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Commit db0e62b8 authored by Yifan Hong's avatar Yifan Hong
Browse files

libsnapshot_fuzzer: construct valid super partition metadata. 

This should hopefully achieve more coverage.

Test: pass
Bug: 154633114
Change-Id: Ice575f2d8c3e22b80465c133d055e7c4368ebdfa
parent 74d1fb45

fs_mgr/libsnapshot/android/snapshot/snapshot_fuzz.proto

+9 −1
Original line number Diff line number Diff line
@@ -77,7 +77,15 @@ message SnapshotManagerActionProto { 
message SnapshotFuzzData {

    FuzzDeviceInfoData device_info_data = 1;

    FuzzSnapshotManagerData manager_data = 2;



    // If true:

    // - if super_data is empty, create empty super partition metadata.

    // - otherwise, create super partition metadata accordingly.

    // If false, no valid super partition metadata (it is zeroed)

    bool is_super_metadata_valid = 3;

    chromeos_update_engine.DeltaArchiveManifest super_data = 4;



    // More data used to prep the test before running actions.

    reserved 3 to 9999;

    reserved 5 to 9999;

    repeated SnapshotManagerActionProto actions = 10000;

}

fs_mgr/libsnapshot/snapshot_fuzz_utils.cpp

+43 −0
Original line number Diff line number Diff line
@@ -47,6 +47,9 @@ using android::base::WriteStringToFile; 
using android::dm::LoopControl;

using android::fiemap::IImageManager;

using android::fiemap::ImageManager;

using android::fs_mgr::BlockDeviceInfo;

using android::fs_mgr::IPartitionOpener;

using chromeos_update_engine::DynamicPartitionMetadata;



// This directory is exempted from pinning in ImageManager.

static const char MNT_DIR[] = "/data/gsi/ota/test/";
@@ -252,6 +255,7 @@ std::unique_ptr<AutoDevice> SnapshotFuzzEnv::CheckMapSuper(const std::string& fa 
std::unique_ptr<ISnapshotManager> SnapshotFuzzEnv::CheckCreateSnapshotManager(

        const SnapshotFuzzData& data) {

    auto partition_opener = std::make_unique<TestPartitionOpener>(super());

    CheckWriteSuperMetadata(data, *partition_opener);

    auto metadata_dir = fake_root_->tmp_path() + "/snapshot_metadata";

    PCHECK(Mkdir(metadata_dir));
@@ -268,4 +272,43 @@ const std::string& SnapshotFuzzEnv::super() const { 
    return fake_super_;

}



void SnapshotFuzzEnv::CheckWriteSuperMetadata(const SnapshotFuzzData& data,

                                              const IPartitionOpener& opener) {

    if (!data.is_super_metadata_valid()) {

        // Leave it zero.

        return;

    }



    BlockDeviceInfo super_device("super", SUPER_IMAGE_SIZE, 0, 0, 4096);

    std::vector<BlockDeviceInfo> devices = {super_device};

    auto builder = MetadataBuilder::New(devices, "super", 65536, 2);

    CHECK(builder != nullptr);



    // Attempt to create a super partition metadata using proto. All errors are ignored.

    for (const auto& group_proto : data.super_data().dynamic_partition_metadata().groups()) {

        (void)builder->AddGroup(group_proto.name(), group_proto.size());

        for (const auto& partition_name : group_proto.partition_names()) {

            (void)builder->AddPartition(partition_name, group_proto.name(),

                                        LP_PARTITION_ATTR_READONLY);

        }

    }



    for (const auto& partition_proto : data.super_data().partitions()) {

        auto p = builder->FindPartition(partition_proto.partition_name());

        if (p == nullptr) continue;

        (void)builder->ResizePartition(p, partition_proto.new_partition_info().size());

    }



    auto metadata = builder->Export();

    // metadata may be nullptr if it is not valid (e.g. partition name too long).

    // In this case, just use empty super partition data.

    if (metadata == nullptr) {

        builder = MetadataBuilder::New(devices, "super", 65536, 2);

        CHECK(builder != nullptr);

        metadata = builder->Export();

        CHECK(metadata != nullptr);

    }

    CHECK(FlashPartitionTable(opener, super(), *metadata.get()));

}



}  // namespace android::snapshot

fs_mgr/libsnapshot/snapshot_fuzz_utils.h

+5 −0
Original line number Diff line number Diff line
@@ -16,8 +16,10 @@ 


#include <android-base/file.h>

#include <android-base/stringprintf.h>

#include <android/snapshot/snapshot_fuzz.pb.h>

#include <libdm/loop_control.h>

#include <libfiemap/image_manager.h>

#include <liblp/liblp.h>

#include <libsnapshot/auto_device.h>

#include <libsnapshot/test_helpers.h>
@@ -68,6 +70,9 @@ class SnapshotFuzzEnv { 
    static std::unique_ptr<AutoDevice> CheckMapSuper(const std::string& fake_persist_path,

                                                     android::dm::LoopControl* control,

                                                     std::string* fake_super);



    void CheckWriteSuperMetadata(const SnapshotFuzzData& proto,

                                 const android::fs_mgr::IPartitionOpener& opener);

};



class SnapshotFuzzDeviceInfo : public ISnapshotManager::IDeviceInfo {