redoubt-zero-core 0.1.0-rc.6

Core zeroization primitives: guards, sentinels, and RAII wrappers
Documentation 
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
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

// Copyright (c) 2025-2026 Federico Hoerth <memparanoid@gmail.com>
// SPDX-License-Identifier: GPL-3.0-only
// See LICENSE in the repository root for full license text.

use crate::assert::assert_zeroize_on_drop;
use crate::collections::{
    collection_zeroed, to_fast_zeroizable_dyn_mut, to_zeroization_probe_dyn_ref, zeroize_collection,
};
use crate::traits::{AssertZeroizeOnDrop, FastZeroizable, ZeroizationProbe};
use crate::zeroize_on_drop_sentinel::ZeroizeOnDropSentinel;
use crate::zeroizing_mut_guard::ZeroizingMutGuard;

struct Foo {
    pub data: Vec<u8>,
    __sentinel: ZeroizeOnDropSentinel,
}

impl Default for Foo {
    fn default() -> Self {
        Self {
            data: vec![1, 2, 3, 4],
            __sentinel: ZeroizeOnDropSentinel::default(),
        }
    }
}

impl FastZeroizable for Foo {
    fn fast_zeroize(&mut self) {
        self.data.fast_zeroize();
        self.__sentinel.fast_zeroize();
    }
}

impl Drop for Foo {
    fn drop(&mut self) {
        self.fast_zeroize();
    }
}

impl ZeroizationProbe for Foo {
    fn is_zeroized(&self) -> bool {
        let fields: [&dyn ZeroizationProbe; 1] = [to_zeroization_probe_dyn_ref(&self.data)];
        // `fields.into_iter()` produces &dyn ZeroizationProbe directly,
        // avoiding the double reference (&&) that `.iter()` would create.
        // No values are copied - we're just iterating over references from the array.
        collection_zeroed(&mut fields.into_iter())
    }
}

impl AssertZeroizeOnDrop for Foo {
    fn clone_sentinel(&self) -> ZeroizeOnDropSentinel {
        self.__sentinel.clone()
    }

    fn assert_zeroize_on_drop(self) {
        assert_zeroize_on_drop(self);
    }
}

struct FunctionalStruct<'a> {
    pub bytes: Vec<u8>,
    pub bytes_16: [u8; 16],
    pub bytes_32: [u8; 32],
    pub foo: ZeroizingMutGuard<'a, Foo>,
    __sentinel: ZeroizeOnDropSentinel,
}

impl<'a> FunctionalStruct<'a> {
    fn new(foo: &'a mut Foo) -> Self {
        let mut bytes = Vec::new();
        bytes.resize_with(128, || u8::MAX);

        Self {
            bytes,
            bytes_16: [u8::MAX; 16],
            bytes_32: [u8::MAX; 32],
            foo: ZeroizingMutGuard::from(foo),
            __sentinel: ZeroizeOnDropSentinel::default(),
        }
    }
}

impl<'a> FastZeroizable for FunctionalStruct<'a> {
    fn fast_zeroize(&mut self) {
        let fields: [&mut dyn FastZeroizable; 5] = [
            to_fast_zeroizable_dyn_mut(&mut self.bytes_16),
            to_fast_zeroizable_dyn_mut(&mut self.bytes_32),
            to_fast_zeroizable_dyn_mut(&mut self.bytes),
            to_fast_zeroizable_dyn_mut(&mut self.foo),
            to_fast_zeroizable_dyn_mut(&mut self.__sentinel),
        ];

        zeroize_collection(&mut fields.into_iter());
    }
}

impl<'a> ZeroizationProbe for FunctionalStruct<'a> {
    fn is_zeroized(&self) -> bool {
        let fields: [&dyn ZeroizationProbe; 4] = [
            to_zeroization_probe_dyn_ref(&self.bytes_16),
            to_zeroization_probe_dyn_ref(&self.bytes_32),
            to_zeroization_probe_dyn_ref(&self.bytes),
            to_zeroization_probe_dyn_ref(&self.foo),
        ];
        // `fields.into_iter()` produces &dyn ZeroizationProbe directly,
        // avoiding the double reference (&&) that `.iter()` would create.
        // No values are copied - we're just iterating over references from the array.
        collection_zeroed(&mut fields.into_iter())
    }
}

impl<'a> AssertZeroizeOnDrop for FunctionalStruct<'a> {
    fn clone_sentinel(&self) -> ZeroizeOnDropSentinel {
        self.__sentinel.clone()
    }

    fn assert_zeroize_on_drop(self) {
        assert_zeroize_on_drop(self);
    }
}

impl<'a> Drop for FunctionalStruct<'a> {
    fn drop(&mut self) {
        self.fast_zeroize();
    }
}

#[test]
fn test_functionl_struct() {
    let mut foo = Foo::default();

    // Assert (not) zeroization! (Foo is not zeroized by default)
    assert!(!foo.is_zeroized());

    let mut fs = FunctionalStruct::new(&mut foo);

    // Assert (not) zeroization! (FunctionalStruct is not zeroized due to Foo)
    assert!(!fs.is_zeroized());

    fs.fast_zeroize();

    // Assert zeroization!
    assert!(fs.is_zeroized());

    fs.assert_zeroize_on_drop();
}