crypto/ec/ec_ameth.c

   1 /*
   2  * Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * ECDH and ECDSA low level APIs are deprecated for public use, but still ok
  12  * for internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <stdio.h>
  17 #include "internal/cryptlib.h"
  18 #include <openssl/x509.h>
  19 #include <openssl/ec.h>
  20 #include <openssl/bn.h>
  21 #include <openssl/cms.h>
  22 #include <openssl/asn1t.h>
  23 #include "crypto/asn1.h"
  24 #include "crypto/evp.h"
  25 #include <openssl/core_names.h>
  26 #include "internal/param_build.h"
  27 #include "ec_local.h"
  28
  29 #ifndef OPENSSL_NO_CMS
  30 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  31 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  32 #endif
  33
  34 static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key)
  35 {
  36     const EC_GROUP *group;
  37     int nid;
  38     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  39         ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
  40         return 0;
  41     }
  42     if (EC_GROUP_get_asn1_flag(group)
  43         && (nid = EC_GROUP_get_curve_name(group)))
  44         /* we have a 'named curve' => just set the OID */
  45     {
  46         *ppval = OBJ_nid2obj(nid);
  47         *pptype = V_ASN1_OBJECT;
  48     } else {                    /* explicit parameters */
  49
  50         ASN1_STRING *pstr = NULL;
  51         pstr = ASN1_STRING_new();
  52         if (pstr == NULL)
  53             return 0;
  54         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  55         if (pstr->length <= 0) {
  56             ASN1_STRING_free(pstr);
  57             ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
  58             return 0;
  59         }
  60         *ppval = pstr;
  61         *pptype = V_ASN1_SEQUENCE;
  62     }
  63     return 1;
  64 }
  65
  66 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  67 {
  68     const EC_KEY *ec_key = pkey->pkey.ec;
  69     void *pval = NULL;
  70     int ptype;
  71     unsigned char *penc = NULL, *p;
  72     int penclen;
  73
  74     if (!eckey_param2type(&ptype, &pval, ec_key)) {
  75         ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
  76         return 0;
  77     }
  78     penclen = i2o_ECPublicKey(ec_key, NULL);
  79     if (penclen <= 0)
  80         goto err;
  81     penc = OPENSSL_malloc(penclen);
  82     if (penc == NULL)
  83         goto err;
  84     p = penc;
  85     penclen = i2o_ECPublicKey(ec_key, &p);
  86     if (penclen <= 0)
  87         goto err;
  88     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
  89                                ptype, pval, penc, penclen))
  90         return 1;
  91  err:
  92     if (ptype == V_ASN1_OBJECT)
  93         ASN1_OBJECT_free(pval);
  94     else
  95         ASN1_STRING_free(pval);
  96     OPENSSL_free(penc);
  97     return 0;
  98 }
  99
 100 static EC_KEY *eckey_type2param(int ptype, const void *pval)
 101 {
 102     EC_KEY *eckey = NULL;
 103     EC_GROUP *group = NULL;
 104
 105     if (ptype == V_ASN1_SEQUENCE) {
 106         const ASN1_STRING *pstr = pval;
 107         const unsigned char *pm = pstr->data;
 108         int pmlen = pstr->length;
 109
 110         if ((eckey = d2i_ECParameters(NULL, &pm, pmlen)) == NULL) {
 111             ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 112             goto ecerr;
 113         }
 114     } else if (ptype == V_ASN1_OBJECT) {
 115         const ASN1_OBJECT *poid = pval;
 116
 117         /*
 118          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 119          */
 120         if ((eckey = EC_KEY_new()) == NULL) {
 121             ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
 122             goto ecerr;
 123         }
 124         group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
 125         if (group == NULL)
 126             goto ecerr;
 127         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 128         if (EC_KEY_set_group(eckey, group) == 0)
 129             goto ecerr;
 130         EC_GROUP_free(group);
 131     } else {
 132         ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 133         goto ecerr;
 134     }
 135
 136     return eckey;
 137
 138  ecerr:
 139     EC_KEY_free(eckey);
 140     EC_GROUP_free(group);
 141     return NULL;
 142 }
 143
 144 static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
 145 {
 146     const unsigned char *p = NULL;
 147     const void *pval;
 148     int ptype, pklen;
 149     EC_KEY *eckey = NULL;
 150     X509_ALGOR *palg;
 151
