android/libwvdrmengine/oemcrypto/util/src/cbor_validator.cpp

// Copyright 2023 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine License
// Agreement.
//
//  Reference implementation utilities of OEMCrypto APIs
//
#include "cbor_validator.h"

#include <stddef.h>

#include <cstdint>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>

namespace wvoec {
namespace util {
std::string CppborMajorTypeToString(cppbor::MajorType type) {
  switch (type) {
    case cppbor::UINT:
      return "UINT";
    case cppbor::NINT:
      return "NINT";
    case cppbor::BSTR:
      return "BSTR";
    case cppbor::TSTR:
      return "TSTR";
    case cppbor::ARRAY:
      return "ARRAY";
    case cppbor::MAP:
      return "MAP";
    case cppbor::SEMANTIC:
      return "SEMANTIC";
    case cppbor::SIMPLE:
      return "SIMPLE";
  }
  return "undefined type";
}

std::string CborMessageStatusToString(CborMessageStatus status) {
  switch (status) {
    case kCborUninitialized:
      return "Uninitialized";
    case kCborParseOk:
      return "ParseOk";
    case kCborParseError:
      return "ParseError";
    case kCborValidateOk:
      return "ValidateOk";
    case kCborValidateWarning:
      return "ValidateWarning";
    case kCborValidateError:
      return "ValidateError";
    case kCborValidateFatal:
      return "ValidateFatal";
  }
  return "undefined status";
}

void CborValidator::Reset() {
  message_status_ = kCborUninitialized;
  parse_result_ = {nullptr, nullptr, ""};
  validate_messages_.clear();
}

CborMessageStatus CborValidator::Parse(const std::vector<uint8_t>& cbor) {
  Reset();
  parse_result_ = cppbor::parse(cbor);
  message_status_ =
      (std::get<0>(parse_result_) && std::get<2>(parse_result_).empty())
          ? kCborParseOk
          : kCborParseError;
  return message_status_;
}

const cppbor::ParseResult* CborValidator::GetParseResult() const {
  if (message_status_ == kCborUninitialized) {
    return nullptr;
  }
  return &parse_result_;
}

std::string CborValidator::GetRawMessage() const {
  if (message_status_ == kCborUninitialized ||
      message_status_ == kCborParseError) {
    return std::string();
  }
  const cppbor::Item* parsed_item = std::get<0>(parse_result_).get();
  if (parsed_item == nullptr) {
    return "<null>";
  }
  return cppbor::prettyPrint(parsed_item);
}

CborMessageStatus CborValidator::Validate() {
  if (message_status_ != kCborParseOk) return message_status_;
  // No other validations to be done than Parse() being successful.
  AddValidationMessage(kCborValidateOk, "No validations are done.");
  return message_status_;
}

std::string CborValidator::GetFormattedMessage() const {
  return GetRawMessage();
}

void CborValidator::AddValidationMessage(CborMessageStatus status,
                                         const std::string& msg) {
  validate_messages_.push_back({status, msg});
  if (status > message_status_) message_status_ = status;
}

// TODO(b/314141962): Replace this with the map lookup function in cppbor
// library
const cppbor::Item* CborValidator::GetMapEntry(const cppbor::Map& map,
                                               const std::string& entry_name) {
  for (auto const& entry : map) {
    if (!entry.first->asTstr()) continue;
    const std::string& name = entry.first->asTstr()->value();
    if (name == entry_name) return entry.second.get();
  }
  return nullptr;
}

std::string CborValidator::CheckMapEntry(const cppbor::Map& map,
                                         cppbor::MajorType major_type,
                                         const std::string& entry_name) {
  const cppbor::Item* value = GetMapEntry(map, entry_name);
  if (!value) {
    return entry_name + " is missing.";
  }
  if (value->type() != major_type) {
    return entry_name + " has the wrong type. Expect: " +
           CppborMajorTypeToString(major_type) +
           ", actual: " + CppborMajorTypeToString(value->type());
  }
  return "";
}
}  // namespace util
}  // namespace wvoec