1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
//! Memory protection.
use std::cmp::{min, Ordering};
use std::fmt;
use std::ops::{Deref, DerefMut};
use memsec;
/// Holds a session key.
///
/// The session key is cleared when dropped.
#[derive(Clone, Eq)]
pub struct Protected(Box<[u8]>);
impl PartialEq for Protected {
fn eq(&self, other: &Self) -> bool {
secure_cmp(&self.0, &other.0) == Ordering::Equal
}
}
impl Protected {
/// Converts to a buffer for modification.
pub unsafe fn into_vec(mut self) -> Vec<u8> {
std::mem::replace(&mut self.0, vec![].into()).into()
}
}
impl Deref for Protected {
type Target = [u8];
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl AsRef<[u8]> for Protected {
fn as_ref(&self) -> &[u8] {
&self.0
}
}
impl DerefMut for Protected {
fn deref_mut(&mut self) -> &mut [u8] {
&mut self.0
}
}
impl From<Vec<u8>> for Protected {
fn from(v: Vec<u8>) -> Self {
Protected(v.into_boxed_slice())
}
}
impl From<Box<[u8]>> for Protected {
fn from(v: Box<[u8]>) -> Self {
Protected(v)
}
}
impl From<&[u8]> for Protected {
fn from(v: &[u8]) -> Self {
Vec::from(v).into()
}
}
impl Drop for Protected {
fn drop(&mut self) {
unsafe {
memsec::memzero(self.0.as_mut_ptr(), self.0.len());
}
}
}
impl fmt::Debug for Protected {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if cfg!(debug_assertions) {
write!(f, "{:?}", self.0)
} else {
f.write_str("[<Redacted>]")
}
}
}
/// Time-constant comparison.
pub fn secure_cmp(a: &[u8], b: &[u8]) -> Ordering {
let ord1 = a.len().cmp(&b.len());
let ord2 = unsafe {
memsec::memcmp(a.as_ptr(), b.as_ptr(), min(a.len(), b.len()))
};
let ord2 = match ord2 {
0 => Ordering::Equal,
a if a < 0 => Ordering::Less,
a if a > 0 => Ordering::Greater,
_ => unreachable!(),
};
if ord1 == Ordering::Equal { ord2 } else { ord1 }
}
|