 152     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 153         return 0;
 154     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 155
 156     eckey = eckey_type2param(ptype, pval);
 157
 158     if (!eckey) {
 159         ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
 160         return 0;
 161     }
 162
 163     /* We have parameters now set public key */
 164     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 165         ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
 166         goto ecerr;
 167     }
 168
 169     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 170     return 1;
 171
 172  ecerr:
 173     EC_KEY_free(eckey);
 174     return 0;
 175 }
 176
 177 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 178 {
 179     int r;
 180     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 181     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 182         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 183     if (group == NULL || pa == NULL || pb == NULL)
 184         return -2;
 185     r = EC_POINT_cmp(group, pa, pb, NULL);
 186     if (r == 0)
 187         return 1;
 188     if (r == 1)
 189         return 0;
 190     return -2;
 191 }
 192
 193 static int eckey_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 194 {
 195     const unsigned char *p = NULL;
 196     const void *pval;
 197     int ptype, pklen;
 198     EC_KEY *eckey = NULL;
 199     const X509_ALGOR *palg;
 200
 201     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 202         return 0;
 203     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 204
 205     eckey = eckey_type2param(ptype, pval);
 206
 207     if (eckey == NULL)
 208         goto ecliberr;
 209
 210     /* We have parameters now set private key */
 211     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 212         ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
 213         goto ecerr;
 214     }
 215
 216     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 217     return 1;
 218
 219  ecliberr:
 220     ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
 221  ecerr:
 222     EC_KEY_free(eckey);
 223     return 0;
 224 }
 225
 226 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 227 {
 228     EC_KEY ec_key = *(pkey->pkey.ec);
 229     unsigned char *ep, *p;
 230     int eplen, ptype;
 231     void *pval;
 232     unsigned int old_flags;
 233
 234     if (!eckey_param2type(&ptype, &pval, &ec_key)) {
 235         ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
 236         return 0;
 237     }
 238
 239     /* set the private key */
 240
 241     /*
 242      * do not include the parameters in the SEC1 private key see PKCS#11
 243      * 12.11
 244      */
 245     old_flags = EC_KEY_get_enc_flags(&ec_key);
 246     EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS);
 247
 248     eplen = i2d_ECPrivateKey(&ec_key, NULL);
 249     if (!eplen) {
 250         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 251         return 0;
 252     }
 253     ep = OPENSSL_malloc(eplen);
 254     if (ep == NULL) {
 255         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 256         return 0;
 257     }
 258     p = ep;
 259     if (!i2d_ECPrivateKey(&ec_key, &p)) {
 260         OPENSSL_free(ep);
 261         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 262         return 0;
 263     }
 264
 265     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 266                          ptype, pval, ep, eplen)) {
 267         OPENSSL_free(ep);
 268         return 0;
 269     }
 270
 271     return 1;
 272 }
 273
 274 static int int_ec_size(const EVP_PKEY *pkey)
 275 {
 276     return ECDSA_size(pkey->pkey.ec);
 277 }
 278
 279 static int ec_bits(const EVP_PKEY *pkey)
 280 {
 281     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 282 }
 283
 284 static int ec_security_bits(const EVP_PKEY *pkey)
 285 {
 286     int ecbits = ec_bits(pkey);
 287     if (ecbits >= 512)
 288         return 256;
 289     if (ecbits >= 384)
 290         return 192;
 291     if (ecbits >= 256)
 292         return 128;
 293     if (ecbits >= 224)
 294         return 112;
 295     if (ecbits >= 160)
 296         return 80;
 297     return ecbits / 2;
 298 }
 299
 300 static int ec_missing_parameters(const EVP_PKEY *pkey)
 301 {
 302     if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 303         return 1;
 304     return 0;
 305 }
 306
 307 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 308 {
 309     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 310
 311     if (group == NULL)
 312         return 0;
