Adding urllib3 requests coverage (#9793)

This change added a new fuzzer `fuzz_requests`. This fuzzes the
`.request` method in urllib3, which opens a lot more coverage.

<img width="653" alt="image"
src="https://user-images.githubusercontent.com/5122866/221026547-8097ef14-bc21-4e4e-a5ab-573048259576.png">

I have created a python `HTTPServer` that provides fuzzed responses to
all the different request types. And I try and drive different
combinations of requests including mixes of headers, bodies and request
types. This gives a nice improvement on current coverage levels [urllib3
fuzz inspector report
2023-02-23](https://storage.googleapis.com/oss-fuzz-introspector/urllib3/inspector-report/20230223/fuzz_report.html).

projects/urllib3/fuzz_requests.py

@@ -0,0 +1,129 @@
+#!/usr/bin/python3
+
+# Copyright 2023 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
+from http.server import BaseHTTPRequestHandler, HTTPServer
+import sys
+import threading
+import time
+
+with atheris.instrument_imports():
+    import urllib3
+
+timeout = urllib3.util.Timeout(connect=1.0, read=1.0)
+urllib_pool = urllib3.PoolManager(timeout=timeout)
+
+PORT = 8011
+
+GLOBAL_RESPONSE_MESSAGE = ""
+GLOBAL_RESPONSE_CODE = 0
+GLOBAL_CONTENT_ENCODING = None
+
+
+class handler(BaseHTTPRequestHandler):
+    def send_fuzzed_response(self):
+        self.send_response(GLOBAL_RESPONSE_CODE)
+        self.send_header("content-type", "text/html")
+        if GLOBAL_CONTENT_ENCODING:
+            self.send_header("content-encoding", GLOBAL_CONTENT_ENCODING)
+        self.end_headers()
+
+        self.wfile.write(bytes(GLOBAL_RESPONSE_MESSAGE, "utf-8"))
+
+    def do_GET(self):
+        self.send_fuzzed_response()
+
+    def do_POST(self):
+        self.send_fuzzed_response()
+
+    def do_PUT(self):
+        self.send_fuzzed_response()
+
+    def do_PATCH(self):
+        self.send_fuzzed_response()
+
+    def do_OPTIONS(self):
+        self.send_fuzzed_response()
+
+    def do_DELETE(self):
+        self.send_fuzzed_response()
+
+    def do_HEAD(self):
+        self.send_fuzzed_response()
+
+    # Supress HTTP log output
+    def log_request(self, code="-", size="-"):
+        return
+
+
+def run_webserver():
+    with HTTPServer(("", PORT), handler) as server:
+        server.serve_forever()
+
+
+REQUEST_METHODS = ["POST", "GET", "HEAD", "PUT", "DELETE", "OPTIONS", "PATCH"]
+CONTENT_ENCODING_TYPES = [None, "gzip", "deflate"]
+
+
+def TestOneInput(input_bytes):
+    global GLOBAL_RESPONSE_MESSAGE, GLOBAL_RESPONSE_CODE, GLOBAL_CONTENT_ENCODING
+    fdp = atheris.FuzzedDataProvider(input_bytes)
+
+    # Fuzz Http Response
+    GLOBAL_RESPONSE_MESSAGE = fdp.ConsumeUnicodeNoSurrogates(sys.maxsize)
+    GLOBAL_RESPONSE_CODE = fdp.ConsumeIntInRange(200, 599)
+    GLOBAL_CONTENT_ENCODING = fdp.PickValueInList(CONTENT_ENCODING_TYPES)
+
+    # Fuzz Http Request
+    requestType = fdp.PickValueInList(REQUEST_METHODS)
+    # Optionally provide request headers
+    requestHeaders = urllib3._collections.HTTPHeaderDict({})
+    for i in range(0, fdp.ConsumeIntInRange(0, 10)):
+        requestHeaders.add(
+            fdp.ConsumeString(sys.maxsize), fdp.ConsumeString(sys.maxsize)
+        )
+    requestHeaders = None if fdp.ConsumeBool() else requestHeaders
+
+    # Optionally generate form data for request
+    formData = {}
+    for i in range(0, fdp.ConsumeIntInRange(0, 100)):
+        formData[fdp.ConsumeString(sys.maxsize)] = fdp.ConsumeString(sys.maxsize)
+    formData = None if fdp.ConsumeBool() else formData
+
+    # Optionally generate request body
+    requestBody = None if fdp.ConsumeBool() else fdp.ConsumeString(sys.maxsize)
+
+    r = urllib_pool.request(
+        requestType,
+        f"http://localhost:{PORT}/",
+        headers=requestHeaders,
+        fields=formData,
+        body=requestBody
+    )
+    r.status
+    r.data
+    r.headers
+
+
+if __name__ == "__main__":
+    x = threading.Thread(target=run_webserver, daemon=True)
+    x.start()
+
+    time.sleep(0.5)  # Short delay to start test server
+    
+    atheris.Setup(sys.argv, TestOneInput)
+
+    atheris.Fuzz()

projects/urllib3/fuzz_urlparse.py

@@ -34,7 +34,7 @@ def TestOneInput(data):
     return
 
 def main():
-    atheris.Setup(sys.argv, TestOneInput, enable_python_coverage=True)
+    atheris.Setup(sys.argv, TestOneInput)
     atheris.Fuzz()
 
 if __name__ == "__main__":