CODEWITHSUNDEEP
androiddatabase
Seung
Seung

Reputation: 833

how to read Memory data from an android app

I'd like to get some numerical data from an app, but they are not stored as files like db. I know there are some memory hack apps for changing in game values although I do not know how they work. I am looking for similar features but I don't need to change anything.

The app I am trying to write just reads some data from a specific app and do some background calculation based on that. If this is not possible, I would need to get information by reading the screen(for example get pixel color), but this seems to be very cumbersome task for getting many data.

Is there a way of achieving this?

Thanks.

EDIT: I'd assume I would need a root permission for this?

Upvotes: 4

Views: 11938

Answers (2)

user1643723
user1643723

Reputation: 4222

Yes, you would need root permission. Additionally your users must have fully rooted device with e.g. SuperSU or other modern Su app, that can lift most SELinux restrictions. There may also be conflicts with KNOX and other similar systems, but I am not really knowledgeable about those.

You would need to attach your process as debugger to the target application and locate the necessary data by scanning it's memory. This can be done in multiple ways, the best reference implementation to look at can be found in scanmem.

The code, performing the actual deed, which requires root rights, — reading/writing target process memory — would reside in a native executable, being run via su. You'd have to write some code to communicate with that executable (probably via it's stdin/stdout or something like that).

You will also have to write additional code to parse the memory layout of target application yourself.

Alternatively, you may prefer to inject a small module in memory of target application and/or have the app itself load a Dex file of you making (especially handy, if your target data is stored in Java memory). This approach have a benefit of minimizing interaction with memory layout of virtual machine, but you still have to initiate loading of initial Dex file. Once Dex file is loaded, you can do the rest in Java code, using good-old reflection API. If you go with this route, a (decently supported!) code for injecting executable snippets in memory of Linux process can be found in compel library, being developed as part of CRIU project[1].

Upvotes: 12

David
David

Reputation: 16277

Two Android processes cannot share memory and communicate with each other directly. So to communicate, objects have to be decomposed into primitives (marshalling) and transfered across process boundaries.

To do this marshalling, one has to write a lot of complicated code, hence Android handles it for us with AIDL (Android Interface Definition Language).

From the OP, as no more details can be found, I would recommend you reading/searching with the keyword "AIDL" and you will be redirected to the concrete solutions.

Upvotes: 1

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