 313     if (to->pkey.ec == NULL) {
 314         to->pkey.ec = EC_KEY_new();
 315         if (to->pkey.ec == NULL)
 316             goto err;
 317     }
 318     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 319         goto err;
 320     EC_GROUP_free(group);
 321     return 1;
 322  err:
 323     EC_GROUP_free(group);
 324     return 0;
 325 }
 326
 327 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 328 {
 329     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 330         *group_b = EC_KEY_get0_group(b->pkey.ec);
 331     if (group_a == NULL || group_b == NULL)
 332         return -2;
 333     if (EC_GROUP_cmp(group_a, group_b, NULL))
 334         return 0;
 335     else
 336         return 1;
 337 }
 338
 339 static void int_ec_free(EVP_PKEY *pkey)
 340 {
 341     EC_KEY_free(pkey->pkey.ec);
 342 }
 343
 344 typedef enum {
 345     EC_KEY_PRINT_PRIVATE,
 346     EC_KEY_PRINT_PUBLIC,
 347     EC_KEY_PRINT_PARAM
 348 } ec_print_t;
 349
 350 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 351 {
 352     const char *ecstr;
 353     unsigned char *priv = NULL, *pub = NULL;
 354     size_t privlen = 0, publen = 0;
 355     int ret = 0;
 356     const EC_GROUP *group;
 357
 358     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 359         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
 360         return 0;
 361     }
 362
 363     if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) {
 364         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 365         if (publen == 0)
 366             goto err;
 367     }
 368
 369     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 370         privlen = EC_KEY_priv2buf(x, &priv);
 371         if (privlen == 0)
 372             goto err;
 373     }
 374
 375     if (ktype == EC_KEY_PRINT_PRIVATE)
 376         ecstr = "Private-Key";
 377     else if (ktype == EC_KEY_PRINT_PUBLIC)
 378         ecstr = "Public-Key";
 379     else
 380         ecstr = "ECDSA-Parameters";
 381
 382     if (!BIO_indent(bp, off, 128))
 383         goto err;
 384     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 385                    EC_GROUP_order_bits(group)) <= 0)
 386         goto err;
 387
 388     if (privlen != 0) {
 389         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 390             goto err;
 391         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 392             goto err;
 393     }
 394
 395     if (publen != 0) {
 396         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 397             goto err;
 398         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 399             goto err;
 400     }
 401
 402     if (!ECPKParameters_print(bp, group, off))
 403         goto err;
 404     ret = 1;
 405  err:
 406     if (!ret)
 407         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
 408     OPENSSL_clear_free(priv, privlen);
 409     OPENSSL_free(pub);
 410     return ret;
 411 }
 412
 413 static int eckey_param_decode(EVP_PKEY *pkey,
 414                               const unsigned char **pder, int derlen)
 415 {
 416     EC_KEY *eckey;
 417
 418     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
 419         ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
 420         return 0;
 421     }
 422     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 423     return 1;
 424 }
 425
 426 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 427 {
 428     return i2d_ECParameters(pkey->pkey.ec, pder);
 429 }
 430
 431 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 432                              ASN1_PCTX *ctx)
 433 {
 434     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 435 }
 436
 437 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 438                            ASN1_PCTX *ctx)
 439 {
 440     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 441 }
 442
 443 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 444                             ASN1_PCTX *ctx)
 445 {
 446     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 447 }
 448
 449 static int old_ec_priv_decode(EVP_PKEY *pkey,
 450                               const unsigned char **pder, int derlen)
 451 {
 452     EC_KEY *ec;
 453
 454     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
 455         ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
 456         return 0;
 457     }
 458     EVP_PKEY_assign_EC_KEY(pkey, ec);
 459     return 1;
 460 }
 461
 462 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 463 {
 464     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 465 }
