chrome/updater/tag.cc

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/updater/tag.h"

#include <map>
#include <utility>

#include "base/no_destructor.h"
#include "base/optional.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "chrome/updater/lib_util.h"
#include "chrome/updater/util.h"

namespace updater {
namespace tagging {
namespace {

// The name of the bundle being installed. If not specified, the first app's
// appname is used.
constexpr base::StringPiece kTagArgBundleName = "bundlename";

// The language of the product the user is installing.
constexpr base::StringPiece kTagArgLanguage = "lang";

// Flag denoting that the user is flighting a new test feature.
constexpr base::StringPiece kTagArgFlighting = "flighting";

// Flag denoting that the user has agreed to provide usage stats, crashreports
// etc.
constexpr base::StringPiece kTagArgUsageStats = "usagestats";

// A unique value for this installation session. It can be used to follow the
// progress from the website to installation completion.
constexpr base::StringPiece kTagArgInstallationId = "iid";

// The Brand Code used for branding.
// If a brand value already exists on the system, it should be ignored.
// This value is used to set the initial brand for the updater and the client
// app.
constexpr base::StringPiece kTagArgBrandCode = "brand";

// The Client ID used for branding.
// If a client value already exists on the system, it should be ignored.
// This value is used to set the initial client for the updater and the client
// app.
constexpr base::StringPiece kTagArgClientId = "client";

// A set of experiment labels used to track installs that are included in
// experiments. Use "experiments" for per-app arguments; use "omahaexperiments"
// for updater-specific labels.
constexpr base::StringPiece kAppArgExperimentLabels = "experiments";
constexpr base::StringPiece kTagArgOmahaExperimentLabels = "omahaexperiments";

// A referral ID used for tracking referrals.
constexpr base::StringPiece kTagArgReferralId = "referral";

// Tells the updater what ap value to set in the registry.
constexpr base::StringPiece kAppArgAdditionalParameters = "ap";

// Indicates which browser to restart on successful install.
constexpr base::StringPiece kTagArgBrowserType = "browser";

// The list of arguments that are needed for a meta-installer, to
// indicate which application is being installed. These are stamped
// inside the meta-installer binary.
constexpr base::StringPiece kTagArgAppId = "appguid";
constexpr base::StringPiece kAppArgAppName = "appname";
constexpr base::StringPiece kAppArgNeedsAdmin = "needsadmin";
constexpr base::StringPiece kAppArgInstallDataIndex = "installdataindex";
constexpr base::StringPiece kAppArgUntrustedData = "untrusteddata";

// This switch allows extra data to be communicated to the application
// installer. The extra data needs to be URL-encoded. The data will be decoded
// and written to the file, that is then passed in the command line to the
// application installer in the form "/installerdata=blah.dat". One per
// application.
constexpr base::StringPiece kAppArgInstallerData = "installerdata";

// Character that is disallowed from appearing in the tag.
constexpr char kDisallowedCharInTag = '/';

base::Optional<AppArgs::NeedsAdmin> ParseNeedsAdminEnum(base::StringPiece str) {
  if (base::EqualsCaseInsensitiveASCII("false", str))
    return AppArgs::NeedsAdmin::kNo;

  if (base::EqualsCaseInsensitiveASCII("true", str))
    return AppArgs::NeedsAdmin::kYes;

  if (base::EqualsCaseInsensitiveASCII("prefers", str))
    return AppArgs::NeedsAdmin::kPrefers;

  return base::nullopt;
}

// Returns base::nullopt if parsing failed.
base::Optional<bool> ParseBool(base::StringPiece str) {
  if (base::EqualsCaseInsensitiveASCII("false", str))
    return false;

  if (base::EqualsCaseInsensitiveASCII("true", str))
    return true;

  return base::nullopt;
}

// A custom comparator functor class for the parse tables.
using ParseTableCompare = CaseInsensitiveASCIICompare<std::string>;

namespace global_attributes {

ErrorCode ParseBundleName(base::StringPiece value, TagArgs* args) {
  value = base::TrimWhitespaceASCII(value, base::TrimPositions::TRIM_ALL);
  if (value.empty())
    return ErrorCode::kGlobal_BundleNameCannotBeWhitespace;

  args->bundle_name = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseInstallationId(base::StringPiece value, TagArgs* args) {
  args->installation_id = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseBrandCode(base::StringPiece value, TagArgs* args) {
  args->brand_code = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseClientId(base::StringPiece value, TagArgs* args) {
  args->client_id = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseOmahaExperimentLabels(base::StringPiece value, TagArgs* args) {
  value = base::TrimWhitespaceASCII(value, base::TrimPositions::TRIM_ALL);
  if (value.empty())
    return ErrorCode::kGlobal_ExperimentLabelsCannotBeWhitespace;

