1 /*
2 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
3 * Use is subject to license terms.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this library; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /* *********************************************************************
25 *
26 * The Original Code is the Elliptic Curve Cryptography library.
27 *
28 * The Initial Developer of the Original Code is
29 * Sun Microsystems, Inc.
30 * Portions created by the Initial Developer are Copyright (C) 2003
31 * the Initial Developer. All Rights Reserved.
32 *
33 * Contributor(s):
34 * Dr Vipul Gupta <vipul.gupta@sun.com> and
35 * Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories
36 *
37 * Last Modified Date from the Original Code: April 2015
38 *********************************************************************** */
39
40 #include "mplogic.h"
41 #include "ec.h"
42 #include "ecl.h"
43
44 #include <sys/types.h>
45 #ifndef _KERNEL
46 #include <stdlib.h>
47 #include <string.h>
48
49 #ifndef _WIN32
50 #include <stdio.h>
51 #include <strings.h>
52 #endif /* _WIN32 */
53
54 #endif
55 #include "ecl-exp.h"
56 #include "mpi.h"
57 #include "ecc_impl.h"
58
59 #ifdef _KERNEL
60 #define PORT_ZFree(p, l) bzero((p), (l)); kmem_free((p), (l))
61 #else
62 #ifndef _WIN32
63 #define PORT_ZFree(p, l) bzero((p), (l)); free((p))
64 #else
65 #define PORT_ZFree(p, l) memset((p), 0, (l)); free((p))
66 #endif /* _WIN32 */
67 #endif
68
69 /*
70 * Returns true if pointP is the point at infinity, false otherwise
71 */
72 PRBool
73 ec_point_at_infinity(SECItem *pointP)
74 {
75 unsigned int i;
76
77 for (i = 1; i < pointP->len; i++) {
78 if (pointP->data[i] != 0x00) return PR_FALSE;
79 }
80
81 return PR_TRUE;
82 }
83
84 /*
85 * Computes scalar point multiplication pointQ = k1 * G + k2 * pointP for
86 * the curve whose parameters are encoded in params with base point G.
87 */
88 SECStatus
89 ec_points_mul(const ECParams *params, const mp_int *k1, const mp_int *k2,
90 const SECItem *pointP, SECItem *pointQ, int kmflag)
91 {
92 mp_int Px, Py, Qx, Qy;
93 mp_int Gx, Gy, order, irreducible, a, b;
94 #if 0 /* currently don't support non-named curves */
95 unsigned int irr_arr[5];
96 #endif
97 ECGroup *group = NULL;
98 SECStatus rv = SECFailure;
99 mp_err err = MP_OKAY;
100 unsigned int len;
101
102 #if EC_DEBUG
103 int i;
104 char mpstr[256];
105
106 printf("ec_points_mul: params [len=%d]:", params->DEREncoding.len);
107 for (i = 0; i < params->DEREncoding.len; i++)
108 printf("%02x:", params->DEREncoding.data[i]);
109 printf("\n");
110
111 if (k1 != NULL) {
112 mp_tohex(k1, mpstr);
113 printf("ec_points_mul: scalar k1: %s\n", mpstr);
114 mp_todecimal(k1, mpstr);
115 printf("ec_points_mul: scalar k1: %s (dec)\n", mpstr);
116 }
117
118 if (k2 != NULL) {
119 mp_tohex(k2, mpstr);
120 printf("ec_points_mul: scalar k2: %s\n", mpstr);
121 mp_todecimal(k2, mpstr);
122 printf("ec_points_mul: scalar k2: %s (dec)\n", mpstr);
123 }
124
125 if (pointP != NULL) {
126 printf("ec_points_mul: pointP [len=%d]:", pointP->len);
127 for (i = 0; i < pointP->len; i++)
128 printf("%02x:", pointP->data[i]);
129 printf("\n");
130 }
131 #endif
132
133 /* NOTE: We only support uncompressed points for now */
134 len = (params->fieldID.size + 7) >> 3;
135 if (pointP != NULL) {
136 if ((pointP->data[0] != EC_POINT_FORM_UNCOMPRESSED) ||
137 (pointP->len != (2 * len + 1))) {
138 return SECFailure;
139 };
140 }
141
142 MP_DIGITS(&Px) = 0;
143 MP_DIGITS(&Py) = 0;
144 MP_DIGITS(&Qx) = 0;
145 MP_DIGITS(&Qy) = 0;
146 MP_DIGITS(&Gx) = 0;
147 MP_DIGITS(&Gy) = 0;
148 MP_DIGITS(&order) = 0;
149 MP_DIGITS(&irreducible) = 0;
150 MP_DIGITS(&a) = 0;
151 MP_DIGITS(&b) = 0;
152 CHECK_MPI_OK( mp_init(&Px, kmflag) );
153 CHECK_MPI_OK( mp_init(&Py, kmflag) );
154 CHECK_MPI_OK( mp_init(&Qx, kmflag) );
155 CHECK_MPI_OK( mp_init(&Qy, kmflag) );
156 CHECK_MPI_OK( mp_init(&Gx, kmflag) );
157 CHECK_MPI_OK( mp_init(&Gy, kmflag) );
158 CHECK_MPI_OK( mp_init(&order, kmflag) );
