commit 7999d0bf6b362972f7e2edab9586435bd4daf563 Author: Chelsea Holland Komlo me@chelseakomlo.com Date: Wed Oct 25 22:22:10 2017 -0400

update tor_allocate and add tests --- src/rust/tor_allocate/tor_allocate.rs | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/rust/tor_allocate/tor_allocate.rs b/src/rust/tor_allocate/tor_allocate.rs index e2fc3ea36..7b348b6d0 100644 --- a/src/rust/tor_allocate/tor_allocate.rs +++ b/src/rust/tor_allocate/tor_allocate.rs @@ -1,5 +1,5 @@ use libc::{c_char, c_void}; -use std::{ptr, slice}; +use std::{ptr, slice, mem};

#[cfg(not(test))] extern "C" { @@ -19,29 +19,35 @@ extern "C" fn tor_malloc_ ( size: usize) -> *mut c_void { /// /// # Inputs /// -/// * `src`, a reference to a String that will be copied. +/// * `src`, a reference to a String. /// /// # Returns /// -/// A `String` that should be freed by tor_free in C +/// A `*mut c_char` that should be freed by tor_free in C /// pub fn allocate_and_copy_string(src: &String) -> *mut c_char { - let bytes = src.as_bytes(); + let bytes: &[u8] = src.as_bytes();

- let size = bytes.len(); - let size_with_null_byte = size + 1; + let size = mem::size_of_val::<[u8]>(bytes); + let size_one_byte = mem::size_of::<u8>(); + + // handle integer overflow when adding one to the calculated length + let size_with_null_byte = match size.checked_add(size_one_byte) { + Some(n) => n, + None => return ptr::null_mut(), + };

let dest = unsafe { tor_malloc_(size_with_null_byte) as *mut u8 };

if dest.is_null() { - return dest as *mut c_char; + return ptr::null_mut(); }

unsafe { ptr::copy_nonoverlapping(bytes.as_ptr(), dest, size) };

// set the last byte as null, using the ability to index into a slice // rather than doing pointer arithmatic - let slice = unsafe { slice::from_raw_parts_mut(dest, size_with_null_byte) }; + let slice = unsafe { slice::from_raw_parts_mut(dest, size_with_null_byte)}; slice[size] = 0; // add a null terminator

dest as *mut c_char