Module: PQCrypto::Seal::IOAPI

Defined in:
lib/pq_crypto/seal/io.rb

Constant Summary collapse

DEFAULT_CHUNK_SIZE = 
1024 * 1024

Class Method Summary collapse

Class Method Details

.add_recipient_file(source, destination, with:, recipient:, current_recipients:, **options) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 142

def add_recipient_file(source, destination, with:, recipient:, current_recipients:, **options)
  rebuild_recipients_file(
    source, destination, with: with,
    recipients: Array(current_recipients) + [recipient], **options
  )
end

.atomic_destination(destination) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 246

def atomic_destination(destination)
  path = File.expand_path(destination)
  directory = File.dirname(path)
  FileUtils.mkdir_p(directory)
  temp = Tempfile.new([".#{File.basename(path)}.", ".pqcseal"], directory)
  temp.binmode
  temp.chmod(0o600)
  begin
    yield temp
    temp.flush
    temp.fsync
    temp.close
    File.rename(temp.path, path)
    fsync_directory(directory)
  ensure
    temp.close! rescue nil
  end
end

.copy_exact(input, output, length, chunk_size) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 294

def copy_exact(input, output, length, chunk_size)
  remaining = length
  while remaining.positive?
    chunk = input.read([remaining, chunk_size].min)
    raise EOFError, "staging input is truncated" unless chunk && !chunk.empty?
    output.write(chunk)
    remaining -= chunk.bytesize
  end
end

.copy_exact_encrypted(input, output, encryptor, length, chunk_size) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 271

def copy_exact_encrypted(input, output, encryptor, length, chunk_size)
  copied = 0
  while copied < length
    chunk = input.read([chunk_size, length - copied].min)
    break unless chunk && !chunk.empty?
    chunk = chunk.b
    output.write(encryptor.update(chunk))
    copied += chunk.bytesize
  end
  copied
end

.decrypt_file(source, destination, with:, staging_directory: nil, chunk_size: DEFAULT_CHUNK_SIZE, **limits) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 91

def decrypt_file(source, destination, with:, staging_directory: nil,
                 chunk_size: DEFAULT_CHUNK_SIZE, **limits)
  File.open(source, "rb") do |input|
    atomic_destination(destination) do |tmp|
      decrypt_io(
        input, tmp, with: with, staging_directory: staging_directory,
        chunk_size: chunk_size, strict_eof: true, **limits
      )
    end
  end
  destination
end

.decrypt_frame_io(input, output, with:, **options) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 73

def decrypt_frame_io(input, output, with:, **options)
  decrypt_io(input, output, with: with, strict_eof: false, **options)
end

.decrypt_io(input, output, with:, staging_directory: nil, chunk_size: DEFAULT_CHUNK_SIZE, strict_eof: true, **limits) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 50

def decrypt_io(input, output, with:, staging_directory: nil, chunk_size: DEFAULT_CHUNK_SIZE,
               strict_eof: true, **limits)
  limits = Format::LIMIT_DEFAULTS.merge(limits)
  chunk_size = validate_chunk_size(chunk_size)
  staging = new_staging("pqcrypto-seal-inner", staging_directory)
  opened = decrypt_to_staging(
    input, staging, with: with, chunk_size: chunk_size, strict_eof: strict_eof, **limits
  )
  staging.flush
  staging.rewind
  content_offset, content_length, metadata = parse_verified_staging(staging, opened[:header].padded_inner_length)
  if content_length > Integer(limits[:max_plaintext_bytes])
    seal(:wipe_string!, metadata)
    raise ResourceLimitError,
          "plaintext #{content_length} exceeds max_plaintext_bytes #{limits[:max_plaintext_bytes]}"
  end
  staging.seek(content_offset, ::IO::SEEK_SET)
  copy_exact(staging, output, content_length, chunk_size)
  Opened.from_header(opened[:header], opened[:section], data: nil, metadata: metadata)
ensure
  staging.close! if defined?(staging) && staging
end