 466
 467 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 468 {
 469     switch (op) {
 470     case ASN1_PKEY_CTRL_PKCS7_SIGN:
 471         if (arg1 == 0) {
 472             int snid, hnid;
 473             X509_ALGOR *alg1, *alg2;
 474             PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
 475             if (alg1 == NULL || alg1->algorithm == NULL)
 476                 return -1;
 477             hnid = OBJ_obj2nid(alg1->algorithm);
 478             if (hnid == NID_undef)
 479                 return -1;
 480             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 481                 return -1;
 482             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 483         }
 484         return 1;
 485 #ifndef OPENSSL_NO_CMS
 486     case ASN1_PKEY_CTRL_CMS_SIGN:
 487         if (arg1 == 0) {
 488             int snid, hnid;
 489             X509_ALGOR *alg1, *alg2;
 490             CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
 491             if (alg1 == NULL || alg1->algorithm == NULL)
 492                 return -1;
 493             hnid = OBJ_obj2nid(alg1->algorithm);
 494             if (hnid == NID_undef)
 495                 return -1;
 496             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 497                 return -1;
 498             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 499         }
 500         return 1;
 501
 502     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 503         if (arg1 == 1)
 504             return ecdh_cms_decrypt(arg2);
 505         else if (arg1 == 0)
 506             return ecdh_cms_encrypt(arg2);
 507         return -2;
 508
 509     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 510         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 511         return 1;
 512 #endif
 513
 514     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 515         if (EVP_PKEY_id(pkey) == EVP_PKEY_SM2) {
 516             /* For SM2, the only valid digest-alg is SM3 */
 517             *(int *)arg2 = NID_sm3;
 518             return 2;            /* Make it mandatory */
 519         }
 520         *(int *)arg2 = NID_sha256;
 521         return 1;
 522
 523     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
 524         return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
 525
 526     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
 527         return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
 528                               POINT_CONVERSION_UNCOMPRESSED, arg2, NULL);
 529
 530     default:
 531         return -2;
 532
 533     }
 534
 535 }
 536
 537 static int ec_pkey_check(const EVP_PKEY *pkey)
 538 {
 539     EC_KEY *eckey = pkey->pkey.ec;
 540
 541     /* stay consistent to what EVP_PKEY_check demands */
 542     if (eckey->priv_key == NULL) {
 543         ECerr(EC_F_EC_PKEY_CHECK, EC_R_MISSING_PRIVATE_KEY);
 544         return 0;
 545     }
 546
 547     return EC_KEY_check_key(eckey);
 548 }
 549
 550 static int ec_pkey_public_check(const EVP_PKEY *pkey)
 551 {
 552     EC_KEY *eckey = pkey->pkey.ec;
 553
 554     /*
 555      * Note: it unnecessary to check eckey->pub_key here since
 556      * it will be checked in EC_KEY_check_key(). In fact, the
 557      * EC_KEY_check_key() mainly checks the public key, and checks
 558      * the private key optionally (only if there is one). So if
 559      * someone passes a whole EC key (public + private), this
 560      * will also work...
 561      */
 562
 563     return EC_KEY_check_key(eckey);
 564 }
 565
 566 static int ec_pkey_param_check(const EVP_PKEY *pkey)
 567 {
 568     EC_KEY *eckey = pkey->pkey.ec;
 569
 570     /* stay consistent to what EVP_PKEY_check demands */
 571     if (eckey->group == NULL) {
 572         ECerr(EC_F_EC_PKEY_PARAM_CHECK, EC_R_MISSING_PARAMETERS);
 573         return 0;
 574     }
 575
 576     return EC_GROUP_check(eckey->group, NULL);
 577 }
 578
 579 static
 580 size_t ec_pkey_dirty_cnt(const EVP_PKEY *pkey)
 581 {
 582     return pkey->pkey.ec->dirty_cnt;
 583 }
 584
 585 static ossl_inline
 586 int ecparams_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl)
 587 {
 588     const EC_GROUP *ecg;
 589     int curve_nid;
 590
 591     if (eckey == NULL)
 592         return 0;
 593
 594     ecg = EC_KEY_get0_group(eckey);
 595     if (ecg == NULL)
 596         return 0;
 597
 598     curve_nid = EC_GROUP_get_curve_name(ecg);
 599
 600     if (curve_nid == NID_undef) {
 601         /* explicit parameters */
 602
 603         /*
 604          * TODO(3.0): should we support explicit parameters curves?
