Help/Support Can a you set a value to a function pointer inside a hook?

[PixelYT 9 Moto E4 7.1.1]

Let's say I found this method and I wanna change the value to 0:

private int ReloadDuration(); // 0x2347C82

I would just do it by hooking it and returning 0 like this:

int (*old_ReloadDuration)(void *instance);
int ReloadDuration(void *instance)
{
  if(instance != NULL)
  {
   return 0; 
  }
  return old_ReloadDuration(instance);
}
// MShookfunction whatever lol

 

But can I do it by making a function pointer and changing the value of it inside a hook and how would I do it?

Would I do it like this?

int (*ReloadDuration)(void *instance) = (int (*)(void *))getAbsoluteAddress(targetLibName, 0xOFFSET); // Function pointer for int ReloadDuration

void (*old_FixedUpdate)(void *instance);
void FixedUpdate(void *instance)
{
 if(instance != NULL)
 {
  int Reloadtime = ReloadDuration(instance); // Declare a variable to our function pointer and call it ReloadTime
   int ReloadTime = 0; // Set the value to 0
 }
  old_FixedUpdate(instance);
}
// MSHookfunction of Fixedupdate, whatever

 

@Ted2 you or anyone can help me please?

[Ted2 39.2k Donor]

No, in programming you have getters and setters;

int getCoins() {
	return coins
}

void setCoins(int newValue) {
	coins = new_value
}

As you can see, to one of those functions you can pass a new value (SET). The other one just returns a variable (GET).

Function pointers are not any different, because the function pointer is that function and so, they work the same.

 

If for some reason you don't want to hook it, then I recommend opening the binary in IDA, go to the ReloadDuration method, and see which variable(s) is being used here (0x<some_value>. I assume this is an Unity game, so on top of the class ReloadDuration is in, you'll find a list of variables. See which one of them is inside ReloadDuration.

You can then change these variables in the FixedUpdate method, like so:

*(int*)((uint64_t)instance + 0x<variable_code> = 0;

 

Updated July 14, 2021 by Ted2

[PixelYT 9 Moto E4 7.1.1]

8 hours ago, Ted2 said:

No, in programming you have getters and setters;

int getCoins() {
	return coins
}

void setCoins(int newValue) {
	coins = new_value
}

As you can see, to one of those functions you can pass a new value (SET). The other one just returns a variable (GET).

Function pointers are not any different, because the function pointer is that function and so, they work the same.

 

If for some reason you don't want to hook it, then I recommend opening the binary in IDA, go to the ReloadDuration method, and see which variable(s) is being used here (0x<some_value>. I assume this is an Unity game, so on top of the class ReloadDuration is in, you'll find a list of variables. See which one of them is inside ReloadDuration.

You can then change these variables in the FixedUpdate method, like so:

*(int*)((uint64_t)instance + 0x<variable_code> = 0;

 

Okay, I don't have a problem with hooking, it's just that I wanted to know if it was possible to set a value to a function inside a hook, but other than that, I have no problem patching or hooking the function.

[PixelYT 9 Moto E4 7.1.1]

@Ted2 I just have one more quick question, that i'll ask here, I already asked on another site, but didn't receive a good response. So there was one class called IAPManager or something like that, and inside it there were many useful functions that if called, would buy you whatever it is supposed to, but inside that class there was no Update/LateUpdate/FixedUpdate method (I know in some cases they can be renamed, but I looked and that wasn't the case), so would I hook Start or Awake and call those functions through a function pointer? Which one works, or does neither work?

[Ted2 39.2k Donor]

19 minutes ago, PixelYT said:

@Ted2 I just have one more quick question, that i'll ask here, I already asked on another site, but didn't receive a good response. So there was one class called IAPManager or something like that, and inside it there were many useful functions that if called, would buy you whatever it is supposed to, but inside that class there was no Update/LateUpdate/FixedUpdate method (I know in some cases they can be renamed, but I looked and that wasn't the case), so would I hook Start or Awake and call those functions through a function pointer? Which one works, or does neither work?

https://docs.unity3d.com/Manual/ExecutionOrder.html

This is a great graph that tells you what and when they're being executed.

So I don't think any of those two will work.

 

It's possible other classes have an instance of this IAPManager class, and handle it there.

But without more info, I can't really answer.

[PixelYT 9 Moto E4 7.1.1]

2 hours ago, Ted2 said:

https://docs.unity3d.com/Manual/ExecutionOrder.html

This is a great graph that tells you what and when they're being executed.

So I don't think any of those two will work.

 

It's possible other classes have an instance of this IAPManager class, and handle it there.

But without more info, I can't really answer.

Alright thanks for the help