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     dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
  95     if (!dctx)
  96         return 0;
  97     dctx->gen_group = NULL;
  98     dctx->md = NULL;
  99
 100     dctx->cofactor_mode = -1;
 101     dctx->co_key = NULL;
 102     dctx->kdf_type = EVP_PKEY_ECDH_KDF_NONE;
 103     dctx->kdf_md = NULL;
 104     dctx->kdf_outlen = 0;
 105     dctx->kdf_ukm = NULL;
 106     dctx->kdf_ukmlen = 0;
 107
 108     ctx->data = dctx;
 109
 110     return 1;
 111 }
 112
 113 static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
 114 {
 115     EC_PKEY_CTX *dctx, *sctx;
 116     if (!pkey_ec_init(dst))
 117         return 0;
 118     sctx = src->data;
 119     dctx = dst->data;
 120     if (sctx->gen_group) {
 121         dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
 122         if (!dctx->gen_group)
 123             return 0;
 124     }
 125     dctx->md = sctx->md;
 126
 127     if (sctx->co_key) {
 128         dctx->co_key = EC_KEY_dup(sctx->co_key);
 129         if (!dctx->co_key)
 130             return 0;
 131     }
 132     dctx->kdf_type = sctx->kdf_type;
 133     dctx->kdf_md = sctx->kdf_md;
 134     dctx->kdf_outlen = sctx->kdf_outlen;
 135     if (sctx->kdf_ukm) {
 136         dctx->kdf_ukm = BUF_memdup(sctx->kdf_ukm, sctx->kdf_ukmlen);
 137         if (!dctx->kdf_ukm)
 138             return 0;
 139     } else
 140         dctx->kdf_ukm = NULL;
 141     dctx->kdf_ukmlen = sctx->kdf_ukmlen;
 142     return 1;
 143 }
 144
 145 static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
 146 {
 147     EC_PKEY_CTX *dctx = ctx->data;
 148     if (dctx) {
 149         if (dctx->gen_group)
 150             EC_GROUP_free(dctx->gen_group);
 151         if (dctx->co_key)
 152             EC_KEY_free(dctx->co_key);
 153         if (dctx->kdf_ukm)
 154             OPENSSL_free(dctx->kdf_ukm);
 155         OPENSSL_free(dctx);
 156     }
 157 }
 158
 159 static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
 160                         const unsigned char *tbs, size_t tbslen)
 161 {
 162     int ret, type;
 163     unsigned int sltmp;
 164     EC_PKEY_CTX *dctx = ctx->data;
 165     EC_KEY *ec = ctx->pkey->pkey.ec;
 166
 167     if (!sig) {
 168         *siglen = ECDSA_size(ec);
 169         return 1;
 170     } else if (*siglen < (size_t)ECDSA_size(ec)) {
 171         ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
 172         return 0;
 173     }
 174
 175     if (dctx->md)
 176         type = EVP_MD_type(dctx->md);
 177     else
 178         type = NID_sha1;
 179
 180     ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
 181
 182     if (ret <= 0)
 183         return ret;
 184     *siglen = (size_t)sltmp;
 185     return 1;
 186 }
 187
 188 static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
 189                           const unsigned char *sig, size_t siglen,
 190                           const unsigned char *tbs, size_t tbslen)
 191 {
 192     int ret, type;
 193     EC_PKEY_CTX *dctx = ctx->data;
 194     EC_KEY *ec = ctx->pkey->pkey.ec;
 195
 196     if (dctx->md)
 197         type = EVP_MD_type(dctx->md);
 198     else
 199         type = NID_sha1;
 200
 201     ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
 202
 203     return ret;
 204 }
 205
 206 #ifndef OPENSSL_NO_EC
 207 static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
 208                           size_t *keylen)
 209 {
 210     int ret;
 211     size_t outlen;
 212     const EC_POINT *pubkey = NULL;
 213     EC_KEY *eckey;
 214     EC_PKEY_CTX *dctx = ctx->data;
 215     if (!ctx->pkey || !ctx->peerkey) {
 216         ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
 217         return 0;
 218     }
 219
 220     eckey = dctx->co_key ? dctx->co_key : ctx->pkey->pkey.ec;
 221
 222     if (!key) {
 223         const EC_GROUP *group;
 224         group = EC_KEY_get0_group(eckey);
 225         *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
 226         return 1;
 227     }
 228     pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
 229
 230     /*
 231      * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is not
 232      * an error, the result is truncated.
