From 13688539bc7bfb3ffef86b3fd41b37671861c17f Mon Sep 17 00:00:00 2001 From: Claire Date: Fri, 20 Oct 2023 10:45:46 +0200 Subject: [PATCH] Fix processing LDSigned activities from actors with unknown public keys (#27474) --- app/lib/activitypub/linked_data_signature.rb | 6 ++-- .../activitypub/linked_data_signature_spec.rb | 34 +++++++++++++++++++ 2 files changed, 38 insertions(+), 2 deletions(-) diff --git a/app/lib/activitypub/linked_data_signature.rb b/app/lib/activitypub/linked_data_signature.rb index ea59879f3..faea63e8f 100644 --- a/app/lib/activitypub/linked_data_signature.rb +++ b/app/lib/activitypub/linked_data_signature.rb @@ -18,8 +18,8 @@ class ActivityPub::LinkedDataSignature return unless type == 'RsaSignature2017' - creator = ActivityPub::TagManager.instance.uri_to_actor(creator_uri) - creator ||= ActivityPub::FetchRemoteKeyService.new.call(creator_uri, id: false) + creator = ActivityPub::TagManager.instance.uri_to_actor(creator_uri) + creator = ActivityPub::FetchRemoteKeyService.new.call(creator_uri, id: false) if creator&.public_key.blank? return if creator.nil? @@ -28,6 +28,8 @@ class ActivityPub::LinkedDataSignature to_be_verified = options_hash + document_hash creator if creator.keypair.public_key.verify(OpenSSL::Digest.new('SHA256'), Base64.decode64(signature), to_be_verified) + rescue OpenSSL::PKey::RSAError + false end def sign!(creator, sign_with: nil) diff --git a/spec/lib/activitypub/linked_data_signature_spec.rb b/spec/lib/activitypub/linked_data_signature_spec.rb index d5b713b34..97268eea6 100644 --- a/spec/lib/activitypub/linked_data_signature_spec.rb +++ b/spec/lib/activitypub/linked_data_signature_spec.rb @@ -34,6 +34,40 @@ RSpec.describe ActivityPub::LinkedDataSignature do 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', id: false) 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', id: false).once + end + end + context 'when signature is missing' do let(:signature) { nil }