payload_consumer/delta_performer.h

//
// Copyright (C) 2010 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.
//

#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_
#define UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_

#include <inttypes.h>

#include <limits>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include <base/time/time.h>
#include <brillo/secure_blob.h>
#include <google/protobuf/repeated_field.h>
#include <gtest/gtest_prod.h>  // for FRIEND_TEST

#include "update_engine/common/hash_calculator.h"
#include "update_engine/common/platform_constants.h"
#include "update_engine/payload_consumer/file_writer.h"
#include "update_engine/payload_consumer/install_plan.h"
#include "update_engine/payload_consumer/partition_writer_interface.h"
#include "update_engine/payload_consumer/payload_metadata.h"
#include "update_engine/payload_consumer/payload_verifier.h"
#include "update_engine/update_metadata.pb.h"

namespace chromeos_update_engine {

class DownloadActionDelegate;
class BootControlInterface;
class HardwareInterface;
class PrefsInterface;

// This class performs the actions in a delta update synchronously. The delta
// update itself should be passed in in chunks as it is received.
class DeltaPerformer : public FileWriter {
 public:
  // Defines the granularity of progress logging in terms of how many "completed
  // chunks" we want to report at the most.
  static const unsigned kProgressLogMaxChunks;
  // Defines a timeout since the last progress was logged after which we want to
  // force another log message (even if the current chunk was not completed).
  static const unsigned kProgressLogTimeoutSeconds;
  // These define the relative weights (0-100) we give to the different work
  // components associated with an update when computing an overall progress.
  // Currently they include the download progress and the number of completed
  // operations. They must add up to one hundred (100).
  static const unsigned kProgressDownloadWeight;
  static const unsigned kProgressOperationsWeight;
  static const uint64_t kCheckpointFrequencySeconds;

  DeltaPerformer(
      PrefsInterface* prefs,
      BootControlInterface* boot_control,
      HardwareInterface* hardware,
      DownloadActionDelegate* download_delegate,
      InstallPlan* install_plan,
      InstallPlan::Payload* payload,
      bool interactive,
      std::string update_certificates_path = constants::kUpdateCertificatesPath)
      : prefs_(prefs),
        boot_control_(boot_control),
        hardware_(hardware),
        download_delegate_(download_delegate),
        install_plan_(install_plan),
        payload_(payload),
        update_certificates_path_(std::move(update_certificates_path)),
        interactive_(interactive) {
    CHECK(install_plan_);
  }

  // FileWriter's Write implementation where caller doesn't care about
  // error codes.
  bool Write(const void* bytes, size_t count) override {
    ErrorCode error{};
    return Write(bytes, count, &error);
  }

  // FileWriter's Write implementation that returns a more specific |error| code
  // in case of failures in Write operation.
  bool Write(const void* bytes, size_t count, ErrorCode* error) override;

  // Wrapper around close. Returns 0 on success or -errno on error.
  // Closes both 'path' given to Open() and the kernel path.
  int Close() override;

  // Open the target and source (if delta payload) file descriptors for the
  // |current_partition_|. The manifest needs to be already parsed for this to
  // work. Returns whether the required file descriptors were successfully open.
  bool OpenCurrentPartition();

  // Closes the current partition file descriptors if open. Returns 0 on success
  // or -errno on error.
  int CloseCurrentPartition();

  // Returns |true| only if the manifest has been processed and it's valid.
  bool IsManifestValid();

  // Verifies the downloaded payload against the signed hash included in the
  // payload, against the update check hash and size using the public key and
  // returns ErrorCode::kSuccess on success, an error code on failure.
  // This method should be called after closing the stream. Note this method
  // skips the signed hash check if the public key is unavailable; it returns
  // ErrorCode::kSignedDeltaPayloadExpectedError if the public key is available
  // but the delta payload doesn't include a signature.
  ErrorCode VerifyPayload(const brillo::Blob& update_check_response_hash,
                          const uint64_t update_check_response_size);

