近两年来工信部对于应用的隐私合规安全问题愈加重视，对 Android 平台的管控程度也要比 IOS 平台严格很多，很多不合规的应用也先后被下架要求整改。笔者就曾遇到过加班整改隐私合规的问题，隐私合规问题主要针对两个方面。
IMEI、AndroidId、MAC 等针对上述两个方面，有以下措施来针对
通过定义注解和工具类，用来定义要处理哪些隐私合规相关的方法，目前笔者已经处理了大部分，请放心食用
/**
* 收集和注解匹配的方法
* visitMethodInsn(int opcode, String owner, String name,String desc)
*
* ======如果 originName 和 originDesc 传""，逻辑会在插件中处理=====
*/
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.METHOD})
public @interface AsmMethodReplace {
/**
* 指令操作码
*/
int targetMethodOpcode();
/**
* 方法所有者类
*/
String targetClass();
/**
* 方法名称
*/
String targetName() default "";
/**
* 方法描述符
*/
String targetDesc() default "";
/**
* 是否进行 hook
*/
boolean hook() default false;
}该注解用来匹配调用隐私合规 api 的字节码指令，例如通过 ASM 调用 getImei 的字节码指令为methodVisitor.visitMethodInsn(INVOKEVIRTUAL, "android/telephony/TelephonyManager", "getImei", "()Ljava/lang/String;", false);。targetName属性和 targetDesc 可以不赋值，这里做了取巧的处理，会根据工具类的 method name 和method descriptor 推断出调用隐私合规方法的字节码指令，这块后面插件会处理。最后的 hook 属性表示是否 hook 掉原始的调用链，将调用指向工具类中的方法。
上述注解可以用在任何地方，笔者将常用的隐私合规的方法聚合起来，方法工具类中统一处理，例如处理 IMEI 的逻辑如下：
@RequiresApi(api = Build.VERSION_CODES.O)
@AsmMethodReplace(targetMethodOpcode = OPCODE_INVOKEVIRTUAL
, targetClass = CLASS_NAME_TELEPHONYMANAGER,hook = true)
public static String getImei(TelephonyManager telephonyManager) {
if (!checkAgreePrivacy("getImei")) {
Log.e(TAG, TIP);
return "";
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
Log.i(TAG, "getImei-SDK_INT above android Q");
return "";
}
return telephonyManager.getImei();
}如果还没有同意隐私协议，直接 return “”，否者走正常的调用方法。同时，通过工具类
@Override
protected void attachBaseContext(Context base) {
super.attachBaseContext(base);
ConfigGlobal.getInstance().setStoreDirectory(base.getExternalCacheDir().getAbsolutePath());
}设置存储调用堆栈和时间的文件路径。
gradle 插件的基本使用在这里就不赘述了，这里主要是两方面的处理
下面这块代码是我们在自定义 gradle 插件时常用的模版代码，供大家使用
package com.zhangyue.ireader
import com.android.build.api.transform.*
import com.android.build.gradle.internal.pipeline.TransformManager
import com.zhangyue.ireader.plugin_privacy.PrivacyGlobalConfig
import com.zhangyue.ireader.util.CommonUtil
import com.zhangyue.ireader.util.Logger
import org.apache.commons.io.FileUtils
import org.apache.commons.io.IOUtils
import org.gradle.api.Project
import java.util.concurrent.AbstractExecutorService
import java.util.concurrent.Callable
import java.util.concurrent.ForkJoinPool
import java.util.jar.JarEntry
import java.util.jar.JarFile
import java.util.jar.JarOutputStream
abstract class BaseTransform extends Transform {
AbstractExecutorService executorService = ForkJoinPool.commonPool()
private List<Callable<Void>> taskList = new ArrayList<>()
protected Project project
BaseTransform(Project project) {
this.project = project
}
@Override
String getName() {
return getClass().simpleName
}
@Override
Set<QualifiedContent.ContentType> getInputTypes() {
return TransformManager.CONTENT_CLASS
}
@Override
Set<? super QualifiedContent.Scope> getScopes() {
return TransformManager.SCOPE_FULL_PROJECT
}
@Override
boolean isIncremental() {
return true
}
@Override
void transform(TransformInvocation transformInvocation) throws TransformException, InterruptedException, IOException {
super.transform(transformInvocation)
println("transform start--------------->")
if (firstTransform()) {
printCopyRight()
}
onTransformStart(transformInvocation)
def startTime = System.currentTimeMillis()
def inputs = transformInvocation.inputs
