crypto/ec/ec_ameth.c

   1 /*
   2  * Copyright 2006-2020 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 "crypto/x509.h"
  26 #include <openssl/core_names.h>
  27 #include "openssl/param_build.h"
  28 #include "ec_local.h"
  29
  30 #ifndef OPENSSL_NO_CMS
  31 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  32 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  33 #endif
  34
  35 static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key)
  36 {
  37     const EC_GROUP *group;
  38     int nid;
  39
  40     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  41         ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
  42         return 0;
  43     }
  44     if (EC_GROUP_get_asn1_flag(group)
  45         && (nid = EC_GROUP_get_curve_name(group)))
  46         /* we have a 'named curve' => just set the OID */
  47     {
  48         ASN1_OBJECT *asn1obj = OBJ_nid2obj(nid);
  49
  50         if (asn1obj == NULL || OBJ_length(asn1obj) == 0) {
  51             ASN1_OBJECT_free(asn1obj);
  52             ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_OID);
  53             return 0;
  54         }
  55         *ppval = asn1obj;
  56         *pptype = V_ASN1_OBJECT;
  57     } else {                    /* explicit parameters */
  58
  59         ASN1_STRING *pstr = NULL;
  60         pstr = ASN1_STRING_new();
  61         if (pstr == NULL)
  62             return 0;
  63         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  64         if (pstr->length <= 0) {
  65             ASN1_STRING_free(pstr);
  66             ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
  67             return 0;
  68         }
  69         *ppval = pstr;
  70         *pptype = V_ASN1_SEQUENCE;
  71     }
  72     return 1;
  73 }
  74
  75 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  76 {
  77     const EC_KEY *ec_key = pkey->pkey.ec;
  78     void *pval = NULL;
  79     int ptype;
  80     unsigned char *penc = NULL, *p;
  81     int penclen;
  82
  83     if (!eckey_param2type(&ptype, &pval, ec_key)) {
  84         ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
  85         return 0;
  86     }
  87     penclen = i2o_ECPublicKey(ec_key, NULL);
  88     if (penclen <= 0)
  89         goto err;
  90     penc = OPENSSL_malloc(penclen);
  91     if (penc == NULL)
  92         goto err;
  93     p = penc;
  94     penclen = i2o_ECPublicKey(ec_key, &p);
  95     if (penclen <= 0)
  96         goto err;
  97     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
  98                                ptype, pval, penc, penclen))
  99         return 1;
 100  err:
 101     if (ptype == V_ASN1_OBJECT)
 102         ASN1_OBJECT_free(pval);
 103     else
 104         ASN1_STRING_free(pval);
 105     OPENSSL_free(penc);
 106     return 0;
 107 }
 108
 109 static EC_KEY *eckey_type2param(int ptype, const void *pval,
 110                                 OPENSSL_CTX *libctx, const char *propq)
 111 {
 112     EC_KEY *eckey = NULL;
 113     EC_GROUP *group = NULL;
 114
 115     if ((eckey = EC_KEY_new_with_libctx(libctx, propq)) == NULL) {
 116         ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
 117         goto ecerr;
 118     }
 119
 120     if (ptype == V_ASN1_SEQUENCE) {
 121         const ASN1_STRING *pstr = pval;
 122         const unsigned char *pm = pstr->data;
 123         int pmlen = pstr->length;
 124
 125
 126         if (d2i_ECParameters(&eckey, &pm, pmlen) == NULL) {
 127             ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 128             goto ecerr;
 129         }
 130     } else if (ptype == V_ASN1_OBJECT) {
 131         const ASN1_OBJECT *poid = pval;
 132
 133         /*
 134          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 135          */
 136
 137         group = EC_GROUP_new_by_curve_name_with_libctx(libctx, propq,
 138                                                        OBJ_obj2nid(poid));
 139         if (group == NULL)
 140             goto ecerr;
 141         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 142         if (EC_KEY_set_group(eckey, group) == 0)
 143             goto ecerr;
 144         EC_GROUP_free(group);
 145     } else {
 146         ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 147         goto ecerr;
 148     }
 149
 150     return eckey;
 151
 152  ecerr:
 153     EC_KEY_free(eckey);
 154     EC_GROUP_free(group);
 155     return NULL;
 156 }
 157
 158 static int eckey_pub_decode(EVP_PKEY *pkey, const X509_PUBKEY *pubkey)
 159 {
 160     const unsigned char *p = NULL;
 161     const void *pval;
 162     int ptype, pklen;
 163     EC_KEY *eckey = NULL;
 164     X509_ALGOR *palg;
 165     OPENSSL_CTX *libctx = NULL;
