Tutorial How to modify Set Methods in Unity's il2cpp

[Numark]

Hey guys, it's SliceCast. So people have been asking, "how do you modify a set method instead of using get?". It's simple, since I'm a nice person, I don't mind sharing this information for you newbies or advanced modders. Let's get started.

Wait, before we actually start anything...

You need to read this tutorial first BEFORE WE START! If you already know how to hook, then skip onto the set tutorial.

Basic Hooking Tutorial - Platinmods.com - Android & iOS MODs, Mobile Games & Apps

Hey guys, it's SliceCast here. This tutorial is for Advanced Modders who wants to step up their games to get better! Could be for newbies too. I will show you some basics examples on how to hook a function. Now let's say our Type Functions are (int, float, bool, double) and that we're doing a...

platinmods.com

So get your set method, we're gonna make our set method a function pointer. We will be splitting this function pointer because when your lib is loaded sometimes, the libil2cpp isnt loaded already, but your lib doesn't know that and already tries to read the address which will result in a null pointer or crash. So here's how this will work.

void (*set_kills)(void *_instance, int AmountOfKills);

Now what were gonna do is use "set_kills" and paste it in our class hook which is get_ that we have made. All you need to do now is do "set_kills(instance, 999999);" without the parenthesis. It's really simple to do.

//the void *instance is a self-created variable.
int (*old_get_Kills)(void *instance);
int get_Kills(void *instance) {
    //Check if instance is NULL to prevent CRASH
    if (instance != NULL)
    {
        set_kills(instance, 999999); //Function Pointer mod
    }
    //return the original value (this code isn't really needed if you have a toggle/switch)
    return old_get_Kills(instance);
}

If this crashes, then you need to log the crashes and find out why.

It's pretty easy and simple. Last thing we need to do now is call the function pointer just like calling your MSHooks to make your mods work.

set_kills = (void (*)(void *, int))getRealOffset(OFFSET);

Also make sure to call your hooks (I forgot)
Note: HOOK_LIB is from LGL's mod menu template.

HOOK_LIB("libil2cpp.so", "0x00000", get_kills, old_get_kills);

Credits to SliceCast & Octowolve.
Discord: Slicey#5894

 

[HizroMxDz]

The only thing I am confused about is do we need to hook the get_ method because in your code you have the hook for it but you didn't call it with MSHook?

 

[Numark]

The only thing I am confused about is do we need to hook the get_ method because in your code you have the hook for it but you didn't call it with MSHook?

Oh yeah my mistake, you need to call it with MSHook, I was busy and rushed

 

[HizroMxDz]

Oh yeah my mistake, you need to call it with MSHook, I was busy and rushed

so let's say I have a method called get_ammo and it has a set_ammo too, so If I wanted to modify set_ammo then I would hook get_ammo and create a function pointer for set_ammo right?

 

[Numark]

so let's say I have a method called get_ammo and it has a set_ammo too, so If I wanted to modify set_ammo then I would hook get_ammo and create a function pointer for set_ammo right?

Yes

 

[HizroMxDz]

Yes

all good, thanks!

 

[ＧＯＤＳ]

I see, so that's how we do it. I always hook Set method directly and after reading this no wonder it didn't work.
Thank you

 

[ＧＯＤＳ]

1 question tho, what if my function don't have any additional parameter?

public double DamageMultiplier
        {
            [Token(Token = "0x6002140")]
            [Address(RVA = "0x4D0E14", Offset = "0x4D0E14", VA = "0x4D0E14")]
            get
            {
                return 0.0;
            }
            [Token(Token = "0x6002141")]
            [Address(RVA = "0x4D0E20", Offset = "0x4D0E20", VA = "0x4D0E20")]
            set

Should I make it like this?

double (*set_DamageMultiplier)(void *instance);


double (*old_get_DamageMultiplier)(void *instance);
double get_DamageMultiplier(void *instance) {
    if(instance != NULL && getdmg) {
        set_DamageMultiplier; 99999;  
    }
    return old_get_DamageMultiplier(instance);
}

 

[HizroMxDz]

1 question tho, what if my function don't have any additional parameter?

public double DamageMultiplier
        {
            [Token(Token = "0x6002140")]
            [Address(RVA = "0x4D0E14", Offset = "0x4D0E14", VA = "0x4D0E14")]
            get
            {
                return 0.0;
            }
            [Token(Token = "0x6002141")]
            [Address(RVA = "0x4D0E20", Offset = "0x4D0E20", VA = "0x4D0E20")]
            set

Should I make it like this?

double (*set_DamageMultiplier)(void *instance);


double (*old_get_DamageMultiplier)(void *instance);
double get_DamageMultiplier(void *instance) {
    if(instance != NULL && getdmg) {
        set_DamageMultiplier; 99999;
    }
    return old_get_DamageMultiplier(instance);
}

you're just at the function, not the setter, go to the set part of that function, it could be something like set_FunctionName or setFunctionName, but yeah for that function there is a getter and setter, just find the setter

 

[ＧＯＤＳ]

you're just at the function, not the setter, go to the set part of that function, it could be something like set_FunctionName or setFunctionName, but yeah for that function there is a getter and setter, just find the setter

ouh I got it.

