【Android 安全】DEX 加密 ( 代理 Application 开发 | 加载 dex 文件 | 使用反射获取方法创建本应用的 dexElements

【Android 安全】DEX 加密 ( 代理 Application 开发 | 加载 dex 文件 | 使用反射获取方法创建本应用的 dexElements | 各版本创建 dex 数组源码对比 )（二）

2022-01-27 15

简介： 【Android 安全】DEX 加密 ( 代理 Application 开发 | 加载 dex 文件 | 使用反射获取方法创建本应用的 dexElements | 各版本创建 dex 数组源码对比 )（二）

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Android 8.0 (Oreo API 25) 系统中创建 Element[] dexElements 的方法 :

/*package*/ final class DexPathList {
    private Element[] dexElements;
    public DexPathList(ClassLoader definingContext, String dexPath,
            String librarySearchPath, File optimizedDirectory) {
        // save dexPath for BaseDexClassLoader
        this.dexElements = makeDexElements(splitDexPath(dexPath), optimizedDirectory,
                                           suppressedExceptions, definingContext);
    }
    private static Element[] makeDexElements(List<File> files, File optimizedDirectory,
                                             List<IOException> suppressedExceptions,
                                             ClassLoader loader) {
  }
    /*
     * TODO (dimitry): Revert after apps stops relying on the existence of this
     * method (see http://b/21957414 and http://b/26317852 for details)
     */
    @SuppressWarnings("unused")
    private static Element[] makePathElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, null);
    }
    /**
     * Makes an array of directory/zip path elements for the native library search path, one per
     * element of the given array.
     */
    private static NativeLibraryElement[] makePathElements(List<File> files) {
    }
}

参考 : 8.0.0_r4/xref/libcore/dalvik/src/main/java/dalvik/system/DexPathList.java

A n d r o i d   9.0   ( P i e   A P I   28 ) \rm Android \ 9.0 \ ( Pie \ API \ 28 )Android 9.0 (Pie API 28) 系统中创建 Element[] dexElements 的方法 :
/*package*/ final class DexPathList {
    private Element[] dexElements;
    public DexPathList(ClassLoader definingContext, String dexPath,
            String librarySearchPath, File optimizedDirectory) {
        // save dexPath for BaseDexClassLoader
        this.dexElements = makeDexElements(splitDexPath(dexPath), optimizedDirectory,
                                           suppressedExceptions, definingContext, isTrusted);
    }
    /**
     * Makes an array of dex/resource path elements, one per element of
     * the given array.
     */
    private static Element[] makeDexElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions, ClassLoader loader) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, loader, false);
    }
    private static Element[] makeDexElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions, ClassLoader loader, boolean isTrusted) {
    }
    /*
     * TODO (dimitry): Revert after apps stops relying on the existence of this
     * method (see http://b/21957414 and http://b/26317852 for details)
     */
    @SuppressWarnings("unused")
    private static Element[] makePathElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, null);
    }
    /**
     * Makes an array of directory/zip path elements for the native library search path, one per
     * element of the given array.
     */
    private static NativeLibraryElement[] makePathElements(List<File> files) {
    }
}

参考 : 9.0.0_r8/xref/libcore/dalvik/src/main/java/dalvik/system/DexPathList.java

A n d r o i d 10.0 ( Q A P I 29 ) \rm Android \ 10.0 \ ( Q \ API \ 29 )Android 10.0 (Q API 29) 系统中创建 Element[] dexElements 的方法 :

/*package*/ final class DexPathList {
    private Element[] dexElements;
    DexPathList(ClassLoader definingContext, String dexPath,
            String librarySearchPath, File optimizedDirectory, boolean isTrusted) {
        // save dexPath for BaseDexClassLoader
        this.dexElements = makeDexElements(splitDexPath(dexPath), optimizedDirectory,
                                           suppressedExceptions, definingContext, isTrusted);
    }
    /**
     * Makes an array of dex/resource path elements, one per element of
     * the given array.
     */
    @UnsupportedAppUsage
    private static Element[] makeDexElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions, ClassLoader loader) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, loader, false);
    }
    private static Element[] makeDexElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions, ClassLoader loader, boolean isTrusted) {
    }
    /*
     * TODO (dimitry): Revert after apps stops relying on the existence of this
     * method (see http://b/21957414 and http://b/26317852 for details)
     */
    @UnsupportedAppUsage
    @SuppressWarnings("unused")
    private static Element[] makePathElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, null);
    }
    /**
     * Makes an array of directory/zip path elements for the native library search path, one per
     * element of the given array.
     */
    @UnsupportedAppUsage
    private static NativeLibraryElement[] makePathElements(List<File> files) {
    }
}

