crypto/ec/ec_pmeth.c

   1 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   2  * project 2006.
   3  */
   4 /* ====================================================================
   5  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  *
  19  * 3. All advertising materials mentioning features or use of this
  20  *    software must display the following acknowledgment:
  21  *    "This product includes software developed by the OpenSSL Project
  22  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  23  *
  24  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  25  *    endorse or promote products derived from this software without
  26  *    prior written permission. For written permission, please contact
  27  *    licensing@OpenSSL.org.
  28  *
  29  * 5. Products derived from this software may not be called "OpenSSL"
  30  *    nor may "OpenSSL" appear in their names without prior written
  31  *    permission of the OpenSSL Project.
  32  *
  33  * 6. Redistributions of any form whatsoever must retain the following
  34  *    acknowledgment:
  35  *    "This product includes software developed by the OpenSSL Project
  36  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  37  *
  38  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  39  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  41  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  44  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  47  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  48  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  49  * OF THE POSSIBILITY OF SUCH DAMAGE.
  50  * ====================================================================
  51  *
  52  * This product includes cryptographic software written by Eric Young
  53  * (eay@cryptsoft.com).  This product includes software written by Tim
  54  * Hudson (tjh@cryptsoft.com).
  55  *
  56  */
  57
  58 #include <stdio.h>
  59 #include "cryptlib.h"
  60 #include <openssl/asn1t.h>
  61 #include <openssl/x509.h>
  62 #include <openssl/ec.h>
  63 #include "ec_lcl.h"
  64 #include <openssl/ecdsa.h>
  65 #include <openssl/evp.h>
  66 #include "evp_locl.h"
  67
  68 /* EC pkey context structure */
  69
  70 typedef struct
  71         {
  72         /* Key and paramgen group */
  73         EC_GROUP *gen_group;
  74         /* message digest */
  75         const EVP_MD *md;
  76         /* Duplicate key if custom cofactor needed */
  77         EC_KEY *co_key;
  78         /* Cofactor mode */
  79         signed char cofactor_mode;
  80         /* KDF (if any) to use for ECDH */
  81         char kdf_type;
  82         /* Message digest to use for key derivation */
  83         const EVP_MD *kdf_md;
  84         /* User key material */
  85         unsigned char *kdf_ukm;
  86         size_t kdf_ukmlen;
  87         /* KDF output length */
  88         size_t kdf_outlen;
  89
  90         } EC_PKEY_CTX;
  91
  92 static int pkey_ec_init(EVP_PKEY_CTX *ctx)
  93         {
  94         EC_PKEY_CTX *dctx;
  95         dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
  96         if (!dctx)
  97                 return 0;
  98         dctx->gen_group = NULL;
  99         dctx->md = NULL;
 100
 101         dctx->cofactor_mode = -1;
 102         dctx->co_key = NULL;
 103         dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;
 104         dctx->kdf_md = NULL;
 105         dctx->kdf_outlen = 0;
 106         dctx->kdf_ukm = NULL;
 107         dctx->kdf_ukmlen = 0;
 108
 109         ctx->data = dctx;
 110
 111         return 1;
 112         }
 113
 114 static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
 115         {
 116         EC_PKEY_CTX *dctx, *sctx;
 117         if (!pkey_ec_init(dst))
 118                 return 0;
 119         sctx = src->data;
 120         dctx = dst->data;
 121         if (sctx->gen_group)
 122                 {
 123                 dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
 124                 if (!dctx->gen_group)
 125                         return 0;
 126                 }
 127         dctx->md = sctx->md;
 128
 129         if (sctx->co_key)
 130                 {
 131                 dctx->co_key = EC_KEY_dup(sctx->co_key);
 132                 if (!dctx->co_key)
 133                         return 0;
 134                 }
 135         dctx->kdf_type = sctx->kdf_type;
 136         dctx->kdf_md = sctx->kdf_md;
 137         dctx->kdf_outlen = sctx->kdf_outlen;
 138         if (sctx->kdf_ukm)
 139                 {
 140                 dctx->kdf_ukm = BUF_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);
 141                 if (!dctx->kdf_ukm)
 142                         return 0;
 143                 }
 144         else
 145                 dctx->kdf_ukm = NULL;
 146         dctx->kdf_ukmlen = sctx->kdf_ukmlen;
 147         return 1;
 148         }
 149
 150 static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
 151         {
 152         EC_PKEY_CTX *dctx = ctx->data;
 153         if (dctx)
 154                 {
 155                 if (dctx->gen_group)
