crypto/ec/ec_pmeth.c

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