Class: Sandbox::Landlock

Inherits:
LinuxBackend show all
Includes:
Utils::Output::Mixin
Defined in:
extend/os/linux/sandbox/landlock.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utils::Output::Mixin

#issue_reporting_message, #odebug, #odeprecated, #odie, #odisabled, #ofail, #oh1, #oh1_title, #ohai, #ohai_title, #onoe, #opoo, #opoo_outside_github_actions, #opoo_without_github_actions_annotation, #pretty_deprecated, #pretty_disabled, #pretty_duration, #pretty_install_status, #pretty_installed, #pretty_uninstalled, #pretty_unmarked, #pretty_upgradable, #pretty_warning

Methods inherited from LinuxBackend

#run, #writable_paths

Constructor Details

#initialize(profile) ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

  • profile (SandboxProfile) 


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# File 'extend/os/linux/sandbox/landlock.rb', line 282

def initialize(profile)
  super
  @writable_paths = T.let([], T::Array[String])
  @readable_paths = T.let([], T::Array[String])
  @error_pipe_path = T.let(nil, T.nilable(String))
  @deny_all_network = T.let(false, T::Boolean)
  @deny_read = T.let(false, T::Boolean)
end

Class Method Details

.abi_version ⇒ Integer?

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 105

def abi_version
  state
  @abi_version
end

.available? ⇒ Boolean

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:

  • (Boolean) 


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# File 'extend/os/linux/sandbox/landlock.rb', line 95

def available?
  state == :available
end

.close_file_descriptor(file_descriptor) ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 227

def close_file_descriptor(file_descriptor)
  @close ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["close"],
      [Fiddle::TYPE_INT],
      Fiddle::TYPE_INT,
    ),
    T.nilable(Fiddle::Function),
  )
  @close.call(file_descriptor)
end

.configuration_command_messages ⇒ Array<String>

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 153

def configuration_command_messages = []

.configuration_commands ⇒ Array<String>

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 150

def configuration_commands = []

.configure! ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

This method returns an undefined value.



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# File 'extend/os/linux/sandbox/landlock.rb', line 145

def configure!
  ensure_available!
end

.ensure_installed!(install_from_tests: false) ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

This method returns an undefined value.

Parameters:

  • install_from_tests (Boolean) (defaults to: false) 


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# File 'extend/os/linux/sandbox/landlock.rb', line 142

def ensure_installed!(install_from_tests: false); end

.failure_reason ⇒ String?

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 111

def failure_reason
  case state
  when :available
    nil
  when :config_disabled
    "Landlock cannot be used because Linux sandboxing is disabled."
  when :missing_fiddle
    "Landlock requires Ruby's bundled Fiddle library."
  when :unsupported
    "Landlock is not supported by this Linux kernel."
  when :disabled
    "Landlock is disabled by this Linux kernel."
  when :unsupported_abi
    abi = @abi_version
    if abi
      "Landlock ABI #{MINIMUM_ABI} or later is required; found ABI #{abi}."
    else
      "Landlock ABI #{MINIMUM_ABI} or later is required."
    end
  else
    "Landlock is not available."
  end
end

.full_write_isolation? ⇒ Boolean

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Landlock cannot restrict chmod, chown, extended attributes or timestamp changes. Callers requiring Bubblewrap-equivalent write isolation must compensate for these limitations: https://www.kernel.org/doc/html/latest/userspace-api/landlock.html#filesystem-flags

Returns:

  • (Boolean) 


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# File 'extend/os/linux/sandbox/landlock.rb', line 92

def full_write_isolation? = false

.install_command ⇒ String?

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 156

def install_command = nil

.landlock_add_rule(ruleset_fd, type, attributes, flags) ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 175

def landlock_add_rule(ruleset_fd, type, attributes, flags)
  @landlock_add_rule ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["syscall"],
      [Fiddle::TYPE_LONG, Fiddle::TYPE_INT, Fiddle::TYPE_INT, Fiddle::TYPE_VOIDP, Fiddle::TYPE_UINT],
      Fiddle::TYPE_LONG,
    ),
    T.nilable(Fiddle::Function),
  )
  @landlock_add_rule.call(ADD_RULE_SYSCALL, ruleset_fd, type, attributes, flags)
end

.landlock_create_ruleset(attributes, size, flags) ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 162

def landlock_create_ruleset(attributes, size, flags)
  @landlock_create_ruleset ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["syscall"],
      [Fiddle::TYPE_LONG, Fiddle::TYPE_VOIDP, Fiddle::TYPE_SIZE_T, Fiddle::TYPE_UINT],
      Fiddle::TYPE_LONG,
    ),
    T.nilable(Fiddle::Function),
  )
  @landlock_create_ruleset.call(CREATE_RULESET_SYSCALL, attributes, size, flags)
end

.landlock_restrict_self(ruleset_fd, flags) ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 188

def landlock_restrict_self(ruleset_fd, flags)
  @landlock_restrict_self ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["syscall"],
      [Fiddle::TYPE_LONG, Fiddle::TYPE_INT, Fiddle::TYPE_UINT],
      Fiddle::TYPE_LONG,
    ),
    T.nilable(Fiddle::Function),
  )
  @landlock_restrict_self.call(RESTRICT_SELF_SYSCALL, ruleset_fd, flags)
end

