Android 反编译之修改Smali 文件输出日志
2016-03-01 本文已影响4990人
imesong
本篇是Android反编译系列的 第五篇, 前四篇的地址在这里
第一篇 Apktool安装
第二篇 Apktool 基本使用方法
第三篇 App汉化与二次签名
第四篇 修改Smali文件，定位关键点
承接上篇Android反编译之修改Smali文件，本篇主要分析如何在 Smali文件中输出日志，帮助我们理解App 业务处理逻辑。
1.我们先写这样一个简单的demo
smaliLogDemoApp.gif
顺便安利一下Android 上gif 截图的软件LICEcap,免费开源，秋百万大神推荐
App 登陆界面，对用户名和密码做简单的逻辑验证，同时有一个FloatingActionBar，点击之后显示Snackbar。
我们现在要做的，在登陆验证的方法里，添加日志输出，分别输出登陆成功，登陆失败。在FloatingActionBar 的响应事件中，添加日志输出。
2.反编译SmaliLogDemo
demo 比较简单，我这里直接给出反编译之后的 Smali 文件。
.class public Lcom/imesong/smalilogdemo/MainActivity;
.super Landroid/support/v7/app/AppCompatActivity;
.source "MainActivity.java"
# instance fields
.field private login:Landroid/widget/Button;
.field private nameEdit:Landroid/support/v7/widget/AppCompatEditText;
.field private passwdEdit:Landroid/support/v7/widget/AppCompatEditText;
# direct methods
.method public constructor <init>()V
.locals 0
.prologue
.line 16
invoke-direct {p0}, Landroid/support/v7/app/AppCompatActivity;-><init>()V
return-void
.end method
.method static synthetic access$000(Lcom/imesong/smalilogdemo/MainActivity;)Landroid/support/v7/widget/AppCompatEditText;
.locals 1
.param p0, "x0" # Lcom/imesong/smalilogdemo/MainActivity;
.prologue
.line 16
iget-object v0, p0, Lcom/imesong/smalilogdemo/MainActivity;->nameEdit:Landroid/support/v7/widget/AppCompatEditText;
return-object v0
.end method
.method static synthetic access$100(Lcom/imesong/smalilogdemo/MainActivity;)Landroid/support/v7/widget/AppCompatEditText;
.locals 1
.param p0, "x0" # Lcom/imesong/smalilogdemo/MainActivity;
.prologue
.line 16
iget-object v0, p0, Lcom/imesong/smalilogdemo/MainActivity;->passwdEdit:Landroid/support/v7/widget/AppCompatEditText;
return-object v0
.end method
.method static synthetic access$200(Lcom/imesong/smalilogdemo/MainActivity;Ljava/lang/String;Ljava/lang/String;)Z
.locals 1
.param p0, "x0" # Lcom/imesong/smalilogdemo/MainActivity;
.param p1, "x1" # Ljava/lang/String;
.param p2, "x2" # Ljava/lang/String;
.prologue
.line 16
invoke-direct {p0, p1, p2}, Lcom/imesong/smalilogdemo/MainActivity;->isLogingInfoValid(Ljava/lang/String;Ljava/lang/String;)Z
move-result v0
return v0
.end method
.method private isLogingInfoValid(Ljava/lang/String;Ljava/lang/String;)Z
.locals 4
.param p1, "name" # Ljava/lang/String;
.param p2, "passwd" # Ljava/lang/String;
.prologue
const/4 v3, 0x0
.line 59
const/4 v0, 0x0
.line 60
.local v0, "isValid":Z
invoke-static {p1}, Landroid/text/TextUtils;->isEmpty(Ljava/lang/CharSequence;)Z
move-result v1
if-nez v1, :cond_0
invoke-static {p2}, Landroid/text/TextUtils;->isEmpty(Ljava/lang/CharSequence;)Z
