折腾：
【已解决】从不同版本的小花生apk中反编译出包含业务逻辑代码的dex和jar包源码
期间，已经试过了v3.6.9所导出dex文件是无效dex：只有一个200多B的dex。
旧版本v1.5，导出dex，部分看起来是有效的，但是dex转jar后的源码，发现都是出错的opcode，找不到要的源码。
现在去尝试使用v3.4.8的版本去试试，是否可行。
把v3.4.8的apk：
安装到夜神模拟器后，再去启动FDex2，设置hook这个小花生app：
然后试了半天，终于hook出3.4.8版本中，N多个看起来是有效的dex文件了：
然后继续去dex转jar
➜ v3.4.8 ll total 81656 -rw------- 1 crifan staff 1.1M 3 19 14:05 com.huili.readingclub1166288.dex -rw------- 1 crifan staff 12M 3 19 14:04 com.huili.readingclub13088280.dex -rw------- 1 crifan staff 1.4M 3 19 14:04 com.huili.readingclub1461452.dex -rw------- 1 crifan staff 187K 3 19 14:04 com.huili.readingclub191572.dex -rw------- 1 crifan staff 2.7M 3 19 14:04 com.huili.readingclub2847840.dex -rw------- 1 crifan staff 3.8M 3 19 14:04 com.huili.readingclub3986968.dex -rw------- 1 crifan staff 8.3M 3 19 14:04 com.huili.readingclub8725900.dex -rw------- 1 crifan staff 8.4M 3 19 14:04 com.huili.readingclub8825612.dex ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub1166288.dex ... GLITCH: 0000 Lcom/android/internal/telephony/uicc/VoiceMailConstants;.getVoiceMailTag(Ljava/lang/String;)Ljava/lang/String; | zero-width instruction op=0xf4 Detail Error Information in File ./com.huili.readingclub1166288-error.zip Please report this file to one of following link if possible (any one). https://sourceforge.net/p/dex2jar/tickets/ https://bitbucket.org/pxb1988/dex2jar/issues https://github.com/pxb1988/dex2jar/issues [email protected] ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub13088280.dex ... GLITCH: 009f Lcom/tencent/bugly/legu/proguard/z;.a(Ljava/lang/Thread;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V | zero-width instruction op=0xf8 Detail Error Information in File ./com.huili.readingclub13088280-error.zip ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub1461452.dex ... GLITCH: 0000 Lcom/google/android/util/SmileyResources;.getSmileys()Lcom/google/android/util/AbstractMessageParser$TrieNode; | zero-width instruction op=0xf4 WARN: can't get operand(s) for sub-double/2addr, out-of-range or not initialized ? WARN: can't get operand(s) for int-to-float, out-of-range or not initialized ? WARN: can't get operand(s) for return-wide, out-of-range or not initialized ? WARN: can't get operand(s) for move-exception, out-of-range or not initialized ? WARN: can't get operand(s) for move-exception, out-of-range or not initialized ? Detail Error Information in File ./com.huili.readingclub1461452-error.zip ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub191572.dex ... GLITCH: 0006 Lcom/android/okhttp/internal/tls/OkHostnameVerifier;.verifyHostName(Ljava/lang/String;Ljava/lang/String;)Z | zero-width instruction op=0xee Detail Error Information in File ./com.huili.readingclub191572-error.zip ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub2847840.dex ... GLITCH: 0006 Lsun/misc/Unsafe;.unpark(Ljava/lang/Object;)V | zero-width instruction op=0xf8 Detail Error Information in File ./com.huili.readingclub2847840-error.zip ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub3986968.dex dex2jar com.huili.readingclub3986968.dex -> ./com.huili.readingclub3986968-dex2jar.jar ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub8725900.dex ... GLITCH: 0000 Landroid/widget/ZoomControls;.setOnZoomOutClickListener(Landroid/view/View$OnClickListener;)V | zero-width instruction op=0xf4 GLITCH: 