Crate bhook

This is a very lightweight hooking crate, which supports the x86, x86_64, arm and aarch64 architectures, you can also use this crate on no-std too by disabling the std feature. here is a quick example of it (with the std feature)

use bhook::hook_fn;
hook_fn! {
     fn hook(val: u64, val2:u32) -> u64 = {
        let orig = unsafe { call_original(val, val2) };
        println!("testhook: val1: {val} val2: {val2}");
        println!("ret: {orig}");
        orig
    }
}
fn main() {
    numbers(98, 87);
    unsafe {
        hook::hook_address(numbers as *mut u8);
    }
    numbers(68, 92);
}
#[inline(never)]
fn numbers(n1: u64, n2: u32) -> u64 {
    println!("im numbers");
    n1 + n2 as u64
}

How does it work??

It writes a simple branch to the target to redirect calls using with instructions suitable for the platform, the maximum amount of bytes it will overwrite is in the BRANCH_LEN constant, however it generally will try to use the least amount of bytes to do the branch

Notices

The BIG disadvantage of the hook_fn macro is that call_original will undo the hook until the call finishes, which can be very unsuitable for mulithreaded envoiroments you can use the functions in the utils module to do things more manually, or use raw_hook

Macros

hook_fn

Constants

BACKUP_LEN

Functions

raw_hook^⚠

Branch hook a function.

setup_hook^⚠

Handle memory protection and save backup bytes before doing branch hooking. You can use ‘unsetup_hook’ to call the original function using this

unsetup_hook^⚠

Handle memory protection and then write back the backup bytes.