move-result v1
if-eqz v1, :cond_1
.line 61
:cond_0
const/4 v0, 0x0
.line 62
const-string v1, "\u7528\u6237\u540d\u3001\u5bc6\u7801\u4e0d\u80fd\u4e3a\u7a7a"
invoke-static {p0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;Ljava/lang/CharSequence;I)Landroid/widget/Toast;
move-result-object v1
invoke-virtual {v1}, Landroid/widget/Toast;->show()V
.line 69
:goto_0
return v0
.line 63
:cond_1
invoke-virtual {p2}, Ljava/lang/String;->length()I
move-result v1
const/4 v2, 0x6
if-ge v1, v2, :cond_2
.line 64
const/4 v0, 0x0
.line 65
const-string v1, "\u5bc6\u7801\u957f\u5ea6\u5c0f\u4e8e6"
invoke-static {p0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;Ljava/lang/CharSequence;I)Landroid/widget/Toast;
move-result-object v1
invoke-virtual {v1}, Landroid/widget/Toast;->show()V
goto :goto_0
.line 67
:cond_2
const/4 v0, 0x1
goto :goto_0
.end method
# virtual methods
.method protected onCreate(Landroid/os/Bundle;)V
.locals 4
.param p1, "savedInstanceState" # Landroid/os/Bundle;
.prologue
.line 24
invoke-super {p0, p1}, Landroid/support/v7/app/AppCompatActivity;->onCreate(Landroid/os/Bundle;)V
.line 25
const v2, 0x7f040019
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->setContentView(I)V
.line 26
const v2, 0x7f0c0069
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->findViewById(I)Landroid/view/View;
move-result-object v1
check-cast v1, Landroid/support/v7/widget/Toolbar;
.line 27
.local v1, "toolbar":Landroid/support/v7/widget/Toolbar;
invoke-virtual {p0, v1}, Lcom/imesong/smalilogdemo/MainActivity;->setSupportActionBar(Landroid/support/v7/widget/Toolbar;)V
.line 29
const v2, 0x7f0c006a
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->findViewById(I)Landroid/view/View;
move-result-object v0
check-cast v0, Landroid/support/design/widget/FloatingActionButton;
.line 30
.local v0, "fab":Landroid/support/design/widget/FloatingActionButton;
new-instance v2, Lcom/imesong/smalilogdemo/MainActivity$1;
invoke-direct {v2, p0}, Lcom/imesong/smalilogdemo/MainActivity$1;-><init>(Lcom/imesong/smalilogdemo/MainActivity;)V
invoke-virtual {v0, v2}, Landroid/support/design/widget/FloatingActionButton;->setOnClickListener(Landroid/view/View$OnClickListener;)V
.line 38
const v2, 0x7f0c006b
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->findViewById(I)Landroid/view/View;
move-result-object v2
check-cast v2, Landroid/support/v7/widget/AppCompatEditText;
iput-object v2, p0, Lcom/imesong/smalilogdemo/MainActivity;->nameEdit:Landroid/support/v7/widget/AppCompatEditText;
.line 39
const v2, 0x7f0c006c
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->findViewById(I)Landroid/view/View;