 166     const char *propq = NULL;
 167
 168     if (!X509_PUBKEY_get0_libctx(&libctx, &propq, pubkey)
 169         || !X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 170         return 0;
 171     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 172
 173     eckey = eckey_type2param(ptype, pval, libctx, propq);
 174
 175     if (!eckey) {
 176         ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
 177         return 0;
 178     }
 179
 180     /* We have parameters now set public key */
 181     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 182         ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
 183         goto ecerr;
 184     }
 185
 186     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 187     return 1;
 188
 189  ecerr:
 190     EC_KEY_free(eckey);
 191     return 0;
 192 }
 193
 194 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 195 {
 196     int r;
 197     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 198     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 199         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 200
 201     if (group == NULL || pa == NULL || pb == NULL)
 202         return -2;
 203     r = EC_POINT_cmp(group, pa, pb, NULL);
 204     if (r == 0)
 205         return 1;
 206     if (r == 1)
 207         return 0;
 208     return -2;
 209 }
 210
 211 static int eckey_priv_decode_with_libctx(EVP_PKEY *pkey,
 212                                          const PKCS8_PRIV_KEY_INFO *p8,
 213                                          OPENSSL_CTX *libctx,
 214                                          const char *propq)
 215 {
 216     const unsigned char *p = NULL;
 217     const void *pval;
 218     int ptype, pklen;
 219     EC_KEY *eckey = NULL;
 220     const X509_ALGOR *palg;
 221
 222     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 223         return 0;
 224     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 225
 226     eckey = eckey_type2param(ptype, pval, libctx, propq);
 227
 228     if (eckey == NULL)
 229         goto ecliberr;
 230
 231     /* We have parameters now set private key */
 232     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 233         ECerr(0, EC_R_DECODE_ERROR);
 234         goto ecerr;
 235     }
 236
 237     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 238     return 1;
 239
 240  ecliberr:
 241     ECerr(0, ERR_R_EC_LIB);
 242  ecerr:
 243     EC_KEY_free(eckey);
 244     return 0;
 245 }
 246
 247 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 248 {
 249     EC_KEY ec_key = *(pkey->pkey.ec);
 250     unsigned char *ep, *p;
 251     int eplen, ptype;
 252     void *pval;
 253     unsigned int old_flags;
 254
 255     if (!eckey_param2type(&ptype, &pval, &ec_key)) {
 256         ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
 257         return 0;
 258     }
 259
 260     /* set the private key */
 261
 262     /*
 263      * do not include the parameters in the SEC1 private key see PKCS#11
 264      * 12.11
 265      */
 266     old_flags = EC_KEY_get_enc_flags(&ec_key);
 267     EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS);
 268
 269     eplen = i2d_ECPrivateKey(&ec_key, NULL);
 270     if (!eplen) {
 271         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 272         return 0;
 273     }
 274     ep = OPENSSL_malloc(eplen);
 275     if (ep == NULL) {
 276         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 277         return 0;
 278     }
 279     p = ep;
 280     if (!i2d_ECPrivateKey(&ec_key, &p)) {
 281         OPENSSL_free(ep);
 282         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 283         return 0;
 284     }
 285
 286     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 287                          ptype, pval, ep, eplen)) {
 288         OPENSSL_free(ep);
 289         return 0;
 290     }
 291
 292     return 1;
 293 }
 294
 295 static int int_ec_size(const EVP_PKEY *pkey)
 296 {
 297     return ECDSA_size(pkey->pkey.ec);
 298 }
 299
 300 static int ec_bits(const EVP_PKEY *pkey)
 301 {
 302     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 303 }
 304
 305 static int ec_security_bits(const EVP_PKEY *pkey)
 306 {
 307     int ecbits = ec_bits(pkey);
 308
 309     if (ecbits >= 512)
 310         return 256;
 311     if (ecbits >= 384)
 312         return 192;
 313     if (ecbits >= 256)
 314         return 128;
 315     if (ecbits >= 224)
 316         return 112;
 317     if (ecbits >= 160)
 318         return 80;
 319     return ecbits / 2;
 320 }
 321
 322 static int ec_missing_parameters(const EVP_PKEY *pkey)
 323 {
 324     if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 325         return 1;