def outputProvider = transformInvocation.outputProvider
def context = transformInvocation.context
def isIncremental = transformInvocation.isIncremental()
if (!isIncremental) {
outputProvider.deleteAll()
}
//1
// inputs.each { input ->
// input.jarInputs.each { JarInput jarInput ->
// forEachJar(jarInput, outputProvider, context, isIncremental)
// }
//
// input.directoryInputs.each { DirectoryInput dirInput ->
// forEachDir(dirInput, outputProvider, context, isIncremental)
// }
// }
//3
inputs.each { input ->
input.jarInputs.each { jarInput ->
submitTask(new Runnable() {
@Override
void run() {
forEachJar(jarInput, outputProvider, context, isIncremental)
}
})
}
input.directoryInputs.each { DirectoryInput dirInput ->
submitTask(new Runnable() {
@Override
void run() {
forEachDir(dirInput, outputProvider, context, isIncremental)
}
})
}
}
def futures = executorService.invokeAll(taskList)
futures.each { it ->
it.get()
}
onTransformEnd(transformInvocation)
println(getName() + "transform end--------------->" + "duration : " + (System.currentTimeMillis() - startTime) + " ms")
}
void submitTask(Runnable runnable) {
taskList.add(new Callable<Void>() {
@Override
Void call() throws Exception {
runnable.run()
return null
}
})
}
void forEachDir(DirectoryInput directoryInput, TransformOutputProvider outputProvider, Context context, boolean isIncremental) {
def inputDir = directoryInput.file
File dest = outputProvider.getContentLocation(
directoryInput.name,
directoryInput.contentTypes,
directoryInput.scopes,
Format.DIRECTORY
)
println "directoryInputPath:" + directoryInput.file.absolutePath
println "destPath:" + dest.absolutePath
def srcDirPath = inputDir.absolutePath
def destDirPath = dest.absolutePath
def temporaryDir = context.temporaryDir
FileUtils.forceMkdir(dest)
Logger.info("srcDirPath:${srcDirPath}, destDirPath:${destDirPath}")
if (isIncremental) {
directoryInput.getChangedFiles().each { entry ->
def classFile = entry.key
switch (entry.value) {
case Status.NOTCHANGED:
Logger.info("处理 class： " + classFile.absoluteFile + " NOTCHANGED")
break
case Status.REMOVED:
Logger.info("处理 class： " + classFile.absoluteFile + " REMOVED")
//最终文件应该存放的路径
def destFilePath = classFile.absolutePath.replace(srcDirPath, destDirPath)
def destFile = File(destFilePath)
if (destFile.exists()) {
destFile.delete()
}
break
case Status.ADDED:
case Status.CHANGED:
Logger.info("处理 class： " + classFile.absoluteFile + " ADDED or CHANGED")
modifyClassFile(classFile, srcDirPath, destDirPath, temporaryDir)
break
default:
break
}
}
} else {
com.android.utils.FileUtils.getAllFiles(inputDir).each { File file ->
modifyClassFile(file, srcDirPath, destDirPath, temporaryDir)
}
}
}
void modifyClassFile(classFile, srcDirPath, destDirPath, temporaryDir) {
Logger.info("处理 class： " + classFile.absoluteFile)
//目标路径
def destFilePath = classFile.absolutePath.replace(srcDirPath, destDirPath)
def destFile = new File(destFilePath)
if (destFile.exists()) {
destFile.delete()
}
Logger.info("处理 class：destFile" + destFile.absoluteFile)
String className = CommonUtil.path2ClassName(classFile.absolutePath.replace(srcDirPath + File.separator, ""))
Logger.info("处理 className： " + className)
File modifyFile = null
if (CommonUtil.isLegalClass(classFile) && shouldHookClass(className)) {
modifyFile = getModifyFile(classFile, temporaryDir, className)
}
if (modifyFile == null) {
