summaryrefslogtreecommitdiff
path: root/lib/dh.c
blob: 82a411934c5a5e7dbfb3e3a7719355730dea4a57 (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
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
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
/*
 * Copyright (C) 2000-2012 Free Software Foundation, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

#include "gnutls_int.h"
#include "errors.h"
#include <datum.h>
#include <x509_b64.h>		/* for PKCS3 PEM decoding */
#include <global.h>
#include <dh.h>
#include <pk.h>
#include <x509/common.h>
#include <gnutls/crypto.h>
#include "x509/x509_int.h"
#include <mpi.h>
#include "debug.h"

/*-
 * _gnutls_get_dh_params - Returns the DH parameters pointer
 * @dh_params: is an DH parameters type, or NULL.
 * @func: is a callback function to receive the parameters or NULL.
 * @session: a gnutls session.
 *
 * This function will return the dh parameters pointer.
 -*/
gnutls_dh_params_t
_gnutls_get_dh_params(gnutls_dh_params_t dh_params,
		      gnutls_params_function * func,
		      gnutls_session_t session)
{
	gnutls_params_st params;
	int ret;

	/* if cached return the cached */
	if (session->internals.params.dh_params)
		return session->internals.params.dh_params;

	if (dh_params) {
		session->internals.params.dh_params = dh_params;
	} else if (func) {
		ret = func(session, GNUTLS_PARAMS_DH, &params);
		if (ret == 0 && params.type == GNUTLS_PARAMS_DH) {
			session->internals.params.dh_params =
			    params.params.dh;
			session->internals.params.free_dh_params =
			    params.deinit;
		}
	}

	return session->internals.params.dh_params;
}

/* returns the prime and the generator of DH params.
 */
const bigint_t *_gnutls_dh_params_to_mpi(gnutls_dh_params_t dh_primes)
{
	if (dh_primes == NULL || dh_primes->params[1] == NULL ||
	    dh_primes->params[0] == NULL) {
		return NULL;
	}

	return dh_primes->params;
}


/**
 * gnutls_dh_params_import_raw:
 * @dh_params: The parameters
 * @prime: holds the new prime
 * @generator: holds the new generator
 *
 * This function will replace the pair of prime and generator for use
 * in the Diffie-Hellman key exchange.  The new parameters should be
 * stored in the appropriate gnutls_datum.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_import_raw(gnutls_dh_params_t dh_params,
			    const gnutls_datum_t * prime,
			    const gnutls_datum_t * generator)
{
	return gnutls_dh_params_import_raw2(dh_params, prime, generator, 0);
}

/**
 * gnutls_dh_params_import_raw2:
 * @dh_params: The parameters
 * @prime: holds the new prime
 * @generator: holds the new generator
 * @key_bits: the private key bits (set to zero when unknown)
 *
 * This function will replace the pair of prime and generator for use
 * in the Diffie-Hellman key exchange.  The new parameters should be
 * stored in the appropriate gnutls_datum.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_import_raw2(gnutls_dh_params_t dh_params,
			     const gnutls_datum_t * prime,
			     const gnutls_datum_t * generator,
			     unsigned key_bits)
{
	bigint_t tmp_prime, tmp_g;
	size_t siz;

	siz = prime->size;
	if (_gnutls_mpi_init_scan_nz(&tmp_prime, prime->data, siz)) {
		gnutls_assert();
		return GNUTLS_E_MPI_SCAN_FAILED;
	}

	siz = generator->size;
	if (_gnutls_mpi_init_scan_nz(&tmp_g, generator->data, siz)) {
		_gnutls_mpi_release(&tmp_prime);
		gnutls_assert();
		return GNUTLS_E_MPI_SCAN_FAILED;
	}

	/* store the generated values
	 */
	dh_params->params[0] = tmp_prime;
	dh_params->params[1] = tmp_g;
	dh_params->q_bits = key_bits;

	return 0;
}

/**
 * gnutls_dh_params_init:
 * @dh_params: The parameters
 *
 * This function will initialize the DH parameters type.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int gnutls_dh_params_init(gnutls_dh_params_t * dh_params)
{

