1 /*
2 * Copyright (c) 2007, 2016, 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: Nov 2016
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 k.dp = (mp_digit)0;
262
263 if (!ecParams || !privKey || !privKeyBytes || (privKeyLen < 0)) {
264 PORT_SetError(SEC_ERROR_INVALID_ARGS);
265 return SECFailure;
266 }
267
268 /* Initialize an arena for the EC key. */
269 if (!(arena = PORT_NewArena(NSS_FREEBL_DEFAULT_CHUNKSIZE)))
270 return SECFailure;
271
272 key = (ECPrivateKey *)PORT_ArenaZAlloc(arena, sizeof(ECPrivateKey),
273 kmflag);
274 if (!key) {
275 PORT_FreeArena(arena, PR_TRUE);
276 return SECFailure;
277 }
278
279 /* Set the version number (SEC 1 section C.4 says it should be 1) */
280 SECITEM_AllocItem(arena, &key->version, 1, kmflag);
281 key->version.data[0] = 1;
282
283 /* Copy all of the fields from the ECParams argument to the
284 * ECParams structure within the private key.
285 */
286 key->ecParams.arena = arena;
287 key->ecParams.type = ecParams->type;
288 key->ecParams.fieldID.size = ecParams->fieldID.size;
289 key->ecParams.fieldID.type = ecParams->fieldID.type;
290 if (ecParams->fieldID.type == ec_field_GFp) {
291 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.prime,
292 &ecParams->fieldID.u.prime, kmflag));
293 } else {
294 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.poly,
295 &ecParams->fieldID.u.poly, kmflag));
296 }
297 key->ecParams.fieldID.k1 = ecParams->fieldID.k1;
298 key->ecParams.fieldID.k2 = ecParams->fieldID.k2;
299 key->ecParams.fieldID.k3 = ecParams->fieldID.k3;
300 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.a,
301 &ecParams->curve.a, kmflag));
302 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.b,
303 &ecParams->curve.b, kmflag));
304 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.seed,
305 &ecParams->curve.seed, kmflag));
306 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.base,
307 &ecParams->base, kmflag));
308 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.order,
309 &ecParams->order, kmflag));
310 key->ecParams.cofactor = ecParams->cofactor;
311 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.DEREncoding,
312 &ecParams->DEREncoding, kmflag));
313 key->ecParams.name = ecParams->name;
314 CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curveOID,
315 &ecParams->curveOID, kmflag));
316
317 len = (ecParams->fieldID.size + 7) >> 3;
318 SECITEM_AllocItem(arena, &key->publicValue, 2*len + 1, kmflag);
319 len = ecParams->order.len;
320 SECITEM_AllocItem(arena, &key->privateValue, len, kmflag);
321
322 /* Copy private key */
323 if (privKeyLen >= len) {
324 memcpy(key->privateValue.data, privKeyBytes, len);
325 } else {
326 memset(key->privateValue.data, 0, (len - privKeyLen));
327 memcpy(key->privateValue.data + (len - privKeyLen), privKeyBytes, privKeyLen);
328 }
329
330 /* Compute corresponding public key */
331 MP_DIGITS(&k) = 0;
332 CHECK_MPI_OK( mp_init(&k, kmflag) );
333 CHECK_MPI_OK( mp_read_unsigned_octets(&k, key->privateValue.data,
334 (mp_size) len) );
335
336 rv = ec_points_mul(ecParams, &k, NULL, NULL, &(key->publicValue), kmflag);
337 if (rv != SECSuccess) goto cleanup;
338 *privKey = key;
339
340 cleanup:
341 mp_clear(&k);
342 if (rv) {
343 PORT_FreeArena(arena, PR_TRUE);
344 }
345
346 #if EC_DEBUG
347 printf("ec_NewKey returning %s\n",
348 (rv == SECSuccess) ? "success" : "failure");
349 #endif
350
351 return rv;
352
353 }
354
355 /* Generates a new EC key pair. The private key is a supplied
356 * random value (in seed) and the public key is the result of
357 * performing a scalar point multiplication of that value with
358 * the curve's base point.