modifyFile = classFile
}
FileUtils.copyFile(modifyFile, destFile)
}
File getModifyFile(File classFile, File temporaryDir, String className) {
byte[] sourceBytes = IOUtils.toByteArray(new FileInputStream(classFile))
def tempFile = new File(temporaryDir, CommonUtil.generateClassFileName(classFile))
if (tempFile.exists()) {
FileUtils.forceDelete(tempFile)
}
def modifyBytes = modifyClass(className, sourceBytes)
if (modifyBytes == null) {
modifyBytes = sourceBytes
}
tempFile.createNewFile()
def fos = new FileOutputStream(tempFile)
fos.write(modifyBytes)
fos.flush()
IOUtils.closeQuietly(fos)
return tempFile
}
void forEachJar(JarInput jarInput, TransformOutputProvider outputProvider, Context context, boolean isIncremental) {
Logger.info("jarInput:" + jarInput.file)
File destFile = outputProvider.getContentLocation(
//防止同名被覆盖
CommonUtil.generateJarFileName(jarInput.file), jarInput.contentTypes, jarInput.scopes, Format.JAR)
//增量编译处理
if (isIncremental) {
Status status = jarInput.status
switch (status) {
case Status.NOTCHANGED:
Logger.info("处理 jar： " + jarInput.file.absoluteFile + " NotChanged")
//Do nothing
return
case Status.REMOVED:
Logger.info("处理 jar： " + jarInput.file.absoluteFile + " REMOVED")
if (destFile.exists()) {
FileUtils.forceDelete(destFile)
}
return
case Status.ADDED:
case Status.CHANGED:
Logger.info("处理 jar： " + jarInput.file.absoluteFile + " ADDED or CHANGED")
break
}
}
if (destFile.exists()) {
FileUtils.forceDelete(destFile)
}
CommonUtil.isLegalJar(jarInput.file) ? transformJar(jarInput.file, context.getTemporaryDir(), destFile)
: FileUtils.copyFile(jarInput.file, destFile)
}
def transformJar(File jarFile, File temporaryDir, File destFile) {
Logger.info("处理 jar： " + jarFile.absoluteFile)
File tempOutputJarFile = new File(temporaryDir, CommonUtil.generateJarFileName(jarFile))
if (tempOutputJarFile.exists()) {
FileUtils.forceDelete(tempOutputJarFile)
}
JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream(tempOutputJarFile))
JarFile inputJarFile = new JarFile(jarFile, false)
try {
def entries = inputJarFile.entries()
while (entries.hasMoreElements()) {
def jarEntry = entries.nextElement()
def entryName = jarEntry.getName()
def inputStream = inputJarFile.getInputStream(jarEntry)
try {
byte[] sourceByteArray = IOUtils.toByteArray(inputStream)
def modifiedByteArray = null
if (!jarEntry.isDirectory() && CommonUtil.isLegalClass(entryName)) {
String className = CommonUtil.path2ClassName(entryName)
if (shouldHookClass(className)) {
modifiedByteArray = modifyClass(className, sourceByteArray)
}
}
if (modifiedByteArray == null) {
modifiedByteArray = sourceByteArray
}
jarOutputStream.putNextEntry(new JarEntry(entryName))
jarOutputStream.write(modifiedByteArray)
jarOutputStream.closeEntry()
} finally {
IOUtils.closeQuietly(inputStream)
}
}
} finally {
jarOutputStream.flush()
IOUtils.closeQuietly(jarOutputStream)
IOUtils.closeQuietly(inputJarFile)
}
FileUtils.copyFile(tempOutputJarFile, destFile)
}
private byte[] modifyClass(String className, byte[] sourceBytes) {
byte[] classBytesCode
try {
classBytesCode = hookClassInner(className, sourceBytes)
} catch (Throwable e) {
e.printStackTrace()
classBytesCode = null
println "throw exception when modify class ${className}"
}
return classBytesCode
}
/**
* 打印日志信息
*/
static void printCopyRight() {
println()
println '#######################################################################'
