Merge pull request #2161 from cryptomator/feature/check-vaultconfig-sig-during-key-recovery

Prevent key recovery for foreign vault

src/main/java/org/cryptomator/ui/recoverykey/RecoveryKeyFactory.java

@@ -7,6 +7,7 @@ import org.cryptomator.cryptolib.api.CryptoException;
 import org.cryptomator.cryptolib.api.InvalidPassphraseException;
 import org.cryptomator.cryptolib.api.Masterkey;
 import org.cryptomator.cryptolib.common.MasterkeyFileAccess;
+import org.jetbrains.annotations.Nullable;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -16,6 +17,7 @@ import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.function.Predicate;
 
 import static org.cryptomator.common.Constants.MASTERKEY_BACKUP_SUFFIX;
 import static org.cryptomator.common.Constants.MASTERKEY_FILENAME;
@@ -102,12 +104,29 @@ public class RecoveryKeyFactory {
 	 * @return <code>true</code> if this seems to be a legitimate recovery key
 	 */
 	public boolean validateRecoveryKey(String recoveryKey) {
+		return validateRecoveryKey(recoveryKey, null);
+	}
+
+	/**
+	 * Checks whether a String is a syntactically correct recovery key with a valid checksum and passes the extended validation.
+	 *
+	 * @param recoveryKey A word sequence which might be a recovery key
+	 * @param extendedValidation Additional verification of the decoded key (optional)
+	 * @return <code>true</code> if this seems to be a legitimate recovery key and passes the extended validation
+	 */
+	public boolean validateRecoveryKey(String recoveryKey, @Nullable Predicate<byte[]> extendedValidation) {
+		byte[] key = new byte[0];
 		try {
-			byte[] key = decodeRecoveryKey(recoveryKey);
-			Arrays.fill(key, (byte) 0x00);
-			return true;
+			key = decodeRecoveryKey(recoveryKey);
+			if (extendedValidation != null) {
+				return extendedValidation.test(key);
+			} else {
+				return true;
+			}
 		} catch (IllegalArgumentException e) {
 			return false;
+		} finally {
+			Arrays.fill(key, (byte) 0x00);
 		}
 	}
 

src/main/java/org/cryptomator/ui/recoverykey/RecoveryKeyModule.java

@@ -4,7 +4,9 @@ import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 import dagger.multibindings.IntoMap;
+import org.cryptomator.common.Nullable;
 import org.cryptomator.common.vaults.Vault;
+import org.cryptomator.cryptofs.VaultConfig;
 import org.cryptomator.ui.common.DefaultSceneFactory;
 import org.cryptomator.ui.common.FxController;
 import org.cryptomator.ui.common.FxControllerKey;
@@ -22,12 +24,25 @@ import javafx.beans.property.StringProperty;
 import javafx.scene.Scene;
 import javafx.stage.Modality;
 import javafx.stage.Stage;
+import java.io.IOException;
 import java.util.Map;
 import java.util.ResourceBundle;
 
 @Module
 abstract class RecoveryKeyModule {
 
+	@Provides
+	@Nullable
+	@RecoveryKeyWindow
+	@RecoveryKeyScoped
+	static VaultConfig.UnverifiedVaultConfig vaultConfig(@RecoveryKeyWindow Vault vault) {
+		try {
+			return vault.getVaultConfigCache().get();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
 	@Provides
 	@RecoveryKeyWindow
 	@RecoveryKeyScoped

src/main/java/org/cryptomator/ui/recoverykey/RecoveryKeyRecoverController.java

@@ -3,10 +3,16 @@ package org.cryptomator.ui.recoverykey;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Strings;
 import dagger.Lazy;
+import org.cryptomator.common.Nullable;
 import org.cryptomator.common.vaults.Vault;
+import org.cryptomator.cryptofs.VaultConfig;
+import org.cryptomator.cryptofs.VaultConfigLoadException;
+import org.cryptomator.cryptofs.VaultKeyInvalidException;
 import org.cryptomator.ui.common.FxController;
 import org.cryptomator.ui.common.FxmlFile;
 import org.cryptomator.ui.common.FxmlScene;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import javax.inject.Inject;
 import javafx.beans.binding.Bindings;
@@ -24,10 +30,12 @@ import java.util.Optional;
 @RecoveryKeyScoped
 public class RecoveryKeyRecoverController implements FxController {
 