 233      */
 234
 235     outlen = *keylen;
 236
 237     ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0);
 238     if (ret <= 0)
 239         return 0;
 240     *keylen = ret;
 241     return 1;
 242 }
 243
 244 static int pkey_ec_kdf_derive(EVP_PKEY_CTX *ctx,
 245                               unsigned char *key, size_t *keylen)
 246 {
 247     EC_PKEY_CTX *dctx = ctx->data;
 248     unsigned char *ktmp = NULL;
 249     size_t ktmplen;
 250     int rv = 0;
 251     if (dctx->kdf_type == EVP_PKEY_ECDH_KDF_NONE)
 252         return pkey_ec_derive(ctx, key, keylen);
 253     if (!key) {
 254         *keylen = dctx->kdf_outlen;
 255         return 1;
 256     }
 257     if (*keylen != dctx->kdf_outlen)
 258         return 0;
 259     if (!pkey_ec_derive(ctx, NULL, &ktmplen))
 260         return 0;
 261     ktmp = OPENSSL_malloc(ktmplen);
 262     if (!ktmp)
 263         return 0;
 264     if (!pkey_ec_derive(ctx, ktmp, &ktmplen))
 265         goto err;
 266     /* Do KDF stuff */
 267     if (!ECDH_KDF_X9_62(key, *keylen, ktmp, ktmplen,
 268                         dctx->kdf_ukm, dctx->kdf_ukmlen, dctx->kdf_md))
 269         goto err;
 270     rv = 1;
 271
 272  err:
 273     if (ktmp) {
 274         OPENSSL_cleanse(ktmp, ktmplen);
 275         OPENSSL_free(ktmp);
 276     }
 277     return rv;
 278 }
 279 #endif
 280
 281 static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 282 {
 283     EC_PKEY_CTX *dctx = ctx->data;
 284     EC_GROUP *group;
 285     switch (type) {
 286     case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
 287         group = EC_GROUP_new_by_curve_name(p1);
 288         if (group == NULL) {
 289             ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
 290             return 0;
 291         }
 292         if (dctx->gen_group)
 293             EC_GROUP_free(dctx->gen_group);
 294         dctx->gen_group = group;
 295         return 1;
 296
 297     case EVP_PKEY_CTRL_EC_PARAM_ENC:
 298         if (!dctx->gen_group) {
 299             ECerr(EC_F_PKEY_EC_CTRL, EC_R_NO_PARAMETERS_SET);
 300             return 0;
 301         }
 302         EC_GROUP_set_asn1_flag(dctx->gen_group, p1);
 303         return 1;
 304
 305 #ifndef OPENSSL_NO_EC
 306     case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:
 307         if (p1 == -2) {
 308             if (dctx->cofactor_mode != -1)
 309                 return dctx->cofactor_mode;
 310             else {
 311                 EC_KEY *ec_key = ctx->pkey->pkey.ec;
 312                 return EC_KEY_get_flags(ec_key) & EC_FLAG_COFACTOR_ECDH ? 1 :
 313                     0;
 314             }
 315         } else if (p1 < -1 || p1 > 1)
 316             return -2;
 317         dctx->cofactor_mode = p1;
 318         if (p1 != -1) {
 319             EC_KEY *ec_key = ctx->pkey->pkey.ec;
 320             if (!ec_key->group)
 321                 return -2;
 322             /* If cofactor is 1 cofactor mode does nothing */
 323             if (BN_is_one(ec_key->group->cofactor))
 324                 return 1;
 325             if (!dctx->co_key) {
 326                 dctx->co_key = EC_KEY_dup(ec_key);
 327                 if (!dctx->co_key)
 328                     return 0;
 329             }
 330             if (p1)
 331                 EC_KEY_set_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
 332             else
 333                 EC_KEY_clear_flags(dctx->co_key, EC_FLAG_COFACTOR_ECDH);
 334         } else if (dctx->co_key) {
 335             EC_KEY_free(dctx->co_key);
 336             dctx->co_key = NULL;
 337         }
 338         return 1;
 339 #endif
 340
 341     case EVP_PKEY_CTRL_EC_KDF_TYPE:
 342         if (p1 == -2)
 343             return dctx->kdf_type;
 344         if (p1 != EVP_PKEY_ECDH_KDF_NONE && p1 != EVP_PKEY_ECDH_KDF_X9_62)
 345             return -2;
 346         dctx->kdf_type = p1;
 347         return 1;
 348
 349     case EVP_PKEY_CTRL_EC_KDF_MD:
 350         dctx->kdf_md = p2;
 351         return 1;
 352
 353     case EVP_PKEY_CTRL_GET_EC_KDF_MD:
 354         *(const EVP_MD **)p2 = dctx->kdf_md;
 355         return 1;
 356
 357     case EVP_PKEY_CTRL_EC_KDF_OUTLEN:
 358         if (p1 <= 0)
 359             return -2;
 360         dctx->kdf_outlen = (size_t)p1;
 361         return 1;
 362
 363     case EVP_PKEY_CTRL_GET_EC_KDF_OUTLEN:
 364         *(int *)p2 = dctx->kdf_outlen;
 365         return 1;
 366
 367     case EVP_PKEY_CTRL_EC_KDF_UKM:
 368         if (dctx->kdf_ukm)
 369             OPENSSL_free(dctx->kdf_ukm);
 370         dctx->kdf_ukm = p2;
 371         if (p2)
 372             dctx->kdf_ukmlen = p1;
 373         else
 374             dctx->kdf_ukmlen = 0;
 375         return 1;