0000 Landroid/widget/ZoomControls;.setZoomSpeed(J)V | zero-width instruction op=0xf4 WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-object/16, out-of-range or not initialized ? WARN: can't get operand(s) for shr-int/2addr, out-of-range or not initialized ? WARN: can't get operand(s) for move/16, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move/16, out-of-range or not initialized ? WARN: can't get operand(s) for move-result, wrong position ? WARN: can't get operand(s) for cmpl-float, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for sput-boolean, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-object/from16, out-of-range or not initialized ? WARN: can't get operand(s) for move-object/from16, out-of-range or not initialized ? WARN: can't get operand(s) for move-object/from16, out-of-range or not initialized ? WARN: can't get operand(s) for move-object/from16, out-of-range or not initialized ? WARN: can't get operand(s) for move-object/from16, out-of-range or not initialized ? WARN: can't get operand(s) for sput-boolean, out-of-range or not initialized ? WARN: can't get operand(s) for sput-boolean, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for aput-char, out-of-range or not initialized ? WARN: can't get operand(s) for mul-float, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for move-wide/16, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for mul-int/2addr, out-of-range or not initialized ? WARN: can't get operand(s) for aput-char, out-of-range or not initialized ? WARN: can't get operand(s) for aput-char, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for sput-byte, out-of-range or not initialized ? WARN: can't get operand(s) for aget-byte, out-of-range or not initialized ? WARN: can't get operand(s) for and-int/2addr, out-of-range or not initialized ? WARN: can't get operand(s) for move/from16, out-of-range or not initialized ? WARN: can't get operand(s) for iput-boolean, out-of-range or not initialized ? WARN: can't get operand(s) for iput-boolean, out-of-range or not initialized ? WARN: can't get operand(s) for move-result-object, wrong position ? WARN: can't get operand(s) for cmpg-float, out-of-range or not initialized ? Detail Error Information in File ./com.huili.readingclub8725900-error.zip Please report this file to one of following link if possible (any one). https://sourceforge.net/p/dex2jar/tickets/ https://bitbucket.org/pxb1988/dex2jar/issues https://github.com/pxb1988/dex2jar/issues [email protected] java.util.IllegalFormatConversionException: d != java.lang.String at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4302) at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2793) at java.util.Formatter$FormatSpecifier.print(Formatter.java:2747) at java.util.Formatter.format(Formatter.java:2520) at java.util.Formatter.format(Formatter.java:2455) at java.lang.String.format(String.java:2940) at com.googlecode.d2j.smali.BaksmaliDumpOut.s(BaksmaliDumpOut.java:68) at com.googlecode.d2j.smali.BaksmaliCodeDumper.visitFilledNewArrayStmt(BaksmaliCodeDumper.java:248) at com.googlecode.d2j.node.insn.FilledNewArrayStmtNode.accept(FilledNewArrayStmtNode.java:19) at com.googlecode.d2j.smali.BaksmaliDumper.accept(BaksmaliDumper.java:569) at com.googlecode.d2j.smali.BaksmaliDumper.baksmaliCode(BaksmaliDumper.java:544) at