359 */
360 SECStatus
361 EC_NewKeyFromSeed(ECParams *ecParams, ECPrivateKey **privKey,
362 const unsigned char *seed, int seedlen, int kmflag)
363 {
364 SECStatus rv = SECFailure;
365 rv = ec_NewKey(ecParams, privKey, seed, seedlen, kmflag);
366 return rv;
367 }
368
369 /* Generate a random private key using the algorithm A.4.1 of ANSI X9.62,
370 * modified a la FIPS 186-2 Change Notice 1 to eliminate the bias in the
371 * random number generator.
372 *
373 * Parameters
374 * - order: a buffer that holds the curve's group order
375 * - len: the length in octets of the order buffer
376 * - random: a buffer of 2 * len random bytes
377 * - randomlen: the length in octets of the random buffer
378 *
379 * Return Value
380 * Returns a buffer of len octets that holds the private key. The caller
381 * is responsible for freeing the buffer with PORT_ZFree.
382 */
383 static unsigned char *
384 ec_GenerateRandomPrivateKey(const unsigned char *order, int len,
385 const unsigned char *random, int randomlen, int kmflag)
386 {
387 SECStatus rv = SECSuccess;
388 mp_err err;
389 unsigned char *privKeyBytes = NULL;
390 mp_int privKeyVal, order_1, one;
391
392 MP_DIGITS(&privKeyVal) = 0;
393 MP_DIGITS(&order_1) = 0;
394 MP_DIGITS(&one) = 0;
395 CHECK_MPI_OK( mp_init(&privKeyVal, kmflag) );
396 CHECK_MPI_OK( mp_init(&order_1, kmflag) );
397 CHECK_MPI_OK( mp_init(&one, kmflag) );
398
399 /*
400 * Reduces the 2*len buffer of random bytes modulo the group order.
401 */
402 if ((privKeyBytes = PORT_Alloc(2*len, kmflag)) == NULL) goto cleanup;
403 if (randomlen != 2 * len) {
404 randomlen = 2 * len;
405 }
406 /* No need to generate - random bytes are now supplied */
407 /* CHECK_SEC_OK( RNG_GenerateGlobalRandomBytes(privKeyBytes, 2*len) );*/
408 memcpy(privKeyBytes, random, randomlen);
409
410 CHECK_MPI_OK( mp_read_unsigned_octets(&privKeyVal, privKeyBytes, 2*len) );
411 CHECK_MPI_OK( mp_read_unsigned_octets(&order_1, order, len) );
412 CHECK_MPI_OK( mp_set_int(&one, 1) );
413 CHECK_MPI_OK( mp_sub(&order_1, &one, &order_1) );
414 CHECK_MPI_OK( mp_mod(&privKeyVal, &order_1, &privKeyVal) );
415 CHECK_MPI_OK( mp_add(&privKeyVal, &one, &privKeyVal) );
416 CHECK_MPI_OK( mp_to_fixlen_octets(&privKeyVal, privKeyBytes, len) );
417 memset(privKeyBytes+len, 0, len);
418 cleanup:
419 mp_clear(&privKeyVal);
420 mp_clear(&order_1);
421 mp_clear(&one);
422 if (err < MP_OKAY) {
423 MP_TO_SEC_ERROR(err);
424 rv = SECFailure;
425 }
426 if (rv != SECSuccess && privKeyBytes) {
427 #ifdef _KERNEL
428 kmem_free(privKeyBytes, 2*len);
429 #else
430 free(privKeyBytes);
431 #endif
432 privKeyBytes = NULL;
433 }
434 return privKeyBytes;
435 }
436
437 /* Generates a new EC key pair. The private key is a random value and
438 * the public key is the result of performing a scalar point multiplication
439 * of that value with the curve's base point.
