Class: Vangrail::Label

Inherits:
Object
  • Object
show all
Defined in:
lib/vangrail/origin.rb

Overview

Immutable security metadata carried by a Cell.

Provenance accumulates. Integrity records the trusted principals whose values contributed to a result; an empty set cannot authorize control flow. Confidentiality is an allowlist of sinks, where nil means no sink restriction. Capability tokens are intersected, and any untrusted provenance removes them.

Constant Summary collapse

DEFAULT_INTEGRITY = 
Object.new.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(provenance:, integrity: DEFAULT_INTEGRITY, confidentiality: nil, capabilities: nil) ⇒ Label

Returns a new instance of Label.

Raises:

  • (ArgumentError) 


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# File 'lib/vangrail/origin.rb', line 124

def initialize(provenance:, integrity: DEFAULT_INTEGRITY, confidentiality: nil,
               capabilities: nil)
  @provenance = Array(provenance).map { |origin| Origin.coerce(origin) }.uniq.freeze
  raise ArgumentError, 'a label needs at least one origin' if @provenance.empty?

  @integrity = normalize(integrity.equal?(DEFAULT_INTEGRITY) ? default_integrity : integrity)
  @confidentiality = normalize_optional(confidentiality)
  @capabilities = if @provenance.any?(&:untrusted?)
                    [].freeze
                  else
                    normalize_optional(capabilities)
                  end
  freeze
end

Instance Attribute Details

#capabilities ⇒ Object (readonly)

Returns the value of attribute capabilities.



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# File 'lib/vangrail/origin.rb', line 122

def capabilities
  @capabilities
end

#confidentiality ⇒ Object (readonly)

Returns the value of attribute confidentiality.



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# File 'lib/vangrail/origin.rb', line 122

def confidentiality
  @confidentiality
end

#integrity ⇒ Object (readonly)

Returns the value of attribute integrity.



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# File 'lib/vangrail/origin.rb', line 122

def integrity
  @integrity
end

#provenance ⇒ Object (readonly)

Returns the value of attribute provenance.



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# File 'lib/vangrail/origin.rb', line 122

def provenance
  @provenance
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql? 



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# File 'lib/vangrail/origin.rb', line 159

def ==(other)
  other.is_a?(self.class) && other.provenance == provenance &&
    other.integrity == integrity && other.confidentiality == confidentiality &&
    other.capabilities == capabilities
end

#hash ⇒ Object 



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# File 'lib/vangrail/origin.rb', line 167

def hash
  [self.class, provenance, integrity, confidentiality, capabilities].hash
end

#mix(other) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/vangrail/origin.rb', line 147

def mix(other)
  raise ArgumentError, 'labels can only mix with labels' unless other.is_a?(self.class)

  combined_provenance = (provenance + other.provenance).uniq
  self.class.new(
    provenance: combined_provenance,
    integrity: merge_integrity(other),
    confidentiality: restrict(confidentiality, other.confidentiality),
    capabilities: merge_capabilities(other, combined_provenance),
  )
end

#privileged? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/vangrail/origin.rb', line 139

def privileged?
  provenance.all?(&:privileged?) && !integrity.empty?
end

#tainted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/vangrail/origin.rb', line 143

def tainted?
  provenance.any?(&:untrusted?)
end

#to_h ⇒ Object 



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# File 'lib/vangrail/origin.rb', line 171

def to_h
  {
    'provenance' => provenance.map(&:to_s),
    'integrity' => integrity.map(&:to_s),
    'confidentiality' => confidentiality&.map(&:to_s),
    'capabilities' => capabilities&.map(&:to_s),
  }.compact
end