For general, what should I do if the function don't have additional parameter?

 

[HizroMxDz]

ouh I got it.

For general, what should I do if the function don't have additional parameter?

then just return the value you want (if it isn't a void) but if it is a void and has no parameters (highly unlikely) then just hook the getter (get) and modify it to return whatever you want

 

[Numark]

Updated Thread

 

[ＧＯＤＳ]

Updated Thread

I have question, Let's say I've "Update" function and a "isKilled" function but it dont have additional parameters and it accept bool as return. So I create a hook for both Update and isKilled. Then create a function pointer for isKilled inside Update.
Will this work? or is there any other way to use function pointer that has no additional parameters?

 

[Tiahh]

I have question, Let's say I've "Update" function and a "isKilled" function but it dont have additional parameters and it accept bool as return. So I create a hook for both Update and isKilled. Then create a function pointer for isKilled inside Update.
Will this work? or is there any other way to use function pointer that has no additional parameters?

you could just set a function pointer on isKilled and hook update.
Then just use iskilled inside update.

bool (*isKilled)(void*instance) = (bool (*)(void*))ScanAddress(...);

void (*old_Update)(void *instance);
void Update(void *instance)
{
    if (instance != NULL) //checks if instance is null
    {
        if (isKilled(instance))
        {
            //here do big hacking..
        }
    }
    old_Update(instance); //run old function.
}

 

[ＧＯＤＳ]

you could just set a function pointer on isKilled and hook update.
Then just use iskilled inside update.

bool (*isKilled)(void*instance) = (bool (*)(void*))ScanAddress(...);

void (*old_Update)(void *instance);
void Update(void *instance)
{
    if (instance != NULL) //checks if instance is null
    {
        if (isKilled(instance))
        {
            //here do big hacking..
        }
    }
    old_Update(instance); //run old function.
}

That's unusual way of using function pointer, I've feeling that will crash the game because it's not splitted.
I'll try that in my next mod.
Anyway thank you for sharing your knowledge with me.

 

[Tiahh]

That's unusual way of using function pointer, I've feeling that will crash the game because it's not splitted.
I'll try that in my next mod.
Anyway thank you for sharing your knowledge with me.

depends, if you load your library after the game library is loaded it will not crash your game, if you want you can split it.

 

[Lop_A1254]

you could just set a function pointer on isKilled and hook update.
Then just use iskilled inside update.

bool (*isKilled)(void*instance) = (bool (*)(void*))ScanAddress(...);

void (*old_Update)(void *instance);
void Update(void *instance)
{
    if (instance != NULL) //checks if instance is null
    {
        if (isKilled(instance))
        {
            //here do big hacking..
        }
    }
    old_Update(instance); //run old function.
}

Just a quick question if you're free to answer it, what if a void has a return default boolean parameter, is there a way to hook it using the update function or do i need to just hook the void's paramater insted? This is the example:




public void SetSPOILERState(bool LLSPOILER = False) { }

 

[ＧＯＤＳ]

Just a quick question if you're free to answer it, what if a void has a return default boolean parameter, is there a way to hook it using the update function or do i need to just hook the void's paramater insted? This is the example:




public void SetSPOILERState(bool LLSPOILER = False) { }

I suggest you to learn C++ first, then only you will understand what actually happened in that code and how you can hook it. Good place to learn C++ w3school. That will get you to understand the basic. First thing to remember when learning modding is, if you don't understand it then you're not ready for it yet. Spend at least 1 week on learning C++ then continue on modding.

I don't mean to be rude lol, in case you already know C++ but don't know how you can hook this, you simply not ready for this yet. I mean just hook anything you can with your current knowledge.

 

[Lop_A1254]

Bruh i already know Cpp its just that i never used it for modding...


Also i was just confusing that function with another so it was very easy to hook.

 

[Leaderide]

I have a void ApplyDamage(float damage, .... ,.. ) function, but I don't really know how to Hook it, the base tutorial isn't really showing what to do in the beginning