Way to search for string occurence during the lifetime of the program

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#4,047 4 comentarios 0 reacciones 0 asignados Ver en GitHub

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Evaluación

Dificultad
5/5
Tiempo estimado
Más de una semana
Aptitud para principiantes
25/100
Tipo de issue
Nueva funcionalidad
Claridad
Necesita aclaración
Estado de actividad
Estancado
Stack tecnológico
cpp, rust
Área
reverse-engineering

Línea de trabajo

Start with the Rust get_user_input() and main() example, then investigate how rr handles replay state after input is dropped. Done would be a defined way to locate a previously observed string or byte sequence and trace it back to its earlier execution context.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

Request

I'm loving this project so much. I'm curious about the possibility of finding a specific string value (or byte sequence in general) that might've occurred and got dropped at some point during the execution of the program. This would be a really helpful feature for debugging, especially in the context of reverse engineering.

Context

I made a dummy Rust code that has a get_user_input() function that prints "Type Something: " and waits for user input, and a main() function that calls get_user_input() inside an infinite loop as shown here:

use std::io::{self, Write};

fn get_user_input() {
    print!("Type something: ");
    std::io::stdout().flush().expect("Failed to flush");

    let mut input = String::new();

    io::stdin()
        .read_line(&mut input)
        .expect("Failed to read line");

    println!("{}", input);
}

fn main() {
    // Print function addresse at runtime
    let addr = get_user_input as *const ();
    println!("Input function location: {:p}", addr);

    loop {
        get_user_input();
    }
}

Rust automatically drops the input variable once the get_user_input() function goes out of scope. The string value itself stays in memory, I was able to verify that using PINCE (a Cheat Engine alternative in Linux). But AFAIU, rr doesn't keep track of unallocated memory because it's unnecessary to reproduce the deterministic outcome of the program. So, in order to find that string in the replay and do a bunch of crazy RE stuff like seeing where it originally came from, I would need to position myself in the right time frame.

Lenguaje dominante
C++
Estrellas
10.7k
Forks
666
Merge medio
2 d 7 h
PR fusionados (30 d)
32

Preparar el entorno

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

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