summaryrefslogtreecommitdiffstats
path: root/src/lib/crypto/mem.h
blob: fe574da9786346aa508ffbddcc259a457efd8c6e (plain)
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
147
148
149
150
151
152
153
154
155
156
157
158
/*-
 * Copyright (c) 2021 Ribose Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef CRYPTO_MEM_H_
#define CRYPTO_MEM_H_

#include "config.h"
#include <array>
#include <vector>
#if defined(CRYPTO_BACKEND_BOTAN)
#include <botan/secmem.h>
#include <botan/ffi.h>
#elif defined(CRYPTO_BACKEND_OPENSSL)
#include <openssl/crypto.h>
#endif

namespace rnp {

#if defined(CRYPTO_BACKEND_BOTAN)
template <typename T> using secure_vector = Botan::secure_vector<T>;
#elif defined(CRYPTO_BACKEND_OPENSSL)
template <typename T> class ossl_allocator {
  public:
    static_assert(std::is_integral<T>::value, "T must be integral type");

    typedef T           value_type;
    typedef std::size_t size_type;

    ossl_allocator() noexcept = default;
    ossl_allocator(const ossl_allocator &) noexcept = default;
    ossl_allocator &operator=(const ossl_allocator &) noexcept = default;
    ~ossl_allocator() noexcept = default;

    template <typename U> ossl_allocator(const ossl_allocator<U> &) noexcept
    {
    }

    T *
    allocate(std::size_t n)
    {
        if (!n) {
            return nullptr;
        }

        /* attempt to use OpenSSL secure alloc */
        T *ptr = static_cast<T *>(OPENSSL_secure_zalloc(n * sizeof(T)));
        if (ptr) {
            return ptr;
        }
        /* fallback to std::alloc if failed */
        ptr = static_cast<T *>(std::calloc(n, sizeof(T)));
        if (!ptr)
            throw std::bad_alloc();
        return ptr;
    }

    void
    deallocate(T *p, std::size_t n)
    {
        if (!p) {
            return;
        }
        if (CRYPTO_secure_allocated(p)) {
            OPENSSL_secure_clear_free(p, n * sizeof(T));
            return;
        }
        OPENSSL_cleanse(p, n * sizeof(T));
        std::free(p);
    }
};

template <typename T> using secure_vector = std::vector<T, ossl_allocator<T> >;
#else
#error Unsupported backend.
#endif

template <typename T, std::size_t N> struct secure_array {
  private:
    static_assert(std::is_integral<T>::value, "T must be integer type");
    std::array<T, N> data_;

  public:
    secure_array() : data_({0})
    {
    }

    T *
    data()
    {
        return &data_[0];
    }

    std::size_t
    size() const
    {
        return data_.size();
    }

    T
    operator[](size_t idx) const
    {
        return data_[idx];
    }

    T &
    operator[](size_t idx)
    {
        return data_[idx];
    }

    ~secure_array()
    {
#if defined(CRYPTO_BACKEND_BOTAN)
        botan_scrub_mem(&data_[0], sizeof(data_));
#elif defined(CRYPTO_BACKEND_OPENSSL)
        OPENSSL_cleanse(&data_[0], sizeof(data_));
#else
#error "Unsupported crypto backend."
#endif
    }
};

typedef enum { HEX_LOWERCASE, HEX_UPPERCASE } hex_format_t;

bool   hex_encode(const uint8_t *buf,
                  size_t         buf_len,
                  char *         hex,
                  size_t         hex_len,
                  hex_format_t   format = HEX_UPPERCASE);
size_t hex_decode(const char *hex, uint8_t *buf, size_t buf_len);
} // namespace rnp

void secure_clear(void *vp, size_t size);

#endif // CRYPTO_MEM_H_