feat(deobf): add classname parsing for Kotlin metadata (PR #842, #758)

jadx-cli/src/main/java/jadx/cli/JadxCLIArgs.java

@@ -85,6 +85,9 @@ public class JadxCLIArgs {
 	@Parameter(names = { "--deobf-use-sourcename" }, description = "use source file name as class name alias")
 	protected boolean deobfuscationUseSourceNameAsAlias = false;
 
+	@Parameter(names = { "--deobf-parse-kotlin-metadata" }, description = "parse kotlin metadata to class and package names")
+	protected boolean deobfuscationParseKotlinMetadata = false;
+
 	@Parameter(
 			names = { "--rename-flags" },
 			description = "what to rename, comma-separated,"
@@ -194,6 +197,7 @@ public JadxArgs toJadxArgs() {
 		args.setDeobfuscationMinLength(deobfuscationMinLength);
 		args.setDeobfuscationMaxLength(deobfuscationMaxLength);
 		args.setUseSourceNameAsClassAlias(deobfuscationUseSourceNameAsAlias);
+		args.setParseKotlinMetadata(deobfuscationParseKotlinMetadata);
 		args.setEscapeUnicode(escapeUnicode);
 		args.setRespectBytecodeAccModifiers(respectBytecodeAccessModifiers);
 		args.setExportAsGradleProject(exportAsGradleProject);
@@ -275,6 +279,10 @@ public boolean isDeobfuscationUseSourceNameAsAlias() {
 		return deobfuscationUseSourceNameAsAlias;
 	}
 
+	public boolean isDeobfuscationParseKotlinMetadata() {
+		return deobfuscationParseKotlinMetadata;
+	}
+
 	public boolean isEscapeUnicode() {
 		return escapeUnicode;
 	}

jadx-core/src/main/java/jadx/api/JadxArgs.java

@@ -49,6 +49,7 @@ public class JadxArgs {
 	private boolean deobfuscationOn = false;
 	private boolean deobfuscationForceSave = false;
 	private boolean useSourceNameAsClassAlias = false;
+	private boolean parseKotlinMetadata = false;
 
 	private int deobfuscationMinLength = 0;
 	private int deobfuscationMaxLength = Integer.MAX_VALUE;
@@ -230,6 +231,14 @@ public void setUseSourceNameAsClassAlias(boolean useSourceNameAsClassAlias) {
 		this.useSourceNameAsClassAlias = useSourceNameAsClassAlias;
 	}
 
+	public boolean isParseKotlinMetadata() {
+		return parseKotlinMetadata;
+	}
+
+	public void setParseKotlinMetadata(boolean parseKotlinMetadata) {
+		this.parseKotlinMetadata = parseKotlinMetadata;
+	}
+
 	public int getDeobfuscationMinLength() {
 		return deobfuscationMinLength;
 	}
@@ -355,6 +364,7 @@ public String toString() {
 				+ ", deobfuscationOn=" + deobfuscationOn
 				+ ", deobfuscationForceSave=" + deobfuscationForceSave
 				+ ", useSourceNameAsClassAlias=" + useSourceNameAsClassAlias
+				+ ", parseKotlinMetadata=" + parseKotlinMetadata
 				+ ", deobfuscationMinLength=" + deobfuscationMinLength
 				+ ", deobfuscationMaxLength=" + deobfuscationMaxLength
 				+ ", escapeUnicode=" + escapeUnicode

jadx-core/src/main/java/jadx/core/deobf/Deobfuscator.java

@@ -37,6 +37,9 @@ public class Deobfuscator {
 
 	public static final String CLASS_NAME_SEPARATOR = ".";
 	public static final String INNER_CLASS_SEPARATOR = "$";
+	public static final String KOTLIN_METADATA_ANNOTATION = "kotlin.Metadata";
+	public static final String KOTLIN_METADATA_D2_PARAMETER = "d2";
+	public static final String KOTLIN_METADATA_CLASSNAME_REGEX = "(L.*;)";
 
 	private final JadxArgs args;
 	@NotNull
@@ -57,6 +60,7 @@ public class Deobfuscator {
 	private final int maxLength;
 	private final int minLength;
 	private final boolean useSourceNameAsAlias;
+	private final boolean parseKotlinMetadata;
 