.decrypt_to_staging(input, staging, with:, chunk_size:, strict_eof:, **limits) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 189

def decrypt_to_staging(input, staging, with:, chunk_size:, strict_eof:, **limits)
  limits = Format::LIMIT_DEFAULTS.merge(limits)
  header = read_header(input)
  Format.check_resource_limits!(
    padded_inner_length: header.padded_inner_length, **Format.pre_auth_limits(limits)
  )
  section = Format.parse_section(read_exact(input, Format.section_length(header)), 0, header)
  estimated = header.raw.bytesize + section.raw.bytesize + header.padded_inner_length + Format::TAG_BYTES
  Format.check_resource_limits!(
    padded_inner_length: header.padded_inner_length,
    envelope_bytes: estimated, **Format.pre_auth_limits(limits)
  )
  dek = seal(:unwrap_dek, header, section, with)
  decryptor = Native::Decryptor.new(dek, header.payload_nonce, Native.sha256(header.raw))
  remaining = header.padded_inner_length
  while remaining.positive?
    take = [remaining, chunk_size].min
    staging.write(decryptor.update(read_exact(input, take)))
    remaining -= take
  end
  tag = read_exact(input, Format::TAG_BYTES)
  raise FormatError, "trailing bytes after envelope" if strict_eof && !input.read(1).nil?
  decryptor.final(tag)
  { header: header, section: section }
ensure
  seal(:wipe_string!, dek) if defined?(dek)
end

.drop_recipient_stanza_file(source, destination, with:, remaining_recipients:, **options) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 149

def drop_recipient_stanza_file(source, destination, with:, remaining_recipients:, **options)
  rebuild_recipients_file(source, destination, with: with, recipients: remaining_recipients, **options)
end

.encrypt_file(source, destination, **options) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 81

def encrypt_file(source, destination, **options)
  File.open(source, "rb") do |input|
    size = input.stat.size
    atomic_destination(destination) do |tmp|
      encrypt_io(input, tmp, size: size, strict_size: true, **options)
    end
  end
  destination
end

.encrypt_frame_io(input, output, size:, to:, **options) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 77

def encrypt_frame_io(input, output, size:, to:, **options)
  encrypt_io(input, output, size: size, to: to, strict_size: false, **options)
end

.encrypt_io(input, output, size:, to:, metadata: "".b, public_metadata: "".b, recipient_capacity: Format::DEFAULT_RECIPIENT_CAPACITY, slot_size: Format::DEFAULT_SLOT_SIZE, padding: :padme, chunk_size: DEFAULT_CHUNK_SIZE, strict_size: true) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 12

def encrypt_io(input, output, size:, to:, metadata: "".b, public_metadata: "".b,
               recipient_capacity: Format::DEFAULT_RECIPIENT_CAPACITY,
               slot_size: Format::DEFAULT_SLOT_SIZE, padding: :padme,
               chunk_size: DEFAULT_CHUNK_SIZE, strict_size: true)
  content_size = Integer(size)
  raise ArgumentError, "size must be non-negative" if content_size.negative?
  metadata = String(metadata).b
  seal(:validate_private_metadata!, metadata)
  recipients = seal(:normalize_public_keys, to)
  capacity = Format.validate_capacity!(recipient_capacity, recipients.length)
  slot_size = Format.validate_slot_size!(slot_size)
  chunk_size = validate_chunk_size(chunk_size)

