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Commit b63e95b0 authored by Steven Moreland's avatar Steven Moreland Committed by Automerger Merge Worker
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Merge changes I118d5c8d,I9c3728cd am: 3bbf1f41 am: 21951c8e am: 63c3034c

parents 19a25ec0 63c3034c
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+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ cc_library_static {
        },
    },
    srcs: [
        "random_binder.cpp",
        "random_fd.cpp",
        "random_parcel.cpp",
        "libbinder_driver.cpp",
+29 −0
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/*
 * Copyright (C) 2022 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.
 */

#pragma once

#include <binder/IBinder.h>
#include <fuzzer/FuzzedDataProvider.h>

namespace android {

// Get a random binder object for use in fuzzing.
//
// may return multiple FDs (e.g. pipe), but will always return at least one
sp<IBinder> getRandomBinder(FuzzedDataProvider* provider);

} // namespace android
+95 −0
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/*
 * Copyright (C) 2022 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 <fuzzbinder/random_binder.h>

#include <fuzzbinder/random_parcel.h>

#include <android-base/logging.h>
#include <binder/IInterface.h>
#include <binder/IServiceManager.h>

namespace android {

class RandomBinder : public BBinder {
public:
    RandomBinder(const String16& descriptor, std::vector<uint8_t>&& bytes)
          : mDescriptor(descriptor),
            mBytes(std::move(bytes)),
            mProvider(mBytes.data(), mBytes.size()) {}
    const String16& getInterfaceDescriptor() const override { return mDescriptor; }

    status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags) override {
        (void)code;
        (void)data;
        (void)reply;
        (void)flags; // note - for maximum coverage even ignore if oneway

        if (mProvider.ConsumeBool()) {
            return mProvider.ConsumeIntegral<status_t>();
        }

        if (reply == nullptr) return OK;

        // TODO: things we could do to increase state space
        // - also pull FDs and binders from 'data'
        //     (optionally combine these into random parcel 'options')
        // - also pull FDs and binders from random parcel 'options'
        RandomParcelOptions options;

        // random output
        std::vector<uint8_t> subData = mProvider.ConsumeBytes<uint8_t>(
                mProvider.ConsumeIntegralInRange<size_t>(0, mProvider.remaining_bytes()));
        fillRandomParcel(reply, FuzzedDataProvider(subData.data(), subData.size()), &options);

        return OK;
    }

private:
    String16 mDescriptor;

    // note may not all be used
    std::vector<uint8_t> mBytes;
    FuzzedDataProvider mProvider;
};

sp<IBinder> getRandomBinder(FuzzedDataProvider* provider) {
    auto makeFunc = provider->PickValueInArray<const std::function<sp<IBinder>()>>({
            [&]() {
                // descriptor is the length of a class name, e.g.
                // "some.package.Foo"
                std::string str = provider->ConsumeRandomLengthString(100 /*max length*/);

                // arbitrarily consume remaining data to create a binder that can return
                // random results - coverage guided fuzzer should ensure all of the remaining
                // data isn't always used
                std::vector<uint8_t> bytes = provider->ConsumeBytes<uint8_t>(
                        provider->ConsumeIntegralInRange<size_t>(0, provider->remaining_bytes()));

                return new RandomBinder(String16(str.c_str()), std::move(bytes));
            },
            []() {
                // this is the easiest remote binder to get ahold of, and it
                // should be able to handle anything thrown at it, and
                // essentially every process can talk to it, so it's a good
                // candidate for checking usage of an actual BpBinder
                return IInterface::asBinder(defaultServiceManager());
            },
            [&]() -> sp<IBinder> { return nullptr; },
    });
    return makeFunc();
}

} // namespace android
+11 −36
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@@ -17,23 +17,14 @@
#include <fuzzbinder/random_parcel.h>

#include <android-base/logging.h>
#include <binder/IServiceManager.h>
#include <binder/RpcSession.h>
#include <binder/RpcTransportRaw.h>
#include <fuzzbinder/random_binder.h>
#include <fuzzbinder/random_fd.h>
#include <utils/String16.h>

namespace android {

class NamedBinder : public BBinder {
public:
    NamedBinder(const String16& descriptor) : mDescriptor(descriptor) {}
    const String16& getInterfaceDescriptor() const override { return mDescriptor; }

private:
    String16 mDescriptor;
};

static void fillRandomParcelData(Parcel* p, FuzzedDataProvider&& provider) {
    std::vector<uint8_t> data = provider.ConsumeBytes<uint8_t>(provider.remaining_bytes());
    CHECK(OK == p->write(data.data(), data.size()));
@@ -89,32 +80,16 @@ void fillRandomParcel(Parcel* p, FuzzedDataProvider&& provider, RandomParcelOpti
                },
                // write binder
                [&]() {
                    auto makeFunc = provider.PickValueInArray<const std::function<sp<IBinder>()>>({
                            [&]() {
                                // descriptor is the length of a class name, e.g.
                                // "some.package.Foo"
                                std::string str =
                                        provider.ConsumeRandomLengthString(100 /*max length*/);
                                return new NamedBinder(String16(str.c_str()));
                            },
                            []() {
                                // this is the easiest remote binder to get ahold of, and it
                                // should be able to handle anything thrown at it, and
                                // essentially every process can talk to it, so it's a good
                                // candidate for checking usage of an actual BpBinder
                                return IInterface::asBinder(defaultServiceManager());
                            },
                            [&]() -> sp<IBinder> {
                    sp<IBinder> binder;
                    if (options->extraBinders.size() > 0 && provider.ConsumeBool()) {
                                    return options->extraBinders.at(
                                            provider.ConsumeIntegralInRange<
                                                    size_t>(0, options->extraBinders.size() - 1));
                        binder = options->extraBinders.at(
                                provider.ConsumeIntegralInRange<size_t>(0,
                                                                        options->extraBinders
                                                                                        .size() -
                                                                                1));
                    } else {
                                    return nullptr;
                        binder = getRandomBinder(&provider);
                    }
                            },
                    });
                    sp<IBinder> binder = makeFunc();
                    CHECK(OK == p->writeStrongBinder(binder));
                },
        });