440 */
441 SECStatus
442 EC_NewKey(ECParams *ecParams, ECPrivateKey **privKey,
443 const unsigned char* random, int randomlen, int kmflag)
444 {
445 SECStatus rv = SECFailure;
446 int len;
447 unsigned char *privKeyBytes = NULL;
448
449 if (!ecParams) {
450 PORT_SetError(SEC_ERROR_INVALID_ARGS);
451 return SECFailure;
452 }
453
454 len = ecParams->order.len;
455 privKeyBytes = ec_GenerateRandomPrivateKey(ecParams->order.data, len,
456 random, randomlen, kmflag);
457 if (privKeyBytes == NULL) goto cleanup;
458 /* generate public key */
459 CHECK_SEC_OK( ec_NewKey(ecParams, privKey, privKeyBytes, len, kmflag) );
460
461 cleanup:
462 if (privKeyBytes) {
463 PORT_ZFree(privKeyBytes, len * 2);
464 }
465 #if EC_DEBUG
466 printf("EC_NewKey returning %s\n",
467 (rv == SECSuccess) ? "success" : "failure");
468 #endif
469
470 return rv;
471 }
472
473 /* Validates an EC public key as described in Section 5.2.2 of
474 * X9.62. The ECDH primitive when used without the cofactor does
475 * not address small subgroup attacks, which may occur when the
476 * public key is not valid. These attacks can be prevented by
477 * validating the public key before using ECDH.
478 */
479 SECStatus
480 EC_ValidatePublicKey(ECParams *ecParams, SECItem *publicValue, int kmflag)
481 {
482 mp_int Px, Py;
483 ECGroup *group = NULL;
484 SECStatus rv = SECFailure;
485 mp_err err = MP_OKAY;
486 unsigned int len;
487
488 if (!ecParams || !publicValue) {
489 PORT_SetError(SEC_ERROR_INVALID_ARGS);
490 return SECFailure;
491 }
492
493 /* NOTE: We only support uncompressed points for now */
494 len = (ecParams->fieldID.size + 7) >> 3;
495 if (publicValue->data[0] != EC_POINT_FORM_UNCOMPRESSED) {
496 PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
497 return SECFailure;
498 } else if (publicValue->len != (2 * len + 1)) {
499 PORT_SetError(SEC_ERROR_BAD_KEY);
500 return SECFailure;
501 }
502
503 MP_DIGITS(&Px) = 0;
504 MP_DIGITS(&Py) = 0;
505 CHECK_MPI_OK( mp_init(&Px, kmflag) );
506 CHECK_MPI_OK( mp_init(&Py, kmflag) );
507
508 /* Initialize Px and Py */
509 CHECK_MPI_OK( mp_read_unsigned_octets(&Px, publicValue->data + 1, (mp_size) len) );
510 CHECK_MPI_OK( mp_read_unsigned_octets(&Py, publicValue->data + 1 + len, (mp_size) len) );
511
512 /* construct from named params */
513 group = ECGroup_fromName(ecParams->name, kmflag);
514 if (group == NULL) {
515 /*
516 * ECGroup_fromName fails if ecParams->name is not a valid
517 * ECCurveName value, or if we run out of memory, or perhaps
518 * for other reasons. Unfortunately if ecParams->name is a
519 * valid ECCurveName value, we don't know what the right error
520 * code should be because ECGroup_fromName doesn't return an
521 * error code to the caller. Set err to MP_UNDEF because
522 * that's what ECGroup_fromName uses internally.
523 */
524 if ((ecParams->name <= ECCurve_noName) ||
525 (ecParams->name >= ECCurve_pastLastCurve)) {
526 err = MP_BADARG;
527 } else {
528 err = MP_UNDEF;
529 }
530 goto cleanup;
531 }
532
533 /* validate public point */
534 if ((err = ECPoint_validate(group, &Px, &Py)) < MP_YES) {
535 if (err == MP_NO) {
536 PORT_SetError(SEC_ERROR_BAD_KEY);
537 rv = SECFailure;
538 err = MP_OKAY; /* don't change the error code */
539 }
540 goto cleanup;
541 }
542
543 rv = SECSuccess;
544
545 cleanup:
546 ECGroup_free(group);
547 mp_clear(&Px);
548 mp_clear(&Py);
549 if (err) {
550 MP_TO_SEC_ERROR(err);
551 rv = SECFailure;
552 }
553 return rv;
554 }
555
556 /*
557 ** Performs an ECDH key derivation by computing the scalar point
558 ** multiplication of privateValue and publicValue (with or without the
559 ** cofactor) and returns the x-coordinate of the resulting elliptic
560 ** curve point in derived secret. If successful, derivedSecret->data
561 ** is set to the address of the newly allocated buffer containing the
562 ** derived secret, and derivedSecret->len is the size of the secret
563 ** produced. It is the caller's responsibility to free the allocated
564 ** buffer containing the derived secret.