  parts = nil
  parts = seal(
    :materialize_crypto_parts,
    recipients: recipients, capacity: capacity, slot_size: slot_size,
    padding: padding, public_metadata: public_metadata,
    content_size: content_size, metadata_size: metadata.bytesize
  )
  output.write(parts[:header])
  output.write(parts[:section])
  encryptor = Native::Encryptor.new(parts[:dek], parts[:payload_nonce], parts[:header_hash])
  output.write(encryptor.update(parts[:inner_prefix]))
  output.write(encryptor.update(metadata)) unless metadata.empty?
  copied = copy_exact_encrypted(input, output, encryptor, content_size, chunk_size)
  raise EOFError, "input ended after #{copied} of #{content_size} bytes" unless copied == content_size
  if strict_size
    raise ArgumentError, "input contains more bytes than declared size" unless input.read(1).nil?
  end
  write_random_encrypted(output, encryptor, parts[:padded_inner_length] - parts[:raw_inner_length], chunk_size)
  output.write(encryptor.final)
  output
ensure
  seal(:wipe_string!, parts[:dek]) if parts
  seal(:wipe_string!, metadata) if metadata.is_a?(String) && !metadata.frozen?
end

.fsync_directory(directory) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 265

def fsync_directory(directory)
  File.open(directory, "r") { |dir| dir.fsync }
rescue SystemCallError, IOError
  nil
end

.inspect_file(source) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 179

def inspect_file(source)
  File.open(source, "rb") do |input|
    header = read_header(input)
    section = Format.parse_section(read_exact(input, Format.section_length(header)), 0, header)
    total = header.raw.bytesize + section.raw.bytesize + header.padded_inner_length + Format::TAG_BYTES
    raise FormatError, "file length does not match envelope" unless File.size(source) == total
    Inspection.from_header(header, section, envelope_bytes: total)
  end
end

.new_staging(prefix, staging_directory) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 315

def new_staging(prefix, staging_directory)
  tempfile = Tempfile.new([prefix, ".bin"], staging_directory)
  tempfile.binmode
  tempfile.chmod(0o600)
  unlink_open_tempfile(tempfile)
  tempfile
end

.parse_verified_staging(staging, expected_size) ⇒ Object

Raises:



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# File 'lib/pq_crypto/seal/io.rb', line 217

def parse_verified_staging(staging, expected_size)
  raise FormatError, "staging size mismatch" unless staging.stat.size == expected_size
  staging.rewind
  prefix = read_exact(staging, 14)
  version = prefix.getbyte(0)
  flags = prefix.getbyte(1)
  raise FormatError, "unsupported inner version" unless version == Format::INNER_VERSION
  raise FormatError, "unknown inner flags" unless flags == Format::INNER_FLAGS
  hi, lo, metadata_length = prefix.byteslice(2, 12).unpack("NNN")
  content_length = (hi << 32) | lo
  raise FormatError, "private metadata is too large" if metadata_length > Format::MAX_PRIVATE_METADATA_BYTES
  minimum = 14 + metadata_length + content_length
  raise FormatError, "inner lengths exceed authenticated frame" if minimum > expected_size
  metadata = read_exact(staging, metadata_length)
  [14 + metadata_length, content_length, metadata]
end

.read_exact(io, length) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 304

def read_exact(io, length)
  return "".b if length.zero?
  buffer = +"".b
  while buffer.bytesize < length
    chunk = io.read(length - buffer.bytesize)
    raise EOFError, "truncated envelope" unless chunk && !chunk.empty?
    buffer << chunk.b
  end
  buffer
end

.read_header(input) ⇒ Object

Raises:



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# File 'lib/pq_crypto/seal/io.rb', line 234

def read_header(input)
  prefix_len = Format::MAGIC.bytesize + 1 + 4
  initial = read_exact(input, prefix_len)
  header_length = initial.byteslice(Format::MAGIC.bytesize + 1, 4).unpack1("N")
  raise FormatError, "invalid header length" if header_length < initial.bytesize || header_length > Format::MAX_HEADER_BYTES
  Format.parse_header(initial + read_exact(input, header_length - initial.bytesize))
end