 326     return 0;
 327 }
 328
 329 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 330 {
 331     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 332
 333     if (group == NULL)
 334         return 0;
 335     if (to->pkey.ec == NULL) {
 336         to->pkey.ec = EC_KEY_new();
 337         if (to->pkey.ec == NULL)
 338             goto err;
 339     }
 340     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 341         goto err;
 342     EC_GROUP_free(group);
 343     return 1;
 344  err:
 345     EC_GROUP_free(group);
 346     return 0;
 347 }
 348
 349 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 350 {
 351     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 352         *group_b = EC_KEY_get0_group(b->pkey.ec);
 353
 354     if (group_a == NULL || group_b == NULL)
 355         return -2;
 356     if (EC_GROUP_cmp(group_a, group_b, NULL))
 357         return 0;
 358     else
 359         return 1;
 360 }
 361
 362 static void int_ec_free(EVP_PKEY *pkey)
 363 {
 364     EC_KEY_free(pkey->pkey.ec);
 365 }
 366
 367 typedef enum {
 368     EC_KEY_PRINT_PRIVATE,
 369     EC_KEY_PRINT_PUBLIC,
 370     EC_KEY_PRINT_PARAM
 371 } ec_print_t;
 372
 373 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 374 {
 375     const char *ecstr;
 376     unsigned char *priv = NULL, *pub = NULL;
 377     size_t privlen = 0, publen = 0;
 378     int ret = 0;
 379     const EC_GROUP *group;
 380
 381     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 382         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
 383         return 0;
 384     }
 385
 386     if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) {
 387         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 388         if (publen == 0)
 389             goto err;
 390     }
 391
 392     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 393         privlen = EC_KEY_priv2buf(x, &priv);
 394         if (privlen == 0)
 395             goto err;
 396     }
 397
 398     if (ktype == EC_KEY_PRINT_PRIVATE)
 399         ecstr = "Private-Key";
 400     else if (ktype == EC_KEY_PRINT_PUBLIC)
 401         ecstr = "Public-Key";
 402     else
 403         ecstr = "ECDSA-Parameters";
 404
 405     if (!BIO_indent(bp, off, 128))
 406         goto err;
 407     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 408                    EC_GROUP_order_bits(group)) <= 0)
 409         goto err;
 410
 411     if (privlen != 0) {
 412         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 413             goto err;
 414         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 415             goto err;
 416     }
 417
 418     if (publen != 0) {
 419         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 420             goto err;
 421         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 422             goto err;
 423     }
 424
 425     if (!ECPKParameters_print(bp, group, off))
 426         goto err;
 427     ret = 1;
 428  err:
 429     if (!ret)
 430         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
 431     OPENSSL_clear_free(priv, privlen);
 432     OPENSSL_free(pub);
 433     return ret;
 434 }
 435
 436 static int eckey_param_decode(EVP_PKEY *pkey,
 437                               const unsigned char **pder, int derlen)
 438 {
 439     EC_KEY *eckey;
 440
 441     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
 442         ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
 443         return 0;
 444     }
 445     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 446     return 1;
 447 }
 448
 449 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 450 {
 451     return i2d_ECParameters(pkey->pkey.ec, pder);
 452 }
 453
 454 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 455                              ASN1_PCTX *ctx)
 456 {
 457     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 458 }
 459
 460 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 461                            ASN1_PCTX *ctx)
 462 {
 463     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 464 }
 465
 466 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 467                             ASN1_PCTX *ctx)
 468 {
 469     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 470 }
 471
 472 static int old_ec_priv_decode(EVP_PKEY *pkey,
 473                               const unsigned char **pder, int derlen)
 474 {
 475     EC_KEY *ec;
 476
 477     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
 478         ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
 479         return 0;
 480     }
 481     EVP_PKEY_assign_EC_KEY(pkey, ec);
 482     return 1;
 483 }
 484
