2 files changed, 187 insertions, 0 deletions
diff --git a/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.cpp b/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.cpp
new file mode 100644
index 0000000000..95982733cd
--- /dev/null
+++ b/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.cpp
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpcrtfuzzing/xpcrtfuzzing.h"
+
+#include "mozilla/Assertions.h"  // MOZ_CRASH
+#include "mozilla/Utf8.h"        // mozilla::Utf8Unit
+
+#include <stdio.h>  // fflush, fprintf, fputs
+
+#include "FuzzingInterface.h"
+#include "jsapi.h"
+
+#include "js/CompilationAndEvaluation.h"  // JS::Evaluate
+#include "js/CompileOptions.h"            // JS::CompileOptions
+#include "js/Conversions.h"               // JS::Conversions
+#include "js/ErrorReport.h"               // JS::PrintError
+#include "js/Exception.h"                 // JS::StealPendingExceptionStack
+#include "js/experimental/TypedData.h"  // JS_GetUint8ClampedArrayData, JS_NewUint8ClampedArray
+#include "js/PropertyAndElement.h"  // JS_SetProperty, JS_HasOwnProperty
+#include "js/RootingAPI.h"          // JS::Rooted
+#include "js/SourceText.h"          // JS::Source{Ownership,Text}
+#include "js/Value.h"               // JS::Value
+
+using mozilla::dom::AutoJSAPI;
+
+static AutoJSAPI* gJsapi = nullptr;
+static std::string gFuzzModuleName;
+
+static void CrashOnPendingException() {
+  if (gJsapi->HasException()) {
+    gJsapi->ReportException();
+
+    MOZ_CRASH("Unhandled exception from JS runtime!");
+  }
+}
+
+int FuzzXPCRuntimeStart(AutoJSAPI* jsapi, int* argc, char*** argv,
+                        LibFuzzerDriver fuzzerDriver) {
+  gFuzzModuleName = getenv("FUZZER");
+  gJsapi = jsapi;
+
+  int ret = FuzzXPCRuntimeInit();
+  if (ret) {
+    fprintf(stderr, "Fuzzing Interface: Error: Initialize callback failed\n");
+    return ret;
+  }
+
+  ret = fuzzerDriver(argc, argv, FuzzXPCRuntimeFuzz);
+  if (!ret) {
+    fprintf(stdout, "Trying to shutdown!\n");
+    int shutdown = FuzzXPCRuntimeShutdown();
+    if (shutdown) {
+      fprintf(stderr, "Fuzzing Interface: Error: Shutdown callback failed\n");
+      return shutdown;
+    }
+  }
+
+  return ret;
+}
+
+int FuzzXPCRuntimeInit() {
+  JSContext* cx = gJsapi->cx();
+  JS::Rooted<JS::Value> v(cx);
+  JS::CompileOptions opts(cx);
+
+  // Load the fuzzing module specified in the FUZZER environment variable
+  JS::EvaluateUtf8Path(cx, opts, gFuzzModuleName.c_str(), &v);
+
+  // Any errors while loading the fuzzing module should be fatal
+  CrashOnPendingException();
+
+  return 0;
+}
+
+int FuzzXPCRuntimeFuzz(const uint8_t* buf, size_t size) {
+  if (!size) {
+    return 0;
+  }
+
+  JSContext* cx = gJsapi->cx();
+
+  JS::Rooted<JSObject*> arr(cx, JS_NewUint8ClampedArray(cx, size));
+  if (!arr) {
+    MOZ_CRASH("OOM");
+  }
+
+  do {
+    JS::AutoCheckCannotGC nogc;
+    bool isShared;
+    uint8_t* data = JS_GetUint8ClampedArrayData(arr, &isShared, nogc);
+    MOZ_RELEASE_ASSERT(!isShared);
+    memcpy(data, buf, size);
+  } while (false);
+
+  JS::Rooted<JSObject*> global(cx, JS::CurrentGlobalOrNull(cx));
+  JS::RootedValue arrVal(cx, JS::ObjectValue(*arr));
+  if (!JS_SetProperty(cx, global, "fuzzBuf", arrVal)) {
+    MOZ_CRASH("JS_SetProperty failed");
+  }
+
+  JS::Rooted<JS::Value> v(cx);
+  JS::CompileOptions opts(cx);
+
+  static const char data[] = "JSFuzzIterate();";
+
+  JS::SourceText<mozilla::Utf8Unit> srcBuf;
+  if (!srcBuf.init(cx, data, strlen(data), JS::SourceOwnership::Borrowed)) {
+    return 1;
+  }
+
+  if (!JS::Evaluate(cx, opts.setFileAndLine(__FILE__, __LINE__), srcBuf, &v) &&
+      !JS_IsExceptionPending(cx)) {
+    // A return value of `false` without a pending exception indicates
+    // a timeout as triggered by the `timeout` shell function.
+    return 1;
+  }
+
+  // The fuzzing module is required to handle any exceptions
+  CrashOnPendingException();
+
+  int32_t ret = 0;
+  if (!ToInt32(cx, v, &ret)) {
+    MOZ_CRASH("Must return an int32 compatible return value!");
+  }
+
+  return ret;
+}
+
+int FuzzXPCRuntimeShutdown() {
+  JSContext* cx = gJsapi->cx();
+  JS::Rooted<JS::Value> v(cx);
+  JS::CompileOptions opts(cx);
+  JS::Rooted<JSObject*> global(cx, JS::CurrentGlobalOrNull(cx));
+
+  bool found = false;
+  if (JS_HasOwnProperty(cx, global, "JSFuzzShutdown", &found)) {
+    if (found) {
+      static const char data[] = "JSFuzzShutdown();";
+      JS::SourceText<mozilla::Utf8Unit> srcBuf;
+      if (!srcBuf.init(cx, data, strlen(data), JS::SourceOwnership::Borrowed)) {
+        return 1;
+      }
+
+      if (!JS::Evaluate(cx, opts.setFileAndLine(__FILE__, __LINE__), srcBuf,
+                        &v) &&
+          !JS_IsExceptionPending(cx)) {
+        // A return value of `false` without a pending exception indicates
+        // a timeout as triggered by the `timeout` shell function.
+        return 1;
+      }
+    }
+  }
+
+  // The fuzzing module is required to handle any exceptions
+  CrashOnPendingException();
+
+  return 0;
+}
diff --git a/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.h b/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.h
new file mode 100644
index 0000000000..89cdf5996b
--- /dev/null
+++ b/js/xpconnect/src/xpcrtfuzzing/xpcrtfuzzing.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// xpcrtfuzzing.h - Functionality for XPC runtime fuzzing
+
+#ifndef shell_xpcrtfuzzing_h
+#define shell_xpcrtfuzzing_h
+
+#include "mozilla/dom/ScriptSettings.h"  // mozilla::dom::AutoJSAPI
+#include "FuzzerRegistry.h"              // LibFuzzerDriver
+
+// This is the entry point of the XPC runtime fuzzing code from the XPC shell
+int FuzzXPCRuntimeStart(mozilla::dom::AutoJSAPI* jsapi, int* argc, char*** argv,
+                        LibFuzzerDriver);
+
+// These are the traditional libFuzzer-style functions for initialization
+// and fuzzing iteration.
+int FuzzXPCRuntimeInit();
+int FuzzXPCRuntimeFuzz(const uint8_t* buf, size_t size);
+int FuzzXPCRuntimeShutdown();
+
+#endif /* shell_xpcrtfuzzing_h */