flask: migrate fuzzers from previous PRs (#7639)

jinja and werkzeug previous initial integration suggestions.

Ref: https://github.com/google/oss-fuzz/pull/4761
Ref: https://github.com/google/oss-fuzz/pull/4998

projects/flask/fuzz_env_jinja_lexer.py

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+# Copyright 2022 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 sys
+import atheris
+
+with atheris.instrument_imports():
+    import jinja2
+
+def TestOneInput(data):
+    fdp = atheris.FuzzedDataProvider(data)
+    original = fdp.ConsumeString(sys.maxsize)
+
+    # Hit the parser
+    env = jinja2.Environment()
+    try:
+        v1 = env.from_string(original)
+    except jinja2.TemplateSyntaxError:
+        return
+    v1.render()
+
+    # Hit tokernizer directly
+    env.lexer.tokenize(original)
+    return
+
+def main():
+    atheris.Setup(sys.argv, TestOneInput, enable_python_coverage=True)
+    atheris.Fuzz()
+
+if __name__ == "__main__":
+    main()

projects/flask/fuzz_werkzeug_url.py

@@ -0,0 +1,40 @@
+#!/usr/bin/python3
+# Copyright 2022 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 sys
+import atheris
+
+with atheris.instrument_imports():
+    import werkzeug
+
+
+def TestOneInput(data):
+    fdp = atheris.FuzzedDataProvider(data)
+    original = fdp.ConsumeUnicode(sys.maxsize)
+    try:
+        werkzeug.urls.url_fix(original)
+    except ValueError:
+        return
+
+    return
+
+
+def main():
+    atheris.Setup(sys.argv, TestOneInput, enable_python_coverage=True)
+    atheris.Fuzz()
+
+
+if __name__ == "__main__":
+    main()