.last_error ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 240

def last_error
  Fiddle.last_error
end

.nested_sandbox? ⇒ Boolean

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:

  • (Boolean) 


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# File 'extend/os/linux/sandbox/landlock.rb', line 159

def nested_sandbox? = false

.open_path(path) ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 214

def open_path(path)
  @open ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["open"],
      [Fiddle::TYPE_CONST_STRING, Fiddle::TYPE_INT],
      Fiddle::TYPE_INT,
    ),
    T.nilable(Fiddle::Function),
  )
  @open.call(path, O_PATH | O_CLOEXEC)
end

.reset_state! ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

This method returns an undefined value.



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# File 'extend/os/linux/sandbox/landlock.rb', line 136

def reset_state!
  @state = T.let(nil, T.nilable(Symbol))
  @abi_version = T.let(nil, T.nilable(Integer))
end

.set_no_new_privileges ⇒ Integer

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 201

def set_no_new_privileges
  @prctl ||= T.let(
    Fiddle::Function.new(
      Fiddle.dlopen(nil)["prctl"],
      [Fiddle::TYPE_INT, Fiddle::TYPE_ULONG, Fiddle::TYPE_ULONG, Fiddle::TYPE_ULONG, Fiddle::TYPE_ULONG],
      Fiddle::TYPE_INT,
    ),
    T.nilable(Fiddle::Function),
  )
  @prctl.call(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
end

.state ⇒ Symbol

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 100

def state
  @state ||= T.let(compute_state, T.nilable(Symbol))
end

Instance Method Details

#apply! ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

This method returns an undefined value.



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# File 'extend/os/linux/sandbox/landlock.rb', line 305

def apply!
  abi = self.class.abi_version
  if !abi || abi < MINIMUM_ABI
    raise self.class.failure_reason || "Landlock ABI #{MINIMUM_ABI} or later is required."
  end

  if @deny_all_network && abi < MINIMUM_FULL_NETWORK_ABI
    opoo "Landlock ABI #{MINIMUM_FULL_NETWORK_ABI} or later is required to deny all network access; " \
         "found ABI #{abi}. Applying the network restrictions supported by this kernel."
  end

  attributes, handled_access_fs, allowed_write_access_fs = ruleset_attributes(abi)
  ruleset_fd = self.class.landlock_create_ruleset(attributes, attributes.bytesize, 0)
  raise_system_call_error("landlock_create_ruleset") if ruleset_fd.negative?

  begin
    # PTY allocation opens `/dev/ptmx` read-write, then configures its
    # dynamically allocated `/dev/pts/*` slave with device ioctls:
    # https://github.com/torvalds/linux/blob/master/drivers/tty/pty.c
    # https://www.kernel.org/doc/html/latest/userspace-api/landlock.html#ioctl-support
    pty_access = ACCESS_FS_WRITE_FILE
    pty_access |= ACCESS_FS_IOCTL_DEV if abi >= 5
    pty_access |= ACCESS_FS_READ_FILE if @deny_read
    ["/dev/ptmx", "/dev/pts"].each do |path|
      next unless File.exist?(path)

      add_path_rule(ruleset_fd, path, pty_access)
    end

    error_pipe_path = @error_pipe_path
    if @deny_all_network && abi >= 9 && error_pipe_path
      add_path_rule(ruleset_fd, error_pipe_path, ACCESS_FS_RESOLVE_UNIX)
    end
    @readable_paths.each do |path|
      allowed_access = File.directory?(path) ? READ_ACCESS_FS : FILE_READ_ACCESS_FS
      add_path_rule(ruleset_fd, path, allowed_access)
    end
    @writable_paths.each do |path|
      allowed_access = if File.directory?(path)
        allowed_write_access_fs
      else
        allowed_write_access_fs & FILE_WRITE_ACCESS_FS
      end
      add_path_rule(ruleset_fd, path, allowed_access & handled_access_fs)
    end

    raise_system_call_error("prctl") if self.class.set_no_new_privileges.negative?
    if self.class.landlock_restrict_self(ruleset_fd, 0).negative?
      raise_system_call_error("landlock_restrict_self")
    end
  ensure
    close_file_descriptor(ruleset_fd)
  end
end

#command(args, tmpdir) ⇒ Array<String, ::Pathname>

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'extend/os/linux/sandbox/landlock.rb', line 292

def command(args, tmpdir)
  paths = writable_paths
  @writable_paths = paths.keys | [File::NULL, tmpdir]
  @writable_paths.each { |path| prepare_writable_path(path, paths.fetch(path, :subpath)) }
  denied_read_paths = self.denied_read_paths
  @readable_paths = readable_paths(denied_read_paths)
  @deny_read = denied_read_paths.any?
  @deny_all_network = deny_all_network?
  @error_pipe_path = File.join(tmpdir, "socket")
  args
end