	(*dh_params) = gnutls_calloc(1, sizeof(dh_params_st));
	if (*dh_params == NULL) {
		gnutls_assert();
		return GNUTLS_E_MEMORY_ERROR;
	}

	return 0;

}

/**
 * gnutls_dh_params_deinit:
 * @dh_params: The parameters
 *
 * This function will deinitialize the DH parameters type.
 **/
void gnutls_dh_params_deinit(gnutls_dh_params_t dh_params)
{
	if (dh_params == NULL)
		return;

	_gnutls_mpi_release(&dh_params->params[0]);
	_gnutls_mpi_release(&dh_params->params[1]);

	gnutls_free(dh_params);

}

/**
 * gnutls_dh_params_cpy:
 * @dst: Is the destination parameters, which should be initialized.
 * @src: Is the source parameters
 *
 * This function will copy the DH parameters structure from source
 * to destination.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int gnutls_dh_params_cpy(gnutls_dh_params_t dst, gnutls_dh_params_t src)
{
	if (src == NULL)
		return GNUTLS_E_INVALID_REQUEST;

	dst->params[0] = _gnutls_mpi_copy(src->params[0]);
	dst->params[1] = _gnutls_mpi_copy(src->params[1]);
	dst->q_bits = src->q_bits;

	if (dst->params[0] == NULL || dst->params[1] == NULL)
		return GNUTLS_E_MEMORY_ERROR;

	return 0;
}


/**
 * gnutls_dh_params_generate2:
 * @dparams: The parameters
 * @bits: is the prime's number of bits
 *
 * This function will generate a new pair of prime and generator for use in
 * the Diffie-Hellman key exchange. The new parameters will be allocated using
 * gnutls_malloc() and will be stored in the appropriate datum.
 * This function is normally slow.
 *
 * Do not set the number of bits directly, use gnutls_sec_param_to_pk_bits() to
 * get bits for %GNUTLS_PK_DSA.
 * Also note that the DH parameters are only useful to servers.
 * Since clients use the parameters sent by the server, it's of
 * no use to call this in client side.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_generate2(gnutls_dh_params_t dparams, unsigned int bits)
{
	int ret;
	gnutls_pk_params_st params;
	
	gnutls_pk_params_init(&params);
	
	ret = _gnutls_pk_generate_params(GNUTLS_PK_DH, bits, &params);
	if (ret < 0)
		return gnutls_assert_val(ret);

	dparams->params[0] = params.params[DSA_P];
	dparams->params[1] = params.params[DSA_G];
	dparams->q_bits = _gnutls_mpi_get_nbits(params.params[DSA_Q]);

	_gnutls_mpi_release(&params.params[DSA_Q]);
		
	return 0;
}

/**
 * gnutls_dh_params_import_pkcs3:
 * @params: The parameters
 * @pkcs3_params: should contain a PKCS3 DHParams structure PEM or DER encoded
 * @format: the format of params. PEM or DER.
 *
 * This function will extract the DHParams found in a PKCS3 formatted
 * structure. This is the format generated by "openssl dhparam" tool.
 *
 * If the structure is PEM encoded, it should have a header
 * of "BEGIN DH PARAMETERS".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_import_pkcs3(gnutls_dh_params_t params,
			      const gnutls_datum_t * pkcs3_params,
			      gnutls_x509_crt_fmt_t format)
{
	ASN1_TYPE c2;
	int result, need_free = 0;
	unsigned int q_bits;
	gnutls_datum_t _params;

	if (format == GNUTLS_X509_FMT_PEM) {

		result = _gnutls_fbase64_decode("DH PARAMETERS",
						pkcs3_params->data,
						pkcs3_params->size,
						&_params);

		if (result <= 0) {
			if (result == 0)
				result = GNUTLS_E_INTERNAL_ERROR;
			gnutls_assert();
			return result;
		}

		need_free = 1;
	} else {
		_params.data = pkcs3_params->data;
		_params.size = pkcs3_params->size;
	}

