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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012- OpenVPN Inc.
//
// SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
// Wrap the OpenSSL cipher API defined in <openssl/evp.h> so
// that it can be used as part of the crypto layer of the OpenVPN core.
#ifndef OPENVPN_OPENSSL_CRYPTO_CIPHER_H
#define OPENVPN_OPENSSL_CRYPTO_CIPHER_H
#include <string>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openvpn/common/size.hpp>
#include <openvpn/common/exception.hpp>
#include <openvpn/crypto/static_key.hpp>
#include <openvpn/crypto/cryptoalgs.hpp>
#include <openvpn/openssl/util/error.hpp>
#include <openvpn/openssl/compat.hpp>
namespace openvpn::OpenSSLCrypto {
class CipherContext
{
/* In OpenSSL 3.0 the method that returns EVP_CIPHER, the cipher needs to be
* freed afterwards, thus needing a non-const type. In contrast, OpenSSL 1.1.1
* and lower returns a const type, needing a const type */
#if OPENSSL_VERSION_NUMBER < 0x30000000L
using evp_cipher_type = const EVP_CIPHER;
#else
using evp_cipher_type = EVP_CIPHER;
#endif
using CIPHER_unique_ptr = std::unique_ptr<evp_cipher_type, decltype(&::EVP_CIPHER_free)>;
CipherContext(const CipherContext &) = delete;
CipherContext &operator=(const CipherContext &) = delete;
public:
OPENVPN_SIMPLE_EXCEPTION(openssl_cipher_mode_error);
OPENVPN_SIMPLE_EXCEPTION(openssl_cipher_uninitialized);
OPENVPN_EXCEPTION(openssl_cipher_error);
// mode parameter for constructor
enum
{
MODE_UNDEF = -1,
ENCRYPT = 1,
DECRYPT = 0
};
// OpenSSL cipher constants
enum
{
MAX_IV_LENGTH = EVP_MAX_IV_LENGTH,
CIPH_CBC_MODE = EVP_CIPH_CBC_MODE
};
CipherContext() = default;
~CipherContext()
{
free_cipher_context();
}
static bool is_supported(SSLLib::Ctx libctx, const CryptoAlgs::Type alg)
{
CIPHER_unique_ptr cipher(cipher_type(libctx, alg), EVP_CIPHER_free);
return (bool)(cipher);
}
void init(SSLLib::Ctx libctx, const CryptoAlgs::Type alg, const unsigned char *key, const int mode)
{
// check that mode is valid
if (!(mode == ENCRYPT || mode == DECRYPT))
throw openssl_cipher_mode_error();
free_cipher_context();
ctx = EVP_CIPHER_CTX_new();
EVP_CIPHER_CTX_reset(ctx);
CIPHER_unique_ptr cipher(cipher_type(libctx, alg), EVP_CIPHER_free);
if (!cipher)
OPENVPN_THROW(openssl_cipher_error, CryptoAlgs::name(alg) << ": not usable");
if (!EVP_CipherInit_ex(ctx, cipher.get(), nullptr, key, nullptr, mode))
{
openssl_clear_error_stack();
free_cipher_context();
throw openssl_cipher_error("EVP_CipherInit_ex (init)");
}
}
void reset(const unsigned char *iv)
{
check_initialized();
if (!EVP_CipherInit_ex(ctx, nullptr, nullptr, nullptr, iv, -1))
{
openssl_clear_error_stack();
throw openssl_cipher_error("EVP_CipherInit_ex (reset)");
}
}
bool update(unsigned char *out,
const size_t max_out_size,
const unsigned char *in,
const size_t in_size,
size_t &out_acc)
{
check_initialized();
int outlen;
if (EVP_CipherUpdate(ctx, out, &outlen, in, int(in_size)))
{
out_acc += outlen;
return true;
}
else
{
openssl_clear_error_stack();
return false;
}
}
bool final(unsigned char *out, const size_t max_out_size, size_t &out_acc)
{
check_initialized();
int outlen;
if (EVP_CipherFinal_ex(ctx, out, &outlen))
{
out_acc += outlen;
return true;
}
else
{
openssl_clear_error_stack();
return false;
}
}
bool is_initialized() const
{
return ctx != nullptr;
}
size_t iv_length() const
{
check_initialized();
return EVP_CIPHER_CTX_iv_length(ctx);
}
size_t block_size() const
{
check_initialized();
return EVP_CIPHER_CTX_block_size(ctx);
}
// return cipher mode (such as CIPH_CBC_MODE, etc.)
int cipher_mode() const
{
check_initialized();
return EVP_CIPHER_CTX_mode(ctx);
}
private:
static evp_cipher_type *cipher_type(SSLLib::Ctx libctx, const CryptoAlgs::Type alg)
{
switch (alg)
{
case CryptoAlgs::AES_128_CBC:
return EVP_CIPHER_fetch(libctx, "AES-128-CBC", nullptr);
case CryptoAlgs::AES_192_CBC:
return EVP_CIPHER_fetch(libctx, "AES-192-CBC", nullptr);
case CryptoAlgs::AES_256_CBC:
return EVP_CIPHER_fetch(libctx, "AES-256-CBC", nullptr);
case CryptoAlgs::AES_256_CTR:
return EVP_CIPHER_fetch(libctx, "AES-256-CTR", nullptr);
case CryptoAlgs::DES_CBC:
return EVP_CIPHER_fetch(libctx, "DES-CBC", nullptr);
case CryptoAlgs::DES_EDE3_CBC:
return EVP_CIPHER_fetch(libctx, "DES-EDE-CBC", nullptr);
case CryptoAlgs::BF_CBC:
return EVP_CIPHER_fetch(libctx, "BF-CBC", nullptr);
default:
return nullptr;
}
}
void free_cipher_context()
{
EVP_CIPHER_CTX_free(ctx);
ctx = nullptr;
}
void check_initialized() const
{
#ifdef OPENVPN_ENABLE_ASSERT
if (ctx == nullptr)
throw openssl_cipher_uninitialized();
#endif
}
EVP_CIPHER_CTX *ctx = nullptr;
};
} // namespace openvpn::OpenSSLCrypto
#endif
|