159 CHECK_MPI_OK( mp_init(&irreducible, kmflag) );
160 CHECK_MPI_OK( mp_init(&a, kmflag) );
161 CHECK_MPI_OK( mp_init(&b, kmflag) );
162
163 if ((k2 != NULL) && (pointP != NULL)) {
164 /* Initialize Px and Py */
165 CHECK_MPI_OK( mp_read_unsigned_octets(&Px, pointP->data + 1, (mp_size) len) );
166 CHECK_MPI_OK( mp_read_unsigned_octets(&Py, pointP->data + 1 + len, (mp_size) len) );
167 }
168
169 /* construct from named params, if possible */
170 if (params->name != ECCurve_noName) {
171 group = ECGroup_fromName(params->name, kmflag);
172 }
173
174 #if 0 /* currently don't support non-named curves */
175 if (group == NULL) {
176 /* Set up mp_ints containing the curve coefficients */
177 CHECK_MPI_OK( mp_read_unsigned_octets(&Gx, params->base.data + 1,
178 (mp_size) len) );
179 CHECK_MPI_OK( mp_read_unsigned_octets(&Gy, params->base.data + 1 + len,
180 (mp_size) len) );
181 SECITEM_TO_MPINT( params->order, &order );
182 SECITEM_TO_MPINT( params->curve.a, &a );
183 SECITEM_TO_MPINT( params->curve.b, &b );
184 if (params->fieldID.type == ec_field_GFp) {
185 SECITEM_TO_MPINT( params->fieldID.u.prime, &irreducible );
186 group = ECGroup_consGFp(&irreducible, &a, &b, &Gx, &Gy, &order, params->cofactor);
187 } else {
188 SECITEM_TO_MPINT( params->fieldID.u.poly, &irreducible );
189 irr_arr[0] = params->fieldID.size;
190 irr_arr[1] = params->fieldID.k1;
191 irr_arr[2] = params->fieldID.k2;
192 irr_arr[3] = params->fieldID.k3;
193 irr_arr[4] = 0;
194 group = ECGroup_consGF2m(&irreducible, irr_arr, &a, &b, &Gx, &Gy, &order, params->cofactor);
195 }
196 }
197 #endif
198 if (group == NULL)
199 goto cleanup;
200
201 if ((k2 != NULL) && (pointP != NULL)) {
202 CHECK_MPI_OK( ECPoints_mul(group, k1, k2, &Px, &Py, &Qx, &Qy) );
203 } else {
204 CHECK_MPI_OK( ECPoints_mul(group, k1, NULL, NULL, NULL, &Qx, &Qy) );
205 }
206
207 /* Construct the SECItem representation of point Q */
208 pointQ->data[0] = EC_POINT_FORM_UNCOMPRESSED;
209 CHECK_MPI_OK( mp_to_fixlen_octets(&Qx, pointQ->data + 1,
210 (mp_size) len) );
211 CHECK_MPI_OK( mp_to_fixlen_octets(&Qy, pointQ->data + 1 + len,
212 (mp_size) len) );
213
214 rv = SECSuccess;
215
216 #if EC_DEBUG
217 printf("ec_points_mul: pointQ [len=%d]:", pointQ->len);
218 for (i = 0; i < pointQ->len; i++)
219 printf("%02x:", pointQ->data[i]);
220 printf("\n");
221 #endif
222
223 cleanup:
224 ECGroup_free(group);
225 mp_clear(&Px);
226 mp_clear(&Py);
227 mp_clear(&Qx);
228 mp_clear(&Qy);
229 mp_clear(&Gx);
230 mp_clear(&Gy);
231 mp_clear(&order);
232 mp_clear(&irreducible);
233 mp_clear(&a);
234 mp_clear(&b);
235 if (err) {
236 MP_TO_SEC_ERROR(err);
237 rv = SECFailure;
238 }
239
240 return rv;
241 }
242
243 /* Generates a new EC key pair. The private key is a supplied
244 * value and the public key is the result of performing a scalar
245 * point multiplication of that value with the curve's base point.
246 */
247 SECStatus
248 ec_NewKey(ECParams *ecParams, ECPrivateKey **privKey,
249 const unsigned char *privKeyBytes, int privKeyLen, int kmflag)
250 {
251 SECStatus rv = SECFailure;
252 PRArenaPool *arena;
253 ECPrivateKey *key;
254 mp_int k;
255 mp_err err = MP_OKAY;
256 int len;
257
258 #if EC_DEBUG
259 printf("ec_NewKey called\n");
260 #endif
261
262 if (!ecParams || !privKey || !privKeyBytes || (privKeyLen < 0)) {
263 PORT_SetError(SEC_ERROR_INVALID_ARGS);
264 return SECFailure;
265 }
266
267 /* Initialize an arena for the EC key. */
268 if (!(arena = PORT_NewArena(NSS_FREEBL_DEFAULT_CHUNKSIZE)))
269 return SECFailure;
270
271 key = (ECPrivateKey *)PORT_ArenaZAlloc(arena, sizeof(ECPrivateKey),
272 kmflag);
273 if (!key) {
274 PORT_FreeArena(arena, PR_TRUE);
275 return SECFailure;
276 }
277
278 /* Set the version number (SEC 1 section C.4 says it should be 1) */
279 SECITEM_AllocItem(arena, &key->version, 1, kmflag);
280 key->version.data[0] = 1;
281
282 /* Copy all of the fields from the ECParams argument to the
283 * ECParams structure within the private key.
