00840f4f2e
* Add handling of Linked Data Signatures in payloads * Add a way to sign JSON, fix canonicalization of signature options * Fix signatureValue encoding, send out signed JSON when distributing * Add missing security context
57 lines
1.7 KiB
Ruby
57 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
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end
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def verify_account!
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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_resource(creator_uri, Account)
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creator ||= ActivityPub::FetchRemoteKeyService.new.call(creator_uri)
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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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if creator.keypair.public_key.verify(OpenSSL::Digest::SHA256.new, Base64.decode64(signature), to_be_verified)
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creator
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end
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end
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def sign!(creator)
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options = {
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'type' => 'RsaSignature2017',
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'creator' => [ActivityPub::TagManager.instance.uri_for(creator), '#main-key'].join,
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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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signature = Base64.strict_encode64(creator.keypair.sign(OpenSSL::Digest::SHA256.new, to_be_signed))
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@json.merge('@context' => merge_context(@json['@context'], CONTEXT), '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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