 485 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 486 {
 487     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 488 }
 489
 490 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 491 {
 492     switch (op) {
 493     case ASN1_PKEY_CTRL_PKCS7_SIGN:
 494         if (arg1 == 0) {
 495             int snid, hnid;
 496             X509_ALGOR *alg1, *alg2;
 497
 498             PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
 499             if (alg1 == NULL || alg1->algorithm == NULL)
 500                 return -1;
 501             hnid = OBJ_obj2nid(alg1->algorithm);
 502             if (hnid == NID_undef)
 503                 return -1;
 504             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 505                 return -1;
 506             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 507         }
 508         return 1;
 509 #ifndef OPENSSL_NO_CMS
 510     case ASN1_PKEY_CTRL_CMS_SIGN:
 511         if (arg1 == 0) {
 512             int snid, hnid;
 513             X509_ALGOR *alg1, *alg2;
 514             CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
 515             if (alg1 == NULL || alg1->algorithm == NULL)
 516                 return -1;
 517             hnid = OBJ_obj2nid(alg1->algorithm);
 518             if (hnid == NID_undef)
 519                 return -1;
 520             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 521                 return -1;
 522             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 523         }
 524         return 1;
 525
 526     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 527         if (arg1 == 1)
 528             return ecdh_cms_decrypt(arg2);
 529         else if (arg1 == 0)
 530             return ecdh_cms_encrypt(arg2);
 531         return -2;
 532
 533     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 534         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 535         return 1;
 536 #endif
 537
 538     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 539         if (EVP_PKEY_id(pkey) == EVP_PKEY_SM2) {
 540             /* For SM2, the only valid digest-alg is SM3 */
 541             *(int *)arg2 = NID_sm3;
 542             return 2;            /* Make it mandatory */
 543         }
 544         *(int *)arg2 = NID_sha256;
 545         return 1;
 546
 547     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
 548         return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
 549
 550     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
 551         return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
 552                               POINT_CONVERSION_UNCOMPRESSED, arg2, NULL);
 553
 554     default:
 555         return -2;
 556
 557     }
 558
 559 }
 560
 561 static int ec_pkey_check(const EVP_PKEY *pkey)
 562 {
 563     EC_KEY *eckey = pkey->pkey.ec;
 564
 565     /* stay consistent to what EVP_PKEY_check demands */
 566     if (eckey->priv_key == NULL) {
 567         ECerr(EC_F_EC_PKEY_CHECK, EC_R_MISSING_PRIVATE_KEY);
 568         return 0;
 569     }
 570
 571     return EC_KEY_check_key(eckey);
 572 }
 573
 574 static int ec_pkey_public_check(const EVP_PKEY *pkey)
 575 {
 576     EC_KEY *eckey = pkey->pkey.ec;
 577
 578     /*
 579      * Note: it unnecessary to check eckey->pub_key here since
 580      * it will be checked in EC_KEY_check_key(). In fact, the
 581      * EC_KEY_check_key() mainly checks the public key, and checks
 582      * the private key optionally (only if there is one). So if
 583      * someone passes a whole EC key (public + private), this
 584      * will also work...
 585      */
 586
 587     return EC_KEY_check_key(eckey);
 588 }
 589
 590 static int ec_pkey_param_check(const EVP_PKEY *pkey)
 591 {
 592     EC_KEY *eckey = pkey->pkey.ec;
 593
 594     /* stay consistent to what EVP_PKEY_check demands */
 595     if (eckey->group == NULL) {
 596         ECerr(EC_F_EC_PKEY_PARAM_CHECK, EC_R_MISSING_PARAMETERS);
 597         return 0;
 598     }
 599
 600     return EC_GROUP_check(eckey->group, NULL);
 601 }
 602
 603 static
 604 size_t ec_pkey_dirty_cnt(const EVP_PKEY *pkey)
 605 {
 606     return pkey->pkey.ec->dirty_cnt;
 607 }
 608
 609 static ossl_inline
 610 int ecparams_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl)
 611 {
 612     const EC_GROUP *ecg;
 613     int curve_nid;
 614
 615     if (eckey == NULL)
 616         return 0;
 617
 618     ecg = EC_KEY_get0_group(eckey);
 619     if (ecg == NULL)
 620         return 0;
 621
 622     curve_nid = EC_GROUP_get_curve_name(ecg);
 623
 624     if (curve_nid == NID_undef) {
 625         /* explicit parameters */
 626
 627         /*
 628          * TODO(3.0): should we support explicit parameters curves?
