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
214
|
/* wsgcrypt.c
* Helper functions for libgcrypt
* By Erik de Jong <erikdejong@gmail.com>
* Copyright 2017 Erik de Jong
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "wsgcrypt.h"
gcry_error_t ws_hmac_buffer(int algo, void *digest, const void *buffer, size_t length, const void *key, size_t keylen)
{
gcry_md_hd_t hmac_handle;
gcry_error_t result = gcry_md_open(&hmac_handle, algo, GCRY_MD_FLAG_HMAC);
if (result) {
return result;
}
result = gcry_md_setkey(hmac_handle, key, keylen);
if (result) {
gcry_md_close(hmac_handle);
return result;
}
gcry_md_write(hmac_handle, buffer, length);
memcpy(digest, gcry_md_read(hmac_handle, 0), gcry_md_get_algo_dlen(algo));
gcry_md_close(hmac_handle);
return GPG_ERR_NO_ERROR;
}
gcry_error_t ws_cmac_buffer(int algo, void *digest, const void *buffer, size_t length, const void *key, size_t keylen)
{
gcry_mac_hd_t cmac_handle;
gcry_error_t result = gcry_mac_open(&cmac_handle, algo, 0, NULL);
if (result) {
return result;
}
result = gcry_mac_setkey(cmac_handle, key, keylen);
if (result) {
gcry_mac_close(cmac_handle);
return result;
}
gcry_mac_write(cmac_handle, buffer, length);
result = gcry_mac_read(cmac_handle, digest, &keylen);
gcry_mac_close(cmac_handle);
return result;
}
void crypt_des_ecb(uint8_t *output, const uint8_t *buffer, const uint8_t *key56)
{
uint8_t key64[8];
gcry_cipher_hd_t handle;
memset(output, 0x00, 8);
/* Transform 56 bits key into 64 bits DES key */
key64[0] = key56[0];
key64[1] = (key56[0] << 7) | (key56[1] >> 1);
key64[2] = (key56[1] << 6) | (key56[2] >> 2);
key64[3] = (key56[2] << 5) | (key56[3] >> 3);
key64[4] = (key56[3] << 4) | (key56[4] >> 4);
key64[5] = (key56[4] << 3) | (key56[5] >> 5);
key64[6] = (key56[5] << 2) | (key56[6] >> 6);
key64[7] = (key56[6] << 1);
if (gcry_cipher_open(&handle, GCRY_CIPHER_DES, GCRY_CIPHER_MODE_ECB, 0)) {
return;
}
if (gcry_cipher_setkey(handle, key64, 8)) {
gcry_cipher_close(handle);
return;
}
gcry_cipher_encrypt(handle, output, 8, buffer, 8);
gcry_cipher_close(handle);
}
size_t rsa_decrypt_inplace(const unsigned len, unsigned char* data, gcry_sexp_t pk, bool pkcs1_padding, char **err)
{
int rc = 0;
size_t decr_len = 0, i = 0;
gcry_sexp_t s_data = NULL, s_plain = NULL;
gcry_mpi_t encr_mpi = NULL, text = NULL;
*err = NULL;
/* create mpi representation of encrypted data */
rc = gcry_mpi_scan(&encr_mpi, GCRYMPI_FMT_USG, data, len, NULL);
if (rc != 0 ) {
*err = ws_strdup_printf("can't convert data to mpi (size %d):%s", len, gcry_strerror(rc));
return 0;
}
/* put the data into a simple list */
rc = gcry_sexp_build(&s_data, NULL, "(enc-val(rsa(a%m)))", encr_mpi);
if (rc != 0) {
*err = ws_strdup_printf("can't build encr_sexp:%s", gcry_strerror(rc));
decr_len = 0;
goto out;
}
/* pass it to libgcrypt */
rc = gcry_pk_decrypt(&s_plain, s_data, pk);
if (rc != 0)
{
*err = ws_strdup_printf("can't decrypt key:%s", gcry_strerror(rc));
decr_len = 0;
goto out;
}
/* convert plain text sexp to mpi format */
text = gcry_sexp_nth_mpi(s_plain, 0, 0);
if (! text) {
*err = g_strdup("can't convert sexp to mpi");
decr_len = 0;
goto out;
}
/* compute size requested for plaintext buffer */
rc = gcry_mpi_print(GCRYMPI_FMT_USG, NULL, 0, &decr_len, text);
if (rc != 0) {
*err = ws_strdup_printf("can't compute decr size:%s", gcry_strerror(rc));
decr_len = 0;
goto out;
}
/* sanity check on out buffer */
if (decr_len > len) {
*err = ws_strdup_printf("decrypted data is too long ?!? (%zu max %d)", decr_len, len);
decr_len = 0;
goto out;
}
/* write plain text to newly allocated buffer */
rc = gcry_mpi_print(GCRYMPI_FMT_USG, data, len, &decr_len, text);
if (rc != 0) {
*err = ws_strdup_printf("can't print decr data to mpi (size %zu):%s", decr_len, gcry_strerror(rc));
decr_len = 0;
goto out;
}
if (pkcs1_padding) {
/* strip the padding*/
rc = 0;
for (i = 1; i < decr_len; i++) {
if (data[i] == 0) {
rc = (int) i+1;
break;
}
}
decr_len -= rc;
memmove(data, data+rc, decr_len);
}
out:
gcry_sexp_release(s_data);
gcry_sexp_release(s_plain);
gcry_mpi_release(encr_mpi);
gcry_mpi_release(text);
return decr_len;
}
gcry_error_t
hkdf_expand(int hashalgo, const uint8_t *prk, unsigned prk_len, const uint8_t *info, unsigned info_len,
uint8_t *out, unsigned out_len)
{
// Current maximum hash output size: 48 bytes for SHA-384.
unsigned char lastoutput[48];
gcry_md_hd_t h;
gcry_error_t err;
const unsigned hash_len = gcry_md_get_algo_dlen(hashalgo);
/* Some sanity checks */
if (!(out_len > 0 && out_len <= 255 * hash_len) ||
!(hash_len > 0 && hash_len <= sizeof(lastoutput))) {
return GPG_ERR_INV_ARG;
}
err = gcry_md_open(&h, hashalgo, GCRY_MD_FLAG_HMAC);
if (err) {
return err;
}
for (unsigned offset = 0; offset < out_len; offset += hash_len) {
gcry_md_reset(h);
gcry_md_setkey(h, prk, prk_len); /* Set PRK */
if (offset > 0) {
gcry_md_write(h, lastoutput, hash_len); /* T(1..N) */
}
gcry_md_write(h, info, info_len); /* info */
gcry_md_putc(h, (uint8_t) (offset / hash_len + 1)); /* constant 0x01..N */
memcpy(lastoutput, gcry_md_read(h, hashalgo), hash_len);
memcpy(out + offset, lastoutput, MIN(hash_len, out_len - offset));
}
gcry_md_close(h);
return 0;
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
|
