Class: Familia::EncryptedFieldType

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

Instance Attribute Summary collapse

Attributes inherited from FieldType

#fast_method_name, #loggable, #method_name, #name, #on_conflict, #options

Instance Method Summary collapse

Methods inherited from FieldType

#deserialize, #generated_methods, #inspect, #install, #serialize, #transient?

Constructor Details

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

Returns a new instance of EncryptedFieldType.



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 10

def initialize(name, aad_fields: [], **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
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 8

def aad_fields
  @aad_fields
end

Instance Method Details

#category ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 134

def category
  :encrypted
end

#decrypt_value(record, encrypted) ⇒ Object

Decrypt a value for the given record



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 123

def decrypt_value(record, encrypted)
  context = build_context(record)
  additional_data = build_aad(record)

  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 86

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
  field_type = 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?

      # Set 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)
      ret.zero? || ret.positive?
    end
  end
end

#define_getter(klass) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 45

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.kind_of?(::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}' does not belong to #{self.class.name}:#{self.identifier}"
      end

      concealed
    end
  end
end

#define_setter(klass) ⇒ Object 



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 16

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|
      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 from database - wrap in ConcealedString without re-encrypting
        concealed = ConcealedString.new(value, 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
    end
  end
end

#encrypt_value(record, value) ⇒ Object

Encrypt a value for the given record



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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 115

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

  Familia::Encryption.encrypt(value, context: context, additional_data: additional_data)
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 139

def encrypted_json?(data)
  Familia::Encryption::EncryptedData.valid?(data)
end

#persistent? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/familia/features/encrypted_fields/encrypted_field_type.rb', line 130

def persistent?
  true
end