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[Q] Not loading class from Classes2.dex?

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By cryptyk, Recognized Contributor on 20th August 2014, 01:17 AM
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I'm trying to hook the following: com.google.android.ulr.ApiRate

It's in com.google.android.gms (Google Play Services). I verified it's in there by dex dumping the Classes2.dex from Play Services.

At runtime, I get this:
Code:
de.robv.android.xposed.XposedHelpers$ClassNotFoundError: java.lang.ClassNotFoundException: com.google.android.ulr.ApiRate
...
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.android.ulr.ApiRate" on path: DexPathList[[zip file "/system/framework/com.android.media.remotedisplay.jar", zip file "/system/framework/com.android.location.provider.jar", zip file "/data/app/com.google.android.gms-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.google.android.gms-2, /vendor/lib, /system/lib, /vendor/lib]]
The only thing I can think of is that it's because it's in Classes2.dex instead of Classes.dex?

Any thoughts?
 
 
21st August 2014, 07:39 PM |#2  
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Looks like you got this fixed. What was the problem?
22nd August 2014, 02:53 AM |#3  
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Quote:
Originally Posted by GermainZ

Looks like you got this fixed. What was the problem?

I wasn't able to fix it. I tried using multidex but never got it working. In the end, i had to dig through a lot of projects dalvik bytecode and follow the call stack back to a place defined in classes.dex, then hook it there. Not ideal, and more chances for side effects, but things seem to be working

I'd love to see a fix at some point!
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28th December 2014, 07:47 AM |#4  
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Quote:
Originally Posted by cryptyk

I wasn't able to fix it. I tried using multidex but never got it working. In the end, i had to dig through a lot of projects dalvik bytecode and follow the call stack back to a place defined in classes.dex, then hook it there. Not ideal, and more chances for side effects, but things seem to be working

I'd love to see a fix at some point!

Could you point me in the right direction here? com.google.android.a.r seems to be pretty close. Lots of references to DexClassLoader.
28th December 2014, 08:50 AM |#5  
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Quote:
Originally Posted by cryptyk

I'm trying to hook the following: com.google.android.ulr.ApiRate

It's in com.google.android.gms (Google Play Services). I verified it's in there by dex dumping the Classes2.dex from Play Services.

At runtime, I get this:

Code:
de.robv.android.xposed.XposedHelpers$ClassNotFoundError: java.lang.ClassNotFoundException: com.google.android.ulr.ApiRate
...
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.android.ulr.ApiRate" on path: DexPathList[[zip file "/system/framework/com.android.media.remotedisplay.jar", zip file "/system/framework/com.android.location.provider.jar", zip file "/data/app/com.google.android.gms-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.google.android.gms-2, /vendor/lib, /system/lib, /vendor/lib]]
The only thing I can think of is that it's because it's in Classes2.dex instead of Classes.dex?

Any thoughts?

I guess this is caused by using the wrong class loader.

Try finding the class with classForName by specifying another class loader:
http://developer.android.com/referen...g.ClassLoader)

You will need to find a way to get to another class loader though.
29th December 2014, 03:17 AM |#6  
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Found a surprisingly easy way to hook any class needed from Play Services. Just hook the Application onCreate. It looks like the initial package class loader will only have the initial dex file loaded. After loading the initial application instance GMS will at some point, I'm guessing, load the additional dexes. The GMS Application Context appears to have a fully loaded class loader associated with it. Tapping into that will give you access to whatever you need. Much simpler than I expected and resistant to per-release obfuscation.
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