284 */
285 key->ecParams.arena = arena;
286 key->ecParams.type = ecParams->type;
287 key->ecParams.fieldID.size = ecParams->fieldID.size;
288 key->ecParams.fieldID.type = ecParams->fieldID.type;
289 if (ecParams->fieldID.type == ec_field_GFp) {
290 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.prime,
291 &ecParams->fieldID.u.prime, kmflag));
292 } else {
293 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.poly,
294 &ecParams->fieldID.u.poly, kmflag));
295 }
296 key->ecParams.fieldID.k1 = ecParams->fieldID.k1;
297 key->ecParams.fieldID.k2 = ecParams->fieldID.k2;
298 key->ecParams.fieldID.k3 = ecParams->fieldID.k3;
299 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.a,
300 &ecParams->curve.a, kmflag));
301 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.b,
302 &ecParams->curve.b, kmflag));
303 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.seed,
304 &ecParams->curve.seed, kmflag));
305 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.base,
306 &ecParams->base, kmflag));
307 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.order,
308 &ecParams->order, kmflag));
309 key->ecParams.cofactor = ecParams->cofactor;
310 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.DEREncoding,
311 &ecParams->DEREncoding, kmflag));
312 key->ecParams.name = ecParams->name;
313 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curveOID,
314 &ecParams->curveOID, kmflag));
315
316 len = (ecParams->fieldID.size + 7) >> 3;
317 SECITEM_AllocItem(arena, &key->publicValue, 2*len + 1, kmflag);
318 len = ecParams->order.len;
319 SECITEM_AllocItem(arena, &key->privateValue, len, kmflag);
320
321 /* Copy private key */
322 if (privKeyLen >= len) {
323 memcpy(key->privateValue.data, privKeyBytes, len);
324 } else {
325 memset(key->privateValue.data, 0, (len - privKeyLen));
326 memcpy(key->privateValue.data + (len - privKeyLen), privKeyBytes, privKeyLen);
327 }
328
329 /* Compute corresponding public key */
330 MP_DIGITS(&k) = 0;
331 CHECK_MPI_OK( mp_init(&k, kmflag) );
332 CHECK_MPI_OK( mp_read_unsigned_octets(&k, key->privateValue.data,
333 (mp_size) len) );
334
335 rv = ec_points_mul(ecParams, &k, NULL, NULL, &(key->publicValue), kmflag);
336 if (rv != SECSuccess) goto cleanup;
337 *privKey = key;
338
339 cleanup:
340 mp_clear(&k);
341 if (rv) {
342 PORT_FreeArena(arena, PR_TRUE);
343 }
344
345 #if EC_DEBUG
346 printf("ec_NewKey returning %s\n",
347 (rv == SECSuccess) ? "success" : "failure");
348 #endif
349
350 return rv;
351
352 }
353
354 /* Generates a new EC key pair. The private key is a supplied
355 * random value (in seed) and the public key is the result of
356 * performing a scalar point multiplication of that value with
357 * the curve's base point.
358 */
359 SECStatus
360 EC_NewKeyFromSeed(ECParams *ecParams, ECPrivateKey **privKey,
361 const unsigned char *seed, int seedlen, int kmflag)
362 {
363 SECStatus rv = SECFailure;
364 rv = ec_NewKey(ecParams, privKey, seed, seedlen, kmflag);
365 return rv;
366 }
367
368 /* Generate a random private key using the algorithm A.4.1 of ANSI X9.62,
369 * modified a la FIPS 186-2 Change Notice 1 to eliminate the bias in the
370 * random number generator.
371 *
372 * Parameters
373 * - order: a buffer that holds the curve's group order
374 * - len: the length in octets of the order buffer
375 * - random: a buffer of 2 * len random bytes
376 * - randomlen: the length in octets of the random buffer
377 *
378 * Return Value
379 * Returns a buffer of len octets that holds the private key. The caller
380 * is responsible for freeing the buffer with PORT_ZFree.
381 */
382 static unsigned char *
383 ec_GenerateRandomPrivateKey(const unsigned char *order, int len,
384 const unsigned char *random, int randomlen, int kmflag)
385 {
386 SECStatus rv = SECSuccess;
387 mp_err err;
388 unsigned char *privKeyBytes = NULL;
389 mp_int privKeyVal, order_1, one;
390
391 MP_DIGITS(&privKeyVal) = 0;
392 MP_DIGITS(&order_1) = 0;
393 MP_DIGITS(&one) = 0;
394 CHECK_MPI_OK( mp_init(&privKeyVal, kmflag) );
395 CHECK_MPI_OK( mp_init(&order_1, kmflag) );
396 CHECK_MPI_OK( mp_init(&one, kmflag) );
397
398 /*
399 * Reduces the 2*len buffer of random bytes modulo the group order.