 156                         EC_GROUP_free(dctx->gen_group);
 157                 if (dctx->co_key)
 158                         EC_KEY_free(dctx->co_key);
 159                 if (dctx->kdf_ukm)
 160                         OPENSSL_free(dctx->kdf_ukm);
 161                 OPENSSL_free(dctx);
 162                 }
 163         }
 164
 165 static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
 166                                         const unsigned char *tbs, size_t tbslen)
 167         {
 168         int ret, type;
 169         unsigned int sltmp;
 170         EC_PKEY_CTX *dctx = ctx->data;
 171         EC_KEY *ec = ctx->pkey->pkey.ec;
 172
 173         if (!sig)
 174                 {
 175                 *siglen = ECDSA_size(ec);
 176                 return 1;
 177                 }
 178         else if(*siglen < (size_t)ECDSA_size(ec))
 179                 {
 180                 ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
 181                 return 0;
 182                 }
 183
 184         if (dctx->md)
 185                 type = EVP_MD_type(dctx->md);
 186         else
 187                 type = NID_sha1;
 188
 189
 190         ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
 191
 192         if (ret <= 0)
 193                 return ret;
 194         *siglen = (size_t)sltmp;
 195         return 1;
 196         }
 197
 198 static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
 199                                         const unsigned char *sig, size_t siglen,
 200                                         const unsigned char *tbs, size_t tbslen)
 201         {
 202         int ret, type;
 203         EC_PKEY_CTX *dctx = ctx->data;
 204         EC_KEY *ec = ctx->pkey->pkey.ec;
 205
 206         if (dctx->md)
 207                 type = EVP_MD_type(dctx->md);
 208         else
 209                 type = NID_sha1;
 210
 211         ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
 212
 213         return ret;
 214         }
 215
 216 static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
 217         {
 218         int ret;
 219         size_t outlen;
 220         const EC_POINT *pubkey = NULL;
 221         EC_KEY *eckey;
 222         EC_PKEY_CTX *dctx = ctx->data;
 223         if (!ctx->pkey || !ctx->peerkey)
 224                 {
 225                 ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
 226                 return 0;
 227                 }
 228
 229         eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec;
 230
 231         if (!key)
 232                 {
 233                 const EC_GROUP *group;
 234                 group = EC_KEY_get0_group(eckey);
 235                 *keylen = (EC_GROUP_get_degree(group) + 7)/8;
 236                 return 1;
 237                 }
 238         pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
 239
 240         /* NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is
 241          * not an error, the result is truncated.
 242          */
 243
 244         outlen = *keylen;
 245
 246         ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0);
 247         if (ret <= 0)
 248                 return 0;
 249         *keylen = ret;
 250         return 1;
 251         }
 252
 253 static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,
 254                                 unsigned char *key, size_t *keylen)
 255         {
 256         EC_PKEY_CTX *dctx = ctx->data;
 257         unsigned char *ktmp = NULL;
 258         size_t ktmplen;
 259         int rv = 0;
 260         if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)
 261                 return pkey_ec_derive(ctx, key, keylen);
 262         if (!key)
 263                 {
 264                 *keylen = dctx->kdf_outlen;
 265                 return 1;
 266                 }
 267         if (*keylen != dctx->kdf_outlen)
 268                 return 0;
 269         if (!pkey_ec_derive(ctx, NULL, &ktmplen))
 270                 return 0;
 271         ktmp = OPENSSL_malloc(ktmplen);
 272         if (!ktmp)
 273                 return 0;
 274         if (!pkey_ec_derive(ctx, ktmp, &ktmplen))
 275                 goto err;
 276         /* Do KDF stuff */
 277         if (!ECDH_KDF_X9_62(key, *keylen, ktmp, ktmplen,
 278                                 dctx->kdf_ukm, dctx->kdf_ukmlen,
 279                                 dctx->kdf_md))
 280                 goto err;
 281         rv = 1;
 282
 283         err:
 284         if (ktmp)
 285                 {
 286                 OPENSSL_cleanse(ktmp, ktmplen);
 287                 OPENSSL_free(ktmp);
 288                 }
 289         return rv;
 290         }
 291
 292 static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 293         {
 294         EC_PKEY_CTX *dctx = ctx->data;
 295         EC_GROUP *group;
 296         switch (type)
 297                 {
 298                 case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
 299                 group = EC_GROUP_new_by_curve_name(p1);
 300                 if (group == NULL)
 301                         {