参考 : 10.0.0_r6/xref/libcore/dalvik/src/main/java/dalvik/system/DexPathList.java

二、不同 Android 系统创建 dex 数组源码对比

A n d r o i d 6.0 、 7.1 、 7.1 、 8.0 、 9.0 、 10 \rm Android \ 6.0 、 7.1、7.1、8.0、9.0、10Android 6.0、7.1、7.1、8.0、9.0、10 系统需要反射如下 makePathElements 方法 ;

@SuppressWarnings("unused")
    private static Element[] makePathElements(List<File> files, File optimizedDirectory,
            List<IOException> suppressedExceptions) {
        return makeDexElements(files, optimizedDirectory, suppressedExceptions, null);
    }

三、 Android 5.1 及以下系统反射方法并创建 Element[] dexElements

Android 5.1 及以下系统反射方法并创建 Element[] dexElements :

if(Build.VERSION.SDK_INT <=
                Build.VERSION_CODES.LOLLIPOP_MR1){ // 5.0, 5.1  makeDexElements
            // 反射 5.0, 5.1, 6.0 版本的 DexPathList 中的 makeDexElements 方法
            makeDexElements = reflexMethod(pathList, "makeDexElements",
                    ArrayList::class.java, File::class.java, ArrayList::class.java)
            var suppressedExceptions: ArrayList<IOException> = ArrayList<IOException>()
            addElements = makeDexElements.invoke(pathList, dexFiles,
                    optimizedDirectory,
                    suppressedExceptions) as Array<Any>
        }

四、 Android 6.0 及以下系统反射方法并创建 Element[] dexElements

Android 6.0 及以下系统反射方法并创建 Element[] dexElements :

}else if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){   // 7.0 以上版本 makePathElements
            // 反射 7.0 以上版本的 DexPathList 中的 makeDexElements 方法
            makeDexElements = reflexMethod(pathList, "makePathElements",
                    ArrayList::class.java, File::class.java, ArrayList::class.java)
            var suppressedExceptions: ArrayList<IOException> = ArrayList<IOException>()
            addElements = makeDexElements.invoke(pathList, dexFiles,
                    optimizedDirectory,
                    suppressedExceptions) as Array<Any>
        }

五、完整代码示例

/*
            2 . 在本应用中创建 Element[] dexElements 数组 , 用于存放解密后的 dex 文件
                不同的 Android 版本中 , 创建 Element[] dexElements 数组的方法不同 , 这里需要做兼容
         */
        var makeDexElements: Method
        var addElements : Array<Any>
        if(Build.VERSION.SDK_INT <=
                Build.VERSION_CODES.LOLLIPOP_MR1){ // 5.0, 5.1  makeDexElements
            // 反射 5.0, 5.1, 6.0 版本的 DexPathList 中的 makeDexElements 方法
            makeDexElements = reflexMethod(pathList, "makeDexElements",
                    ArrayList::class.java, File::class.java, ArrayList::class.java)
            var suppressedExceptions: ArrayList<IOException> = ArrayList<IOException>()
            addElements = makeDexElements.invoke(pathList, dexFiles,
                    optimizedDirectory,
                    suppressedExceptions) as Array<Any>
        }else if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){   // 7.0 以上版本 makePathElements
            // 反射 7.0 以上版本的 DexPathList 中的 makeDexElements 方法
            makeDexElements = reflexMethod(pathList, "makePathElements",
                    ArrayList::class.java, File::class.java, ArrayList::class.java)
            var suppressedExceptions: ArrayList<IOException> = ArrayList<IOException>()
            addElements = makeDexElements.invoke(pathList, dexFiles,
                    optimizedDirectory,
                    suppressedExceptions) as Array<Any>
        }