565 */
566 SECStatus
567 ECDH_Derive(SECItem *publicValue,
568 ECParams *ecParams,
569 SECItem *privateValue,
570 PRBool withCofactor,
571 SECItem *derivedSecret,
572 int kmflag)
573 {
574 SECStatus rv = SECFailure;
575 unsigned int len = 0;
576 SECItem pointQ = {siBuffer, NULL, 0};
577 mp_int k; /* to hold the private value */
578 mp_int cofactor;
579 mp_err err = MP_OKAY;
580 #if EC_DEBUG
581 int i;
582 #endif
583
584 if (!publicValue || !ecParams || !privateValue ||
585 !derivedSecret) {
586 PORT_SetError(SEC_ERROR_INVALID_ARGS);
587 return SECFailure;
588 }
589
590 if (EC_ValidatePublicKey(ecParams, publicValue, kmflag) != SECSuccess) {
591 return SECFailure;
592 }
593
594 memset(derivedSecret, 0, sizeof *derivedSecret);
595 len = (ecParams->fieldID.size + 7) >> 3;
596 pointQ.len = 2*len + 1;
597 if ((pointQ.data = PORT_Alloc(2*len + 1, kmflag)) == NULL) goto cleanup;
598
599 MP_DIGITS(&k) = 0;
600 CHECK_MPI_OK( mp_init(&k, kmflag) );
601 CHECK_MPI_OK( mp_read_unsigned_octets(&k, privateValue->data,
602 (mp_size) privateValue->len) );
603
604 if (withCofactor && (ecParams->cofactor != 1)) {
605 /* multiply k with the cofactor */
606 MP_DIGITS(&cofactor) = 0;
607 CHECK_MPI_OK( mp_init(&cofactor, kmflag) );
608 mp_set(&cofactor, ecParams->cofactor);
609 CHECK_MPI_OK( mp_mul(&k, &cofactor, &k) );
610 }
611
612 /* Multiply our private key and peer's public point */
613 if ((ec_points_mul(ecParams, NULL, &k, publicValue, &pointQ, kmflag) != SECSuccess) ||
614 ec_point_at_infinity(&pointQ))
615 goto cleanup;
616
617 /* Allocate memory for the derived secret and copy
618 * the x co-ordinate of pointQ into it.
619 */
620 SECITEM_AllocItem(NULL, derivedSecret, len, kmflag);
621 memcpy(derivedSecret->data, pointQ.data + 1, len);
622
623 rv = SECSuccess;
624
625 #if EC_DEBUG
626 printf("derived_secret:\n");
627 for (i = 0; i < derivedSecret->len; i++)
628 printf("%02x:", derivedSecret->data[i]);
629 printf("\n");
630 #endif
631
632 cleanup:
633 mp_clear(&k);
634
635 if (pointQ.data) {
636 PORT_ZFree(pointQ.data, 2*len + 1);
637 }
638
639 return rv;
640 }
641
642 /* Computes the ECDSA signature (a concatenation of two values r and s)
643 * on the digest using the given key and the random value kb (used in
644 * computing s).
