Outline ![]()
Files ![]()
loading...
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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
/*
* RSA
* Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "asn1.h"
#include "bignum.h"
#include "rsa.h"
struct crypto_rsa_key {
int private_key; /* whether private key is set */
struct bignum *n; /* modulus (p * q) */
struct bignum *e; /* public exponent */
/* The following parameters are available only if private_key is set */
struct bignum *d; /* private exponent */
struct bignum *p; /* prime p (factor of n) */
struct bignum *q; /* prime q (factor of n) */
struct bignum *dmp1; /* d mod (p - 1); CRT exponent */
struct bignum *dmq1; /* d mod (q - 1); CRT exponent */
struct bignum *iqmp; /* 1 / q mod p; CRT coefficient */
};
static const u8 * crypto_rsa_parse_integer(const u8 *pos, const u8 *end,
struct bignum *num)
{
struct asn1_hdr hdr;
if (pos == NULL)
return NULL;
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_integer(&hdr)) {
asn1_unexpected(&hdr, "RSA: Expected INTEGER");
return NULL;
}
if (bignum_set_unsigned_bin(num, hdr.payload, hdr.length) < 0) {
wpa_printf(MSG_DEBUG, "RSA: Failed to parse INTEGER");
return NULL;
}
return hdr.payload + hdr.length;
}
/**
* crypto_rsa_import_public_key - Import an RSA public key
* @buf: Key buffer (DER encoded RSA public key)
* @len: Key buffer length in bytes
* Returns: Pointer to the public key or %NULL on failure
*/
struct crypto_rsa_key *
crypto_rsa_import_public_key(const u8 *buf, size_t len)
{
struct crypto_rsa_key *key;
struct asn1_hdr hdr;
const u8 *pos, *end;
key = os_zalloc(sizeof(*key));
if (key == NULL)
return NULL;
key->n = bignum_init();
key->e = bignum_init();
if (key->n == NULL || key->e == NULL) {
crypto_rsa_free(key);
return NULL;
}
/*
* PKCS #1, 7.1:
* RSAPublicKey ::= SEQUENCE {
* modulus INTEGER, -- n
* publicExponent INTEGER -- e
* }
*/
if (asn1_get_next(buf, len, &hdr) < 0 || !asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr, "RSA: Expected SEQUENCE (public key)");
goto error;
}
pos = hdr.payload;
end = pos + hdr.length;
pos = crypto_rsa_parse_integer(pos, end, key->n);
pos = crypto_rsa_parse_integer(pos, end, key->e);
if (pos == NULL)
goto error;
if (pos != end) {
wpa_hexdump(MSG_DEBUG,
"RSA: Extra data in public key SEQUENCE",
pos, end - pos);
goto error;
}
return key;
error:
crypto_rsa_free(key);
return NULL;
}
struct crypto_rsa_key *
crypto_rsa_import_public_key_parts(const u8 *n, size_t n_len,
const u8 *e, size_t e_len)
{
struct crypto_rsa_key *key;
key = os_zalloc(sizeof(*key));
if (key == NULL)
return NULL;
key->n = bignum_init();
key->e = bignum_init();
if (key->n == NULL || key->e == NULL ||
bignum_set_unsigned_bin(key->n, n, n_len) < 0 ||
bignum_set_unsigned_bin(key->e, e, e_len) < 0) {
crypto_rsa_free(key);
return NULL;
}
return key;
}
/**
* crypto_rsa_import_private_key - Import an RSA private key
* @buf: Key buffer (DER encoded RSA private key)
* @len: Key buffer length in bytes
* Returns: Pointer to the private key or %NULL on failure
*/
struct crypto_rsa_key *
crypto_rsa_import_private_key(const u8 *buf, size_t len)
{
struct crypto_rsa_key *key;
struct bignum *zero;
struct asn1_hdr hdr;
const u8 *pos, *end;
key = os_zalloc(sizeof(*key));
if (key == NULL)
return NULL;
key->private_key = 1;
key->n = bignum_init();
key->e = bignum_init();
key->d = bignum_init();
key->p = bignum_init();
key->q = bignum_init();
key->dmp1 = bignum_init();
key->dmq1 = bignum_init();
key->iqmp = bignum_init();
if (key->n == NULL || key->e == NULL || key->d == NULL ||
key->p == NULL || key->q == NULL || key->dmp1 == NULL ||
key->dmq1 == NULL || key->iqmp == NULL) {
crypto_rsa_free(key);
return NULL;
}
/*
* PKCS #1, 7.2:
* RSAPrivateKey ::= SEQUENCE {
* version Version,
* modulus INTEGER, -- n
* publicExponent INTEGER, -- e
* privateExponent INTEGER, -- d
* prime1 INTEGER, -- p
* prime2 INTEGER, -- q
* exponent1 INTEGER, -- d mod (p-1)
* exponent2 INTEGER, -- d mod (q-1)
* coefficient INTEGER -- (inverse of q) mod p
* }
*
* Version ::= INTEGER -- shall be 0 for this version of the standard
*/
if (asn1_get_next(buf, len, &hdr) < 0 || !asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr, "RSA: Expected SEQUENCE (public key)");