  // Converts an ordered collection of Extent objects which contain data of
  // length full_length to a comma-separated string. For each Extent, the
  // string will have the start offset and then the length in bytes.
  // The length value of the last extent in the string may be short, since
  // the full length of all extents in the string is capped to full_length.
  // Also, an extent starting at kSparseHole, appears as -1 in the string.
  // For example, if the Extents are {1, 1}, {4, 2}, {kSparseHole, 1},
  // {0, 1}, block_size is 4096, and full_length is 5 * block_size - 13,
  // the resulting string will be: "4096:4096,16384:8192,-1:4096,0:4083"
  static bool ExtentsToBsdiffPositionsString(
      const google::protobuf::RepeatedPtrField<Extent>& extents,
      uint64_t block_size,
      uint64_t full_length,
      std::string* positions_string);

  // Returns true if a previous update attempt can be continued based on the
  // persistent preferences and the new update check response hash.
  static bool CanResumeUpdate(PrefsInterface* prefs,
                              const std::string& update_check_response_hash);

  // Resets the persistent update progress state to indicate that an update
  // can't be resumed. Performs a quick update-in-progress reset if |quick| is
  // true, otherwise resets all progress-related update state.
  // If |skip_dynamic_partititon_metadata_updated| is true, do not reset
  // dynamic-partition-metadata-updated.
  // Returns true on success, false otherwise.
  static bool ResetUpdateProgress(
      PrefsInterface* prefs,
      bool quick,
      bool skip_dynamic_partititon_metadata_updated = false);

  // Attempts to parse the update metadata starting from the beginning of
  // |payload|. On success, returns kMetadataParseSuccess. Returns
  // kMetadataParseInsufficientData if more data is needed to parse the complete
  // metadata. Returns kMetadataParseError if the metadata can't be parsed given
  // the payload.
  MetadataParseResult ParsePayloadMetadata(const brillo::Blob& payload,
                                           ErrorCode* error);

  void set_public_key_path(const std::string& public_key_path) {
    public_key_path_ = public_key_path;
  }

  // Return true if header parsing is finished and no errors occurred.
  bool IsHeaderParsed() const;

  // Checkpoints the update progress into persistent storage to allow this
  // update attempt to be resumed after reboot.
  // If |force| is false, checkpoint may be throttled.
  // Exposed for testing purposes.
  bool CheckpointUpdateProgress(bool force);

  // Initialize partitions and allocate required space for an update with the
  // given |manifest|. |update_check_response_hash| is used to check if the
  // previous call to this function corresponds to the same payload.
  // - Same payload: not make any persistent modifications (not write to disk)
  // - Different payload: make persistent modifications (write to disk)
  // In both cases, in-memory flags are updated. This function must be called
  // on the payload at least once (to update in-memory flags) before writing
  // (applying) the payload.
  // If error due to insufficient space, |required_size| is set to the required
  // size on the device to apply the payload.
  static bool PreparePartitionsForUpdate(
      PrefsInterface* prefs,
      BootControlInterface* boot_control,
      BootControlInterface::Slot target_slot,
      const DeltaArchiveManifest& manifest,
      const std::string& update_check_response_hash,
      uint64_t* required_size);

 protected:
  // Exposed as virtual for testing purposes.
  virtual std::unique_ptr<PartitionWriterInterface> CreatePartitionWriter(
      const PartitionUpdate& partition_update,
      const InstallPlan::Partition& install_part,
      DynamicPartitionControlInterface* dynamic_control,
      size_t block_size,
      bool is_interactive,
      bool is_dynamic_partition);

  // return true if it has been long enough and a checkpoint should be saved.
  // Exposed for unittest purposes.
  virtual bool ShouldCheckpoint();

 private:
  friend class DeltaPerformerTest;
  friend class DeltaPerformerIntegrationTest;
  FRIEND_TEST(DeltaPerformerTest, BrilloMetadataSignatureSizeTest);
  FRIEND_TEST(DeltaPerformerTest, BrilloParsePayloadMetadataTest);
  FRIEND_TEST(DeltaPerformerTest, UsePublicKeyFromResponse);

  // Obtain the operation index for current partition. If all operations for
  // current partition is are finished, return # of operations. This is mostly
  // intended to be used by CheckpointUpdateProgress, where partition writer
  // needs to know the current operation number to properly checkpoint update.
  size_t GetPartitionOperationNum();

  // Parse and move the update instructions of all partitions into our local
  // |partitions_| variable based on the version of the payload. Requires the
  // manifest to be parsed and valid.
  bool ParseManifestPartitions(ErrorCode* error);