400 */
401 if ((privKeyBytes = PORT_Alloc(2*len, kmflag)) == NULL) goto cleanup;
402 if (randomlen != 2 * len) {
403 randomlen = 2 * len;
404 }
405 /* No need to generate - random bytes are now supplied */
406 /* CHECK_SEC_OK( RNG_GenerateGlobalRandomBytes(privKeyBytes, 2*len) );*/
407 memcpy(privKeyBytes, random, randomlen);
408
409 CHECK_MPI_OK( mp_read_unsigned_octets(&privKeyVal, privKeyBytes, 2*len) );
410 CHECK_MPI_OK( mp_read_unsigned_octets(&order_1, order, len) );
411 CHECK_MPI_OK( mp_set_int(&one, 1) );
412 CHECK_MPI_OK( mp_sub(&order_1, &one, &order_1) );
413 CHECK_MPI_OK( mp_mod(&privKeyVal, &order_1, &privKeyVal) );
414 CHECK_MPI_OK( mp_add(&privKeyVal, &one, &privKeyVal) );
415 CHECK_MPI_OK( mp_to_fixlen_octets(&privKeyVal, privKeyBytes, len) );
416 memset(privKeyBytes+len, 0, len);
417 cleanup:
418 mp_clear(&privKeyVal);
419 mp_clear(&order_1);
420 mp_clear(&one);
421 if (err < MP_OKAY) {
422 MP_TO_SEC_ERROR(err);
423 rv = SECFailure;
424 }
425 if (rv != SECSuccess && privKeyBytes) {
426 #ifdef _KERNEL
427 kmem_free(privKeyBytes, 2*len);
428 #else
429 free(privKeyBytes);
430 #endif
431 privKeyBytes = NULL;
432 }
433 return privKeyBytes;
434 }
435
436 /* Generates a new EC key pair. The private key is a random value and
437 * the public key is the result of performing a scalar point multiplication
438 * of that value with the curve's base point.
439 */
440 SECStatus
441 EC_NewKey(ECParams *ecParams, ECPrivateKey **privKey,
442 const unsigned char* random, int randomlen, int kmflag)
443 {
444 SECStatus rv = SECFailure;
445 int len;
446 unsigned char *privKeyBytes = NULL;
447
448 if (!ecParams) {
449 PORT_SetError(SEC_ERROR_INVALID_ARGS);
450 return SECFailure;
451 }
452
453 len = ecParams->order.len;
454 privKeyBytes = ec_GenerateRandomPrivateKey(ecParams->order.data, len,
455 random, randomlen, kmflag);
456 if (privKeyBytes == NULL) goto cleanup;
457 /* generate public key */
458 CHECK_SEC_OK( ec_NewKey(ecParams, privKey, privKeyBytes, len, kmflag) );
459
460 cleanup:
461 if (privKeyBytes) {
462 PORT_ZFree(privKeyBytes, len * 2);
463 }
464 #if EC_DEBUG
465 printf("EC_NewKey returning %s\n",
466 (rv == SECSuccess) ? "success" : "failure");
467 #endif
468
469 return rv;
470 }
471
472 /* Validates an EC public key as described in Section 5.2.2 of
473 * X9.62. The ECDH primitive when used without the cofactor does
474 * not address small subgroup attacks, which may occur when the
475 * public key is not valid. These attacks can be prevented by
476 * validating the public key before using ECDH.
477 */
478 SECStatus
479 EC_ValidatePublicKey(ECParams *ecParams, SECItem *publicValue, int kmflag)
480 {
481 mp_int Px, Py;
482 ECGroup *group = NULL;
483 SECStatus rv = SECFailure;
484 mp_err err = MP_OKAY;
485 unsigned int len;
486
487 if (!ecParams || !publicValue) {
488 PORT_SetError(SEC_ERROR_INVALID_ARGS);
489 return SECFailure;
490 }
491
492 /* NOTE: We only support uncompressed points for now */
493 len = (ecParams->fieldID.size + 7) >> 3;
494 if (publicValue->data[0] != EC_POINT_FORM_UNCOMPRESSED) {
495 PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
496 return SECFailure;
497 } else if (publicValue->len != (2 * len + 1)) {
498 PORT_SetError(SEC_ERROR_BAD_KEY);
499 return SECFailure;
500 }
501
502 MP_DIGITS(&Px) = 0;
503 MP_DIGITS(&Py) = 0;
504 CHECK_MPI_OK( mp_init(&Px, kmflag) );
505 CHECK_MPI_OK( mp_init(&Py, kmflag) );
506
507 /* Initialize Px and Py */
508 CHECK_MPI_OK( mp_read_unsigned_octets(&Px, publicValue->data + 1, (mp_size) len) );
509 CHECK_MPI_OK( mp_read_unsigned_octets(&Py, publicValue->data + 1 + len, (mp_size) len) );
510
511 /* construct from named params */
512 group = ECGroup_fromName(ecParams->name, kmflag);
513 if (group == NULL) {
514 /*
515 * ECGroup_fromName fails if ecParams->name is not a valid
516 * ECCurveName value, or if we run out of memory, or perhaps
517 * for other reasons. Unfortunately if ecParams->name is a
518 * valid ECCurveName value, we don't know what the right error
519 * code should be because ECGroup_fromName doesn't return an
520 * error code to the caller. Set err to MP_UNDEF because
521 * that's what ECGroup_fromName uses internally.
