Accessing Lists Field...

[afk-Legacy]

I intend to access a field which is a list, I am pretty new to ts and frida in genreal so not sure how to do so,

[vfsfitvnm]

You have to handle it like a general Il2CppObject.
System.Collections.Generic.List<T> is a Il2CppObject under any point of view - it doesn't have a corresponding Il2CppTypeEnum so it doesn't have to be handled specially.

const Point = object.fields.Point;

// System.Collections.Generic.List<System.Int64>
console.log(Point.type.name);

// it will print the System.Collections.Generic.List<System.Int64> class
console.log(Point.type.class);

const PointValue = Point.value as Il2Cpp.Object;

const size = PointValue.methods.get_Count.invoke<number>();
PointValue.methods.Add.invoke<void>(1234);
const newSize = PointValue.methods.get_Count.invoke<number>();
console.log(size + 1 == newSize);

[afk-Legacy]

pointInString.implementation = function (format : Il2Cpp.String) : Il2Cpp.String
    {
        
        const PointValue = this.fields.Point.value as Il2Cpp.Object;
        
        const val = PointValue.methods.get_Item.invoke<number>(0);


        //log(JSON.stringify(state));
        return this.methods["ToString_"].invoke<Il2Cpp.String>(format);
    }

Generating Error:

Error: expected a NativePointer object
    at NativeFunction.<anonymous> (<anonymous>)
    at Il2CppMethod.invokeRaw (../../node_modules/frida-il2cpp-bridge/dist/il2cpp/structs/method.js:141:1)
    at Il2CppMethod.<anonymous> (../../node_modules/frida-il2cpp-bridge/dist/il2cpp/structs/method.js:149:1)
    at Il2CppObject.pointInString.implementation (index.ts:40:49)
    at InvocationContext.replaceCallback (../../node_modules/frida-il2cpp-bridge/dist/il2cpp/structs/method.js:95:1)

[afk-Legacy]

hey sorry for the late reply, the class is EgoPoint and the hooked function is public string ToString(string format) , there is only one field here whose data I am trying to log.

[afk-Legacy]

The ToString is always being called in game so you wont have much of difficulty managing to execute it.

[afk-Legacy]

Also, how can we get the address of a variable, for example I want to find the address of variable "Point" in memory, navigating to the provided memory address would reveal the contents of the list, size and so on....

[vfsfitvnm]

It looks like a bug that happens with inflated methods.
Calling an inflated method requires the corresponding Il2CppMethod to be appended to the parameter list, but this is not true for every inflated method (I don't know why, maybe it is only true for constructors?).

However, the bug occurred because I was prepending (instead of appending) that extra "pointer" type parameter:
for get_Item, I was generating ["pointer", "pointer", "int32"] instead of ["pointer", "int32", "pointer"] (instance, index, method). So that's why Frida got angry. You can check the generated signature yourself via Il2Cpp.Method.fridaSignature.

It is funny how this bug wasn't discovered earlier (probably a regression?).

I'll push a new version as soon as I can, I want to investigate a little more, first.

Meanwhile, you can declare your own get_Item like this:

const AssemblyCSharp = Il2Cpp.Domain.assemblies["Assembly-CSharp"].image;
const EgoPoint = AssemblyCSharp.classes.EgoPoint;

const get_Item = new NativeFunction(EgoPoint.fields.Point.type.class.methods.get_Item.virtualAddress, "int64", ["pointer", "int32"]); // in this case, that statement it's not true

EgoPoint.methods.ToString_.implementation = function (format: Il2Cpp.String): Il2Cpp.String {
    const Point = this.fields.Point.value as Il2Cpp.Object;
        
    const firstValue: Int64 = get_Item.invoke(Point, 0);

    return this.methods.ToString_.invoke(format);
};

[vfsfitvnm]

Fixed in 0.5.6