645 */
646 SECStatus
647 ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
648 const SECItem *digest, const unsigned char *kb, const int kblen, int kmflag)
649 {
650 SECStatus rv = SECFailure;
651 mp_int x1;
652 mp_int d, k; /* private key, random integer */
653 mp_int r, s; /* tuple (r, s) is the signature */
654 mp_int n;
655 mp_err err = MP_OKAY;
656 ECParams *ecParams = NULL;
657 SECItem kGpoint = { siBuffer, NULL, 0};
658 int flen = 0; /* length in bytes of the field size */
659 unsigned olen; /* length in bytes of the base point order */
660
661 #if EC_DEBUG
662 char mpstr[256];
663 #endif
664
665 /* Initialize MPI integers. */
666 /* must happen before the first potential call to cleanup */
667 MP_DIGITS(&x1) = 0;
668 MP_DIGITS(&d) = 0;
669 MP_DIGITS(&k) = 0;
670 MP_DIGITS(&r) = 0;
671 MP_DIGITS(&s) = 0;
672 MP_DIGITS(&n) = 0;
673
674 /* Check args */
675 if (!key || !signature || !digest || !kb || (kblen < 0)) {
676 PORT_SetError(SEC_ERROR_INVALID_ARGS);
677 goto cleanup;
678 }
679
680 ecParams = &(key->ecParams);
681 flen = (ecParams->fieldID.size + 7) >> 3;
682 olen = ecParams->order.len;
683 if (signature->data == NULL) {
684 /* a call to get the signature length only */
685 goto finish;
686 }
687 if (signature->len < 2*olen) {
688 PORT_SetError(SEC_ERROR_OUTPUT_LEN);
689 rv = SECBufferTooSmall;
690 goto cleanup;
691 }
692
693
694 CHECK_MPI_OK( mp_init(&x1, kmflag) );
695 CHECK_MPI_OK( mp_init(&d, kmflag) );
696 CHECK_MPI_OK( mp_init(&k, kmflag) );
697 CHECK_MPI_OK( mp_init(&r, kmflag) );
698 CHECK_MPI_OK( mp_init(&s, kmflag) );
699 CHECK_MPI_OK( mp_init(&n, kmflag) );
700
701 SECITEM_TO_MPINT( ecParams->order, &n );
702 SECITEM_TO_MPINT( key->privateValue, &d );
703 CHECK_MPI_OK( mp_read_unsigned_octets(&k, kb, kblen) );
704 /* Make sure k is in the interval [1, n-1] */
705 if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
706 #if EC_DEBUG
707 printf("k is outside [1, n-1]\n");
708 mp_tohex(&k, mpstr);
709 printf("k : %s \n", mpstr);
710 mp_tohex(&n, mpstr);
711 printf("n : %s \n", mpstr);
712 #endif
713 PORT_SetError(SEC_ERROR_NEED_RANDOM);
714 goto cleanup;
715 }
716
717 /*
718 ** ANSI X9.62, Section 5.3.2, Step 2
719 **
720 ** Compute kG
721 */
722 kGpoint.len = 2*flen + 1;
723 kGpoint.data = PORT_Alloc(2*flen + 1, kmflag);
724 if ((kGpoint.data == NULL) ||
725 (ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint, kmflag)
726 != SECSuccess))
727 goto cleanup;
728
729 /*
730 ** ANSI X9.62, Section 5.3.3, Step 1
731 **
732 ** Extract the x co-ordinate of kG into x1
733 */
734 CHECK_MPI_OK( mp_read_unsigned_octets(&x1, kGpoint.data + 1,
735 (mp_size) flen) );
736
737 /*
738 ** ANSI X9.62, Section 5.3.3, Step 2
739 **
740 ** r = x1 mod n NOTE: n is the order of the curve
741 */
742 CHECK_MPI_OK( mp_mod(&x1, &n, &r) );
743
744 /*
745 ** ANSI X9.62, Section 5.3.3, Step 3
746 **
747 ** verify r != 0
748 */
749 if (mp_cmp_z(&r) == 0) {
750 PORT_SetError(SEC_ERROR_NEED_RANDOM);
751 goto cleanup;
752 }
753
754 /*
755 ** ANSI X9.62, Section 5.3.3, Step 4
756 **
757 ** s = (k**-1 * (HASH(M) + d*r)) mod n
758 */
759 SECITEM_TO_MPINT(*digest, &s); /* s = HASH(M) */
760
761 /* In the definition of EC signing, digests are truncated
762 * to the length of n in bits.