com.googlecode.d2j.smali.BaksmaliDumper.baksmaliMethod(BaksmaliDumper.java:482) at com.googlecode.d2j.smali.BaksmaliDumper.baksmaliMethod(BaksmaliDumper.java:428) at com.googlecode.dex2jar.tools.BaksmaliBaseDexExceptionHandler.dumpMethod(BaksmaliBaseDexExceptionHandler.java:148) at com.googlecode.dex2jar.tools.BaksmaliBaseDexExceptionHandler.dumpTxt0(BaksmaliBaseDexExceptionHandler.java:126) at com.googlecode.dex2jar.tools.BaksmaliBaseDexExceptionHandler.dumpZip(BaksmaliBaseDexExceptionHandler.java:135) at com.googlecode.dex2jar.tools.BaksmaliBaseDexExceptionHandler.dump(BaksmaliBaseDexExceptionHandler.java:92) at com.googlecode.dex2jar.tools.Dex2jarCmd.doCommandLine(Dex2jarCmd.java:120) at com.googlecode.dex2jar.tools.BaseCmd.doMain(BaseCmd.java:290) at com.googlecode.dex2jar.tools.Dex2jarCmd.main(Dex2jarCmd.java:33) ➜ v3.4.8 /Users/crifan/dev/dev_tool/android/reverse_engineering/dex-tools/dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.huili.readingclub8825612.dex dex2jar com.huili.readingclub8825612.dex -> ./com.huili.readingclub8825612-dex2jar.jar ➜ v3.4.8 ll total 125288 -rw------- 1 crifan staff 469K 3 21 09:55 com.huili.readingclub1166288-dex2jar.jar -rw-r--r-- 1 crifan staff 14K 3 21 09:55 com.huili.readingclub1166288-error.zip -rw------- 1 crifan staff 1.1M 3 19 14:05 com.huili.readingclub1166288.dex -rw------- 1 crifan staff 121K 3 21 09:56 com.huili.readingclub13088280-dex2jar.jar -rw-r--r-- 1 crifan staff 16K 3 21 09:56 com.huili.readingclub13088280-error.zip -rw------- 1 crifan staff 12M 3 19 14:04 com.huili.readingclub13088280.dex -rw------- 1 crifan staff 669K 3 21 09:56 com.huili.readingclub1461452-dex2jar.jar -rw-r--r-- 1 crifan staff 25K 3 21 09:56 com.huili.readingclub1461452-error.zip -rw------- 1 crifan staff 1.4M 3 19 14:04 com.huili.readingclub1461452.dex -rw------- 1 crifan staff 103K 3 21 09:57 com.huili.readingclub191572-dex2jar.jar -rw-r--r-- 1 crifan staff 7.0K 3 21 09:57 com.huili.readingclub191572-error.zip -rw------- 1 crifan staff 187K 3 19 14:04 com.huili.readingclub191572.dex -rw------- 1 crifan staff 1.6M 3 21 09:58 com.huili.readingclub2847840-dex2jar.jar -rw-r--r-- 1 crifan staff 47K 3 21 09:58 com.huili.readingclub2847840-error.zip -rw------- 1 crifan staff 2.7M 3 19 14:04 com.huili.readingclub2847840.dex -rw------- 1 crifan staff 3.5M 3 21 09:59 com.huili.readingclub3986968-dex2jar.jar -rw------- 1 crifan staff 3.8M 3 19 14:04 com.huili.readingclub3986968.dex -rw------- 1 crifan staff 5.1M 3 21 10:00 com.huili.readingclub8725900-dex2jar.jar -rw-r--r-- 1 crifan staff 68K 3 21 10:00 com.huili.readingclub8725900-error.zip -rw------- 1 crifan staff 8.3M 3 19 14:04 com.huili.readingclub8725900.dex -rw------- 1 crifan staff 9.5M 3 21 10:00 com.huili.readingclub8825612-dex2jar.jar -rw------- 1 crifan staff 8.4M 3 19 14:04 com.huili.readingclub8825612.dex
然后再去看看，哪个jar包是包含业务逻辑代码，用jd-gui去打开并导出代码
然后看到了：
之前dex转jar时，没有报错的：
从：
8.8MB com.huili.readingclub8825612.dex
转出：
10MB com.huili.readingclub8825612-dex2jar.jar
打开后：
可以看到里面有我们要的
/com/huili/readingclub/activity/classroom/SelfReadingActivity.class
其中onSuccess中，就是我们希望得到的，对于J字段解密的逻辑。
【总结】
经过尝试，小花生的v3.4.8的安卓app，是可以用FDex2去hook导出有用的dex文件，且包含了我们希望的业务逻辑的那个dex，在dex转jar期间，是完美的不出错的，然后得到jar后，去用jd-gui打开后，导出全部代码，即可看到完整的代码，其中包含我们需要的，网络请求返回响应中json中的J字段的解密解码逻辑。
后续继续去：
【已未解决】从反编译小花生apk得到的包含业务逻辑代码中找到J字段解码的逻辑并用Python实现