goto error;
}
pos = hdr.payload;
end = pos + hdr.length;
zero = bignum_init();
if (zero == NULL)
goto error;
pos = crypto_rsa_parse_integer(pos, end, zero);
if (pos == NULL || bignum_cmp_d(zero, 0) != 0) {
wpa_printf(MSG_DEBUG, "RSA: Expected zero INTEGER in the "
"beginning of private key; not found");
bignum_deinit(zero);
goto error;
}
bignum_deinit(zero);
pos = crypto_rsa_parse_integer(pos, end, key->n);
pos = crypto_rsa_parse_integer(pos, end, key->e);
pos = crypto_rsa_parse_integer(pos, end, key->d);
pos = crypto_rsa_parse_integer(pos, end, key->p);
pos = crypto_rsa_parse_integer(pos, end, key->q);
pos = crypto_rsa_parse_integer(pos, end, key->dmp1);
pos = crypto_rsa_parse_integer(pos, end, key->dmq1);
pos = crypto_rsa_parse_integer(pos, end, key->iqmp);
if (pos == NULL)
goto error;
if (pos != end) {
wpa_hexdump(MSG_DEBUG,
"RSA: Extra data in public key SEQUENCE",
pos, end - pos);
goto error;
}
return key;
error:
crypto_rsa_free(key);
return NULL;
}
/**
* crypto_rsa_get_modulus_len - Get the modulus length of the RSA key
* @key: RSA key
* Returns: Modulus length of the key
*/
size_t crypto_rsa_get_modulus_len(struct crypto_rsa_key *key)
{
return bignum_get_unsigned_bin_len(key->n);
}
/**
* crypto_rsa_exptmod - RSA modular exponentiation
* @in: Input data
* @inlen: Input data length
* @out: Buffer for output data
* @outlen: Maximum size of the output buffer and used size on success
* @key: RSA key
* @use_private: 1 = Use RSA private key, 0 = Use RSA public key
* Returns: 0 on success, -1 on failure
*/
int crypto_rsa_exptmod(const u8 *in, size_t inlen, u8 *out, size_t *outlen,
struct crypto_rsa_key *key, int use_private)
{
struct bignum *tmp, *a = NULL, *b = NULL;
int ret = -1;
size_t modlen;
if (use_private && !key->private_key)
return -1;
tmp = bignum_init();
if (tmp == NULL)
return -1;
if (bignum_set_unsigned_bin(tmp, in, inlen) < 0)
goto error;
if (bignum_cmp(key->n, tmp) < 0) {
/* Too large input value for the RSA key modulus */
goto error;
}
if (use_private) {
/*
* Decrypt (or sign) using Chinese remainder theorem to speed
* up calculation. This is equivalent to tmp = tmp^d mod n
* (which would require more CPU to calculate directly).
*
* dmp1 = (1/e) mod (p-1)
* dmq1 = (1/e) mod (q-1)
* iqmp = (1/q) mod p, where p > q
* m1 = c^dmp1 mod p
* m2 = c^dmq1 mod q
* h = q^-1 (m1 - m2) mod p
* m = m2 + hq
*/
a = bignum_init();
b = bignum_init();
if (a == NULL || b == NULL)
goto error;
/* a = tmp^dmp1 mod p */
if (bignum_exptmod(tmp, key->dmp1, key->p, a) < 0)
goto error;
/* b = tmp^dmq1 mod q */
if (bignum_exptmod(tmp, key->dmq1, key->q, b) < 0)
goto error;
/* tmp = (a - b) * (1/q mod p) (mod p) */
if (bignum_sub(a, b, tmp) < 0 ||
bignum_mulmod(tmp, key->iqmp, key->p, tmp) < 0)
goto error;
/* tmp = b + q * tmp */
if (bignum_mul(tmp, key->q, tmp) < 0 ||
bignum_add(tmp, b, tmp) < 0)
goto error;
} else {
/* Encrypt (or verify signature) */
/* tmp = tmp^e mod N */
if (bignum_exptmod(tmp, key->e, key->n, tmp) < 0)
goto error;
}
modlen = crypto_rsa_get_modulus_len(key);
if (modlen > *outlen) {
*outlen = modlen;
goto error;
}
if (bignum_get_unsigned_bin_len(tmp) > modlen)
goto error; /* should never happen */
*outlen = modlen;
os_memset(out, 0, modlen);
if (bignum_get_unsigned_bin(
tmp, out +
(modlen - bignum_get_unsigned_bin_len(tmp)), NULL) < 0)
goto error;
ret = 0;
error:
bignum_deinit(tmp);
bignum_deinit(a);
bignum_deinit(b);
return ret;
}
/**
* crypto_rsa_free - Free RSA key
* @key: RSA key to be freed
*
* This function frees an RSA key imported with either
* crypto_rsa_import_public_key() or crypto_rsa_import_private_key().
*/
void crypto_rsa_free(struct crypto_rsa_key *key)
{
if (key) {
bignum_deinit(key->n);
bignum_deinit(key->e);
bignum_deinit(key->d);
bignum_deinit(key->p);
bignum_deinit(key->q);
bignum_deinit(key->dmp1);
bignum_deinit(key->dmq1);
bignum_deinit(key->iqmp);
os_free(key);
}
}
Details ![]()
Show: from Types: Columns: ![]( "Show Project Names")
![]( "Show Locations")
![]( "Show Referring Symbols")
![]( "Show Scope")
This file uses the notable symbols shown below. Click anywhere in the file to view more details.