feat: initial work on attaching with ptrace

src/lib.rs

@@ -0,0 +1,4 @@
+#[ctor::ctor]
+fn constructor() {
+	println!("Hello world!");
+}

src/main.rs

@@ -0,0 +1,56 @@
+use std::ffi::c_void;
+use nix::{sys::ptrace, unistd::Pid, errno::Errno};
+use clap::Parser;
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct NeedleArgs {
+	/// target process pid
+	pid: i32,
+
+	/// word size on OS (check with $ getconf WORD_BIT)
+	#[arg(long, default_value_t = 32)]
+	word: u32,
+}
+
+pub fn write_buffer(pid: Pid, addr: usize, payload: &[u8], word:u32) -> Result<(), Errno> {
+	let mut buffer = payload.to_vec();
+
+	while buffer.len() % word as usize != 0 {
+		buffer.push(0); // pad with zeros because we copy chunks of size 'word'
+	}
+
+	for i in (0..buffer.len()).step_by(word as usize) {
+		unsafe {
+			let offset = (addr + i) as *mut c_void;
+			let data = (buffer.as_ptr().add(i)) as *mut c_void;
+			ptrace::write(pid, offset, data)?;
+		}
+	}
+
+	Ok(())
+}
+
+fn main() {
+	let args = NeedleArgs::parse();
+	let pid = Pid::from_raw(args.pid);
+
+	if let Err(e) = ptrace::attach(pid) {
+		eprintln!("Could not attach to process : {}", e);
+		return;
+	}
+
+	println!("Attached to process #{}", args.pid);
+
+	let shellcode = [42; 20];
+
+	if let Err(e) = write_buffer(pid, 0x66666, &shellcode, args.word) {
+		eprintln!("Failed writing shellcode into process memory space: {}", e);
+	}
+
+	if let Err(e) = ptrace::cont(pid, None) {
+		eprintln!("Could not resume process : {}", e);
+	} else {
+		println!("Released process #{}", args.pid);
+	}
+}