 302                         ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
 303                         return 0;
 304                         }
 305                 if (dctx->gen_group)
 306                         EC_GROUP_free(dctx->gen_group);
 307                 dctx->gen_group = group;
 308                 return 1;
 309
 310                 case EVP_PKEY_CTRL_EC_PARAM_ENC:
 311                 if (!dctx->gen_group)
 312                         {
 313                         ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET);
 314                         return 0;
 315                         }
 316                 EC_GROUP_set_asn1_flag(dctx->gen_group, p1);
 317                 return 1;
 318
 319                 case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:
 320                 if (p1 == -2)
 321                         {
 322                         if (dctx->cofactor_mode != -1)
 323                                 return dctx->cofactor_mode;
 324                         else
 325                                 {
 326                                 EC_KEY *ec_key = ctx->pkey->pkey.ec;
 327                                 return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 : 0;
 328                                 }
 329                         }
 330                 else if (p1 < -1 || p1 > 1)
 331                         return -2;
 332                 dctx->cofactor_mode = p1;
 333                 if (p1 != -1)
 334                         {
 335                         EC_KEY *ec_key = ctx->pkey->pkey.ec;
 336                         if (!ec_key->group)
 337                                 return -2;
 338                         /* If cofactor is 1 cofactor mode does nothing */
 339                         if (BN_is_one(ec_key->group->cofactor))
 340                                 return 1;
 341                         if (!dctx->co_key)
 342                                 {
 343                                 dctx->co_key = EC_KEY_dup(ec_key);
 344                                 if (!dctx->co_key)
 345                                         return 0;
 346                                 }
 347                         if (p1)
 348                                 EC_KEY_set_flags(dctx->co_key,
 349                                                         EC_FLAG_COFACTOR_ECDH);
 350                         else
 351                                 EC_KEY_clear_flags(dctx->co_key,
 352                                                         EC_FLAG_COFACTOR_ECDH);
 353                         }
 354                 else if (dctx->co_key)
 355                         {
 356                         EC_KEY_free(dctx->co_key);
 357                         dctx->co_key = NULL;
 358                         }
 359                 return 1;
 360
 361                 case EVP_PKEY_CTRL_EC_KDF_TYPE:
 362                 if (p1 == -2)
 363                         return dctx->kdf_type;
 364                 if (p1 != EVP_PKEY_ECDH_KDF_NONE &&
 365                     p1 != EVP_PKEY_ECDH_KDF_X9_62)
 366                         return -2;
 367                 dctx->kdf_type = p1;
 368                 return 1;
 369
 370                 case EVP_PKEY_CTRL_EC_KDF_MD:
 371                 dctx->kdf_md = p2;
 372                 return 1;
 373
 374                 case EVP_PKEY_CTRL_GET_EC_KDF_MD:
 375                 *(const EVP_MD **)p2 = dctx->kdf_md;
 376                 return 1;
 377
 378                 case EVP_PKEY_CTRL_EC_KDF_OUTLEN:
 379                 if (p1 <= 0)
 380                         return -2;
 381                 dctx->kdf_outlen = (size_t)p1;
 382                 return 1;
 383
 384                 case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:
 385                 *(int *)p2 = dctx->kdf_outlen;
 386                 return 1;
 387
 388                 case EVP_PKEY_CTRL_EC_KDF_UKM:
 389                 if (dctx->kdf_ukm)
 390                         OPENSSL_free(dctx->kdf_ukm);
 391                 dctx->kdf_ukm = p2;
 392                 if (p2)
 393                         dctx->kdf_ukmlen = p1;
 394                 else
 395                         dctx->kdf_ukmlen = 0;
 396                 return 1;
 397
 398                 case EVP_PKEY_CTRL_GET_EC_KDF_UKM:
 399                 *(unsigned char **)p2 = dctx->kdf_ukm;
 400                 return dctx->kdf_ukmlen;
 401
 402                 case EVP_PKEY_CTRL_MD:
 403                 if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
 404                     EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
 405                     EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
 406                     EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
 407                     EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
 408                     EVP_MD_type((const EVP_MD *)p2) != NID_sha512)
 409                         {
 410                         ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
 411                         return 0;
