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標題: BT種子搜尋1.5.7簽名校驗解密過程簡介 [打印本頁]
作者: fam1001    時間: 2016-3-22 15:14
標題: BT種子搜尋1.5.7簽名校驗解密過程簡介
軟體有積分限制，有廣告，這裡不做破解介紹。只簡單介紹簽名破解部分。

反編譯軟體，在smalicom        xbnx（軟體代碼目錄）搜尋「signatures」，定位到getSign方法：

.method public static getSign(Landroid/content/Context;)Ljava/lang/String;
.locals 6
.param p0, "context" # Landroid/content/Context;

.prologue
.line 374
const-string v4, ""

sget-object v5, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

invoke-virtual {v4, v5}, Ljava/lang/String;->equals(Ljava/lang/Object;)Z

move-result v4

if-nez v4, :cond_0

.line 375
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

.line 385
:goto_0
return-object v4

.line 376
:cond_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageManager()Landroid/content/pm/PackageManager;

move-result-object v2

.line 378
.local v2, "pm":Landroid/content/pm/PackageManager;
:try_start_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageName()Ljava/lang/String;

move-result-object v4

const/16 v5, 0x40

invoke-virtual {v2, v4, v5}, Landroid/content/pm/PackageManager;->getPackageInfo(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;

move-result-object v1

.line 380
.local v1, "packageinfo":Landroid/content/pm/PackageInfo;
iget-object v4, v1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

const/4 v5, 0x0

aget-object v3, v4, v5

.line 382
.local v3, "sign":Landroid/content/pm/Signature;
invoke-virtual {v3}, Landroid/content/pm/Signature;->toCharsString()Ljava/lang/String;

move-result-object v4

sput-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

.line 383
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;
:try_end_0
.catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

goto :goto_0

.line 384
.end local v1 # "packageinfo":Landroid/content/pm/PackageInfo;
.end local v3 # "sign":Landroid/content/pm/Signature;
:catch_0
move-exception v0

.line 385
.local v0, "e":Ljava/lang/Exception;
const/4 v4, 0x0

goto :goto_0
.end method


上面方法大概意思就是獲取軟體的簽名，然後將簽名轉為字符串，並保存到V4寄存器中（紅色字體部分）。

想過簽名校驗，必須知道官方簽名時V4的值。

參考另一篇smali注入帖（http://apk.tw/thread-758504-1-1.html），這裡構造個crack.smali，代碼如下：
  1. .class public Lcrack;
  2. .super Ljava/lang/Object;
  3. .source "crack.java"

  5. .method public static puts(Ljava/lang/String;)V
  6.     .locals 7

  8.     .prologue
  9.     :try_start_0

  11.     const-string v3, "/sdcard/debug.txt"


  14.     new-instance v2, Ljava/io/FileOutputStream;

  16.     const/4 v5, 0x0

  18.     invoke-direct {v2, v3, v5}, Ljava/io/FileOutputStream;-><init>(Ljava/lang/String;Z)V

  20.     .line 19
  21.     new-instance v4, Ljava/io/OutputStreamWriter;

  23.     const-string v5, "gb2312"

  25.     invoke-direct {v4, v2, v5}, Ljava/io/OutputStreamWriter;-><init>(Ljava/io/OutputStream;Ljava/lang/String;)V

  27.     .line 21
  28.     invoke-virtual {v4, p0}, Ljava/io/OutputStreamWriter;->write(Ljava/lang/String;)V

  30.     .line 23
  31.     invoke-virtual {v4}, Ljava/io/OutputStreamWriter;->flush()V

  33.     .line 25
  34.     invoke-virtual {v4}, Ljava/io/OutputStreamWriter;->close()V

  36.     .line 27
  37.     invoke-virtual {v2}, Ljava/io/FileOutputStream;->close()V
  38.     :try_end_0
  39.     .catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

  41.     .line 37

  43.     :cond_0
  44.     :goto_0
  45.     return-void

  47.     .line 30
  48.     :catch_0
  49.     move-exception v0

  51.     .line 34
  52.     const-string v5, "debug"

  54.     const-string v6, "file write error"

  56.     invoke-static {v5, v6}, Landroid/util/Log;->e(Ljava/lang/String;Ljava/lang/String;)I

  58.     goto :goto_0
  59. .end method
複製代碼


上面代碼大概作用是保存字符串寄存器的值vx到/sdcard/debug.txt。

把構造好的crack.smali放入smali根目錄。

修改getSign方法，如下（紅色部分為修改內容）：
.method public static getSign(Landroid/content/Context;)Ljava/lang/String;
.locals 6
.param p0, "context" # Landroid/content/Context;