 605          */
 606         return 0;
 607     } else {
 608         /* named curve */
 609         const char *curve_name = NULL;
 610
 611         if ((curve_name = OBJ_nid2sn(curve_nid)) == NULL)
 612             return 0;
 613
 614         if (!ossl_param_bld_push_utf8_string(tmpl, OSSL_PKEY_PARAM_EC_NAME, curve_name, 0))
 615             return 0;
 616     }
 617
 618     return 1;
 619 }
 620
 621 static
 622 int ec_pkey_export_to(const EVP_PKEY *from, void *to_keydata,
 623                       EVP_KEYMGMT *to_keymgmt)
 624 {
 625     const EC_KEY *eckey = NULL;
 626     const EC_GROUP *ecg = NULL;
 627     unsigned char *pub_key_buf = NULL;
 628     size_t pub_key_buflen;
 629     OSSL_PARAM_BLD tmpl;
 630     OSSL_PARAM *params = NULL;
 631     const BIGNUM *priv_key = NULL;
 632     const EC_POINT *pub_point = NULL;
 633     int selection = 0;
 634     int rv = 0;
 635
 636     if (from == NULL
 637             || (eckey = from->pkey.ec) == NULL
 638             || (ecg = EC_KEY_get0_group(eckey)) == NULL)
 639         return 0;
 640
 641     /*
 642      * If the EC_KEY method is foreign, then we can't be sure of anything,
 643      * and can therefore not export or pretend to export.
 644      */
 645     if (EC_KEY_get_method(eckey) != EC_KEY_OpenSSL())
 646         return 0;
 647
 648     ossl_param_bld_init(&tmpl);
 649
 650     /* export the domain parameters */
 651     if (!ecparams_to_params(eckey, &tmpl))
 652         goto err;
 653     selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS;
 654
 655     priv_key = EC_KEY_get0_private_key(eckey);
 656     pub_point = EC_KEY_get0_public_key(eckey);
 657
 658     if (pub_point != NULL) {
 659         /* convert pub_point to a octet string according to the SECG standard */
 660         if ((pub_key_buflen = EC_POINT_point2buf(ecg, pub_point,
 661                                                  POINT_CONVERSION_COMPRESSED,
 662                                                  &pub_key_buf, NULL)) == 0
 663             || !ossl_param_bld_push_octet_string(&tmpl,
 664                                                  OSSL_PKEY_PARAM_PUB_KEY,
 665                                                  pub_key_buf,
 666                                                  pub_key_buflen))
 667             goto err;
 668         selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY;
 669     }
 670
 671     if (priv_key != NULL) {
 672         size_t sz;
 673         int ecbits;
 674         int ecdh_cofactor_mode;
 675
 676         /*
 677          * Key import/export should never leak the bit length of the secret
 678          * scalar in the key.
 679          *
 680          * For this reason, on export we use padded BIGNUMs with fixed length.
 681          *
 682          * When importing we also should make sure that, even if short lived,
 683          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 684          * soon as possible, so that any processing of this BIGNUM might opt for
 685          * constant time implementations in the backend.
 686          *
 687          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 688          * to preallocate the BIGNUM internal buffer to a fixed public size big
 689          * enough that operations performed during the processing never trigger
 690          * a realloc which would leak the size of the scalar through memory
 691          * accesses.
 692          *
 693          * Fixed Length
 694          * ------------
 695          *
 696          * The order of the large prime subgroup of the curve is our choice for
 697          * a fixed public size, as that is generally the upper bound for
 698          * generating a private key in EC cryptosystems and should fit all valid
 699          * secret scalars.
 700          *
 701          * For padding on export we just use the bit length of the order
 702          * converted to bytes (rounding up).
 703          *
 704          * For preallocating the BIGNUM storage we look at the number of "words"
 705          * required for the internal representation of the order, and we
 706          * preallocate 2 extra "words" in case any of the subsequent processing
 707          * might temporarily overflow the order length.
 708          */
 709         ecbits = EC_GROUP_order_bits(ecg);
 710         if (ecbits <= 0)
 711             goto err;
 712
 713         sz = (ecbits + 7 ) / 8;
 714         if (!ossl_param_bld_push_BN_pad(&tmpl,
 715                                         OSSL_PKEY_PARAM_PRIV_KEY,
 716                                         priv_key, sz))
 717             goto err;
 718         selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY;
 719
 720         /*
 721          * The ECDH Cofactor Mode is defined only if the EC_KEY actually
 722          * contains a private key, so we check for the flag and export it only
 723          * in this case.