println '########## '
println '########## 欢迎使用隐私合规处理插件'
println '########## '
println '#######################################################################'
println '########## '
println '########## 插件配置参数 '
println '########## '
println '########## -isDebug: ' + PrivacyGlobalConfig.isDebug
println '########## -handleAnnotationName: ' + PrivacyGlobalConfig.handleAnnotationName
println '########## -exclude: ' + PrivacyGlobalConfig.exclude
println '########## '
println '########## '
println '########## '
println '#######################################################################'
println()
}
protected boolean firstTransform() {
return false
}
boolean shouldHookClass(String className) {
def excludes = PrivacyGlobalConfig.exclude
if (excludes != null) {
for (String string : excludes) {
if (className.startsWith(string)) {
return false
}
}
}
return shouldHookClassInner(className)
}
protected abstract boolean shouldHookClassInner(String className)
protected abstract byte[] hookClassInner(String className, byte[] bytes)
protected abstract void onTransformStart(TransformInvocation transformInvocation)
protected abstract void onTransformEnd(TransformInvocation transformInvocation)
}收集和处理具有特定注解的字节码指令,给下一个 transform 使用
@Override
byte[] hookClassInner(String className, byte[] bytes) {
ClassReader cr = new ClassReader(bytes)
ClassNode classNode = new ClassNode()
cr.accept(classNode, 0)
classNode.methods.each { methodNode ->
//编译期注解
methodNode.invisibleAnnotations.
each { annotationNode ->
if (PrivacyGlobalConfig.getHandleAnnotationName() == annotationNode.desc) {
collectPrivacyMethod(annotationNode, methodNode, cr.className)
}
}
}
return bytes
}
/**
* 收集注解和注解关联的方法
* @param annotationNode 注解信息
* @param methodNode 方法信息
*/
static collectPrivacyMethod(AnnotationNode annotationNode, MethodNode methodNode, String className) {
List<Object> values = annotationNode.values
Logger.info("annotation values : ${values}")
MethodReplaceItem item = new MethodReplaceItem(values, methodNode, CommonUtil.getClassInternalName(className))
PrivacyGlobalConfig.methodReplaceItemList.offer(item)
Logger.info("collectPrivacyMethod success: ${item}")
println("collectPrivacyMethod success: ${item}")
}MethodReplaceItem中封装了收集到的字节码属性，同时会根据注解关联方法的字节码指令推断出想要处理的隐私合规 api 的字节码指令。
MethodReplaceItem(List<Object> annotationPair, MethodNode methodNode, String owner) {
replaceOpcode = Opcodes.INVOKESTATIC
replaceClass = owner
replaceMethod = methodNode.name
replaceDesc = methodNode.desc
for (int i = 0; i < annotationPair.size(); i = i + 2) {
def key = annotationPair[i]
def value = annotationPair[i + 1]
if (key == "targetMethodOpcode") {
targetOpcode = value
} else if (key == "targetClass") {
targetOwner = value
} else if (key == "targetName") {
targetMethod = value
} else if (key == "targetDesc") {
targetDesc = value
}else if(key == "hook"){
willHook = value
}
}
Logger.info("=====targetOpcode:${targetOpcode},targetOwner:${targetOwner} , replaceDesc${replaceDesc}")
if (isEmpty(targetMethod)) {
targetMethod = replaceMethod
}
if (isEmpty(targetDesc)) {
//静态方法，oriDesc 跟 targetDesc 一样
if (targetOpcode == Opcodes.INVOKESTATIC) {
targetDesc = replaceDesc
} else {
//非静态方法，约定第一个参数是实例类名，oriDesc 比 targetDesc 少一个参数，处理一下
// (Landroid/telephony/TelephonyManager;)Ljava/lang/String -> ()Ljava/lang/String
def param = replaceDesc.split('\)')[0] + ")"
