commit 7999d0bf6b362972f7e2edab9586435bd4daf563
Author: Chelsea Holland Komlo <m...@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
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