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         EC_GROUP_free(dctx->gen_group);
 150         EC_KEY_free(dctx->co_key);
 151         if (dctx->kdf_ukm)
 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         if (dctx->kdf_ukm)
 363             OPENSSL_free(dctx->kdf_ukm);
 364         dctx->kdf_ukm = p2;
 365         if (p2)
 366             dctx->kdf_ukmlen = p1;
 367         else
 368             dctx->kdf_ukmlen = 0;
 369         return 1;
 370
 371     case EVP_PKEY_CTRL_GET_EC_KDF_UKM:
 372         *(unsigned char **)p2 = dctx->kdf_ukm;
 373         return dctx->kdf_ukmlen;
 374
 375     case EVP_PKEY_CTRL_MD:
 376         if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
 377             EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
 378             EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
 379             EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
 380             EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
 381             EVP_MD_type((const EVP_MD *)p2) != NID_sha512) {
 382             ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
 383             return 0;
 384         }
 385         dctx->md = p2;
 386         return 1;
 387
 388     case EVP_PKEY_CTRL_GET_MD:
 389         *(const EVP_MD **)p2 = dctx->md;
 390         return 1;
 391
 392     case EVP_PKEY_CTRL_PEER_KEY:
 393         /* Default behaviour is OK */
 394     case EVP_PKEY_CTRL_DIGESTINIT:
 395     case EVP_PKEY_CTRL_PKCS7_SIGN:
 396     case EVP_PKEY_CTRL_CMS_SIGN:
 397         return 1;
 398
 399     default:
 400         return -2;
 401
 402     }
 403 }
 404
 405 static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
 406                             const char *type, const char *value)
 407 {
 408     if (!strcmp(type, "ec_paramgen_curve")) {
 409         int nid;
 410         nid = EC_curve_nist2nid(value);
 411         if (nid == NID_undef)
 412             nid = OBJ_sn2nid(value);
 413         if (nid == NID_undef)
 414             nid = OBJ_ln2nid(value);
 415         if (nid == NID_undef) {
 416             ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
 417             return 0;
 418         }
 419         return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
 420     } else if (!strcmp(type, "ec_param_enc")) {
 421         int param_enc;
 422         if (!strcmp(value, "explicit"))
 423             param_enc = 0;
 424         else if (!strcmp(value, "named_curve"))
 425             param_enc = OPENSSL_EC_NAMED_CURVE;
 426         else
 427             return -2;
 428         return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
 429     } else if (!strcmp(type, "ecdh_kdf_md")) {
 430         const EVP_MD *md;
 431         if (!(md = EVP_get_digestbyname(value))) {
 432             ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);
 433             return 0;
 434         }
 435         return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
 436     } else if (!strcmp(type, "ecdh_cofactor_mode")) {
 437         int co_mode;
 438         co_mode = atoi(value);
 439         return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
 440     }
 441
 442     return -2;
 443 }
 444
 445 static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 446 {
 447     EC_KEY *ec = NULL;
 448     EC_PKEY_CTX *dctx = ctx->data;
 449     int ret = 0;
 450     if (dctx->gen_group == NULL) {
 451         ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
 452         return 0;
 453     }
 454     ec = EC_KEY_new();
 455     if (!ec)
 456         return 0;
 457     ret = EC_KEY_set_group(ec, dctx->gen_group);
 458     if (ret)
 459         EVP_PKEY_assign_EC_KEY(pkey, ec);
 460     else
 461         EC_KEY_free(ec);
 462     return ret;
 463 }
 464
 465 static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 466 {
 467     EC_KEY *ec = NULL;
 468     EC_PKEY_CTX *dctx = ctx->data;
 469     if (ctx->pkey == NULL && dctx->gen_group == NULL) {
 470         ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
 471         return 0;
 472     }
 473     ec = EC_KEY_new();
 474     if (!ec)
 475         return 0;
 476     EVP_PKEY_assign_EC_KEY(pkey, ec);
 477     if (ctx->pkey) {
 478         /* Note: if error return, pkey is freed by parent routine */
 479         if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
 480             return 0;
 481     } else {
 482         if (!EC_KEY_set_group(ec, dctx->gen_group))
 483             return 0;
 484     }
 485     return EC_KEY_generate_key(pkey->pkey.ec);
 486 }
 487
 488 const EVP_PKEY_METHOD ec_pkey_meth = {
 489     EVP_PKEY_EC,
 490     0,
 491     pkey_ec_init,
 492     pkey_ec_copy,
 493     pkey_ec_cleanup,
 494
 495     0,
 496     pkey_ec_paramgen,
 497
 498     0,
 499     pkey_ec_keygen,
 500
 501     0,
 502     pkey_ec_sign,
 503
 504     0,
 505     pkey_ec_verify,
 506
 507     0, 0,
 508
 509     0, 0, 0, 0,
 510
 511     0, 0,
 512
 513     0, 0,
 514
 515     0,
 516 #ifndef OPENSSL_NO_EC
 517     pkey_ec_kdf_derive,
 518 #else
 519     0,
 520 #endif
 521     pkey_ec_ctrl,
 522     pkey_ec_ctrl_str
 523 };