Struct zerodrop::ZeroDrop

pub struct ZeroDrop<T>(_)
 where
    T: Copy;

Zeroing drop wrapper type for Copy type.

Assuming T: Copy, a ZeroDrop<T> wraps a Box<T> and zeros it when dropped. We must use Box because LLVM moves data on the stack willy nilly.

let p : *const [u8; 32];
let s = zerodrop::ZeroDrop::new_copy(&[3u8; 32]);  
p = &*s;
std::mem::drop(s);
unsafe { assert_eq!(*p,[0u8; 32]); }

We recommend abstracting usage of ZeroDrop as follows because ZeroDrop does not mlock data. rust,ignore type Secret<T> = ZeroDrop<T> where T: Copy+Default; We similarly encurage wrapping ZeroDrop yourself so as to limit where and how secret data can be used in your code, including avoiding any trait magic that seems overly subtle. rust,ignore struct MySecret(pub ZeroDrop<[u8; 32]>);

Methods

impl<T> ZeroDrop<T> where
    T: Copy, 

Create a ZeroDrop<T> for a T: Copy consisting of a Box<T> that will be zeroed when dropped.

fn new_insecure(t: T) -> ZeroDrop<T>

Insecure as t likely gets placed on the stack

fn new_box(b: Box<T>) -> ZeroDrop<T>

Use provided Box<T>

unsafe fn new_uninitialized() -> ZeroDrop<T>

Secure but unsafe

fn new_copy(t: &T) -> ZeroDrop<T>

Allocate box and copy data into it from reference

unsafe fn zero_out(&mut self)

fn new_zeroed() -> ZeroDrop<T>

Trait Implementations

impl<T: Debug> Debug for ZeroDrop<T> where
    T: Copy, 

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T> Drop for ZeroDrop<T> where
    T: Copy, 

Zero a ZeroDrop<T> when dropped.

fn drop(&mut self)

A method called when the value goes out of scope.

impl<T> Default for ZeroDrop<T> where
    T: Copy + Default, 

fn default() -> ZeroDrop<T>

Returns the "default value" for a type.

impl<T> Clone for ZeroDrop<T> where
    T: Copy, 

Clone the underlying Box

fn clone(&self) -> ZeroDrop<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &ZeroDrop<T>)

Performs copy-assignment from source.

impl<T> Deref for ZeroDrop<T> where
    T: Copy, 

Delegate Deref to Box

type Target = T

The resulting type after dereferencing

fn deref(&self) -> &T

The method called to dereference a value

impl<T> DerefMut for ZeroDrop<T> where
    T: Copy, 

Delegate DerefMut to Box

fn deref_mut(&mut self) -> &mut T

The method called to mutably dereference a value

impl<T> AsRef<T> for ZeroDrop<T> where
    T: Copy, 

Delegate AsRef<_> to Box

fn as_ref(&self) -> &T

Performs the conversion.

impl<T> AsMut<T> for ZeroDrop<T> where
    T: Copy, 

Delegate AsMut<_> to Box

fn as_mut(&mut self) -> &mut T

Performs the conversion.

impl<T> Borrow<T> for ZeroDrop<T> where
    T: Copy, 

Delegate Borrow<_> to Box

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T> BorrowMut<T> for ZeroDrop<T> where
    T: Copy, 

Delegate BorrowMut<_> to Box

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value.