move-result-object v2
check-cast v2, Landroid/support/v7/widget/AppCompatEditText;
iput-object v2, p0, Lcom/imesong/smalilogdemo/MainActivity;->passwdEdit:Landroid/support/v7/widget/AppCompatEditText;
.line 41
const v2, 0x7f0c006d
invoke-virtual {p0, v2}, Lcom/imesong/smalilogdemo/MainActivity;->findViewById(I)Landroid/view/View;
move-result-object v2
check-cast v2, Landroid/widget/Button;
iput-object v2, p0, Lcom/imesong/smalilogdemo/MainActivity;->login:Landroid/widget/Button;
.line 43
iget-object v2, p0, Lcom/imesong/smalilogdemo/MainActivity;->login:Landroid/widget/Button;
new-instance v3, Lcom/imesong/smalilogdemo/MainActivity$2;
invoke-direct {v3, p0}, Lcom/imesong/smalilogdemo/MainActivity$2;-><init>(Lcom/imesong/smalilogdemo/MainActivity;)V
invoke-virtual {v2, v3}, Landroid/widget/Button;->setOnClickListener(Landroid/view/View$OnClickListener;)V
.line 56
return-void
.end method
代码没有混淆，看起来很清楚。类名 是 MainActivity.java,有三个成员变量，一个 Button，两个 AppCompatEditText。下面还有 isLogingInfoValid 方法，有两个参数，分别是 name 和 passwd。最后的是 onCreate 方法。不过，大致浏览之后，好像没有发现 FloatingActionBar 的踪迹啊，不要着急，我们先把登陆逻辑判断的日志处理好，回过头来再查找 FloatingActionBar 也不迟。
我们先分析 isLogingInfValid 的处理逻辑。
方法第一行 .logcals ,表示使用4个寄存器，.param p1 表示形参 name, .param p2 表示形参 passwd。紧接着 .prologue 表示方法执行开始
#定义变量 v3，并赋值为0
#smali 中注释使用#
const/4 v3,0x0
#定义Boolean变量 isValid,默认为false
.local v0,"isValid":Z
#调用TextUtils.isEmpty(string) 方法
#invoke-static ，调用一个static的静态方法
#{p1} 是 static 方法的入参
#Landroid/text/TextUtils 是这个方法的决定路径，L表示这是一个Object，Smali中只有两种类型 基础类型和引用类型（Object，使用L表示）
#->这个表示调用isEmpty 方法，熟悉脚本语言的开发，应该很熟悉，小括号中定义入参的类型，使用 ';' 结尾
#最后的 **Z** 表示代表返回值为Boolean 类型。
#这样完成了TextUtils.isEmpty(name) 方法的调用
invoke-static {p1}, Landroid/text/TextUtils;->isEmpty(Ljava/lang/CharSequence;)Z
#将结果赋值给 v1
move-result v1
#如果 v1 != 0 跳转到 ：cond_0
#如果 v1==true 跳转到 ：cond_0,如果是 false ，接着往下走
if-nez v1, :cond_0
#赋值 v0 == 0
:cond_0
const/4 v0, 0x0
#下面紧接着定义 变量 v1,调用 Toast.make(context,"string",Toast.SHORT).show();方法
#之后执行：goto_0 返回 v0 的值。
#这个逻辑走下来，说明如果第一个参数，用户名为null,直接弹出Toast,返回false，符合我们都看到的现象。
如果要在用户名为空的时候添加一条日志怎么添加呢？下面我们看下如何添加日志。
1.修改寄存器数量
如果要添加日志，我们要输出我们想要显示的信息，这些也是要申请寄存器存放。
将 .logcal 4 修改为 .logcal 5
2.新增变量，定义我们要输出的信息
为了方便，这里讲 Tag 和信息定义相同，如果不想定义一致，可以再增加一个寄存器。
const-string v4 ,"nameNull"
3.调用Log.d("info","info");方法。
#注意参数，返回值必须完全正确
invoke-static {v4,v4};Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
这样我们就完成了name 为空时的日志添加。我们重新打包，签名，运行看下结果。
apktool b smalilogdemo -o smalilogdemo_unsigned.apk
执行之后，却遇到下面的问题
I: Using Apktool 2.0.3
I: Checking whether sources has changed...
I: Checking whether resources has changed...
I: Building resources...