 724          */
 725         ecdh_cofactor_mode =
 726             (EC_KEY_get_flags(eckey) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 727
 728         /* Export the ECDH_COFACTOR_MODE parameter */
 729         if (!ossl_param_bld_push_int(&tmpl,
 730                                      OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 731                                      ecdh_cofactor_mode))
 732             goto err;
 733         selection |= OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS;
 734     }
 735
 736     params = ossl_param_bld_to_param(&tmpl);
 737
 738     /* We export, the provider imports */
 739     rv = evp_keymgmt_import(to_keymgmt, to_keydata, selection, params);
 740
 741  err:
 742     ossl_param_bld_free(params);
 743     OPENSSL_free(pub_key_buf);
 744     return rv;
 745 }
 746
 747 static int ec_pkey_import_from(const OSSL_PARAM params[], void *key)
 748 {
 749     EVP_PKEY *pkey = key;
 750     EC_KEY *ec = EC_KEY_new();
 751
 752     if (ec == NULL) {
 753         ERR_raise(ERR_LIB_DH, ERR_R_MALLOC_FAILURE);
 754         return 0;
 755     }
 756
 757     if (!ec_key_domparams_fromdata(ec, params)
 758         || !ec_key_otherparams_fromdata(ec, params)
 759         || !ec_key_fromdata(ec, params, 1)
 760         || !EVP_PKEY_assign_EC_KEY(pkey, ec)) {
 761         EC_KEY_free(ec);
 762         return 0;
 763     }
 764     return 1;
 765 }
 766
 767 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 768     EVP_PKEY_EC,
 769     EVP_PKEY_EC,
 770     0,
 771     "EC",
 772     "OpenSSL EC algorithm",
 773
 774     eckey_pub_decode,
 775     eckey_pub_encode,
 776     eckey_pub_cmp,
 777     eckey_pub_print,
 778
 779     eckey_priv_decode,
 780     eckey_priv_encode,
 781     eckey_priv_print,
 782
 783     int_ec_size,
 784     ec_bits,
 785     ec_security_bits,
 786
 787     eckey_param_decode,
 788     eckey_param_encode,
 789     ec_missing_parameters,
 790     ec_copy_parameters,
 791     ec_cmp_parameters,
 792     eckey_param_print,
 793     0,
 794
 795     int_ec_free,
 796     ec_pkey_ctrl,
 797     old_ec_priv_decode,
 798     old_ec_priv_encode,
 799
 800     0, 0, 0,
 801
 802     ec_pkey_check,
 803     ec_pkey_public_check,
 804     ec_pkey_param_check,
 805
 806     0, /* set_priv_key */
 807     0, /* set_pub_key */
 808     0, /* get_priv_key */
 809     0, /* get_pub_key */
 810
 811     ec_pkey_dirty_cnt,
 812     ec_pkey_export_to,
 813     ec_pkey_import_from
 814 };
 815
 816 #if !defined(OPENSSL_NO_SM2)
 817 const EVP_PKEY_ASN1_METHOD sm2_asn1_meth = {
 818    EVP_PKEY_SM2,
 819    EVP_PKEY_EC,
 820    ASN1_PKEY_ALIAS
 821 };
 822 #endif
 823
 824 int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
 825 {
 826     int private = EC_KEY_get0_private_key(x) != NULL;
 827
 828     return do_EC_KEY_print(bp, x, off,
 829                 private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC);
 830 }
 831
 832 int ECParameters_print(BIO *bp, const EC_KEY *x)
 833 {
 834     return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM);
 835 }
 836
 837 #ifndef OPENSSL_NO_CMS
 838
 839 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 840                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 841 {
 842     const ASN1_OBJECT *aoid;
 843     int atype;
 844     const void *aval;
 845     int rv = 0;
 846     EVP_PKEY *pkpeer = NULL;
 847     EC_KEY *ecpeer = NULL;
 848     const unsigned char *p;
 849     int plen;
 850     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 851     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
 852         goto err;
 853     /* If absent parameters get group from main key */
 854     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
 855         const EC_GROUP *grp;
 856         EVP_PKEY *pk;
 857         pk = EVP_PKEY_CTX_get0_pkey(pctx);
 858         if (pk == NULL)
 859             goto err;
 860         grp = EC_KEY_get0_group(pk->pkey.ec);
 861         ecpeer = EC_KEY_new();
 862         if (ecpeer == NULL)
 863             goto err;
 864         if (!EC_KEY_set_group(ecpeer, grp))
 865             goto err;
 866     } else {
 867         ecpeer = eckey_type2param(atype, aval);
 868         if (!ecpeer)
 869             goto err;
 870     }
 871     /* We have parameters now set public key */
 872     plen = ASN1_STRING_length(pubkey);
 873     p = ASN1_STRING_get0_data(pubkey);
 874     if (p == NULL || plen == 0)
 875         goto err;
 876     if (!o2i_ECPublicKey(&ecpeer, &p, plen))
