55 lines
1.7 KiB
Ruby
55 lines
1.7 KiB
Ruby
# frozen_string_literal: true
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class ActivityPub::LinkedDataSignature
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include JsonLdHelper
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CONTEXT = 'https://w3id.org/identity/v1'
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def initialize(json)
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@json = json.with_indifferent_access
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end
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def verify_actor!
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return unless @json['signature'].is_a?(Hash)
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type = @json['signature']['type']
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creator_uri = @json['signature']['creator']
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signature = @json['signature']['signatureValue']
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return unless type == 'RsaSignature2017'
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creator = ActivityPub::TagManager.instance.uri_to_actor(creator_uri)
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creator ||= ActivityPub::FetchRemoteKeyService.new.call(creator_uri, id: false)
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return if creator.nil?
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options_hash = hash(@json['signature'].without('type', 'id', 'signatureValue').merge('@context' => CONTEXT))
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document_hash = hash(@json.without('signature'))
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to_be_verified = options_hash + document_hash
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creator if creator.keypair.public_key.verify(OpenSSL::Digest.new('SHA256'), Base64.decode64(signature), to_be_verified)
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end
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def sign!(creator, sign_with: nil)
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options = {
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'type' => 'RsaSignature2017',
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'creator' => ActivityPub::TagManager.instance.key_uri_for(creator),
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'created' => Time.now.utc.iso8601,
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}
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options_hash = hash(options.without('type', 'id', 'signatureValue').merge('@context' => CONTEXT))
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document_hash = hash(@json.without('signature'))
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to_be_signed = options_hash + document_hash
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keypair = sign_with.present? ? OpenSSL::PKey::RSA.new(sign_with) : creator.keypair
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signature = Base64.strict_encode64(keypair.sign(OpenSSL::Digest.new('SHA256'), to_be_signed))
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@json.merge('signature' => options.merge('signatureValue' => signature))
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end
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private
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def hash(obj)
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Digest::SHA256.hexdigest(canonicalize(obj))
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end
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end
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