  args->experiment_labels = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseReferralId(base::StringPiece value, TagArgs* args) {
  args->referral_id = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseBrowserType(base::StringPiece value, TagArgs* args) {
  int browser_type = 0;
  if (!base::StringToInt(value, &browser_type))
    return ErrorCode::kGlobal_BrowserTypeIsInvalid;

  if (browser_type < 0)
    return ErrorCode::kGlobal_BrowserTypeIsInvalid;

  args->browser_type =
      (browser_type < static_cast<int>(TagArgs::BrowserType::kMax))
          ? TagArgs::BrowserType(browser_type)
          : TagArgs::BrowserType::kUnknown;

  return ErrorCode::kSuccess;
}

ErrorCode ParseLanguage(base::StringPiece value, TagArgs* args) {
  // Even if we don't support the language, we want to pass it to the
  // installer. Omaha will pick its language later. See http://b/1336966.
  args->language = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseFlighting(base::StringPiece value, TagArgs* args) {
  const base::Optional<bool> flighting = ParseBool(value);
  if (!flighting.has_value())
    return ErrorCode::kGlobal_FlightingValueIsNotABoolean;

  args->flighting = flighting.value();
  return ErrorCode::kSuccess;
}

ErrorCode ParseUsageStats(base::StringPiece value, TagArgs* args) {
  int tristate = 0;
  if (!base::StringToInt(value, &tristate))
    return ErrorCode::kGlobal_UsageStatsValueIsInvalid;

  if (tristate == 0) {
    args->usage_stats_enable = false;
  } else if (tristate == 1) {
    args->usage_stats_enable = true;
  } else if (tristate == 2) {
    args->usage_stats_enable = base::nullopt;
  } else {
    return ErrorCode::kGlobal_UsageStatsValueIsInvalid;
  }
  return ErrorCode::kSuccess;
}

// Parses an app ID and adds it to the list of apps in |args|, if valid.
ErrorCode ParseAppId(base::StringPiece value, TagArgs* args) {
  if (!base::IsStringASCII(value))
    return ErrorCode::kApp_AppIdIsNotValid;

  args->apps.push_back(AppArgs(value));
  return ErrorCode::kSuccess;
}

// |value| must not be empty.
// |args| must not be null.
using ParseGlobalAttributeFunPtr = ErrorCode (*)(base::StringPiece value,
                                                 TagArgs* args);

using GlobalParseTable =
    std::map<base::StringPiece, ParseGlobalAttributeFunPtr, ParseTableCompare>;

const GlobalParseTable& GetTable() {
  static const base::NoDestructor<GlobalParseTable> instance{{
      {kTagArgBundleName, &ParseBundleName},
      {kTagArgInstallationId, &ParseInstallationId},
      {kTagArgBrandCode, &ParseBrandCode},
      {kTagArgClientId, &ParseClientId},
      {kTagArgOmahaExperimentLabels, &ParseOmahaExperimentLabels},
      {kTagArgReferralId, &ParseReferralId},
      {kTagArgBrowserType, &ParseBrowserType},
      {kTagArgLanguage, &ParseLanguage},
      {kTagArgFlighting, &ParseFlighting},
      {kTagArgUsageStats, &ParseUsageStats},
      {kTagArgAppId, &ParseAppId},
  }};
  return *instance;
}

}  // namespace global_attributes

namespace app_attributes {

ErrorCode ParseAdditionalParameters(base::StringPiece value, AppArgs* args) {
  args->ap = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseExperimentLabels(base::StringPiece value, AppArgs* args) {
  value = base::TrimWhitespaceASCII(value, base::TrimPositions::TRIM_ALL);
  if (value.empty())
    return ErrorCode::kApp_ExperimentLabelsCannotBeWhitespace;

  args->experiment_labels = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseAppName(base::StringPiece value, AppArgs* args) {
  value = base::TrimWhitespaceASCII(value, base::TrimPositions::TRIM_ALL);
  if (value.empty())
    return ErrorCode::kApp_AppNameCannotBeWhitespace;

  args->app_name = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseNeedsAdmin(base::StringPiece value, AppArgs* args) {
  const auto needs_admin = ParseNeedsAdminEnum(value);
  if (!needs_admin.has_value())
    return ErrorCode::kApp_NeedsAdminValueIsInvalid;

  args->needs_admin = needs_admin.value();
  return ErrorCode::kSuccess;
}

ErrorCode ParseInstallDataIndex(base::StringPiece value, AppArgs* args) {
  args->install_data_index = value.as_string();
  return ErrorCode::kSuccess;
}