  // Appends up to |*count_p| bytes from |*bytes_p| to |buffer_|, but only to
  // the extent that the size of |buffer_| does not exceed |max|. Advances
  // |*cbytes_p| and decreases |*count_p| by the actual number of bytes copied,
  // and returns this number.
  size_t CopyDataToBuffer(const char** bytes_p, size_t* count_p, size_t max);

  // If |op_result| is false, emits an error message using |op_type_name| and
  // sets |*error| accordingly. Otherwise does nothing. Returns |op_result|.
  bool HandleOpResult(bool op_result,
                      const char* op_type_name,
                      ErrorCode* error);

  // Logs the progress of downloading/applying an update.
  void LogProgress(const char* message_prefix);

  // Update overall progress metrics, log as necessary.
  void UpdateOverallProgress(bool force_log, const char* message_prefix);

  // Returns true if enough of the delta file has been passed via Write()
  // to be able to perform a given install operation.
  bool CanPerformInstallOperation(const InstallOperation& operation);

  // Checks the integrity of the payload manifest. Returns true upon success,
  // false otherwise.
  ErrorCode ValidateManifest();

  // Validates that the hash of the blobs corresponding to the given |operation|
  // matches what's specified in the manifest in the payload.
  // Returns ErrorCode::kSuccess on match or a suitable error code otherwise.
  ErrorCode ValidateOperationHash(const InstallOperation& operation);

  // Returns true on success.
  bool PerformInstallOperation(const InstallOperation& operation);

  // These perform a specific type of operation and return true on success.
  // |error| will be set if source hash mismatch, otherwise |error| might not be
  // set even if it fails.
  bool PerformReplaceOperation(const InstallOperation& operation);
  bool PerformZeroOrDiscardOperation(const InstallOperation& operation);
  bool PerformSourceCopyOperation(const InstallOperation& operation,
                                  ErrorCode* error);
  bool PerformDiffOperation(const InstallOperation& operation,
                            ErrorCode* error);

  // Extracts the payload signature message from the current |buffer_| if the
  // offset matches the one specified by the manifest. Returns whether the
  // signature was extracted.
  bool ExtractSignatureMessage();

  // Updates the payload hash calculator with the bytes in |buffer_|, also
  // updates the signed hash calculator with the first |signed_hash_buffer_size|
  // bytes in |buffer_|. Then discard the content, ensuring that memory is being
  // deallocated. If |do_advance_offset|, advances the internal offset counter
  // accordingly.
  void DiscardBuffer(bool do_advance_offset, size_t signed_hash_buffer_size);

  // Primes the required update state. Returns true if the update state was
  // successfully initialized to a saved resume state or if the update is a new
  // update. Returns false otherwise.
  bool PrimeUpdateState();

  // Get the public key to be used to verify metadata signature or payload
  // signature. Always use |public_key_path_| if exists, otherwise if the Omaha
  // response contains a public RSA key and we're allowed to use it (e.g. if
  // we're in developer mode), decode the key from the response and store it in
  // |out_public_key|. Returns false on failures.
  bool GetPublicKey(std::string* out_public_key);

  // Creates a PayloadVerifier from the zip file containing certificates. If the
  // path to the zip file doesn't exist, falls back to use the public key.
  // Returns a tuple with the created PayloadVerifier and if we should perform
  // the verification.
  std::pair<std::unique_ptr<PayloadVerifier>, bool> CreatePayloadVerifier();

  // After install_plan_ is filled with partition names and sizes, initialize
  // metadata of partitions and map necessary devices before opening devices.
  // Also see comment for the static PreparePartitionsForUpdate().
  bool PreparePartitionsForUpdate(uint64_t* required_size);

  // Check if current manifest contains timestamp errors.
  // Return:
  // - kSuccess if update is valid.
  // - kPayloadTimestampError if downgrade is detected
  // - kDownloadManifestParseError if |new_version| has an incorrect format
  // - Other error values if the source of error is known, or kError for
  //   a generic error on the device.
  ErrorCode CheckTimestampError() const;

  // Check if partition `part_name` is a dynamic partition.
  bool IsDynamicPartition(const std::string& part_name, uint32_t slot);

  void CheckSPLDowngrade();