 376
 377     case EVP_PKEY_CTRL_GET_EC_KDF_UKM:
 378         *(unsigned char **)p2 = dctx->kdf_ukm;
 379         return dctx->kdf_ukmlen;
 380
 381     case EVP_PKEY_CTRL_MD:
 382         if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
 383             EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
 384             EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
 385             EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
 386             EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
 387             EVP_MD_type((const EVP_MD *)p2) != NID_sha512) {
 388             ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
 389             return 0;
 390         }
 391         dctx->md = p2;
 392         return 1;
 393
 394     case EVP_PKEY_CTRL_GET_MD:
 395         *(const EVP_MD **)p2 = dctx->md;
 396         return 1;
 397
 398     case EVP_PKEY_CTRL_PEER_KEY:
 399         /* Default behaviour is OK */
 400     case EVP_PKEY_CTRL_DIGESTINIT:
 401     case EVP_PKEY_CTRL_PKCS7_SIGN:
 402     case EVP_PKEY_CTRL_CMS_SIGN:
 403         return 1;
 404
 405     default:
 406         return -2;
 407
 408     }
 409 }
 410
 411 static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
 412                             const char *type, const char *value)
 413 {
 414     if (!strcmp(type, "ec_paramgen_curve")) {
 415         int nid;
 416         nid = EC_curve_nist2nid(value);
 417         if (nid == NID_undef)
 418             nid = OBJ_sn2nid(value);
 419         if (nid == NID_undef)
 420             nid = OBJ_ln2nid(value);
 421         if (nid == NID_undef) {
 422             ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
 423             return 0;
 424         }
 425         return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
 426     } else if (!strcmp(type, "ec_param_enc")) {
 427         int param_enc;
 428         if (!strcmp(value, "explicit"))
 429             param_enc = 0;
 430         else if (!strcmp(value, "named_curve"))
 431             param_enc = OPENSSL_EC_NAMED_CURVE;
 432         else
 433             return -2;
 434         return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
 435     } else if (!strcmp(type, "ecdh_kdf_md")) {
 436         const EVP_MD *md;
 437         if (!(md = EVP_get_digestbyname(value))) {
 438             ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);
 439             return 0;
 440         }
 441         return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
 442     } else if (!strcmp(type, "ecdh_cofactor_mode")) {
 443         int co_mode;
 444         co_mode = atoi(value);
 445         return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
 446     }
 447
 448     return -2;
 449 }
 450
 451 static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 452 {
 453     EC_KEY *ec = NULL;
 454     EC_PKEY_CTX *dctx = ctx->data;
 455     int ret = 0;
 456     if (dctx->gen_group == NULL) {
 457         ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
 458         return 0;
 459     }
 460     ec = EC_KEY_new();
 461     if (!ec)
 462         return 0;
 463     ret = EC_KEY_set_group(ec, dctx->gen_group);
 464     if (ret)
 465         EVP_PKEY_assign_EC_KEY(pkey, ec);
 466     else
 467         EC_KEY_free(ec);
 468     return ret;
 469 }
 470
 471 static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 472 {
 473     EC_KEY *ec = NULL;
 474     EC_PKEY_CTX *dctx = ctx->data;
 475     if (ctx->pkey == NULL && dctx->gen_group == NULL) {
 476         ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
 477         return 0;
 478     }
 479     ec = EC_KEY_new();
 480     if (!ec)
 481         return 0;
 482     EVP_PKEY_assign_EC_KEY(pkey, ec);
 483     if (ctx->pkey) {
 484         /* Note: if error return, pkey is freed by parent routine */
 485         if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
 486             return 0;
 487     } else {
 488         if (!EC_KEY_set_group(ec, dctx->gen_group))
 489             return 0;
 490     }
 491     return EC_KEY_generate_key(pkey->pkey.ec);
 492 }
 493
 494 const EVP_PKEY_METHOD ec_pkey_meth = {
 495     EVP_PKEY_EC,
 496     0,
 497     pkey_ec_init,
 498     pkey_ec_copy,
 499     pkey_ec_cleanup,
 500
 501     0,
 502     pkey_ec_paramgen,
 503
 504     0,
 505     pkey_ec_keygen,
 506
 507     0,
 508     pkey_ec_sign,
 509
 510     0,
 511     pkey_ec_verify,
 512
 513     0, 0,
 514
 515     0, 0, 0, 0,
 516
 517     0, 0,
 518
 519     0, 0,
 520
 521     0,
 522 #ifndef OPENSSL_NO_EC
 523     pkey_ec_kdf_derive,
 524 #else
 525     0,
 526 #endif
 527     pkey_ec_ctrl,
 528     pkey_ec_ctrl_str
 529 };