Question: Is it possible to inject functions into libraries dynamically?

nagisa / rust_libloading

Bindings around the platform's dynamic library loading primitives with greatly improved memory safety.

https://docs.rs/libloading

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Question: Is it possible to inject functions into libraries dynamically? #126

Closed phenax closed 1 year ago

phenax commented 1 year ago

Dumb question: Is something like this possible?

// library.c
unsigned int injectable() { return 0; }

// main.rs
fn injected_func() -> u32 { 5 }

let lib = libloading::Library::new("/path/to/liblibrary.so")?;
let func: libloading::Symbol<*mut fn() -> u32> = lib.get(b"injectable");
if let Ok(func) = func {
  **func = injected_func;
}

phenax commented 1 year ago

Defining it as a pointer does the trick

unsigned int (*injectable)() { return 0; }