media/utils/fuzzers/ServiceUtilitiesFuzz.cpp

/*
 * Copyright 2020 The Android Open Source Project
 *
 * 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.
 */

#include <fcntl.h>

#include <functional>
#include  <type_traits>

#include <android/media/permission/Identity.h>
#include "fuzzer/FuzzedDataProvider.h"
#include "mediautils/ServiceUtilities.h"

static constexpr int kMaxOperations = 50;
static constexpr int kMaxStringLen = 256;

using android::media::permission::Identity;

const std::vector<std::function<void(FuzzedDataProvider*, android::MediaPackageManager)>>
    operations = {
        [](FuzzedDataProvider* data_provider, android::MediaPackageManager pm) -> void {
            uid_t uid = data_provider->ConsumeIntegral<uid_t>();
            pm.allowPlaybackCapture(uid);
        },
        [](FuzzedDataProvider* data_provider, android::MediaPackageManager pm) -> void {
            int spaces = data_provider->ConsumeIntegral<int>();

            // Dump everything into /dev/null
            int fd = open("/dev/null", O_WRONLY);
            pm.dump(fd, spaces);
            close(fd);
        },
};

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
    FuzzedDataProvider data_provider(data, size);
    int32_t uid = data_provider.ConsumeIntegral<int32_t>();
    int32_t pid = data_provider.ConsumeIntegral<int32_t>();
    audio_source_t source = static_cast<audio_source_t>(data_provider
        .ConsumeIntegral<std::underlying_type_t<audio_source_t>>());

    std::string packageNameStr = data_provider.ConsumeRandomLengthString(kMaxStringLen);
    std::string msgStr = data_provider.ConsumeRandomLengthString(kMaxStringLen);
    android::String16 msgStr16(packageNameStr.c_str());
    Identity identity;
    identity.packageName = packageNameStr;
    identity.uid = uid;
    identity.pid = pid;

    // There is not state here, and order is not significant,
    // so we can simply call all of the target functions
    android::isServiceUid(uid);
    android::isAudioServerUid(uid);
    android::isAudioServerOrSystemServerUid(uid);
    android::isAudioServerOrMediaServerUid(uid);
    android::recordingAllowed(identity);
    android::startRecording(identity, msgStr16, source);
    android::finishRecording(identity, source);
    android::captureAudioOutputAllowed(identity);
    android::captureMediaOutputAllowed(identity);
    android::captureHotwordAllowed(identity);
    android::modifyPhoneStateAllowed(identity);
    android::bypassInterruptionPolicyAllowed(identity);
    android::settingsAllowed();
    android::modifyAudioRoutingAllowed();
    android::modifyDefaultAudioEffectsAllowed();
    android::dumpAllowed();

    // MediaPackageManager does have state, so we need the fuzzer to decide order
    android::MediaPackageManager packageManager;
    size_t ops_run = 0;
    while (data_provider.remaining_bytes() > 0 && ops_run++ < kMaxOperations) {
        uint8_t op = data_provider.ConsumeIntegralInRange<uint8_t>(0, operations.size() - 1);
        operations[op](&data_provider, packageManager);
    }

    return 0;
}