Internal support for oss-fuzz testing

Tests/oss-fuzz/fuzz_pillow.py

@@ -0,0 +1,45 @@
+#!/usr/bin/python3
+
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import atheris_no_libfuzzer as atheris
+import sys
+import os
+import io
+import warnings
+from PIL import Image, ImageFile, ImageFilter
+
+def TestOneInput(data):
+    try:
+        with Image.open(io.BytesIO(data)) as im:
+          im.rotate(45)
+          im.filter(ImageFilter.DETAIL)
+          im.save(io.BytesIO(), "BMP")
+    except Exception:
+        # We're catching all exceptions because Pillow's exceptions are
+        # directly inheriting from Exception.
+        return
+    return
+
+def main():
+    ImageFile.LOAD_TRUNCATED_IMAGES = True
+    warnings.filterwarnings("ignore")
+    warnings.simplefilter('error', Image.DecompressionBombWarning)
+    atheris.Setup(sys.argv, TestOneInput, enable_python_coverage=True)
+    atheris.Fuzz()
+
+if __name__ == "__main__":
+    main()
+

setup.py

@@ -840,7 +840,7 @@ class pil_build_ext(build_ext):
 
 
 def debug_build():
-    return hasattr(sys, "gettotalrefcount")
+    return hasattr(sys, "gettotalrefcount") or os.environ.get("LIB_FUZZING_ENGINE", None)
 
 
 files = ["src/_imaging.c"]