 412                         }
 413                 dctx->md = p2;
 414                 return 1;
 415
 416                 case EVP_PKEY_CTRL_GET_MD:
 417                 *(const EVP_MD **)p2 = dctx->md;
 418                 return 1;
 419
 420                 case EVP_PKEY_CTRL_PEER_KEY:
 421                 /* Default behaviour is OK */
 422                 case EVP_PKEY_CTRL_DIGESTINIT:
 423                 case EVP_PKEY_CTRL_PKCS7_SIGN:
 424                 case EVP_PKEY_CTRL_CMS_SIGN:
 425                 return 1;
 426
 427                 default:
 428                 return -2;
 429
 430                 }
 431         }
 432
 433 static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
 434                         const char *type, const char *value)
 435         {
 436         if (!strcmp(type, "ec_paramgen_curve"))
 437                 {
 438                 int nid;
 439                 nid = EC_curve_nist2nid(value);
 440                 if (nid == NID_undef)
 441                         nid = OBJ_sn2nid(value);
 442                 if (nid == NID_undef)
 443                         nid = OBJ_ln2nid(value);
 444                 if (nid == NID_undef)
 445                         {
 446                         ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
 447                         return 0;
 448                         }
 449                 return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
 450                 }
 451         else if (!strcmp(type, "ec_param_enc"))
 452                 {
 453                 int param_enc;
 454                 if (!strcmp(value, "explicit"))
 455                         param_enc = 0;
 456                 else if (!strcmp(value, "named_curve"))
 457                         param_enc = OPENSSL_EC_NAMED_CURVE;
 458                 else
 459                         return -2;
 460                 return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
 461                 }
 462         else if (!strcmp(type, "ecdh_kdf_md"))
 463                 {
 464                 const EVP_MD *md;
 465                 if (!(md = EVP_get_digestbyname(value)))
 466                         {
 467                         ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);
 468                         return 0;
 469                         }
 470                 return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
 471                 }
 472         else if (!strcmp(type, "ecdh_cofactor_mode"))
 473                 {
 474                 int co_mode;
 475                 co_mode = atoi(value);
 476                 return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
 477                 }
 478
 479         return -2;
 480         }
 481
 482 static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 483         {
 484         EC_KEY *ec = NULL;
 485         EC_PKEY_CTX *dctx = ctx->data;
 486         int ret = 0;
 487         if (dctx->gen_group == NULL)
 488                 {
 489                 ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
 490                 return 0;
 491                 }
 492         ec = EC_KEY_new();
 493         if (!ec)
 494                 return 0;
 495         ret = EC_KEY_set_group(ec, dctx->gen_group);
 496         if (ret)
 497                 EVP_PKEY_assign_EC_KEY(pkey, ec);
 498         else
 499                 EC_KEY_free(ec);
 500         return ret;
 501         }
 502
 503 static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 504         {
 505         EC_KEY *ec = NULL;
 506         EC_PKEY_CTX *dctx = ctx->data;
 507         if (ctx->pkey == NULL && dctx->gen_group == NULL)
 508                 {
 509                 ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
 510                 return 0;
 511                 }
 512         ec = EC_KEY_new();
 513         if (!ec)
 514                 return 0;
 515         EVP_PKEY_assign_EC_KEY(pkey, ec);
 516         if (ctx->pkey)
 517                 {
 518                 /* Note: if error return, pkey is freed by parent routine */
 519                 if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
 520                         return 0;
 521                 }
 522         else
 523                 {
 524                 if (!EC_KEY_set_group(ec, dctx->gen_group))
 525                         return 0;
 526                 }
 527         return EC_KEY_generate_key(pkey->pkey.ec);
 528         }
 529
 530 const EVP_PKEY_METHOD ec_pkey_meth =
 531         {
 532         EVP_PKEY_EC,
 533         0,
 534         pkey_ec_init,
 535         pkey_ec_copy,
 536         pkey_ec_cleanup,
 537
 538         0,
 539         pkey_ec_paramgen,
 540
 541         0,
 542         pkey_ec_keygen,
 543
 544         0,
 545         pkey_ec_sign,
 546
 547         0,
 548         pkey_ec_verify,
 549
 550         0,0,
 551
 552         0,0,0,0,
 553
 554         0,0,
 555
 556         0,0,
 557
 558         0,
 559         pkey_ec_kdf_derive,
 560
 561         pkey_ec_ctrl,
 562         pkey_ec_ctrl_str
 563
 564         };