 877         goto err;
 878     pkpeer = EVP_PKEY_new();
 879     if (pkpeer == NULL)
 880         goto err;
 881     EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
 882     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 883         rv = 1;
 884  err:
 885     EC_KEY_free(ecpeer);
 886     EVP_PKEY_free(pkpeer);
 887     return rv;
 888 }
 889
 890 /* Set KDF parameters based on KDF NID */
 891 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 892 {
 893     int kdf_nid, kdfmd_nid, cofactor;
 894     const EVP_MD *kdf_md;
 895     if (eckdf_nid == NID_undef)
 896         return 0;
 897
 898     /* Lookup KDF type, cofactor mode and digest */
 899     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 900         return 0;
 901
 902     if (kdf_nid == NID_dh_std_kdf)
 903         cofactor = 0;
 904     else if (kdf_nid == NID_dh_cofactor_kdf)
 905         cofactor = 1;
 906     else
 907         return 0;
 908
 909     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 910         return 0;
 911
 912     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
 913         return 0;
 914
 915     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 916     if (!kdf_md)
 917         return 0;
 918
 919     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 920         return 0;
 921     return 1;
 922 }
 923
 924 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 925 {
 926     int rv = 0;
 927
 928     X509_ALGOR *alg, *kekalg = NULL;
 929     ASN1_OCTET_STRING *ukm;
 930     const unsigned char *p;
 931     unsigned char *der = NULL;
 932     int plen, keylen;
 933     const EVP_CIPHER *kekcipher;
 934     EVP_CIPHER_CTX *kekctx;
 935
 936     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 937         return 0;
 938
 939     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 940         ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
 941         return 0;
 942     }
 943
 944     if (alg->parameter->type != V_ASN1_SEQUENCE)
 945         return 0;
 946
 947     p = alg->parameter->value.sequence->data;
 948     plen = alg->parameter->value.sequence->length;
 949     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 950     if (!kekalg)
 951         goto err;
 952     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 953     if (!kekctx)
 954         goto err;
 955     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 956     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 957         goto err;
 958     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 959         goto err;
 960     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 961         goto err;
 962
 963     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 964     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 965         goto err;
 966
 967     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
 968
 969     if (!plen)
 970         goto err;
 971
 972     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
 973         goto err;
 974     der = NULL;
 975
 976     rv = 1;
 977  err:
 978     X509_ALGOR_free(kekalg);
 979     OPENSSL_free(der);
 980     return rv;
 981 }
 982
 983 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
 984 {
 985     EVP_PKEY_CTX *pctx;
 986     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 987     if (!pctx)
 988         return 0;
 989     /* See if we need to set peer key */
 990     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 991         X509_ALGOR *alg;
 992         ASN1_BIT_STRING *pubkey;
 993         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 994                                                  NULL, NULL, NULL))
 995             return 0;
 996         if (!alg || !pubkey)
 997             return 0;
 998         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
 999             ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
1000             return 0;
1001         }
1002     }
1003     /* Set ECDH derivation parameters and initialise unwrap context */
1004     if (!ecdh_cms_set_shared_info(pctx, ri)) {
1005         ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
1006         return 0;
1007     }
1008     return 1;
1009 }
1010
1011 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
1012 {
1013     EVP_PKEY_CTX *pctx;
1014     EVP_PKEY *pkey;
1015     EVP_CIPHER_CTX *ctx;
1016     int keylen;
1017     X509_ALGOR *talg, *wrap_alg = NULL;
1018     const ASN1_OBJECT *aoid;
1019     ASN1_BIT_STRING *pubkey;
1020     ASN1_STRING *wrap_str;