 	private int pkgIndex = 0;
 	private int clsIndex = 0;
@@ -70,6 +74,7 @@ public Deobfuscator(JadxArgs args, @NotNull List<DexNode> dexNodes, Path deobfMa
 		this.minLength = args.getDeobfuscationMinLength();
 		this.maxLength = args.getDeobfuscationMaxLength();
 		this.useSourceNameAsAlias = args.isUseSourceNameAsClassAlias();
+		this.parseKotlinMetadata = args.isParseKotlinMetadata();
 
 		this.deobfPresets = new DeobfPresets(this, deobfMapFile);
 	}
@@ -392,21 +397,59 @@ public String getPkgAlias(ClassNode cls) {
 
 	private String makeClsAlias(ClassNode cls) {
 		ClassInfo classInfo = cls.getClassInfo();
+
+		String metadataClassName = "";
+		String metadataPackageName = "";
+		if (this.parseKotlinMetadata) {
+			String rawClassName = getRawClassNameFromMetadata(cls);
+			if (rawClassName != null) {
+				metadataClassName = rawClassName.substring(rawClassName.lastIndexOf(".") + 1, rawClassName.length() - 1);
+				if (rawClassName.lastIndexOf(".") != -1) {
+					metadataPackageName = rawClassName.substring(1, rawClassName.lastIndexOf("."));
+				}
+			}
+		}
 		String alias = null;
 
 		if (this.useSourceNameAsAlias) {
 			alias = getAliasFromSourceFile(cls);
 		}
 
 		if (alias == null) {
-			String clsName = classInfo.getShortName();
-			alias = String.format("C%04d%s", clsIndex++, prepareNamePart(clsName));
+			if (metadataClassName.isEmpty()) {
+				String clsName = classInfo.getShortName();
+				alias = String.format("C%04d%s", clsIndex++, prepareNamePart(clsName));
+			} else {
+				alias = metadataClassName;
+			}
+		}
+		PackageNode pkg;
+		if (metadataPackageName.isEmpty()) {
+			pkg = getPackageNode(classInfo.getPackage(), true);
+		} else {
+			pkg = getPackageNode(metadataPackageName, true);
 		}
-		PackageNode pkg = getPackageNode(classInfo.getPackage(), true);
 		clsMap.put(classInfo, new DeobfClsInfo(this, cls, pkg, alias));
 		return alias;
 	}
 
+	@Nullable
+	private String getRawClassNameFromMetadata(ClassNode cls) {
+		if (cls.getAnnotation(KOTLIN_METADATA_ANNOTATION) != null
+				&& cls.getAnnotation(KOTLIN_METADATA_ANNOTATION).getValues().get(KOTLIN_METADATA_D2_PARAMETER) != null
+				&& cls.getAnnotation(KOTLIN_METADATA_ANNOTATION).getValues().get(KOTLIN_METADATA_D2_PARAMETER) instanceof List) {
+			Object rawClassNameObject =
+					((List) cls.getAnnotation(KOTLIN_METADATA_ANNOTATION).getValues().get(KOTLIN_METADATA_D2_PARAMETER)).get(0);
+			if (rawClassNameObject instanceof String) {
+				String rawClassName = ((String) rawClassNameObject).trim().replace("/", ".");
+				if (rawClassName.length() > 1 && rawClassName.matches(KOTLIN_METADATA_CLASSNAME_REGEX)) {
+					return rawClassName;
+				}
+			}
+		}
+		return null;
+	}
+
 	@Nullable
 	private String getAliasFromSourceFile(ClassNode cls) {
 		SourceFileAttr sourceFileAttr = cls.get(AType.SOURCE_FILE);

jadx-gui/src/main/java/jadx/gui/settings/JadxSettings.java

@@ -279,6 +279,10 @@ public void setDeobfuscationUseSourceNameAsAlias(boolean deobfuscationUseSourceN
 		this.deobfuscationUseSourceNameAsAlias = deobfuscationUseSourceNameAsAlias;
 	}
 
+	public void setDeobfuscationParseKotlinMetadata(boolean deobfuscationParseKotlinMetadata) {
+		this.deobfuscationParseKotlinMetadata = deobfuscationParseKotlinMetadata;
+	}
+
 	public void updateRenameFlag(JadxArgs.RenameEnum flag, boolean enabled) {
 		if (enabled) {
 			renameFlags.add(flag);
@@ -387,6 +391,7 @@ private void upgradeSettings(int fromVersion) {
 		if (fromVersion == 0) {
 			setDeobfuscationMinLength(3);
 			setDeobfuscationUseSourceNameAsAlias(true);
+			setDeobfuscationParseKotlinMetadata(true);
 			setDeobfuscationForceSave(true);
 			setThreadsCount(1);
 			setReplaceConsts(true);

jadx-gui/src/main/java/jadx/gui/settings/JadxSettingsWindow.java

@@ -167,15 +167,24 @@ private SettingsGroup makeDeobfuscationGroup() {
 			needReload();
 		});
 