522 */
523 if ((ecParams->name <= ECCurve_noName) ||
524 (ecParams->name >= ECCurve_pastLastCurve)) {
525 err = MP_BADARG;
526 } else {
527 err = MP_UNDEF;
528 }
529 goto cleanup;
530 }
531
532 /* validate public point */
533 if ((err = ECPoint_validate(group, &Px, &Py)) < MP_YES) {
534 if (err == MP_NO) {
535 PORT_SetError(SEC_ERROR_BAD_KEY);
536 rv = SECFailure;
537 err = MP_OKAY; /* don't change the error code */
538 }
539 goto cleanup;
540 }
541
542 rv = SECSuccess;
543
544 cleanup:
545 ECGroup_free(group);
546 mp_clear(&Px);
547 mp_clear(&Py);
548 if (err) {
549 MP_TO_SEC_ERROR(err);
550 rv = SECFailure;
551 }
552 return rv;
553 }
554
555 /*
556 ** Performs an ECDH key derivation by computing the scalar point
557 ** multiplication of privateValue and publicValue (with or without the
558 ** cofactor) and returns the x-coordinate of the resulting elliptic
559 ** curve point in derived secret. If successful, derivedSecret->data
560 ** is set to the address of the newly allocated buffer containing the
561 ** derived secret, and derivedSecret->len is the size of the secret
562 ** produced. It is the caller's responsibility to free the allocated
563 ** buffer containing the derived secret.
564 */
565 SECStatus
566 ECDH_Derive(SECItem *publicValue,
567 ECParams *ecParams,
568 SECItem *privateValue,
569 PRBool withCofactor,
570 SECItem *derivedSecret,
571 int kmflag)
572 {
573 SECStatus rv = SECFailure;
574 unsigned int len = 0;
575 SECItem pointQ = {siBuffer, NULL, 0};
576 mp_int k; /* to hold the private value */
577 mp_int cofactor;
578 mp_err err = MP_OKAY;
579 #if EC_DEBUG
580 int i;
581 #endif
582
583 if (!publicValue || !ecParams || !privateValue ||
584 !derivedSecret) {
585 PORT_SetError(SEC_ERROR_INVALID_ARGS);
586 return SECFailure;
587 }
588
589 if (EC_ValidatePublicKey(ecParams, publicValue, kmflag) != SECSuccess) {
590 return SECFailure;
591 }
592
593 memset(derivedSecret, 0, sizeof *derivedSecret);
594 len = (ecParams->fieldID.size + 7) >> 3;
595 pointQ.len = 2*len + 1;
596 if ((pointQ.data = PORT_Alloc(2*len + 1, kmflag)) == NULL) goto cleanup;
597
598 MP_DIGITS(&k) = 0;
599 CHECK_MPI_OK( mp_init(&k, kmflag) );
600 CHECK_MPI_OK( mp_read_unsigned_octets(&k, privateValue->data,
601 (mp_size) privateValue->len) );
602
603 if (withCofactor && (ecParams->cofactor != 1)) {
604 /* multiply k with the cofactor */
605 MP_DIGITS(&cofactor) = 0;
606 CHECK_MPI_OK( mp_init(&cofactor, kmflag) );
607 mp_set(&cofactor, ecParams->cofactor);
608 CHECK_MPI_OK( mp_mul(&k, &cofactor, &k) );
609 }
610
611 /* Multiply our private key and peer's public point */
612 if ((ec_points_mul(ecParams, NULL, &k, publicValue, &pointQ, kmflag) != SECSuccess) ||
613 ec_point_at_infinity(&pointQ))
614 goto cleanup;
615
616 /* Allocate memory for the derived secret and copy
617 * the x co-ordinate of pointQ into it.
618 */
619 SECITEM_AllocItem(NULL, derivedSecret, len, kmflag);
620 memcpy(derivedSecret->data, pointQ.data + 1, len);
621
622 rv = SECSuccess;
623
624 #if EC_DEBUG
625 printf("derived_secret:\n");
626 for (i = 0; i < derivedSecret->len; i++)
627 printf("%02x:", derivedSecret->data[i]);
628 printf("\n");
629 #endif
630
631 cleanup:
632 mp_clear(&k);
633
634 if (pointQ.data) {
635 PORT_ZFree(pointQ.data, 2*len + 1);
636 }
637
638 return rv;
639 }
640
641 /* Computes the ECDSA signature (a concatenation of two values r and s)
642 * on the digest using the given key and the random value kb (used in
643 * computing s).
