third_party/blink/renderer/modules/webcodecs/video_encoder_fuzzer.cc

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/run_loop.h"
#include "testing/libfuzzer/proto/lpm_interface.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_encoded_video_chunk_output_callback.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_video_decoder_config.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_video_encoder_init.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_webcodecs_error_callback.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/testing/dummy_page_holder.h"
#include "third_party/blink/renderer/modules/webcodecs/encoded_video_chunk.h"
#include "third_party/blink/renderer/modules/webcodecs/fuzzer_inputs.pb.h"
#include "third_party/blink/renderer/modules/webcodecs/fuzzer_utils.h"
#include "third_party/blink/renderer/modules/webcodecs/video_encoder.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "third_party/blink/renderer/platform/bindings/script_state.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/testing/blink_fuzzer_test_support.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

#include <string>

#include "third_party/protobuf/src/google/protobuf/text_format.h"

namespace blink {

DEFINE_TEXT_PROTO_FUZZER(
    const wc_fuzzer::VideoEncoderApiInvocationSequence& proto) {
  static BlinkFuzzerTestSupport test_support = BlinkFuzzerTestSupport();
  static DummyPageHolder* page_holder = []() {
    auto page_holder = std::make_unique<DummyPageHolder>();
    page_holder->GetFrame().GetSettings()->SetScriptEnabled(true);
    return page_holder.release();
  }();
  // Request a full GC upon returning.
  auto scoped_gc =
      MakeScopedGarbageCollectionRequest(test_support.GetIsolate());

  //
  // NOTE: GC objects that need to survive iterations of the loop below
  // must be Persistent<>!
  //
  // GC may be triggered by the RunLoop().RunUntilIdle() below, which will GC
  // raw pointers on the stack. This is not required in production code because
  // GC typically runs at the top of the stack, or is conservative enough to
  // keep stack pointers alive.
  //

  // Scoping Persistent<> refs so GC can collect these at the end.
  {
    Persistent<ScriptState> script_state =
        ToScriptStateForMainWorld(&page_holder->GetFrame());
    ScriptState::Scope scope(script_state);

    Persistent<ScriptFunction> error_function =
        MakeGarbageCollected<ScriptFunction>(
            script_state, MakeGarbageCollected<FakeFunction>("error"));
    Persistent<V8WebCodecsErrorCallback> error_callback =
        V8WebCodecsErrorCallback::Create(error_function->V8Function());
    Persistent<ScriptFunction> output_function =
        MakeGarbageCollected<ScriptFunction>(
            script_state, MakeGarbageCollected<FakeFunction>("output"));
    Persistent<V8EncodedVideoChunkOutputCallback> output_callback =
        V8EncodedVideoChunkOutputCallback::Create(
            output_function->V8Function());

    Persistent<VideoEncoderInit> video_encoder_init =
        MakeGarbageCollected<VideoEncoderInit>();
    video_encoder_init->setError(error_callback);
    video_encoder_init->setOutput(output_callback);

    Persistent<VideoEncoder> video_encoder = VideoEncoder::Create(
        script_state, video_encoder_init, IGNORE_EXCEPTION_FOR_TESTING);

    if (video_encoder) {
      for (auto& invocation : proto.invocations()) {
        switch (invocation.Api_case()) {
          case wc_fuzzer::VideoEncoderApiInvocation::kConfigure: {
            VideoEncoderConfig* config =
                MakeVideoEncoderConfig(invocation.configure());

            // Use the same config to fuzz isConfigSupported().
            VideoEncoder::isConfigSupported(script_state, config,
                                            IGNORE_EXCEPTION_FOR_TESTING);

            video_encoder->configure(config, IGNORE_EXCEPTION_FOR_TESTING);
            break;
          }
          case wc_fuzzer::VideoEncoderApiInvocation::kEncode: {
            VideoFrame* frame;
            switch (invocation.encode().Frames_case()) {
              case wc_fuzzer::EncodeVideo::kFrame:
                frame =
                    MakeVideoFrame(script_state, invocation.encode().frame());
                break;
              case wc_fuzzer::EncodeVideo::kFrameFromBuffer:
                frame = MakeVideoFrame(script_state,
                                       invocation.encode().frame_from_buffer());
                break;
              default:
                frame = nullptr;
                break;
            }

            // Often the fuzzer input will be too crazy to produce a valid frame
            // (e.g. bitmap width > bitmap length). In these cases, return early
            // to discourage this sort of fuzzer input. WebIDL doesn't allow
            // callers to pass null, so this is not a real concern.
            if (!frame)
              return;

            video_encoder->encode(
                frame, MakeEncodeOptions(invocation.encode().options()),
                IGNORE_EXCEPTION_FOR_TESTING);
            break;
          }
          case wc_fuzzer::VideoEncoderApiInvocation::kFlush: {
            // TODO(https://crbug.com/1119253): Fuzz whether to await resolution
            // of the flush promise.
            video_encoder->flush(IGNORE_EXCEPTION_FOR_TESTING);
            break;
          }
          case wc_fuzzer::VideoEncoderApiInvocation::kReset:
            video_encoder->reset(IGNORE_EXCEPTION_FOR_TESTING);
            break;
          case wc_fuzzer::VideoEncoderApiInvocation::kClose:
            video_encoder->close(IGNORE_EXCEPTION_FOR_TESTING);
            break;
          case wc_fuzzer::VideoEncoderApiInvocation::API_NOT_SET:
            break;
        }

        // Give other tasks a chance to run (e.g. calling our output callback).
        base::RunLoop().RunUntilIdle();
      }
    }
  }
}

}  // namespace blink