def result = replaceDesc.split('\)')[1]
def index = replaceDesc.indexOf(targetOwner)
if (index != -1) {
param = "(" + param.substring(index + targetOwner.length() + 1)
}
Logger.info("index::: ${index}")
targetDesc = param + result
}
}
}再次扫描整个项目，根据在上一个 transform 中收集到的要处理的隐私合规的 api，遍历字节码指令，当匹配上时，在当前的类中注入写文件的方法，同时在调用隐私合规的字节码指令前插入写文件的字节码指令，用来记录。
@Override
byte[] hookClassInner(String className, byte[] bytes) {
Logger.info("${getName()} modifyClassInner--------------->")
def findHookPoint = false
Map<MethodNode, InsertInsnPoint> collectMap = new HashMap<>()
ClassReader cr = new ClassReader(bytes)
ClassNode classNode = new ClassNode()
cr.accept(classNode, ClassReader.EXPAND_FRAMES)
classNode.methods.each { methodNode ->
//过滤掉含有特定注解的方法
if (isNotHookMethod(cr.className, methodNode)) {
methodNode.instructions.each { insnNode ->
//判断字节码能否匹配
def methodReplaceItem = searchHookPoint(insnNode)
if (methodReplaceItem != null) {
//判断是否需要 hook 掉当前指令
def inject = methodReplaceItem.willHook
//记录隐私合规 api 所在的类及方法
logHookPoint(classNode.name, methodReplaceItem, methodNode, insnNode.opcode, insnNode.owner, insnNode.name, insnNode.desc, inject)
if (inject) {
//hook
injectInsn(insnNode, methodReplaceItem)
}
//插入写文件方法指令，收集调用隐私方法的堆栈
collectInsertInsn(insnNode, methodNode, classNode, collectMap, inject)
findHookPoint = true
}
}
}
}
if (!collectMap.isEmpty() && findHookPoint) {
//插入写文件指令，用来展示堆栈信息
collectMap.each { key, value ->
key.instructions.insert(value.hookInsnNode, value.instList)
}
//插入 writeToFile 方法
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS)
classNode.accept(cw)
insertWriteToFileMethod(cw)
return cw.toByteArray()
}
return bytes
}在 collectInsertInsn 方法中，通过 throwable来收集当前的堆栈
/**
* 收集 在调用特定的方法前插入调用写入文件的方法的指令
* @param insnNode
* @param methodNode
* @param classNode
* @param collectMap
*/
static void collectInsertInsn(insnNode, methodNode, classNode, collectMap, Inject) {
def className = classNode.name
def methodName = methodNode.name
def methodDesc = methodNode.desc
def owner = null
def name = null
def desc = null
if (insnNode instanceof MethodInsnNode) {
owner = insnNode.owner
name = insnNode.name
desc = insnNode.desc
}
//------log
StringBuilder lintLog = new StringBuilder()
lintLog.append(className)
lintLog.append(" -> ")
lintLog.append(methodName)
lintLog.append(" -> ")
lintLog.append(methodDesc)
lintLog.append("\r\n")
lintLog.append(owner)
lintLog.append(" -> ")
lintLog.append(name)
lintLog.append(" -> ")
lintLog.append(desc)
//------要插入字节码指令
lintLog.append("\r\n")
InsnList insnList = new InsnList()
insnList.add(new LdcInsnNode(lintLog.toString()))
insnList.add(new TypeInsnNode(Opcodes.NEW, "java/lang/Throwable"))
insnList.add(new InsnNode(Opcodes.DUP))
insnList.add(new MethodInsnNode(Opcodes.INVOKESPECIAL, "java/lang/Throwable", "<init>", "()V", false))
insnList.add(new MethodInsnNode(Opcodes.INVOKESTATIC, className, writeToFileMethodName, writeToFileMethodDesc))
println "插入指令完成 =---------->"
collectMap.put(methodNode, new InsertInsnPoint(insnList, insnNode))
}最终，在项目编译完成之后，会在项目的根目录下生成 replaceInsn.txt文件，记录包含隐私合规 api 的类和相关方法。
当项目运行起来之后，会在设置的路径中（笔者设置在 getExternalCacheDir 中）生成 privacy_log.txt 文件，里面会记录隐私合规 api 的调用堆栈和时间，根据该调用链，我们就可以快速定位是哪一块业务执行了敏感操作。
通过 ASM + gradle plugin ，能够排查出大部分的隐私合规问题。有什么不足之处，也请读者多多提意见和建议。
改项目已经在 github 上开源，希望大家多多围观。https://github.com/season-max/asm_hook.git
参考链接：
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