	if ((result = asn1_create_element
	     (_gnutls_get_gnutls_asn(), "GNUTLS.DHParameter", &c2))
	    != ASN1_SUCCESS) {
		gnutls_assert();
		if (need_free != 0) {
			gnutls_free(_params.data);
			_params.data = NULL;
		}
		return _gnutls_asn2err(result);
	}

	result = asn1_der_decoding(&c2, _params.data, _params.size, NULL);

	if (need_free != 0) {
		gnutls_free(_params.data);
		_params.data = NULL;
	}

	if (result != ASN1_SUCCESS) {
		/* couldn't decode DER */

		_gnutls_debug_log("DHParams: Decoding error %d\n", result);
		gnutls_assert();
		asn1_delete_structure(&c2);
		return _gnutls_asn2err(result);
	}

	/* Read q length */
	result = _gnutls_x509_read_uint(c2, "privateValueLength", &q_bits);
	if (result < 0) {
		gnutls_assert();
		params->q_bits = 0;
	} else
		params->q_bits = q_bits;

	/* Read PRIME 
	 */
	result = _gnutls_x509_read_int(c2, "prime", &params->params[0]);
	if (result < 0) {
		asn1_delete_structure(&c2);
		gnutls_assert();
		return result;
	}

	if (_gnutls_mpi_cmp_ui(params->params[0], 0) == 0) {
		asn1_delete_structure(&c2);
		return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
	}

	/* read the generator
	 */
	result = _gnutls_x509_read_int(c2, "base", &params->params[1]);
	if (result < 0) {
		asn1_delete_structure(&c2);
		_gnutls_mpi_release(&params->params[0]);
		gnutls_assert();
		return result;
	}

	if (_gnutls_mpi_cmp_ui(params->params[1], 0) == 0) {
		asn1_delete_structure(&c2);
		_gnutls_mpi_release(&params->params[0]);
		return gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
	}

	asn1_delete_structure(&c2);

	return 0;
}

/**
 * gnutls_dh_params_export_pkcs3:
 * @params: Holds the DH parameters
 * @format: the format of output params. One of PEM or DER.
 * @params_data: will contain a PKCS3 DHParams structure PEM or DER encoded
 * @params_data_size: holds the size of params_data (and will be replaced by the actual size of parameters)
 *
 * This function will export the given dh parameters to a PKCS3
 * DHParams structure. This is the format generated by "openssl dhparam" tool.
 * If the buffer provided is not long enough to hold the output, then
 * GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN DH PARAMETERS".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_export_pkcs3(gnutls_dh_params_t params,
			      gnutls_x509_crt_fmt_t format,
			      unsigned char *params_data,
			      size_t * params_data_size)
{
	gnutls_datum_t out;
	int ret;

	ret = gnutls_dh_params_export2_pkcs3(params, format, &out);
	if (ret < 0)
		return gnutls_assert_val(ret);

	if (*params_data_size < (unsigned) out.size + 1) {
		gnutls_assert();
		gnutls_free(out.data);
		*params_data_size = out.size + 1;
		return GNUTLS_E_SHORT_MEMORY_BUFFER;
	}

	*params_data_size = out.size;
	if (params_data) {
		memcpy(params_data, out.data, out.size);
		params_data[out.size] = 0;
	}

	gnutls_free(out.data);

	return 0;
}

/**
 * gnutls_dh_params_export2_pkcs3:
 * @params: Holds the DH parameters
 * @format: the format of output params. One of PEM or DER.
 * @out: will contain a PKCS3 DHParams structure PEM or DER encoded
 *
 * This function will export the given dh parameters to a PKCS3
 * DHParams structure. This is the format generated by "openssl dhparam" tool.
 * The data in @out will be allocated using gnutls_malloc().
 *
 * If the structure is PEM encoded, it will have a header
 * of "BEGIN DH PARAMETERS".
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 *
 * Since: 3.1.3
 **/
int
gnutls_dh_params_export2_pkcs3(gnutls_dh_params_t params,
			       gnutls_x509_crt_fmt_t format,
			       gnutls_datum_t * out)
{
	ASN1_TYPE c2;
	int result;
	size_t g_size, p_size;
	uint8_t *p_data, *g_data;
	uint8_t *all_data;

