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//
// Copyright (C) 2018 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_PAYLOAD_METADATA_H_
#define UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_METADATA_H_
#include <inttypes.h>
#include <string>
#include <vector>
#include <base/macros.h>
#include <brillo/secure_blob.h>
#include "update_engine/common/error_code.h"
#include "update_engine/common/platform_constants.h"
#include "update_engine/payload_consumer/payload_verifier.h"
#include "update_engine/update_metadata.pb.h"
namespace chromeos_update_engine {
enum class MetadataParseResult {
kSuccess,
kError,
kInsufficientData,
};
// This class parses payload metadata and validate its signature.
class PayloadMetadata {
public:
static const uint64_t kDeltaVersionOffset;
static const uint64_t kDeltaVersionSize;
static const uint64_t kDeltaManifestSizeOffset;
static const uint64_t kDeltaManifestSizeSize;
static const uint64_t kDeltaMetadataSignatureSizeSize;
PayloadMetadata() = default;
// Attempts to parse the update payload header 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 ParsePayloadHeader(const brillo::Blob& payload,
ErrorCode* error);
MetadataParseResult ParsePayloadHeader(const unsigned char* payload,
size_t size,
ErrorCode* error);
// Simpler version of the above, returns true on success.
bool ParsePayloadHeader(const brillo::Blob& payload);
// Given the |payload|, verifies that the signed hash of its metadata matches
// |metadata_signature| (if present) or the metadata signature in payload
// itself (if present). Returns ErrorCode::kSuccess on match or a suitable
// error code otherwise. This method must be called before any part of the
// metadata is parsed so that an on-path attack on the SSL connection
// to the payload server doesn't exploit any vulnerability in the code that
// parses the protocol buffer.
ErrorCode ValidateMetadataSignature(
const brillo::Blob& payload,
const std::string& metadata_signature,
const PayloadVerifier& payload_verifier) const;
// Returns the major payload version. If the version was not yet parsed,
// returns zero.
uint64_t GetMajorVersion() const { return major_payload_version_; }
// Returns the size of the payload metadata, which includes the payload header
// and the manifest. If the header was not yet parsed, returns zero.
uint64_t GetMetadataSize() const { return metadata_size_; }
// Returns the size of the payload metadata signature. If the header was not
// yet parsed, returns zero.
uint32_t GetMetadataSignatureSize() const { return metadata_signature_size_; }
// Set |*out_manifest| to the manifest in |payload|.
// Returns true on success.
bool GetManifest(const brillo::Blob& payload,
DeltaArchiveManifest* out_manifest) const;
bool GetManifest(const unsigned char* payload,
size_t size,
DeltaArchiveManifest* out_manifest) const;
// Parses a payload file |payload_path| and prepares the metadata properties,
// manifest and metadata signatures. Can be used as an easy to use utility to
// get the payload information without manually the process.
bool ParsePayloadFile(const std::string& payload_path,
DeltaArchiveManifest* manifest,
Signatures* metadata_signatures);
private:
// Returns the byte offset at which the manifest protobuf begins in a payload.
uint64_t GetManifestOffset() const;
// Returns the byte offset where the size of the metadata signature is stored
// in a payload.
uint64_t GetMetadataSignatureSizeOffset() const;
uint64_t metadata_size_{0};
uint64_t manifest_size_{0};
uint32_t metadata_signature_size_{0};
uint64_t major_payload_version_{0};
DISALLOW_COPY_AND_ASSIGN(PayloadMetadata);
};
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_METADATA_H_