+		JCheckBox deobfKotlinMetadata = new JCheckBox();
+		deobfKotlinMetadata.setSelected(settings.isDeobfuscationParseKotlinMetadata());
+		deobfKotlinMetadata.addItemListener(e -> {
+			settings.setDeobfuscationParseKotlinMetadata(e.getStateChange() == ItemEvent.SELECTED);
+			needReload();
+		});
+
 		SettingsGroup deobfGroup = new SettingsGroup(NLS.str("preferences.deobfuscation"));
 		deobfGroup.addRow(NLS.str("preferences.deobfuscation_on"), deobfOn);
 		deobfGroup.addRow(NLS.str("preferences.deobfuscation_force"), deobfForce);
 		deobfGroup.addRow(NLS.str("preferences.deobfuscation_min_len"), minLenSpinner);
 		deobfGroup.addRow(NLS.str("preferences.deobfuscation_max_len"), maxLenSpinner);
 		deobfGroup.addRow(NLS.str("preferences.deobfuscation_source_alias"), deobfSourceAlias);
+		deobfGroup.addRow(NLS.str("preferences.deobfuscation_kotlin_metadata"), deobfKotlinMetadata);
 		deobfGroup.end();
 
-		Collection<JComponent> connectedComponents = Arrays.asList(deobfForce, minLenSpinner, maxLenSpinner, deobfSourceAlias);
+		Collection<JComponent> connectedComponents =
+				Arrays.asList(deobfForce, minLenSpinner, maxLenSpinner, deobfSourceAlias, deobfKotlinMetadata);
 		deobfOn.addItemListener(e -> enableComponentList(connectedComponents, e.getStateChange() == ItemEvent.SELECTED));
 		enableComponentList(connectedComponents, settings.isDeobfuscationOn());
 		return deobfGroup;

jadx-gui/src/main/resources/i18n/Messages_de_DE.properties

@@ -118,6 +118,7 @@ preferences.deobfuscation_force=Deobfuscationskartendatei umschreiben erzwingen
 preferences.deobfuscation_min_len=Minimale Namenlänge
 preferences.deobfuscation_max_len=Maximale Namenlänge
 preferences.deobfuscation_source_alias=Quelldateiname als Klassennamen-Alias verwenden
+preferences.deobfuscation_kotlin_metadata=Analysieren Sie Kotlin-Metadaten nach Klassen- und Paketnamen
 preferences.save=Speichern
 preferences.cancel=Abbrechen
 preferences.reset=Zurücksetzen

jadx-gui/src/main/resources/i18n/Messages_en_US.properties

@@ -118,6 +118,7 @@ preferences.deobfuscation_force=Force rewrite deobfuscation map file
 preferences.deobfuscation_min_len=Minimum name length
 preferences.deobfuscation_max_len=Maximum name length
 preferences.deobfuscation_source_alias=Use source file name as class name alias
+preferences.deobfuscation_kotlin_metadata=Parse Kotlin metadata for class and package names
 preferences.save=Save
 preferences.cancel=Cancel
 preferences.reset=Reset

jadx-gui/src/main/resources/i18n/Messages_es_ES.properties

@@ -118,6 +118,7 @@ preferences.deobfuscation_force=Forzar reescritura del fichero de ofuscación
 preferences.deobfuscation_min_len=Longitud mínima del nombre
 preferences.deobfuscation_max_len=Longitud máxima del nombre
 preferences.deobfuscation_source_alias=Usar el nombre del source como alias para la clase
+preferences.deobfuscation_kotlin_metadata=Parse Kotlin metadatos para nombres de clase y paquete
 preferences.save=Guardar
 preferences.cancel=Cancelar
 preferences.reset=Reestablecer

jadx-gui/src/main/resources/i18n/Messages_zh_CN.properties

@@ -118,6 +118,7 @@ preferences.deobfuscation_force=强制覆盖反混淆映射文件
 preferences.deobfuscation_min_len=最小命名长度
 preferences.deobfuscation_max_len=最大命名长度
 preferences.deobfuscation_source_alias=使用资源名作为类的别名
+preferences.deobfuscation_kotlin_metadata=解析Kotlin元数据以获得类和包名
 preferences.save=保存
 preferences.cancel=取消
 preferences.reset=重置