Module: Hawk::AuthorizationHeader

Extended by:
AuthorizationHeader
Included in:
AuthorizationHeader
Defined in:
lib/hawk/authorization_header.rb

Constant Summary collapse

REQUIRED_OPTIONS = 
[:method, :request_uri, :host, :port].freeze
REQUIRED_CREDENTIAL_MEMBERS = 
[:id, :key, :algorithm].freeze
SUPPORTED_ALGORITHMS = 
['sha256', 'sha1'].freeze
HEADER_PARTS = 
[:id, :ts, :nonce, :hash, :ext, :mac].freeze
DEFAULT_TIMESTAMP_SKEW =

±60 seconds

60.freeze
MissingOptionError = 
Class.new(StandardError)
InvalidCredentialsError = 
Class.new(StandardError)
InvalidAlgorithmError = 
Class.new(StandardError)

Instance Method Summary collapse

Instance Method Details

#authenticate(header, options) ⇒ Object 



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# File 'lib/hawk/authorization_header.rb', line 56

def authenticate(header, options)
  options = options.dup

  parts = parse(header)
  options.delete(:payload) unless parts[:hash]

  now = Time.now.to_i

  options[:timestamp_skew] ||= DEFAULT_TIMESTAMP_SKEW

  if options[:server_response]
    credentials = options[:credentials]
    parts.merge!(
      :ts => options[:ts],
      :nonce => options[:nonce]
    )
  else
    unless options[:credentials_lookup].respond_to?(:call) && (credentials = options[:credentials_lookup].call(parts[:id]))
      return AuthenticationFailure.new(:id, "Unidentified id")
    end

    if (now - parts[:ts].to_i > options[:timestamp_skew]) || (parts[:ts].to_i - now > options[:timestamp_skew])
      # Stale timestamp
      return AuthenticationFailure.new(:ts, "Stale ts", :credentials => credentials)
    end

    unless parts[:nonce]
      return AuthenticationFailure.new(:nonce, "Missing nonce")
    end

    if options[:nonce_lookup].respond_to?(:call) && options[:nonce_lookup].call(parts[:nonce])
      # Replay
      return AuthenticationFailure.new(:nonce, "Invalid nonce")
    end
  end

  expected_mac = Crypto.mac(options.merge(
    :credentials => credentials,
    :ts => parts[:ts],
    :nonce => parts[:nonce],
    :ext => parts[:ext],
    :app => options[:app] || parts[:app],
    :dig => options[:dig] || parts[:dig]
  ))
  unless expected_mac == parts[:mac]
    return AuthenticationFailure.new(:mac, "Invalid mac")
  end

  expected_hash = parts[:hash] ? Crypto.hash(options.merge(:credentials => credentials)) : nil
  if expected_hash && expected_hash != parts[:hash]
    return AuthenticationFailure.new(:hash, "Invalid hash")
  end

  credentials
end

#build(options, only = nil) ⇒ Object 



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# File 'lib/hawk/authorization_header.rb', line 16

def build(options, only=nil)
  options[:ts] ||= Time.now.to_i
  options[:nonce] ||= SecureRandom.hex(4)

  REQUIRED_OPTIONS.each do |key|
    unless options.has_key?(key)
      raise MissingOptionError.new("#{key.inspect} is missing!")
    end
  end

  credentials = options[:credentials]
  REQUIRED_CREDENTIAL_MEMBERS.each do |key|
    unless credentials.has_key?(key)
      raise InvalidCredentialsError.new("#{key.inspect} is missing!")
    end
  end

  unless SUPPORTED_ALGORITHMS.include?(credentials[:algorithm])
    raise InvalidAlgorithmError.new("#{credentials[:algorithm].inspect} is not a supported algorithm! Use one of the following: #{SUPPORTED_ALGORITHMS.join(', ')}")
  end

  hash = Crypto.hash(options)
  mac = Crypto.mac(options)

  parts = {
    :id => credentials[:id],
    :ts => options[:ts],
    :nonce => options[:nonce],
    :mac => mac
  }
  parts[:hash] = hash if options.has_key?(:payload) && !options[:payload].nil?
  parts[:ext] = options[:ext] if options.has_key?(:ext)

  "Hawk " << (only || HEADER_PARTS).inject([]) { |memo, key|
    next memo unless parts.has_key?(key)
    memo << %(#{key}="#{parts[key]}")
    memo
  }.join(', ')
end

#parse(header) ⇒ Object 



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# File 'lib/hawk/authorization_header.rb', line 112

def parse(header)
  parts = header.sub(/\AHawk\s+/, '').split(/,\s*/)
  parts.inject(Hash.new) do |memo, part|
    next memo unless part =~ %r{([a-z]+)=(['"])([^\2]+)\2}
    key, val = $1, $3
    memo[key.to_sym] = val
    memo
  end
end