644 */
645 SECStatus
646 ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
647 const SECItem *digest, const unsigned char *kb, const int kblen, int kmflag)
648 {
649 SECStatus rv = SECFailure;
650 mp_int x1;
651 mp_int d, k; /* private key, random integer */
652 mp_int r, s; /* tuple (r, s) is the signature */
653 mp_int n;
654 mp_err err = MP_OKAY;
655 ECParams *ecParams = NULL;
656 SECItem kGpoint = { siBuffer, NULL, 0};
657 int flen = 0; /* length in bytes of the field size */
658 unsigned olen; /* length in bytes of the base point order */
659
660 #if EC_DEBUG
661 char mpstr[256];
662 #endif
663
664 /* Initialize MPI integers. */
665 /* must happen before the first potential call to cleanup */
666 MP_DIGITS(&x1) = 0;
667 MP_DIGITS(&d) = 0;
668 MP_DIGITS(&k) = 0;
669 MP_DIGITS(&r) = 0;
670 MP_DIGITS(&s) = 0;
671 MP_DIGITS(&n) = 0;
672
673 /* Check args */
674 if (!key || !signature || !digest || !kb || (kblen < 0)) {
675 PORT_SetError(SEC_ERROR_INVALID_ARGS);
676 goto cleanup;
677 }
678
679 ecParams = &(key->ecParams);
680 flen = (ecParams->fieldID.size + 7) >> 3;
681 olen = ecParams->order.len;
682 if (signature->data == NULL) {
683 /* a call to get the signature length only */
684 goto finish;
685 }
686 if (signature->len < 2*olen) {
687 PORT_SetError(SEC_ERROR_OUTPUT_LEN);
688 rv = SECBufferTooSmall;
689 goto cleanup;
690 }
691
692
693 CHECK_MPI_OK( mp_init(&x1, kmflag) );
694 CHECK_MPI_OK( mp_init(&d, kmflag) );
695 CHECK_MPI_OK( mp_init(&k, kmflag) );
696 CHECK_MPI_OK( mp_init(&r, kmflag) );
697 CHECK_MPI_OK( mp_init(&s, kmflag) );
698 CHECK_MPI_OK( mp_init(&n, kmflag) );
699
700 SECITEM_TO_MPINT( ecParams->order, &n );
701 SECITEM_TO_MPINT( key->privateValue, &d );
702 CHECK_MPI_OK( mp_read_unsigned_octets(&k, kb, kblen) );
703 /* Make sure k is in the interval [1, n-1] */
704 if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
705 #if EC_DEBUG
706 printf("k is outside [1, n-1]\n");
707 mp_tohex(&k, mpstr);
708 printf("k : %s \n", mpstr);
709 mp_tohex(&n, mpstr);
710 printf("n : %s \n", mpstr);
711 #endif
712 PORT_SetError(SEC_ERROR_NEED_RANDOM);
713 goto cleanup;
714 }
715
716 /*
717 ** ANSI X9.62, Section 5.3.2, Step 2
718 **
719 ** Compute kG
720 */
721 kGpoint.len = 2*flen + 1;
722 kGpoint.data = PORT_Alloc(2*flen + 1, kmflag);
723 if ((kGpoint.data == NULL) ||
724 (ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint, kmflag)
725 != SECSuccess))
726 goto cleanup;
727
728 /*
729 ** ANSI X9.62, Section 5.3.3, Step 1
730 **
731 ** Extract the x co-ordinate of kG into x1
732 */
733 CHECK_MPI_OK( mp_read_unsigned_octets(&x1, kGpoint.data + 1,
734 (mp_size) flen) );
735
736 /*
737 ** ANSI X9.62, Section 5.3.3, Step 2
738 **
739 ** r = x1 mod n NOTE: n is the order of the curve
740 */
741 CHECK_MPI_OK( mp_mod(&x1, &n, &r) );
742
743 /*
744 ** ANSI X9.62, Section 5.3.3, Step 3
745 **
746 ** verify r != 0
747 */
748 if (mp_cmp_z(&r) == 0) {
749 PORT_SetError(SEC_ERROR_NEED_RANDOM);
750 goto cleanup;
751 }
752
753 /*
754 ** ANSI X9.62, Section 5.3.3, Step 4
755 **
756 ** s = (k**-1 * (HASH(M) + d*r)) mod n
757 */
758 SECITEM_TO_MPINT(*digest, &s); /* s = HASH(M) */
759
760 /* In the definition of EC signing, digests are truncated
761 * to the length of n in bits.
762 * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
763 if (digest->len*8 > (unsigned int)ecParams->fieldID.size) {
764 mpl_rsh(&s,&s,digest->len*8 - ecParams->fieldID.size);
765 }
766
767 #if EC_DEBUG
768 mp_todecimal(&n, mpstr);
769 printf("n : %s (dec)\n", mpstr);
770 mp_todecimal(&d, mpstr);
771 printf("d : %s (dec)\n", mpstr);
772 mp_tohex(&x1, mpstr);
773 printf("x1: %s\n", mpstr);
774 mp_todecimal(&s, mpstr);
775 printf("digest: %s (decimal)\n", mpstr);
776 mp_todecimal(&r, mpstr);
777 printf("r : %s (dec)\n", mpstr);
778 mp_tohex(&r, mpstr);
779 printf("r : %s\n", mpstr);
780 #endif
781
782 CHECK_MPI_OK( mp_invmod(&k, &n, &k) ); /* k = k**-1 mod n */
783 CHECK_MPI_OK( mp_mulmod(&d, &r, &n, &d) ); /* d = d * r mod n */
784 CHECK_MPI_OK( mp_addmod(&s, &d, &n, &s) ); /* s = s + d mod n */
785 CHECK_MPI_OK( mp_mulmod(&s, &k, &n, &s) ); /* s = s * k mod n */
786
787 #if EC_DEBUG
788 mp_todecimal(&s, mpstr);
789 printf("s : %s (dec)\n", mpstr);
790 mp_tohex(&s, mpstr);
791 printf("s : %s\n", mpstr);
792 #endif
793
794 /*
795 ** ANSI X9.62, Section 5.3.3, Step 5
796 **
797 ** verify s != 0
798 */
799 if (mp_cmp_z(&s) == 0) {
800 PORT_SetError(SEC_ERROR_NEED_RANDOM);
801 goto cleanup;
802 }
803
804 /*
805 **
806 ** Signature is tuple (r, s)
807 */
808 CHECK_MPI_OK( mp_to_fixlen_octets(&r, signature->data, olen) );
809 CHECK_MPI_OK( mp_to_fixlen_octets(&s, signature->data + olen, olen) );
810 finish:
811 signature->len = 2*olen;
812
813 rv = SECSuccess;
814 err = MP_OKAY;
815 cleanup:
816 mp_clear(&x1);
817 mp_clear(&d);
818 mp_clear(&k);
819 mp_clear(&r);
820 mp_clear(&s);
821 mp_clear(&n);
822
823 if (kGpoint.data) {
824 PORT_ZFree(kGpoint.data, 2*flen + 1);
825 }
826
827 if (err) {
828 MP_TO_SEC_ERROR(err);
829 rv = SECFailure;
830 }
831
832 #if EC_DEBUG
833 printf("ECDSA signing with seed %s\n",
834 (rv == SECSuccess) ? "succeeded" : "failed");
835 #endif
836
837 return rv;
838 }
839
840 /*
841 ** Computes the ECDSA signature on the digest using the given key
842 ** and a random seed.