	_gnutls_mpi_print_lz(params->params[1], NULL, &g_size);
	_gnutls_mpi_print_lz(params->params[0], NULL, &p_size);

	all_data = gnutls_malloc(g_size + p_size);
	if (all_data == NULL) {
		gnutls_assert();
		return GNUTLS_E_MEMORY_ERROR;
	}

	p_data = &all_data[0];
	_gnutls_mpi_print_lz(params->params[0], p_data, &p_size);

	g_data = &all_data[p_size];
	_gnutls_mpi_print_lz(params->params[1], g_data, &g_size);


	/* Ok. Now we have the data. Create the asn1 structures
	 */

	if ((result = asn1_create_element
	     (_gnutls_get_gnutls_asn(), "GNUTLS.DHParameter", &c2))
	    != ASN1_SUCCESS) {
		gnutls_assert();
		gnutls_free(all_data);
		return _gnutls_asn2err(result);
	}

	/* Write PRIME 
	 */
	if ((result = asn1_write_value(c2, "prime",
				       p_data, p_size)) != ASN1_SUCCESS) {
		gnutls_assert();
		gnutls_free(all_data);
		asn1_delete_structure(&c2);
		return _gnutls_asn2err(result);
	}

	if (params->q_bits > 0)
		result =
		    _gnutls_x509_write_uint32(c2, "privateValueLength",
					      params->q_bits);
	else
		result =
		    asn1_write_value(c2, "privateValueLength", NULL, 0);

	if (result < 0) {
		gnutls_assert();
		gnutls_free(all_data);
		asn1_delete_structure(&c2);
		return _gnutls_asn2err(result);
	}

	/* Write the GENERATOR
	 */
	if ((result = asn1_write_value(c2, "base",
				       g_data, g_size)) != ASN1_SUCCESS) {
		gnutls_assert();
		gnutls_free(all_data);
		asn1_delete_structure(&c2);
		return _gnutls_asn2err(result);
	}

	gnutls_free(all_data);


	if (format == GNUTLS_X509_FMT_DER) {
		result = _gnutls_x509_der_encode(c2, "", out, 0);

		asn1_delete_structure(&c2);

		if (result < 0)
			return gnutls_assert_val(result);

	} else {		/* PEM */
		gnutls_datum_t t;

		result = _gnutls_x509_der_encode(c2, "", &t, 0);

		asn1_delete_structure(&c2);

		if (result < 0)
			return gnutls_assert_val(result);

		result =
		    _gnutls_fbase64_encode("DH PARAMETERS", t.data, t.size,
					   out);

		gnutls_free(t.data);

		if (result < 0) {
			gnutls_assert();
			return result;
		}
	}

	return 0;
}

/**
 * gnutls_dh_params_export_raw:
 * @params: Holds the DH parameters
 * @prime: will hold the new prime
 * @generator: will hold the new generator
 * @bits: if non null will hold the secret key's number of bits
 *
 * This function will export the pair of prime and generator for use
 * in the Diffie-Hellman key exchange.  The new parameters will be
 * allocated using gnutls_malloc() and will be stored in the
 * appropriate datum.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
 *   otherwise a negative error code is returned.
 **/
int
gnutls_dh_params_export_raw(gnutls_dh_params_t params,
			    gnutls_datum_t * prime,
			    gnutls_datum_t * generator, unsigned int *bits)
{
	int ret;

	if (params->params[1] == NULL || params->params[0] == NULL) {
		gnutls_assert();
		return GNUTLS_E_INVALID_REQUEST;
	}

	ret = _gnutls_mpi_dprint(params->params[1], generator);
	if (ret < 0) {
		gnutls_assert();
		return ret;
	}

	ret = _gnutls_mpi_dprint(params->params[0], prime);
	if (ret < 0) {
		gnutls_assert();
		_gnutls_free_datum(generator);
		return ret;
	}

	if (bits)
		*bits = params->q_bits;

	return 0;

}