/Users/ericsong/Documents/android_decode/crack/smalilogdemo/res/layout-v21/abc_screen_toolbar.xml:5: error: No resource identifier found for attribute 'touchscreenBlocksFocus' in package 'android'
layout-v21 里面有个属性，我们现在的framework-resource 不支持，简单粗暴的解决方法，删除 layout-v21 文件夹。删除掉这些异常的Resource 文件之后，我们就可以正常打包了。
暂时没有找到比较好的回编译的方法，如果有新的发现，会及时更新
如果每个想要添加日志的地方，都这样修改，感觉还是很繁琐，能不能偷懒下，把日志输出的Smali 语法封装成一个文件，我们只需要调用这个文件就可以了呢？这样当然是可以的。
下面贴出 LogUtil.smali 文件
.class public LLogUtil;
.super Ljava/lang/Object;
.source "LLogUtil.java"
.method public static d(Ljava/lang/String;)V
.locals 1
.prologue
const-string v0,"SmaliLogDemo"
invoke-static {v0, p0}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
return-void
.end method
.method public static d()V
.locals 1
.prologue
const-string v0,"SmaliLogDemo"
invoke-static {v0,v0},Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
return-void
.end method
.method public static e(Ljava/lang/String;)V
.locals 1
.prologue
const-string v0, "SmaliLogDemo"
invoke-static {v0, p0}, Landroid/util/Log;->e(Ljava/lang/String;Ljava/lang/String;)I
return-void
.end method
.method public static I(I)V
.locals 2
.prologue
const-string v0, "SmaliLogDemo_I"
invoke-static {p0}, Ljava/lang/String;->valueOf(I)Ljava/lang/String;
move-result-object v1
invoke-static {v0, v1}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
return-void
.end method
#打印Long 参数
.method public static d(J)V
.locals 2
.prologue
const-string v0, "SmaliLogDemo_Long"
invoke-static {p0, p1}, Ljava/lang/String;->valueOf(J)Ljava/lang/String;
move-result-object v1
invoke-static {v0, v1}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
return-void
.end method
#无参数 System.out.println("SmaliLogDemo_out")
.method public static p()V
.locals 2
.prologue
const-string v0,"SmaliLogDemo_out"
sget-object v1,Ljava/lang/System;->out:Ljava/io/PrintStream;
invoke-virtual {v1,v0},Ljava/io/PrintStream;->println(Ljava/langString;)V
return-void
.end method
#打印boolean
.method public static p(Z)V
.locals 2
.prologue
const-string v0,"SmaliLogDemo_out_boolean"
sget-object v1,Ljava/lang/System;->out:Ljava/io/PrintStream;
invoke-virtual {v1,p0},Ljava/io/PrintStream;->println(Z)V
return-void
.end method
现在的封装，基本上满足日常的需求，后面会持续完善。
我们再给出添加日志之后，MainActivity 中 isLogingInfoValid() 的代码
.method private isLogingInfoValid(Ljava/lang/String;Ljava/lang/String;)Z
.locals 5
.param p1, "name" # Ljava/lang/String;
.param p2, "passwd" # Ljava/lang/String;
.prologue
const/4 v3, 0x0
const-string v4,"isLogingInfoValid"
invoke-static {v4},LLogUtil;->d(Ljava/lang/String;)V
.line 58
const/4 v0, 0x0
.line 59
.local v0, "isValid":Z
invoke-static {p1}, Landroid/text/TextUtils;->isEmpty(Ljava/lang/CharSequence;)Z
move-result v1
if-nez v1, :cond_0
invoke-static {p2}, Landroid/text/TextUtils;->isEmpty(Ljava/lang/CharSequence;)Z
move-result v1
if-eqz v1, :cond_1
.line 60
:cond_0
const/4 v0, 0x0
const-string v4,"isLogingInfoValid11111111111"
invoke-static {v4},LLogUtil;->d(Ljava/lang/String;)V
.line 61
const-string v1, "\u7528\u6237\u540d\u3001\u5bc6\u7801\u4e0d\u80fd\u4e3a\u7a7a"
invoke-static {p0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;Ljava/lang/CharSequence;I)Landroid/widget/Toast;