763 * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
764 if (digest->len*8 > (unsigned int)ecParams->fieldID.size) {
765 mpl_rsh(&s,&s,digest->len*8 - ecParams->fieldID.size);
766 }
767
768 #if EC_DEBUG
769 mp_todecimal(&n, mpstr);
770 printf("n : %s (dec)\n", mpstr);
771 mp_todecimal(&d, mpstr);
772 printf("d : %s (dec)\n", mpstr);
773 mp_tohex(&x1, mpstr);
774 printf("x1: %s\n", mpstr);
775 mp_todecimal(&s, mpstr);
776 printf("digest: %s (decimal)\n", mpstr);
777 mp_todecimal(&r, mpstr);
778 printf("r : %s (dec)\n", mpstr);
779 mp_tohex(&r, mpstr);
780 printf("r : %s\n", mpstr);
781 #endif
782
783 CHECK_MPI_OK( mp_invmod(&k, &n, &k) ); /* k = k**-1 mod n */
784 CHECK_MPI_OK( mp_mulmod(&d, &r, &n, &d) ); /* d = d * r mod n */
785 CHECK_MPI_OK( mp_addmod(&s, &d, &n, &s) ); /* s = s + d mod n */
786 CHECK_MPI_OK( mp_mulmod(&s, &k, &n, &s) ); /* s = s * k mod n */
787
788 #if EC_DEBUG
789 mp_todecimal(&s, mpstr);
790 printf("s : %s (dec)\n", mpstr);
791 mp_tohex(&s, mpstr);
792 printf("s : %s\n", mpstr);
793 #endif
794
795 /*
796 ** ANSI X9.62, Section 5.3.3, Step 5
797 **
798 ** verify s != 0
799 */
800 if (mp_cmp_z(&s) == 0) {
801 PORT_SetError(SEC_ERROR_NEED_RANDOM);
802 goto cleanup;
803 }
804
805 /*
806 **
807 ** Signature is tuple (r, s)
808 */
809 CHECK_MPI_OK( mp_to_fixlen_octets(&r, signature->data, olen) );
810 CHECK_MPI_OK( mp_to_fixlen_octets(&s, signature->data + olen, olen) );
811 finish:
812 signature->len = 2*olen;
813
814 rv = SECSuccess;
815 err = MP_OKAY;
816 cleanup:
817 mp_clear(&x1);
818 mp_clear(&d);
819 mp_clear(&k);
820 mp_clear(&r);
821 mp_clear(&s);
822 mp_clear(&n);
823
824 if (kGpoint.data) {
825 PORT_ZFree(kGpoint.data, 2*flen + 1);
826 }
827
828 if (err) {
829 MP_TO_SEC_ERROR(err);
830 rv = SECFailure;
831 }
832
833 #if EC_DEBUG
834 printf("ECDSA signing with seed %s\n",
835 (rv == SECSuccess) ? "succeeded" : "failed");
836 #endif
837
838 return rv;
839 }
840
841 /*
842 ** Computes the ECDSA signature on the digest using the given key
843 ** and a random seed.
844 */
845 SECStatus
846 ECDSA_SignDigest(ECPrivateKey *key, SECItem *signature, const SECItem *digest,
847 const unsigned char* random, int randomLen, int kmflag)
848 {
849 SECStatus rv = SECFailure;
850 int len;
851 unsigned char *kBytes= NULL;
852
853 if (!key) {
854 PORT_SetError(SEC_ERROR_INVALID_ARGS);
855 return SECFailure;
856 }
857
858 /* Generate random value k */
859 len = key->ecParams.order.len;
860 kBytes = ec_GenerateRandomPrivateKey(key->ecParams.order.data, len,
861 random, randomLen, kmflag);
862 if (kBytes == NULL) goto cleanup;
863
864 /* Generate ECDSA signature with the specified k value */
865 rv = ECDSA_SignDigestWithSeed(key, signature, digest, kBytes, len, kmflag);
866
867 cleanup:
868 if (kBytes) {
869 PORT_ZFree(kBytes, len * 2);
870 }
871
872 #if EC_DEBUG
873 printf("ECDSA signing %s\n",
874 (rv == SECSuccess) ? "succeeded" : "failed");
875 #endif
876
877 return rv;
878 }
879
880 /*
881 ** Checks the signature on the given digest using the key provided.