843 */
844 SECStatus
845 ECDSA_SignDigest(ECPrivateKey *key, SECItem *signature, const SECItem *digest,
846 const unsigned char* random, int randomLen, int kmflag)
847 {
848 SECStatus rv = SECFailure;
849 int len;
850 unsigned char *kBytes= NULL;
851
852 if (!key) {
853 PORT_SetError(SEC_ERROR_INVALID_ARGS);
854 return SECFailure;
855 }
856
857 /* Generate random value k */
858 len = key->ecParams.order.len;
859 kBytes = ec_GenerateRandomPrivateKey(key->ecParams.order.data, len,
860 random, randomLen, kmflag);
861 if (kBytes == NULL) goto cleanup;
862
863 /* Generate ECDSA signature with the specified k value */
864 rv = ECDSA_SignDigestWithSeed(key, signature, digest, kBytes, len, kmflag);
865
866 cleanup:
867 if (kBytes) {
868 PORT_ZFree(kBytes, len * 2);
869 }
870
871 #if EC_DEBUG
872 printf("ECDSA signing %s\n",
873 (rv == SECSuccess) ? "succeeded" : "failed");
874 #endif
875
876 return rv;
877 }
878
879 /*
880 ** Checks the signature on the given digest using the key provided.
881 */
882 SECStatus
883 ECDSA_VerifyDigest(ECPublicKey *key, const SECItem *signature,
884 const SECItem *digest, int kmflag)
885 {
886 SECStatus rv = SECFailure;
887 mp_int r_, s_; /* tuple (r', s') is received signature) */
888 mp_int c, u1, u2, v; /* intermediate values used in verification */
889 mp_int x1;
890 mp_int n;
891 mp_err err = MP_OKAY;
892 ECParams *ecParams = NULL;
893 SECItem pointC = { siBuffer, NULL, 0 };
894 int slen; /* length in bytes of a half signature (r or s) */
895 int flen; /* length in bytes of the field size */
896 unsigned olen; /* length in bytes of the base point order */
897
898 #if EC_DEBUG
899 char mpstr[256];
900 printf("ECDSA verification called\n");
901 #endif
902
903 /* Initialize MPI integers. */
904 /* must happen before the first potential call to cleanup */
905 MP_DIGITS(&r_) = 0;
906 MP_DIGITS(&s_) = 0;
907 MP_DIGITS(&c) = 0;
908 MP_DIGITS(&u1) = 0;
909 MP_DIGITS(&u2) = 0;
910 MP_DIGITS(&x1) = 0;
911 MP_DIGITS(&v) = 0;
912 MP_DIGITS(&n) = 0;
913
914 /* Check args */
915 if (!key || !signature || !digest) {
916 PORT_SetError(SEC_ERROR_INVALID_ARGS);
917 goto cleanup;
918 }
919
920 ecParams = &(key->ecParams);
921 flen = (ecParams->fieldID.size + 7) >> 3;
922 olen = ecParams->order.len;
923 if (signature->len == 0 || signature->len%2 != 0 ||
924 signature->len > 2*olen) {
925 PORT_SetError(SEC_ERROR_INPUT_LEN);
926 goto cleanup;
927 }
928 slen = signature->len/2;
929
930 SECITEM_AllocItem(NULL, &pointC, 2*flen + 1, kmflag);
931 if (pointC.data == NULL)
932 goto cleanup;
933
934 CHECK_MPI_OK( mp_init(&r_, kmflag) );
935 CHECK_MPI_OK( mp_init(&s_, kmflag) );
936 CHECK_MPI_OK( mp_init(&c, kmflag) );
937 CHECK_MPI_OK( mp_init(&u1, kmflag) );
938 CHECK_MPI_OK( mp_init(&u2, kmflag) );
939 CHECK_MPI_OK( mp_init(&x1, kmflag) );
940 CHECK_MPI_OK( mp_init(&v, kmflag) );
941 CHECK_MPI_OK( mp_init(&n, kmflag) );
942
943 /*
944 ** Convert received signature (r', s') into MPI integers.