ErrorCode ParseUntrustedData(base::StringPiece value, AppArgs* args) {
  args->untrusted_data = value.as_string();
  return ErrorCode::kSuccess;
}

// |value| must not be empty.
// |args| must not be null.
using ParseAppAttributeFunPtr = ErrorCode (*)(base::StringPiece value,
                                              AppArgs* args);

using AppParseTable =
    std::map<base::StringPiece, ParseAppAttributeFunPtr, ParseTableCompare>;

const AppParseTable& GetTable() {
  static const base::NoDestructor<AppParseTable> instance{{
      {kAppArgAdditionalParameters, &ParseAdditionalParameters},
      {kAppArgExperimentLabels, &ParseExperimentLabels},
      {kAppArgAppName, &ParseAppName},
      {kAppArgNeedsAdmin, &ParseNeedsAdmin},
      {kAppArgInstallDataIndex, &ParseInstallDataIndex},
      {kAppArgUntrustedData, &ParseUntrustedData},
  }};
  return *instance;
}

}  // namespace app_attributes

namespace installer_data_attributes {

// Search for the given appid specified by |value| in |args->apps| and write its
// index to |current_app_index|.
ErrorCode FindAppIdInTagArgs(base::StringPiece value,
                             TagArgs* args,
                             base::Optional<size_t>* current_app_index) {
  if (!base::IsStringASCII(value))
    return ErrorCode::kApp_AppIdIsNotValid;

  // Find the app in the existing list.
  for (size_t i = 0; i < args->apps.size(); i++) {
    if (base::EqualsCaseInsensitiveASCII(args->apps[i].app_id, value)) {
      *current_app_index = i;
    }
  }

  if (!current_app_index->has_value())
    return ErrorCode::kAppInstallerData_AppIdNotFound;

  return ErrorCode::kSuccess;
}

ErrorCode ParseInstallerData(base::StringPiece value,
                             TagArgs* args,
                             base::Optional<size_t>* current_app_index) {
  if (!current_app_index->has_value())
    return ErrorCode::
        kAppInstallerData_InstallerDataCannotBeSpecifiedBeforeAppId;

  args->apps[current_app_index->value()].encoded_installer_data =
      value.as_string();

  return ErrorCode::kSuccess;
}

// |value| must not be empty.
// |args| must not be null.
// |current_app_index| is an in/out parameter. It stores the index of the
// current app and nullopt if no app has been set yet. Writing to it will set
// the index for future calls to these functions.
using ParseInstallerDataAttributeFunPtr =
    ErrorCode (*)(base::StringPiece value,
                  TagArgs* args,
                  base::Optional<size_t>* current_app_index);

using InstallerDataParseTable = std::map<base::StringPiece,
                                         ParseInstallerDataAttributeFunPtr,
                                         ParseTableCompare>;

const InstallerDataParseTable& GetTable() {
  static const base::NoDestructor<InstallerDataParseTable> instance{{
      {kTagArgAppId, &FindAppIdInTagArgs},
      {kAppArgInstallerData, &ParseInstallerData},
  }};
  return *instance;
}

}  // namespace installer_data_attributes

namespace query_string {

// An attribute in a metainstaller tag or app installer data args string.
// - The first value is the "name" of the attribute.
// - The second value is the "value" of the attribute.
using Attribute = std::pair<base::StringPiece, std::string>;

// Splits |query_string| into |Attribute|s. Attribute values will be unescaped
// if |unescape_value| is true.
//
// Ownership follows the same rules as |base::SplitStringPiece|.
std::vector<Attribute> Split(base::StringPiece query_string,
                             bool unescape_value = true) {
  std::vector<Attribute> attributes;
  for (const auto& attribute_string :
       base::SplitStringPiece(query_string, "&", base::TRIM_WHITESPACE,
                              base::SPLIT_WANT_NONEMPTY)) {
    size_t separate_pos = attribute_string.find_first_of("=");
    if (separate_pos == base::StringPiece::npos) {
      // Add a name-only attribute.
      base::StringPiece name = base::TrimWhitespaceASCII(
          attribute_string, base::TrimPositions::TRIM_ALL);
      attributes.emplace_back(name, "");
    } else {
      base::StringPiece name =
          base::TrimWhitespaceASCII(attribute_string.substr(0, separate_pos),
                                    base::TrimPositions::TRIM_ALL);
      base::StringPiece value =
          base::TrimWhitespaceASCII(attribute_string.substr(separate_pos + 1),
                                    base::TrimPositions::TRIM_ALL);
      attributes.emplace_back(name, unescape_value
                                        ? updater::UnescapeURLComponent(value)
                                        : value.as_string());
    }
  }
  return attributes;
}

