require 'rails_helper' RSpec.describe ActivityPub::LinkedDataSignature do include JsonLdHelper let!(:sender) { Fabricate(:account, uri: 'http://example.com/alice') } let(:raw_json) do { '@context' => 'https://www.w3.org/ns/activitystreams', 'id' => 'http://example.com/hello-world', } end let(:json) { raw_json.merge('signature' => signature) } subject { described_class.new(json) } before do stub_jsonld_contexts! end describe '#verify_actor!' do context 'when signature matches' do let(:raw_signature) do { 'creator' => 'http://example.com/alice', 'created' => '2017-09-23T20:21:34Z', } end let(:signature) { raw_signature.merge('type' => 'RsaSignature2017', 'signatureValue' => sign(sender, raw_signature, raw_json)) } it 'returns creator' do expect(subject.verify_actor!).to eq sender end end context 'when local account record is missing a public key' do let(:raw_signature) do { 'creator' => 'http://example.com/alice', 'created' => '2017-09-23T20:21:34Z', } end let(:signature) { raw_signature.merge('type' => 'RsaSignature2017', 'signatureValue' => sign(sender, raw_signature, raw_json)) } let(:service_stub) { instance_double(ActivityPub::FetchRemoteKeyService) } before do # Ensure signature is computed with the old key signature # Unset key old_key = sender.public_key sender.update!(private_key: '', public_key: '') allow(ActivityPub::FetchRemoteKeyService).to receive(:new).and_return(service_stub) allow(service_stub).to receive(:call).with('http://example.com/alice') do sender.update!(public_key: old_key) sender end end it 'fetches key and returns creator' do expect(subject.verify_actor!).to eq sender expect(service_stub).to have_received(:call).with('http://example.com/alice').once end end context 'when signature is missing' do let(:signature) { nil } it 'returns nil' do expect(subject.verify_actor!).to be_nil end end context 'when signature is tampered' do let(:raw_signature) do { 'creator' => 'http://example.com/alice', 'created' => '2017-09-23T20:21:34Z', } end let(:signature) { raw_signature.merge('type' => 'RsaSignature2017', 'signatureValue' => 's69F3mfddd99dGjmvjdjjs81e12jn121Gkm1') } it 'returns nil' do expect(subject.verify_actor!).to be_nil end end end describe '#sign!' do subject { described_class.new(raw_json).sign!(sender) } it 'returns a hash' do expect(subject).to be_a Hash end it 'contains signature' do expect(subject['signature']).to be_a Hash expect(subject['signature']['signatureValue']).to be_present end it 'can be verified again' do expect(described_class.new(subject).verify_actor!).to eq sender end end def sign(from_actor, options, document) options_hash = Digest::SHA256.hexdigest(canonicalize(options.merge('@context' => ActivityPub::LinkedDataSignature::CONTEXT))) document_hash = Digest::SHA256.hexdigest(canonicalize(document)) to_be_verified = options_hash + document_hash Base64.strict_encode64(from_actor.keypair.sign(OpenSSL::Digest.new('SHA256'), to_be_verified)) end end