Add fuzzer for TURN unwrap.

This is called on received network packets if dump_rtp_packets_ is on.

NOTRY=true

Review-Url: https://codereview.webrtc.org/2126463002
Cr-Commit-Position: refs/heads/master@{#13394}

webrtc/test/fuzzers/BUILD.gn

@@ -7,8 +7,9 @@
 # be found in the AUTHORS file in the root of the source tree.
 
 import("//build/config/features.gni")
-import("//testing/test.gni")
+import("//build_overrides/webrtc.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
+import("//testing/test.gni")
 
 static_library("webrtc_fuzzer_main") {
   public_configs = [ "../..:common_inherited_config" ]
@@ -175,3 +176,17 @@ webrtc_fuzzer_test("audio_decoder_opus_redundant_fuzzer") {
     "../../modules/audio_coding:webrtc_opus",
   ]
 }
+
+# TODO(katrielc) Enable in Chromium when CL 2022833002 lands.
+# Although the dependency on media compiles in standalone, it is
+# flagged by gn check, so breaks when rolled into Chromium.
+if (!build_with_chromium) {
+  webrtc_fuzzer_test("turn_unwrap_fuzzer") {
+    sources = [
+      "turn_unwrap_fuzzer.cc",
+    ]
+    deps = [
+      "../../media:media",
+    ]
+  }
+}

webrtc/test/fuzzers/turn_unwrap_fuzzer.cc

@@ -0,0 +1,22 @@
+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "webrtc/media/base/turnutils.h"
+
+namespace webrtc {
+void FuzzOneInput(const uint8_t* data, size_t size) {
+  size_t content_position;
+  size_t content_size;
+  cricket::UnwrapTurnPacket(data, size, &content_position, &content_size);
+}
+}  // namespace webrtc