}  // namespace query_string

// Parses global and app-specific attributes from |tag|.
ErrorCode ParseTag(base::StringPiece tag, TagArgs* args) {
  const auto& global_func_lookup_table = global_attributes::GetTable();
  const auto& app_func_lookup_table = app_attributes::GetTable();

  for (const auto& attribute : query_string::Split(tag)) {
    // Attribute names are only ASCII, so no i18n case folding needed.
    const base::StringPiece name = attribute.first;
    const base::StringPiece value = attribute.second;

    if (global_func_lookup_table.find(name) != global_func_lookup_table.end()) {
      if (value.empty())
        return ErrorCode::kAttributeMustHaveValue;

      const ErrorCode result = global_func_lookup_table.at(name)(value, args);
      if (result != ErrorCode::kSuccess)
        return result;
    } else if (app_func_lookup_table.find(name) !=
               app_func_lookup_table.end()) {
      if (args->apps.empty())
        return ErrorCode::kApp_AppIdNotSpecified;

      if (value.empty())
        return ErrorCode::kAttributeMustHaveValue;

      AppArgs* current_app = &args->apps.back();
      const ErrorCode result =
          app_func_lookup_table.at(name)(value, current_app);
      if (result != ErrorCode::kSuccess)
        return result;
    } else {
      return ErrorCode::kUnrecognizedName;
    }
  }

  // The bundle name inherits the first app's name, if not set.
  if (args->bundle_name.empty() && !args->apps.empty())
    args->bundle_name = args->apps[0].app_name;

  return ErrorCode::kSuccess;
}

// Parses app-specific installer data from |app_installer_data_args|.
ErrorCode ParseAppInstallerDataArgs(base::StringPiece app_installer_data_args,
                                    TagArgs* args) {
  // The currently tracked app index to apply installer data to.
  base::Optional<size_t> current_app_index;

  // Installer data is assumed to be URL-encoded, so we don't unescape it.
  bool unescape_value = false;

  for (const auto& attribute :
       query_string::Split(app_installer_data_args, unescape_value)) {
    const base::StringPiece name = attribute.first;
    const base::StringPiece value = attribute.second;
    if (value.empty())
      return ErrorCode::kAttributeMustHaveValue;

    const auto& func_lookup_table = installer_data_attributes::GetTable();
    if (func_lookup_table.find(name) == func_lookup_table.end())
      return ErrorCode::kUnrecognizedName;

    const ErrorCode result =
        func_lookup_table.at(name)(value, args, &current_app_index);
    if (result != ErrorCode::kSuccess)
      return result;
  }

  return ErrorCode::kSuccess;
}

// Checks that |args| does not contain |kDisallowedCharInTag|.
bool IsValidArgs(base::StringPiece args) {
  return !base::Contains(args, kDisallowedCharInTag);
}

}  // namespace

AppArgs::AppArgs(base::StringPiece app_id)
    : app_id(base::ToLowerASCII(app_id)) {
  CHECK(!app_id.empty());
}

AppArgs::~AppArgs() = default;
AppArgs::AppArgs(AppArgs& other) = default;
AppArgs& AppArgs::operator=(AppArgs& other) = default;
AppArgs::AppArgs(AppArgs&& other) = default;
AppArgs& AppArgs::operator=(AppArgs&& other) = default;

TagArgs::TagArgs() = default;
TagArgs::~TagArgs() = default;
TagArgs::TagArgs(TagArgs& other) = default;
TagArgs& TagArgs::operator=(TagArgs& other) = default;
TagArgs::TagArgs(TagArgs&& other) = default;
TagArgs& TagArgs::operator=(TagArgs&& other) = default;

ErrorCode Parse(base::StringPiece tag,
                base::Optional<base::StringPiece> app_installer_data_args,
                TagArgs* args) {
  if (!IsValidArgs(tag))
    return ErrorCode::kTagIsInvalid;

  const ErrorCode result = ParseTag(tag, args);
  if (result != ErrorCode::kSuccess)
    return result;

  if (!app_installer_data_args.has_value())
    return ErrorCode::kSuccess;

  if (!IsValidArgs(app_installer_data_args.value()))
    return ErrorCode::kTagIsInvalid;

  return ParseAppInstallerDataArgs(app_installer_data_args.value(), args);
}

}  // namespace tagging
}  // namespace updater