1 files changed, 145 insertions, 0 deletions
diff --git a/spec/lib/gitlab/encrypted_configuration_spec.rb b/spec/lib/gitlab/encrypted_configuration_spec.rb
new file mode 100644
index 00000000000..eadc2cf71a7
--- /dev/null
+++ b/spec/lib/gitlab/encrypted_configuration_spec.rb
@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Gitlab::EncryptedConfiguration do
+  subject(:configuration) { described_class.new }
+
+  let!(:config_tmp_dir) { Dir.mktmpdir('config-') }
+
+  after do
+    FileUtils.rm_f(config_tmp_dir)
+  end
+
+  describe '#initialize' do
+    it 'accepts all args as optional fields' do
+      expect { configuration }.not_to raise_exception
+
+      expect(configuration.key).to be_nil
+      expect(configuration.previous_keys).to be_empty
+    end
+
+    it 'generates 32 byte key when provided a larger base key' do
+      configuration = described_class.new(base_key: 'A' * 64)
+
+      expect(configuration.key.bytesize).to eq 32
+    end
+
+    it 'generates 32 byte key when provided a smaller base key' do
+      configuration = described_class.new(base_key: 'A' * 16)
+
+      expect(configuration.key.bytesize).to eq 32
+    end
+
+    it 'throws an error when the base key is too small' do
+      expect { described_class.new(base_key: 'A' * 12) }.to raise_error 'Base key too small'
+    end
+  end
+
+  context 'when provided a config file but no key' do
+    let(:config_path) { File.join(config_tmp_dir, 'credentials.yml.enc') }
+
+    it 'throws an error when writing without a key' do
+      expect { described_class.new(content_path: config_path).write('test') }.to raise_error Gitlab::EncryptedConfiguration::MissingKeyError
+    end
+
+    it 'throws an error when reading without a key' do
+      config = described_class.new(content_path: config_path)
+      File.write(config_path, 'test')
+      expect { config.read }.to raise_error Gitlab::EncryptedConfiguration::MissingKeyError
+    end
+  end
+
+  context 'when provided key and config file' do
+    let(:credentials_config_path) { File.join(config_tmp_dir, 'credentials.yml.enc') }
+    let(:credentials_key) { SecureRandom.hex(64) }
+
+    describe '#write' do
+      it 'encrypts the file using the provided key' do
+        encryptor = ActiveSupport::MessageEncryptor.new(Gitlab::EncryptedConfiguration.generate_key(credentials_key), cipher: 'aes-256-gcm')
+        config = described_class.new(content_path: credentials_config_path, base_key: credentials_key)
+
+        config.write('sample-content')
+        expect(encryptor.decrypt_and_verify(File.read(credentials_config_path))).to eq('sample-content')
+      end
+    end
+
+    describe '#read' do
+      it 'reads yaml configuration' do
+        config = described_class.new(content_path: credentials_config_path, base_key: credentials_key)
+
+        config.write({ foo: { bar: true } }.to_yaml)
+        expect(config[:foo][:bar]).to be true
+      end
+
+      it 'allows referencing top level keys via dot syntax' do
+        config = described_class.new(content_path: credentials_config_path, base_key: credentials_key)
+
+        config.write({ foo: { bar: true } }.to_yaml)
+        expect(config.foo[:bar]).to be true
+      end
+
+      it 'throws a custom error when referencing an invalid key map config' do
+        config = described_class.new(content_path: credentials_config_path, base_key: credentials_key)
+
+        config.write("stringcontent")
+        expect { config[:foo] }.to raise_error Gitlab::EncryptedConfiguration::InvalidConfigError
+      end
+    end
+
+    describe '#change' do
+      it 'changes yaml configuration' do
+        config = described_class.new(content_path: credentials_config_path, base_key: credentials_key)
+
+        config.write({ foo: { bar: true } }.to_yaml)
+        config.change do |unencrypted_contents|
+          contents = YAML.safe_load(unencrypted_contents, permitted_classes: [Symbol])
+          contents.merge(beef: "stew").to_yaml
+        end
+        expect(config.foo[:bar]).to be true
+        expect(config.beef).to eq('stew')
+      end
+    end
+
+    context 'when provided previous_keys for rotation' do
+      let(:credential_key_original) { SecureRandom.hex(64) }
+      let(:credential_key_latest) { SecureRandom.hex(64) }
+      let(:config_path_original) { File.join(config_tmp_dir, 'credentials-orig.yml.enc') }
+      let(:config_path_latest) { File.join(config_tmp_dir, 'credentials-latest.yml.enc') }
+
+      def encryptor(key)
+        ActiveSupport::MessageEncryptor.new(Gitlab::EncryptedConfiguration.generate_key(key), cipher: 'aes-256-gcm')
+      end
+
+      describe '#write' do
+        it 'rotates the key when provided a new key' do
+          config1 = described_class.new(content_path: config_path_original, base_key: credential_key_original)
+          config1.write('sample-content1')
+
+          config2 = described_class.new(content_path: config_path_latest, base_key: credential_key_latest, previous_keys: [credential_key_original])
+          config2.write('sample-content2')
+
+          original_key_encryptor = encryptor(credential_key_original) # can read with the initial key
+          latest_key_encryptor = encryptor(credential_key_latest) # can read with the new key
+          both_key_encryptor = encryptor(credential_key_latest) # can read with either key
+          both_key_encryptor.rotate(Gitlab::EncryptedConfiguration.generate_key(credential_key_original))
+
+          expect(original_key_encryptor.decrypt_and_verify(File.read(config_path_original))).to eq('sample-content1')
+          expect(both_key_encryptor.decrypt_and_verify(File.read(config_path_original))).to eq('sample-content1')
+          expect(latest_key_encryptor.decrypt_and_verify(File.read(config_path_latest))).to eq('sample-content2')
+          expect(both_key_encryptor.decrypt_and_verify(File.read(config_path_latest))).to eq('sample-content2')
+          expect { original_key_encryptor.decrypt_and_verify(File.read(config_path_latest)) }.to raise_error(ActiveSupport::MessageEncryptor::InvalidMessage)
+        end
+      end
+
+      describe '#read' do
+        it 'supports reading using rotated config' do
+          described_class.new(content_path: config_path_original, base_key: credential_key_original).write({ foo: { bar: true } }.to_yaml)
+
+          config = described_class.new(content_path: config_path_original, base_key: credential_key_latest,  previous_keys: [credential_key_original])
+          expect(config[:foo][:bar]).to be true
+        end
+      end
+    end
+  end
+end