.prologue
.line 374
const-string v4, ""

sget-object v5, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

invoke-virtual {v4, v5}, Ljava/lang/String;->equals(Ljava/lang/Object;)Z

move-result v4

if-nez v4, :cond_0

.line 375
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

.line 385
:goto_0
return-object v4

.line 376
:cond_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageManager()Landroid/content/pm/PackageManager;

move-result-object v2

.line 378
.local v2, "pm":Landroid/content/pm/PackageManager;
:try_start_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageName()Ljava/lang/String;

move-result-object v4
const-string v4, "/sdcard/download/bt.apk"

const/16 v5, 0x40

invoke-virtual {v2, v4, v5}, Landroid/content/pm/PackageManager;->getPackageArchiveInfo(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;

move-result-object v1

.line 380
.local v1, "packageinfo":Landroid/content/pm/PackageInfo;
iget-object v4, v1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

const/4 v5, 0x0

aget-object v3, v4, v5

.line 382
.local v3, "sign":Landroid/content/pm/Signature;
invoke-virtual {v3}, Landroid/content/pm/Signature;->toCharsString()Ljava/lang/String;

move-result-object v4

invoke-static {v4}, Lcrack;->puts(Ljava/lang/String;)V

sput-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;
.line 383
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;
:try_end_0
.catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

goto :goto_0

.line 384
.end local v1 # "packageinfo":Landroid/content/pm/PackageInfo;
.end local v3 # "sign":Landroid/content/pm/Signature;
:catch_0
move-exception v0

.line 385
.local v0, "e":Ljava/lang/Exception;
const/4 v4, 0x0

goto :goto_0
.end method

保存修改後，回編譯軟體並簽名。把官方版apk改名為「bt.apk」並放到/sdcard/download/目錄下。

上面修改主要利用了getPackageInfo和getPackageArchiveInfo的相同點與不同點。


兩者都可以用來獲取軟體的簽名訊息。getPackageInfo根據包名讀取已安裝的軟體的簽名，getPackageArchiveInfo根據路徑讀取APK壓縮包的簽名。詳情查看Google安卓文件。


安裝並執行編譯好的軟體。


開啟/sdcard/debug.txt，大致內容如下：

  1. 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
複製代碼


複製該內容。

重新修改getSign方法，如下：

.method public static getSign(Landroid/content/Context;)Ljava/lang/String;
.locals 6
.param p0, "context" # Landroid/content/Context;

.prologue
.line 374
const-string v4, ""

sget-object v5, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

invoke-virtual {v4, v5}, Ljava/lang/String;->equals(Ljava/lang/Object;)Z

move-result v4

if-nez v4, :cond_0

.line 375
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

.line 385
:goto_0
return-object v4

.line 376
:cond_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageManager()Landroid/content/pm/PackageManager;

move-result-object v2

.line 378
.local v2, "pm":Landroid/content/pm/PackageManager;
:try_start_0
invoke-virtual {p0}, Landroid/content/Context;->getPackageName()Ljava/lang/String;

move-result-object v4

const/16 v5, 0x40

invoke-virtual {v2, v4, v5}, Landroid/content/pm/PackageManager;->getPackageInfo(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;

move-result-object v1

.line 380
.local v1, "packageinfo":Landroid/content/pm/PackageInfo;
iget-object v4, v1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

const/4 v5, 0x0

aget-object v3, v4, v5

.line 382
.local v3, "sign":Landroid/content/pm/Signature;
invoke-virtual {v3}, Landroid/content/pm/Signature;->toCharsString()Ljava/lang/String;

move-result-object v4

const-string v4, "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"

sput-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;

.line 383
sget-object v4, Lcom/txbnx/torrentsearcher/Utils;->mPublicKey:Ljava/lang/String;
:try_end_0
.catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

goto :goto_0

.line 384
.end local v1 # "packageinfo":Landroid/content/pm/PackageInfo;
.end local v3 # "sign":Landroid/content/pm/Signature;
:catch_0
move-exception v0

.line 385
.local v0, "e":Ljava/lang/Exception;
const/4 v4, 0x0

goto :goto_0
.end method

相比官方版getSign方法，修改部分為紅色字體（無換行）。刪除crack.smali，保存並回編譯。到此簽名校驗破解結束。



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