-	private final static CharMatcher ALLOWED_CHARS = CharMatcher.inRange('a', 'z').or(CharMatcher.is(' '));
+	private static final Logger LOG = LoggerFactory.getLogger(RecoveryKeyCreationController.class);
+	private static final CharMatcher ALLOWED_CHARS = CharMatcher.inRange('a', 'z').or(CharMatcher.is(' '));
 
 	private final Stage window;
 	private final Vault vault;
+	private final VaultConfig.UnverifiedVaultConfig unverifiedVaultConfig;
 	private final StringProperty recoveryKey;
 	private final RecoveryKeyFactory recoveryKeyFactory;
 	private final BooleanBinding validRecoveryKey;
@@ -37,9 +45,10 @@ public class RecoveryKeyRecoverController implements FxController {
 	public TextArea textarea;
 
 	@Inject
-	public RecoveryKeyRecoverController(@RecoveryKeyWindow Stage window, @RecoveryKeyWindow Vault vault, @RecoveryKeyWindow StringProperty recoveryKey, RecoveryKeyFactory recoveryKeyFactory, @FxmlScene(FxmlFile.RECOVERYKEY_RESET_PASSWORD) Lazy<Scene> resetPasswordScene) {
+	public RecoveryKeyRecoverController(@RecoveryKeyWindow Stage window, @RecoveryKeyWindow Vault vault, @RecoveryKeyWindow @Nullable VaultConfig.UnverifiedVaultConfig unverifiedVaultConfig, @RecoveryKeyWindow StringProperty recoveryKey, RecoveryKeyFactory recoveryKeyFactory, @FxmlScene(FxmlFile.RECOVERYKEY_RESET_PASSWORD) Lazy<Scene> resetPasswordScene) {
 		this.window = window;
 		this.vault = vault;
+		this.unverifiedVaultConfig = unverifiedVaultConfig;
 		this.recoveryKey = recoveryKey;
 		this.recoveryKeyFactory = recoveryKeyFactory;
 		this.validRecoveryKey = Bindings.createBooleanBinding(this::isValidRecoveryKey, recoveryKey);
@@ -96,6 +105,20 @@ public class RecoveryKeyRecoverController implements FxController {
 		window.setScene(resetPasswordScene.get());
 	}
 
+	private boolean checkKeyAgainstVaultConfig(byte[] key) {
+		try {
+			var config = unverifiedVaultConfig.verify(key, unverifiedVaultConfig.allegedVaultVersion());
+			LOG.info("Provided recovery key matches vault config signature for vault {}", config.getId());
+			return true;
+		} catch (VaultKeyInvalidException e) {
+			LOG.debug("Provided recovery key does not match vault config signature.");
+			return false;
+		} catch (VaultConfigLoadException e) {
+			LOG.error("Failed to parse vault config", e);
+			return false;
+		}
+	}
+
 	/* Getter/Setter */
 
 	public Vault getVault() {
@@ -107,7 +130,11 @@ public class RecoveryKeyRecoverController implements FxController {
 	}
 
 	public boolean isValidRecoveryKey() {
-		return recoveryKeyFactory.validateRecoveryKey(recoveryKey.get());
+		if (unverifiedVaultConfig != null) {
+			return recoveryKeyFactory.validateRecoveryKey(recoveryKey.get(), this::checkKeyAgainstVaultConfig);
+		} else {
+			return recoveryKeyFactory.validateRecoveryKey(recoveryKey.get());
+		}
 	}
 
 	public TextFormatter getRecoveryKeyTextFormatter() {

src/test/java/org/cryptomator/ui/recoverykey/RecoveryKeyFactoryTest.java

@@ -7,10 +7,13 @@ import org.cryptomator.cryptolib.common.MasterkeyFileAccess;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.mockito.Mockito;
 
 import java.io.IOException;
 import java.nio.file.Path;
+import java.util.function.Predicate;
 
 public class RecoveryKeyFactoryTest {
 
@@ -75,4 +78,19 @@ public class RecoveryKeyFactoryTest {
 		Assertions.assertTrue(result);
 	}
 
+	@ParameterizedTest(name = "passing validation = {0}")
+	@DisplayName("validateRecoveryKey() with extended validation")
+	@ValueSource(booleans = {true, false})
+	public void testValidateValidateRecoveryKeyWithValidKey(boolean extendedValidationResult) {
+		Predicate<byte[]> validator = Mockito.mock(Predicate.class);
+		Mockito.doReturn(extendedValidationResult).when(validator).test(Mockito.any());
+		boolean result = inTest.validateRecoveryKey("""
+				pathway lift abuse plenty export texture gentleman landscape beyond ceiling around leaf cafe charity \
+				border breakdown victory surely computer cat linger restrict infer crowd live computer true written amazed \
+				investor boot depth left theory snow whereby terminal weekly reject happiness circuit partial cup ad \
+				""", validator);
+		Mockito.verify(validator).test(Mockito.any());
+		Assertions.assertEquals(extendedValidationResult, result);
+	}
+
 }