1021     ASN1_OCTET_STRING *ukm;
1022     unsigned char *penc = NULL;
1023     int penclen;
1024     int rv = 0;
1025     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
1026     const EVP_MD *kdf_md;
1027     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
1028     if (!pctx)
1029         return 0;
1030     /* Get ephemeral key */
1031     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
1032     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
1033                                              NULL, NULL, NULL))
1034         goto err;
1035     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
1036     /* Is everything uninitialised? */
1037     if (aoid == OBJ_nid2obj(NID_undef)) {
1038
1039         EC_KEY *eckey = pkey->pkey.ec;
1040         /* Set the key */
1041         unsigned char *p;
1042
1043         penclen = i2o_ECPublicKey(eckey, NULL);
1044         if (penclen <= 0)
1045             goto err;
1046         penc = OPENSSL_malloc(penclen);
1047         if (penc == NULL)
1048             goto err;
1049         p = penc;
1050         penclen = i2o_ECPublicKey(eckey, &p);
1051         if (penclen <= 0)
1052             goto err;
1053         ASN1_STRING_set0(pubkey, penc, penclen);
1054         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
1055         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
1056
1057         penc = NULL;
1058         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
1059                         V_ASN1_UNDEF, NULL);
1060     }
1061
1062     /* See if custom parameters set */
1063     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
1064     if (kdf_type <= 0)
1065         goto err;
1066     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
1067         goto err;
1068     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
1069     if (ecdh_nid < 0)
1070         goto err;
1071     else if (ecdh_nid == 0)
1072         ecdh_nid = NID_dh_std_kdf;
1073     else if (ecdh_nid == 1)
1074         ecdh_nid = NID_dh_cofactor_kdf;
1075
1076     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
1077         kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
1078         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
1079             goto err;
1080     } else
1081         /* Unknown KDF */
1082         goto err;
1083     if (kdf_md == NULL) {
1084         /* Fixme later for better MD */
1085         kdf_md = EVP_sha1();
1086         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
1087             goto err;
1088     }
1089
1090     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
1091         goto err;
1092
1093     /* Lookup NID for KDF+cofactor+digest */
1094
1095     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
1096         goto err;
1097     /* Get wrap NID */
1098     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
1099     wrap_nid = EVP_CIPHER_CTX_type(ctx);
1100     keylen = EVP_CIPHER_CTX_key_length(ctx);
1101
1102     /* Package wrap algorithm in an AlgorithmIdentifier */
1103
1104     wrap_alg = X509_ALGOR_new();
1105     if (wrap_alg == NULL)
1106         goto err;
1107     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
1108     wrap_alg->parameter = ASN1_TYPE_new();
1109     if (wrap_alg->parameter == NULL)
1110         goto err;
1111     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
1112         goto err;
1113     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
1114         ASN1_TYPE_free(wrap_alg->parameter);
1115         wrap_alg->parameter = NULL;
1116     }
1117
1118     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
1119         goto err;
1120
1121     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
1122
1123     if (!penclen)
1124         goto err;
1125
1126     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
1127         goto err;
1128     penc = NULL;
1129
1130     /*
1131      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
1132      * of another AlgorithmIdentifier.
1133      */
1134     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
1135     if (!penc || !penclen)
1136         goto err;
1137     wrap_str = ASN1_STRING_new();
1138     if (wrap_str == NULL)
1139         goto err;
1140     ASN1_STRING_set0(wrap_str, penc, penclen);
1141     penc = NULL;
1142     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
1143
1144     rv = 1;
1145
1146  err:
1147     OPENSSL_free(penc);
1148     X509_ALGOR_free(wrap_alg);
1149     return rv;
1150 }
1151
1152 #endif