.rebuild_recipients_file(source, destination, with:, recipients:, chunk_size: DEFAULT_CHUNK_SIZE) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 104

def rebuild_recipients_file(source, destination, with:, recipients:, chunk_size: DEFAULT_CHUNK_SIZE)
  chunk_size = validate_chunk_size(chunk_size)
  File.open(source, "rb") do |input|
    header = read_header(input)
    old_section = Format.parse_section(read_exact(input, Format.section_length(header)), 0, header)
    dek = seal(:unwrap_dek, header, old_section, with)
    public_keys = seal(:normalize_public_keys, recipients)
    Format.validate_capacity!(header.recipient_capacity, public_keys.length)
    new_section = seal(
      :build_recipient_section,
      recipients: public_keys, capacity: header.recipient_capacity,
      slot_size: header.slot_size, payload_id: header.payload_id,
      header_hash: Native.sha256(header.raw), dek: dek,
      wrap_suite_id: Format::WRAP_SUITE_MLKEM768_X25519_AEGIS256
    )
    atomic_destination(destination) do |tmp|
      tmp.write(header.raw)
      tmp.write(new_section)
      verifier = Native::Decryptor.new(dek, header.payload_nonce, Native.sha256(header.raw))
      remaining = header.padded_inner_length
      while remaining.positive?
        take = [remaining, chunk_size].min
        ciphertext_chunk = read_exact(input, take)
        tmp.write(ciphertext_chunk)
        seal(:wipe_string!, verifier.update(ciphertext_chunk))
        remaining -= take
      end
      payload_tag = read_exact(input, Format::TAG_BYTES)
      raise FormatError, "trailing bytes after envelope" unless input.read(1).nil?
      verifier.final(payload_tag)
      tmp.write(payload_tag)
    end
  ensure
    seal(:wipe_string!, dek) if defined?(dek)
  end
  destination
end

.rotate_dek_file(source, destination, with:, recipients:, padding: :preserve, staging_directory: nil, chunk_size: DEFAULT_CHUNK_SIZE) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 153

def rotate_dek_file(source, destination, with:, recipients:, padding: :preserve,
                    staging_directory: nil, chunk_size: DEFAULT_CHUNK_SIZE)
  plaintext = new_staging("pqcrypto-seal-rotation", staging_directory)
  opened = nil
  File.open(source, "rb") do |input|
    opened = decrypt_io(input, plaintext, with: with,
                        staging_directory: staging_directory, chunk_size: chunk_size, strict_eof: true)
  end
  plaintext.flush
  plaintext.rewind
  info = inspect_file(source)
  padding = { to: info.envelope_bytes } if padding == :preserve
  atomic_destination(destination) do |tmp|
    encrypt_io(
      plaintext, tmp, size: plaintext.stat.size, to: recipients,
      metadata: opened.metadata, public_metadata: opened.public_metadata,
      recipient_capacity: info.recipient_capacity, slot_size: info.slot_size,
      padding: padding, chunk_size: chunk_size, strict_size: true
    )
  end
  destination
ensure
  plaintext.close! if defined?(plaintext) && plaintext
  seal(:wipe_string!, opened.metadata) if defined?(opened) && opened && opened.metadata
end

.seal(name, *args, **kwargs) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 242

def seal(name, *args, **kwargs)
  Seal.send(name, *args, **kwargs)
end

.unlink_open_tempfile(tempfile) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 323

def unlink_open_tempfile(tempfile)
  tempfile.unlink
rescue SystemCallError, IOError, NotImplementedError
  nil
end

.validate_chunk_size(value) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/pq_crypto/seal/io.rb', line 329

def validate_chunk_size(value)
  size = Integer(value)
  raise ArgumentError, "chunk_size must be positive" unless size.positive?
  size
end

.write_random_encrypted(output, encryptor, length, chunk_size) ⇒ Object 



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# File 'lib/pq_crypto/seal/io.rb', line 283

def write_random_encrypted(output, encryptor, length, chunk_size)
  remaining = length
  while remaining.positive?
    take = [remaining, chunk_size].min
    random = Native.random_bytes(take)
    output.write(encryptor.update(random))
    seal(:wipe_string!, random)
    remaining -= take
  end
end