move-result-object v1
invoke-virtual {v1}, Landroid/widget/Toast;->show()V
.line 68
:goto_0
return v0
.line 62
:cond_1
invoke-virtual {p2}, Ljava/lang/String;->length()I
move-result v1
const/4 v2, 0x6
if-ge v1, v2, :cond_2
.line 63
const/4 v0, 0x0
const-string v4,"isLogingInfoValid2222222222222"
invoke-static {v4},LLogUtil;->d(Ljava/lang/String;)V
.line 64
const-string v1, "\u5bc6\u7801\u957f\u5ea6\u5c0f\u4e8e6"
invoke-static {p0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;Ljava/lang/CharSequence;I)Landroid/widget/Toast;
move-result-object v1
invoke-virtual {v1}, Landroid/widget/Toast;->show()V
goto :goto_0
.line 66
:cond_2
const-string v4,"isLogingInfoValid33333333333"
invoke-static {v4},LLogUtil;->d(Ljava/lang/String;)V
const/4 v0, 0x1
goto :goto_0
.end method
里面一共打印了四组日志。
我们再看下 onClick 响应事件中的日志信息。
# virtual methods
.method public onClick(Landroid/view/View;)V
.locals 4
.param p1, "v" # Landroid/view/View;
.prologue
.line 47
iget-object v0, p0, Lcom/imesong/smalilogdemo/MainActivity$2;->this$0:Lcom/imesong/smalilogdemo/MainActivity;
iget-object v1, p0, Lcom/imesong/smalilogdemo/MainActivity$2;->this$0:Lcom/imesong/smalilogdemo/MainActivity;
# getter for: Lcom/imesong/smalilogdemo/MainActivity;->nameEdit:Landroid/support/v7/widget/AppCompatEditText;
invoke-static {v1}, Lcom/imesong/smalilogdemo/MainActivity;->access$000(Lcom/imesong/smalilogdemo/MainActivity;)Landroid/support/v7/widget/AppCompatEditText;
move-result-object v1
invoke-virtual {v1}, Landroid/support/v7/widget/AppCompatEditText;->getText()Landroid/text/Editable;
move-result-object v1
invoke-virtual {v1}, Ljava/lang/Object;->toString()Ljava/lang/String;
move-result-object v1
iget-object v2, p0, Lcom/imesong/smalilogdemo/MainActivity$2;->this$0:Lcom/imesong/smalilogdemo/MainActivity;
# getter for: Lcom/imesong/smalilogdemo/MainActivity;->passwdEdit:Landroid/support/v7/widget/AppCompatEditText;
invoke-static {v2}, Lcom/imesong/smalilogdemo/MainActivity;->access$100(Lcom/imesong/smalilogdemo/MainActivity;)Landroid/support/v7/widget/AppCompatEditText;
move-result-object v2
invoke-virtual {v2}, Landroid/support/v7/widget/AppCompatEditText;->getText()Landroid/text/Editable;
move-result-object v2
invoke-virtual {v2}, Ljava/lang/Object;->toString()Ljava/lang/String;
move-result-object v2
# invokes: Lcom/imesong/smalilogdemo/MainActivity;->isLogingInfoValid(Ljava/lang/String;Ljava/lang/String;)Z
invoke-static {v0, v1, v2}, Lcom/imesong/smalilogdemo/MainActivity;->access$200(Lcom/imesong/smalilogdemo/MainActivity;Ljava/lang/String;Ljava/lang/String;)Z
move-result v0
if-eqz v0, :cond_0
.line 48
const-string v3,"commit onclick"
invoke-static {v3},LLogUtil;->e(Ljava/lang/String;)V
iget-object v0, p0, Lcom/imesong/smalilogdemo/MainActivity$2;->this$0:Lcom/imesong/smalilogdemo/MainActivity;
const-string v1, "\u767b\u9646\u6210\u529f"
const/4 v2, 0x0
invoke-static {v0, v1, v2}, Landroid/widget/Toast;->makeText(Landroid/content/Context;Ljava/lang/CharSequence;I)Landroid/widget/Toast;
move-result-object v0
invoke-virtual {v0}, Landroid/widget/Toast;->show()V
.line 53
:cond_0
return-void
.end method
最后 看下 效果图
smaliLogDemoAppLog.gif
关于SmaliLogDemo 的理解，就到这里，最后附上 项目代码和Smali 文件
