trivial testcase to notice uninitialized memory use in Rust

membleed.rs

use std::vec;

// Use the system allocator so we can substitute it with a custom one via LD_PRELOAD
use std::alloc::System;
#[global_allocator]
static GLOBAL: System = System;

/// Returns the sum of all values in a vector of uninitialized memory
fn sum_uninitialized() -> u64 {
    let mut my_vec: Vec<u64> = Vec::with_capacity(2048);
    unsafe {my_vec.set_len(2048);}
    let mut sum = 0;
    for element in my_vec {
        sum += element;
    }
    sum
}

// The program will panic if the use of uninitialized memory is noticed.
fn main() {
    let first_run_result = sum_uninitialized();
    let second_run_result = sum_uninitialized();
    println!("Sum is {}", first_run_result);
    assert!(first_run_result == second_run_result);
}