945 */
946 CHECK_MPI_OK( mp_read_unsigned_octets(&r_, signature->data, slen) );
947 CHECK_MPI_OK( mp_read_unsigned_octets(&s_, signature->data + slen, slen) );
948
949 /*
950 ** ANSI X9.62, Section 5.4.2, Steps 1 and 2
951 **
952 ** Verify that 0 < r' < n and 0 < s' < n
953 */
954 SECITEM_TO_MPINT(ecParams->order, &n);
955 if (mp_cmp_z(&r_) <= 0 || mp_cmp_z(&s_) <= 0 ||
956 mp_cmp(&r_, &n) >= 0 || mp_cmp(&s_, &n) >= 0) {
957 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
958 goto cleanup; /* will return rv == SECFailure */
959 }
960
961 /*
962 ** ANSI X9.62, Section 5.4.2, Step 3
963 **
964 ** c = (s')**-1 mod n
965 */
966 CHECK_MPI_OK( mp_invmod(&s_, &n, &c) ); /* c = (s')**-1 mod n */
967
968 /*
969 ** ANSI X9.62, Section 5.4.2, Step 4
970 **
971 ** u1 = ((HASH(M')) * c) mod n
972 */
973 SECITEM_TO_MPINT(*digest, &u1); /* u1 = HASH(M) */
974
975 /* In the definition of EC signing, digests are truncated
976 * to the length of n in bits.
977 * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
978 /* u1 = HASH(M') */
979 if (digest->len*8 > (unsigned int)ecParams->fieldID.size) {
980 mpl_rsh(&u1,&u1,digest->len*8- ecParams->fieldID.size);
981 }
982
983 #if EC_DEBUG
984 mp_todecimal(&r_, mpstr);
985 printf("r_: %s (dec)\n", mpstr);
986 mp_todecimal(&s_, mpstr);
987 printf("s_: %s (dec)\n", mpstr);
988 mp_todecimal(&c, mpstr);
989 printf("c : %s (dec)\n", mpstr);
990 mp_todecimal(&u1, mpstr);
991 printf("digest: %s (dec)\n", mpstr);
992 #endif
993
994 CHECK_MPI_OK( mp_mulmod(&u1, &c, &n, &u1) ); /* u1 = u1 * c mod n */
995
996 /*
997 ** ANSI X9.62, Section 5.4.2, Step 4
998 **
999 ** u2 = ((r') * c) mod n
1000 */
1001 CHECK_MPI_OK( mp_mulmod(&r_, &c, &n, &u2) );
1002
1003 /*
1004 ** ANSI X9.62, Section 5.4.3, Step 1
1005 **
1006 ** Compute u1*G + u2*Q
1007 ** Here, A = u1.G B = u2.Q and C = A + B
1008 ** If the result, C, is the point at infinity, reject the signature
1009 */
1010 if (ec_points_mul(ecParams, &u1, &u2, &key->publicValue, &pointC, kmflag)
1011 != SECSuccess) {
1012 rv = SECFailure;
1013 goto cleanup;
1014 }
1015 if (ec_point_at_infinity(&pointC)) {
1016 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
1017 rv = SECFailure;
1018 goto cleanup;
1019 }
1020
1021 CHECK_MPI_OK( mp_read_unsigned_octets(&x1, pointC.data + 1, flen) );
1022
1023 /*
1024 ** ANSI X9.62, Section 5.4.4, Step 2
1025 **
1026 ** v = x1 mod n
1027 */
1028 CHECK_MPI_OK( mp_mod(&x1, &n, &v) );
1029
1030 #if EC_DEBUG
1031 mp_todecimal(&r_, mpstr);
1032 printf("r_: %s (dec)\n", mpstr);
1033 mp_todecimal(&v, mpstr);
1034 printf("v : %s (dec)\n", mpstr);
1035 #endif
1036
1037 /*
1038 ** ANSI X9.62, Section 5.4.4, Step 3
1039 **
1040 ** Verification: v == r'
1041 */
1042 if (mp_cmp(&v, &r_)) {
1043 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
1044 rv = SECFailure; /* Signature failed to verify. */
1045 } else {
1046 rv = SECSuccess; /* Signature verified. */
1047 }
1048
1049 #if EC_DEBUG
1050 mp_todecimal(&u1, mpstr);
1051 printf("u1: %s (dec)\n", mpstr);
1052 mp_todecimal(&u2, mpstr);
1053 printf("u2: %s (dec)\n", mpstr);
1054 mp_tohex(&x1, mpstr);
1055 printf("x1: %s\n", mpstr);
1056 mp_todecimal(&v, mpstr);
1057 printf("v : %s (dec)\n", mpstr);
1058 #endif
1059
1060 cleanup:
1061 mp_clear(&r_);
1062 mp_clear(&s_);
1063 mp_clear(&c);
1064 mp_clear(&u1);
1065 mp_clear(&u2);
1066 mp_clear(&x1);
1067 mp_clear(&v);
1068 mp_clear(&n);
1069
1070 if (pointC.data) SECITEM_FreeItem(&pointC, PR_FALSE);
1071 if (err) {
1072 MP_TO_SEC_ERROR(err);
1073 rv = SECFailure;
1074 }
1075
1076 #if EC_DEBUG
1077 printf("ECDSA verification %s\n",
1078 (rv == SECSuccess) ? "succeeded" : "failed");
1079 #endif
1080
1081 return rv;
1082 }