882 */
883 SECStatus
884 ECDSA_VerifyDigest(ECPublicKey *key, const SECItem *signature,
885 const SECItem *digest, int kmflag)
886 {
887 SECStatus rv = SECFailure;
888 mp_int r_, s_; /* tuple (r', s') is received signature) */
889 mp_int c, u1, u2, v; /* intermediate values used in verification */
890 mp_int x1;
891 mp_int n;
892 mp_err err = MP_OKAY;
893 ECParams *ecParams = NULL;
894 SECItem pointC = { siBuffer, NULL, 0 };
895 int slen; /* length in bytes of a half signature (r or s) */
896 int flen; /* length in bytes of the field size */
897 unsigned olen; /* length in bytes of the base point order */
898
899 #if EC_DEBUG
900 char mpstr[256];
901 printf("ECDSA verification called\n");
902 #endif
903
904 /* Initialize MPI integers. */
905 /* must happen before the first potential call to cleanup */
906 MP_DIGITS(&r_) = 0;
907 MP_DIGITS(&s_) = 0;
908 MP_DIGITS(&c) = 0;
909 MP_DIGITS(&u1) = 0;
910 MP_DIGITS(&u2) = 0;
911 MP_DIGITS(&x1) = 0;
912 MP_DIGITS(&v) = 0;
913 MP_DIGITS(&n) = 0;
914
915 /* Check args */
916 if (!key || !signature || !digest) {
917 PORT_SetError(SEC_ERROR_INVALID_ARGS);
918 goto cleanup;
919 }
920
921 ecParams = &(key->ecParams);
922 flen = (ecParams->fieldID.size + 7) >> 3;
923 olen = ecParams->order.len;
924 if (signature->len == 0 || signature->len%2 != 0 ||
925 signature->len > 2*olen) {
926 PORT_SetError(SEC_ERROR_INPUT_LEN);
927 goto cleanup;
928 }
929 slen = signature->len/2;
930
931 SECITEM_AllocItem(NULL, &pointC, 2*flen + 1, kmflag);
932 if (pointC.data == NULL)
933 goto cleanup;
934
935 CHECK_MPI_OK( mp_init(&r_, kmflag) );
936 CHECK_MPI_OK( mp_init(&s_, kmflag) );
937 CHECK_MPI_OK( mp_init(&c, kmflag) );
938 CHECK_MPI_OK( mp_init(&u1, kmflag) );
939 CHECK_MPI_OK( mp_init(&u2, kmflag) );
940 CHECK_MPI_OK( mp_init(&x1, kmflag) );
941 CHECK_MPI_OK( mp_init(&v, kmflag) );
942 CHECK_MPI_OK( mp_init(&n, kmflag) );
943
944 /*
945 ** Convert received signature (r', s') into MPI integers.
946 */
947 CHECK_MPI_OK( mp_read_unsigned_octets(&r_, signature->data, slen) );
948 CHECK_MPI_OK( mp_read_unsigned_octets(&s_, signature->data + slen, slen) );
949
950 /*
951 ** ANSI X9.62, Section 5.4.2, Steps 1 and 2
952 **
953 ** Verify that 0 < r' < n and 0 < s' < n
954 */
955 SECITEM_TO_MPINT(ecParams->order, &n);
956 if (mp_cmp_z(&r_) <= 0 || mp_cmp_z(&s_) <= 0 ||
957 mp_cmp(&r_, &n) >= 0 || mp_cmp(&s_, &n) >= 0) {
958 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
959 goto cleanup; /* will return rv == SECFailure */
960 }
961
962 /*
963 ** ANSI X9.62, Section 5.4.2, Step 3
964 **
965 ** c = (s')**-1 mod n
966 */
967 CHECK_MPI_OK( mp_invmod(&s_, &n, &c) ); /* c = (s')**-1 mod n */
968
969 /*
970 ** ANSI X9.62, Section 5.4.2, Step 4
971 **
972 ** u1 = ((HASH(M')) * c) mod n
973 */
974 SECITEM_TO_MPINT(*digest, &u1); /* u1 = HASH(M) */
975
976 /* In the definition of EC signing, digests are truncated
977 * to the length of n in bits.
