Class: Familia::EncryptedFieldType

Inherits:
FieldType
  • Object
show all
Defined in:
lib/familia/features/encrypted_fields/encrypted_field_type.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, aad_fields: [], key_material: nil, **options) ⇒ EncryptedFieldType

Returns a new instance of EncryptedFieldType.



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 14

def initialize(name, aad_fields: [], key_material: nil, **options)
  # Encrypted fields are not loggable by default for security
  super(name, **options.merge(on_conflict: :raise, loggable: false))
  @aad_fields = Array(aad_fields).freeze
  @key_material = key_material # Proc returning entropy string
end

Instance Attribute Details

#aad_fields ⇒ Object (readonly)

Returns the value of attribute aad_fields.



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 12

def aad_fields
  @aad_fields
end

#key_material ⇒ Object (readonly)

Returns the value of attribute key_material.



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 12

def key_material
  @key_material
end

Instance Method Details

#category ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 166

def category
  :encrypted
end

#decrypt_value(record, encrypted) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 144

def decrypt_value(record, encrypted)
  envelope = Familia::Encryption::EncryptedData.from_json(encrypted)
  context = build_context(record)

  if envelope.envelope_version && envelope.envelope_version >= 2
    # v2 envelopes are self-describing: a nil stored_aad_fields means the
    # value was encrypted with no AAD fields. Fall back to [] (not the
    # current class-level @aad_fields) so that adding aad_fields to a model
    # later cannot break decryption of already-stored v2 envelopes.
    additional_data = build_aad(record, fields: envelope.stored_aad_fields || [])
    context = context_with_entropy(context, build_key_material(record)) if envelope.has_key_material?
  else
    additional_data = build_aad(record)
  end

  Familia::Encryption.decrypt(encrypted, context: context, additional_data: additional_data)
end

#define_fast_writer(klass) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 101

def define_fast_writer(klass)
  # Encrypted fields override base fast writer for security
  return unless @fast_method_name&.to_s&.end_with?('!')

  field_name = @name
  method_name = @method_name
  fast_method_name = @fast_method_name
  self

  handle_method_conflict(klass, fast_method_name) do
    klass.define_method fast_method_name do |val|
      raise ArgumentError, "#{fast_method_name} requires a value" if val.nil?

      # Use via the setter method to get proper ConcealedString wrapping
      send(:"#{method_name}=", val) if method_name

      # Get the ConcealedString and extract encrypted data for storage
      concealed = instance_variable_get(:"@#{field_name}")
      encrypted_data = concealed&.encrypted_value

      return false if encrypted_data.nil?

      ret = hset(field_name, encrypted_data)
      Familia.success?(ret)
    end
  end
end

#define_getter(klass) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 57

def define_getter(klass)
  field_name = @name
  method_name = @method_name
  field_type = self

  handle_method_conflict(klass, method_name) do
    klass.define_method method_name do
      # Return ConcealedString directly - no auto-decryption!
      # Caller must use .reveal { } for plaintext access
      concealed = instance_variable_get(:"@#{field_name}")

      # Return nil directly if that's what was set
      return nil if concealed.nil?

      # If we have a raw string (from direct instance variable manipulation),
      # wrap it in ConcealedString which will trigger validation
      if concealed.is_a?(::String) && !concealed.is_a?(ConcealedString)
        # This happens when someone directly sets the instance variable
        # (e.g., during tampering tests). Wrapping in ConcealedString
        # will trigger validate_decryptable! and catch invalid algorithms
        begin
          concealed = ConcealedString.new(concealed, self, field_type)
          instance_variable_set(:"@#{field_name}", concealed)
        rescue Familia::EncryptionError => e
          # Increment derivation counter for failed validation attempts (similar to decrypt failures)
          Familia::Encryption.derivation_count.increment
          raise e
        end
      end

      # Context validation: detect cross-context attacks
      # Only validate if we have a proper ConcealedString instance
      if concealed.is_a?(ConcealedString) && !concealed.belongs_to_context?(self, field_name)
        raise Familia::EncryptionError,
              "Context isolation violation: encrypted field '#{field_name}' accessed from " \
              "#{self.class.name}:#{field_name}:#{identifier} but was encrypted for " \
              "#{concealed.context_description}"
      end

      concealed
    end
  end
end

#define_setter(klass) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 21

def define_setter(klass)
  field_name = @name
  method_name = @method_name
  field_type = self

  handle_method_conflict(klass, :"#{method_name}=") do
    klass.define_method :"#{method_name}=" do |value|
      old_value = instance_variable_get(:"@#{field_name}")

      if value.nil?
        instance_variable_set(:"@#{field_name}", nil)
      elsif value.is_a?(::String) && value.empty?
        # Handle empty strings - treat as nil for encrypted fields
        instance_variable_set(:"@#{field_name}", nil)
      elsif value.is_a?(ConcealedString)
        # Already concealed, store as-is
        instance_variable_set(:"@#{field_name}", value)
      elsif field_type.encrypted_json?(value)
        # Already encrypted (JSON string or Hash from database) - wrap in ConcealedString without re-encrypting
        # Convert Hash back to JSON string if needed (v2.0 deserialization returns Hash)
        encrypted_string = value.is_a?(Hash) ? Familia::JsonSerializer.dump(value) : value
        concealed = ConcealedString.new(encrypted_string, self, field_type)
        instance_variable_set(:"@#{field_name}", concealed)
      else
        # Encrypt plaintext and wrap in ConcealedString
        encrypted = field_type.encrypt_value(self, value)
        concealed = ConcealedString.new(encrypted, self, field_type)
        instance_variable_set(:"@#{field_name}", concealed)
      end

      # Track the change for dirty-tracking (only for Horreum instances)
      mark_dirty!(field_name, old_value) if respond_to?(:mark_dirty!)
    end
  end
end

#encrypt_value(record, value) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 129

def encrypt_value(record, value)
  context = build_context(record)
  additional_data = build_aad(record)
  entropy = build_key_material(record)
  context = context_with_entropy(context, entropy)

  result = Familia::Encryption.encrypt(value, context: context, additional_data: additional_data)

  Familia::Encryption::EncryptedData.from_json(result).with_metadata(
    envelope_version: 2,
    aad_fields: @aad_fields.empty? ? nil : @aad_fields.map(&:to_s),
    key_material_fields: entropy ? ['key_material'] : nil
  ).to_json
end

#encrypted_json?(data) ⇒ Boolean

Check if a string looks like encrypted JSON data

Returns:

  • (Boolean) 


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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 171

def encrypted_json?(data)
  # Support both JSON strings (legacy) and Hashes (v2.0 deserialization)
  if data.is_a?(Hash)
    required_keys = %w[algorithm nonce ciphertext auth_tag key_version]
    required_keys.all? { |key| data.key?(key) || data.key?(key.to_sym) }
  else
    Familia::Encryption::EncryptedData.valid?(data)
  end
end

#persistent? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 162

def persistent?
  true
end