  // Update Engine preference store.
  PrefsInterface* prefs_;

  // BootControl and Hardware interface references.
  BootControlInterface* boot_control_;
  HardwareInterface* hardware_;

  // The DownloadActionDelegate instance monitoring the DownloadAction, or a
  // nullptr if not used.
  DownloadActionDelegate* download_delegate_;

  // Install Plan based on Omaha Response.
  InstallPlan* install_plan_;

  // Pointer to the current payload in install_plan_.payloads.
  InstallPlan::Payload* payload_{nullptr};

  PayloadMetadata payload_metadata_;

  // Parsed manifest. Set after enough bytes to parse the manifest were
  // downloaded.
  DeltaArchiveManifest manifest_;
  bool manifest_parsed_{false};
  bool manifest_valid_{false};
  uint64_t metadata_size_{0};
  uint32_t metadata_signature_size_{0};
  uint64_t major_payload_version_{0};

  // Accumulated number of operations per partition. The i-th element is the
  // sum of the number of operations for all the partitions from 0 to i
  // inclusive. Valid when |manifest_valid_| is true.
  std::vector<size_t> acc_num_operations_;

  // The total operations in a payload. Valid when |manifest_valid_| is true,
  // otherwise 0.
  size_t num_total_operations_{0};

  // The list of partitions to update as found in the manifest major
  // version 2. When parsing an older manifest format, the information is
  // converted over to this format instead.
  std::vector<PartitionUpdate> partitions_;

  // Index in the list of partitions (|partitions_| member) of the current
  // partition being processed.
  size_t current_partition_{0};

  // Index of the next operation to perform in the manifest. The index is
  // linear on the total number of operation on the manifest.
  size_t next_operation_num_{0};

  // A buffer used for accumulating downloaded data. Initially, it stores the
  // payload metadata; once that's downloaded and parsed, it stores data for
  // the next update operation.
  brillo::Blob buffer_;
  // Offset of buffer_ in the binary blobs section of the update.
  uint64_t buffer_offset_{0};

  // Last |next_operation_num_| value updated as part of the progress update.
  uint64_t last_updated_operation_num_{std::numeric_limits<uint64_t>::max()};

  // The block size (parsed from the manifest).
  uint32_t block_size_{0};

  // Calculates the whole payload file hash, including headers and signatures.
  HashCalculator payload_hash_calculator_;

  // Calculates the hash of the portion of the payload signed by the payload
  // signature. This hash skips the metadata signature portion, located after
  // the metadata and doesn't include the payload signature itself.
  HashCalculator signed_hash_calculator_;

  // Signatures message blob extracted directly from the payload.
  std::string signatures_message_data_;

  // The public key to be used. Provided as a member so that tests can
  // override with test keys.
  std::string public_key_path_{constants::kUpdatePayloadPublicKeyPath};

  // The path to the zip file with X509 certificates.
  const std::string update_certificates_path_;

  // The number of bytes received so far, used for progress tracking.
  size_t total_bytes_received_{0};

  // An overall progress counter, which should reflect both download progress
  // and the ratio of applied operations. Range is 0-100.
  unsigned overall_progress_{0};

  // The last progress chunk recorded.
  unsigned last_progress_chunk_{0};

  // If |true|, the update is user initiated (vs. periodic update checks).
  bool interactive_{false};

  // The timeout after which we should force emitting a progress log
  // (constant), and the actual point in time for the next forced log to be
  // emitted.
  const base::TimeDelta forced_progress_log_wait_{
      base::TimeDelta::FromSeconds(kProgressLogTimeoutSeconds)};
  base::TimeTicks forced_progress_log_time_;

  // The frequency that we should write an update checkpoint (constant), and
  // the point in time at which the next checkpoint should be written.
  const base::TimeDelta update_checkpoint_wait_{
      base::TimeDelta::FromSeconds(kCheckpointFrequencySeconds)};
  base::TimeTicks update_checkpoint_time_;

  std::unique_ptr<PartitionWriterInterface> partition_writer_;

  DISALLOW_COPY_AND_ASSIGN(DeltaPerformer);
};

}  // namespace chromeos_update_engine

#endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_DELTA_PERFORMER_H_