978 * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
979 /* u1 = HASH(M') */
980 if (digest->len*8 > (unsigned int)ecParams->fieldID.size) {
981 mpl_rsh(&u1,&u1,digest->len*8- ecParams->fieldID.size);
982 }
983
984 #if EC_DEBUG
985 mp_todecimal(&r_, mpstr);
986 printf("r_: %s (dec)\n", mpstr);
987 mp_todecimal(&s_, mpstr);
988 printf("s_: %s (dec)\n", mpstr);
989 mp_todecimal(&c, mpstr);
990 printf("c : %s (dec)\n", mpstr);
991 mp_todecimal(&u1, mpstr);
992 printf("digest: %s (dec)\n", mpstr);
993 #endif
994
995 CHECK_MPI_OK( mp_mulmod(&u1, &c, &n, &u1) ); /* u1 = u1 * c mod n */
996
997 /*
998 ** ANSI X9.62, Section 5.4.2, Step 4
999 **
1000 ** u2 = ((r') * c) mod n
1001 */
1002 CHECK_MPI_OK( mp_mulmod(&r_, &c, &n, &u2) );
1003
1004 /*
1005 ** ANSI X9.62, Section 5.4.3, Step 1
1006 **
1007 ** Compute u1*G + u2*Q
1008 ** Here, A = u1.G B = u2.Q and C = A + B
1009 ** If the result, C, is the point at infinity, reject the signature
1010 */
1011 if (ec_points_mul(ecParams, &u1, &u2, &key->publicValue, &pointC, kmflag)
1012 != SECSuccess) {
1013 rv = SECFailure;
1014 goto cleanup;
1015 }
1016 if (ec_point_at_infinity(&pointC)) {
1017 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
1018 rv = SECFailure;
1019 goto cleanup;
1020 }
1021
1022 CHECK_MPI_OK( mp_read_unsigned_octets(&x1, pointC.data + 1, flen) );
1023
1024 /*
1025 ** ANSI X9.62, Section 5.4.4, Step 2
1026 **
1027 ** v = x1 mod n
1028 */
1029 CHECK_MPI_OK( mp_mod(&x1, &n, &v) );
1030
1031 #if EC_DEBUG
1032 mp_todecimal(&r_, mpstr);
1033 printf("r_: %s (dec)\n", mpstr);
1034 mp_todecimal(&v, mpstr);
1035 printf("v : %s (dec)\n", mpstr);
1036 #endif
1037
1038 /*
1039 ** ANSI X9.62, Section 5.4.4, Step 3
1040 **
1041 ** Verification: v == r'
1042 */
1043 if (mp_cmp(&v, &r_)) {
1044 PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
1045 rv = SECFailure; /* Signature failed to verify. */
1046 } else {
1047 rv = SECSuccess; /* Signature verified. */
1048 }
1049
1050 #if EC_DEBUG
1051 mp_todecimal(&u1, mpstr);
1052 printf("u1: %s (dec)\n", mpstr);
1053 mp_todecimal(&u2, mpstr);
1054 printf("u2: %s (dec)\n", mpstr);
1055 mp_tohex(&x1, mpstr);
1056 printf("x1: %s\n", mpstr);
1057 mp_todecimal(&v, mpstr);
1058 printf("v : %s (dec)\n", mpstr);
1059 #endif
1060
1061 cleanup:
1062 mp_clear(&r_);
1063 mp_clear(&s_);
1064 mp_clear(&c);
1065 mp_clear(&u1);
1066 mp_clear(&u2);
1067 mp_clear(&x1);
1068 mp_clear(&v);
1069 mp_clear(&n);
1070
1071 if (pointC.data) SECITEM_FreeItem(&pointC, PR_FALSE);
1072 if (err) {
1073 MP_TO_SEC_ERROR(err);
1074 rv = SECFailure;
1075 }
1076
1077 #if EC_DEBUG
1078 printf("ECDSA verification %s\n",
1079 (rv == SECSuccess) ? "succeeded" : "failed");
1080 #endif
1081
1082 return rv;
1083 }