35 lines
1.2 KiB
Go
35 lines
1.2 KiB
Go
// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
|
|
// Use of this source code is governed by an MIT license
|
|
// that can be found in the LICENSE file.
|
|
|
|
// Package subtle implements functions that are often useful in cryptographic
|
|
// code but require careful thought to use correctly.
|
|
|
|
module subtle
|
|
|
|
// NOTE: require unsafe in future
|
|
|
|
// any_overlap reports whether x and y share memory at any (not necessarily
|
|
// corresponding) index. The memory beyond the slice length is ignored.
|
|
pub fn any_overlap(x, y []byte) bool {
|
|
// NOTE: Remember to come back to this (joe-c)
|
|
return x.len > 0 && y.len > 0 &&
|
|
// &x.data[0] <= &y.data[y.len-1] &&
|
|
// &y.data[0] <= &x.data[x.len-1]
|
|
&x[0] <= &y[y.len-1] &&
|
|
&y[0] <= &x[x.len-1]
|
|
}
|
|
|
|
// inexact_overlap reports whether x and y share memory at any non-corresponding
|
|
// index. The memory beyond the slice length is ignored. Note that x and y can
|
|
// have different lengths and still not have any inexact overlap.
|
|
//
|
|
// inexact_overlap can be used to implement the requirements of the crypto/cipher
|
|
// AEAD, Block, BlockMode and Stream interfaces.
|
|
pub fn inexact_overlap(x, y []byte) bool {
|
|
if x.len == 0 || y.len == 0 || &x[0] == &y[0] {
|
|
return false
|
|
}
|
|
return any_overlap(x, y)
|
|
}
|