/fuzz_resources.py
index 1c4d3dcf4..0f01b3ae2 100644
--- a/projects/g-cloud-logging-py/fuzz_resources.py
+++ b/projects/g-cloud-logging-py/fuzz_resources.py
@@ -15,19 +15,35 @@
 
 import atheris
 import sys
+import mock
+
 with atheris.instrument_imports():
-    import google.cloud.logging_v2.handlers._monitored_resources as resources
+    from google.cloud.logging_v2.handlers import _monitored_resources
+
+
+global_fdp = None
+def mock_retrieve_metadata_server(endpoint):
+    """Mock for retrieve_metadata_server"""
+    if global_fdp is None:
+        return None
+    if global_fdp.ConsumeIntInRange(1, 10) < 3:
+        return None
+    return global_fdp.ConsumeUnicodeNoSurrogates(30)
 
 def TestInput(data):
-    fdp = atheris.FuzzedDataProvider(data)
+    global global_fdp
+    global_fdp = atheris.FuzzedDataProvider(data)
+
+    # Mock the metadata server to avoid connections. The
+    # retrieve_metadata_server will return fuzzer-seeded data.
+    patch = mock.patch(
+        "google.cloud.logging_v2.handlers._monitored_resources.retrieve_metadata_server",
+        wraps=mock_retrieve_metadata_server,
+    )
+    # TODO: randomise relevant environment variables.
+    with patch:
+        _monitored_resources.detect_resource()
 
-    resources._create_functions_resource()
-    resources._create_kubernetes_resource()
-    resources._create_compute_resource()
-    resources._create_cloud_run_resource()
-    resources._create_app_engine_resource()
-    resources._create_global_resource(fdp.ConsumeString(100))
-    resources.detect_resource(fdp.ConsumeString(100))
 
 def main():
     atheris.Setup(sys.argv, TestInput, enable_python_coverage=True)