Android去掉/混淆Log,反编译都看不到
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来源丨proguard官方
https://www.guardsquare.com/en/proguard/manual/examples#logging
出发点:
当然是由于编程习惯太好,打了一堆中文log,其实只是想给测试看。然而如果包被反编译,看log基本都能理解流程了,有点尴尬。所以此文主要探究proguard配置,以去除log。
以下过程示例,来自于这段代码。
public class MainActivity extends AppCompatActivity
{
private
static
final
String TAG ="MainActivity"
;private
String a ="a"
;private
String b ="b"
;@Override
protected
void
onCreate
(Bundle savedInstanceState)
{super
.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.d(TAG,"This is"
+ a + b); }}啥都不配置的情况下,反编译的smali代码如下:
# virtual methods method public
onCreate
(Landroid/os/Bundle;
)V .locals 2 invoke-super {p0, p1}, Landroid/support/v7/app/c;->onCreate(Landroid/os/Bundle;)Vconst
p1,0x7f09001b
invoke-virtual
{p0, p1}, Lcom/rentee/logremove/MainActivity;->setContentView(I)Vconst
-string
p1,"MainActivity"
new
-instance v0, Ljava/lang/StringBuilder;
const
-string
v1,"This is"
invoke-direct {v0, v1}, Ljava/lang/StringBuilder;->(Ljava/lang/String;)V iget-object
v1, p0, Lcom/rentee/logremove/MainActivity;->m:Ljava/lang/String; invoke-virtual
{v0, v1}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder; iget-object
v1, p0, Lcom/rentee/logremove/MainActivity;->n:Ljava/lang/String; invoke-virtual
{v0, v1}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder; invoke-virtual
{v0}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String; move-result-object
v0 invoke-static
{p1, v0}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I
return
-void
.end method很明显,整条字元串拼接过程是由StringBuilder完成的。
1.在build.gradle配置proguard-android-optimize.txt,因为默认的proguard-android.txt优化开关是关了的,而proguard的assumenosideeffects、assumenoexternalsideeffects配置是需要开启优化开关的。
buildTypes release minifyEnabled true "proguard-android-optimize.txt" "proguard-rules.pro"
} }
在proguard-rules.pro文件中配置assumenosideeffects。这是网上的通用大解。
class android util Log-assumenosideeffects
public
static
boolean
isLoggable
(java.lang.String,
int
);public
static
int
v
(...)
;public
static
int
i
(...)
;public
static
int
w
(...)
;public
static
int
d
(...)
;public
static
int
e
(...)
;}不过也的确存在一个问题,就是去除不干净,反编译后,smail如下:
# virtual methods method public onCreate Landroid/os/Bundle;
const
p1,0x7f09001b
invoke-virtual
{p0, p1}, Lcom/rentee/logremove/MainActivity;->setContentView(I)Vnew
-instance p1, Ljava/lang/StringBuilder;const
-string
v0,"This is"
invoke-direct {p1, v0}, Ljava/lang/StringBuilder;->(Ljava/lang/String;)V iget-object
v0, p0, Lcom/rentee/logremove/MainActivity;->m:Ljava/lang/String; invoke-virtual
{p1, v0}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder; iget-object
v0, p0, Lcom/rentee/logremove/MainActivity;->n:Ljava/lang/String; invoke-virtual
{p1, v0}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;return
-void
.end methodLog的相关代码没了,但是还是有StringBuilder的拼接过程在,这个从根本上解决不了问题。
2.进化版,proguard 6.0以上版本新增了assumenoexternalsideeffects和assumenoexternalreturnvalues,这两个属性6.0才引入,Android自带proguard-gradle插件并没有这么新,所以要在工程项目根目录配置如下strategy,强制将progurad指定到6.0以上版本。
"net.sf.proguard:proguard-gradle:6.0.3"buildscript { configurations.all { resolutionStrategy { force
然后在progaurd-rules.txt文件中增加如下配置:
class java lang StringBuilder-assumenoexternalsideeffects
public
java.lang.StringBuilder();public
java.lang.StringBuilder(int
);public
java.lang.StringBuilder(java.lang.String);public
java.lang.StringBuilder
append
(java.lang.Object)
;public
java.lang.StringBuilder
append
(java.lang.String)
;public
java.lang.StringBuilder
append
(java.lang.StringBuffer)
;public
java.lang.StringBuilder
append
(
char
[]);public
java.lang.StringBuilder
append
(
char
[],int
,int
);public
java.lang.StringBuilder
append
(
boolean
);public
java.lang.StringBuilder
append
(
char
);public
java.lang.StringBuilder
append
(
int
);public
java.lang.StringBuilder
append
(
long
);public
java.lang.StringBuilder
append
(
float
);public
java.lang.StringBuilder
append
(
double
);public
java.lang.String
toString
()
;}-assumenoexternalreturnvaluespublic
final
class
java
.lang
.StringBuilder
{public
java.lang.StringBuilder
append
(java.lang.Object)
;public
java.lang.StringBuilder
append
(java.lang.String)
;public
java.lang.StringBuilder
append
(java.lang.StringBuffer)
;public
java.lang.StringBuilder
append
(
char
[]);public
java.lang.StringBuilder
append
(
char
[],int
,int
);public
java.lang.StringBuilder
append
(
boolean
);public
java.lang.StringBuilder
append
(
char
);public
java.lang.StringBuilder
append
(
int
);public
java.lang.StringBuilder
append
(
long
);public
java.lang.StringBuilder
append
(
float
);public
java.lang.StringBuilder
append
(
double
);}这段配置的作用是,去除返回值无用的StringBuilder的相关操作,由于在第2点配置后,Log相关代码被去除,所以Log中的字元串拼接也是无用的,会被去除。配置后smali代码是:
# virtual methods method public onCreate Landroid/os/Bundle;
const
p1,0x7f09001b
invoke-virtual
{p0, p1}, Lcom/rentee/logremove/MainActivity;->setContentView(I)Vreturn
-void
.end method是的,一句都没有了,干干净净,爽!
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