 629          */
 630         return 0;
 631     } else {
 632         /* named curve */
 633         const char *curve_name = NULL;
 634
 635         if ((curve_name = OBJ_nid2sn(curve_nid)) == NULL)
 636             return 0;
 637
 638         if (!OSSL_PARAM_BLD_push_utf8_string(tmpl, OSSL_PKEY_PARAM_GROUP_NAME,
 639                                              curve_name, 0))
 640             return 0;
 641     }
 642
 643     return 1;
 644 }
 645
 646 static
 647 int ec_pkey_export_to(const EVP_PKEY *from, void *to_keydata,
 648                       EVP_KEYMGMT *to_keymgmt, OPENSSL_CTX *libctx,
 649                       const char *propq)
 650 {
 651     const EC_KEY *eckey = NULL;
 652     const EC_GROUP *ecg = NULL;
 653     unsigned char *pub_key_buf = NULL;
 654     size_t pub_key_buflen;
 655     OSSL_PARAM_BLD *tmpl;
 656     OSSL_PARAM *params = NULL;
 657     const BIGNUM *priv_key = NULL;
 658     const EC_POINT *pub_point = NULL;
 659     int selection = 0;
 660     int rv = 0;
 661     BN_CTX *bnctx = NULL;
 662
 663     if (from == NULL
 664             || (eckey = from->pkey.ec) == NULL
 665             || (ecg = EC_KEY_get0_group(eckey)) == NULL)
 666         return 0;
 667
 668     /*
 669      * If the EC_KEY method is foreign, then we can't be sure of anything,
 670      * and can therefore not export or pretend to export.
 671      */
 672     if (EC_KEY_get_method(eckey) != EC_KEY_OpenSSL())
 673         return 0;
 674
 675     tmpl = OSSL_PARAM_BLD_new();
 676     if (tmpl == NULL)
 677         return 0;
 678
 679     /* export the domain parameters */
 680     if (!ecparams_to_params(eckey, tmpl))
 681         goto err;
 682     selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS;
 683
 684     priv_key = EC_KEY_get0_private_key(eckey);
 685     pub_point = EC_KEY_get0_public_key(eckey);
 686
 687     if (pub_point != NULL) {
 688         /*
 689          * EC_POINT_point2buf() can generate random numbers in some
 690          * implementations so we need to ensure we use the correct libctx.
 691          */
 692         bnctx = BN_CTX_new_ex(libctx);
 693         if (bnctx == NULL)
 694             goto err;
 695
 696         /* convert pub_point to a octet string according to the SECG standard */
 697         if ((pub_key_buflen = EC_POINT_point2buf(ecg, pub_point,
 698                                                  POINT_CONVERSION_COMPRESSED,
 699                                                  &pub_key_buf, bnctx)) == 0
 700             || !OSSL_PARAM_BLD_push_octet_string(tmpl,
 701                                                  OSSL_PKEY_PARAM_PUB_KEY,
 702                                                  pub_key_buf,
 703                                                  pub_key_buflen))
 704             goto err;
 705         selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY;
 706     }
 707
 708     if (priv_key != NULL) {
 709         size_t sz;
 710         int ecbits;
 711         int ecdh_cofactor_mode;
 712
 713         /*
 714          * Key import/export should never leak the bit length of the secret
 715          * scalar in the key.
 716          *
 717          * For this reason, on export we use padded BIGNUMs with fixed length.
 718          *
 719          * When importing we also should make sure that, even if short lived,
 720          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 721          * soon as possible, so that any processing of this BIGNUM might opt for
 722          * constant time implementations in the backend.
 723          *
 724          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 725          * to preallocate the BIGNUM internal buffer to a fixed public size big
 726          * enough that operations performed during the processing never trigger
 727          * a realloc which would leak the size of the scalar through memory
 728          * accesses.
 729          *
 730          * Fixed Length
 731          * ------------
 732          *
 733          * The order of the large prime subgroup of the curve is our choice for
 734          * a fixed public size, as that is generally the upper bound for
 735          * generating a private key in EC cryptosystems and should fit all valid
 736          * secret scalars.
 737          *
 738          * For padding on export we just use the bit length of the order
 739          * converted to bytes (rounding up).
 740          *
 741          * For preallocating the BIGNUM storage we look at the number of "words"
 742          * required for the internal representation of the order, and we
 743          * preallocate 2 extra "words" in case any of the subsequent processing
 744          * might temporarily overflow the order length.
 745          */
 746         ecbits = EC_GROUP_order_bits(ecg);
 747         if (ecbits <= 0)
 748             goto err;
 749
 750         sz = (ecbits + 7 ) / 8;
 751         if (!OSSL_PARAM_BLD_push_BN_pad(tmpl,
 752                                         OSSL_PKEY_PARAM_PRIV_KEY,
 753                                         priv_key, sz))
 754             goto err;
 755         selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY;
 756
 757         /*
 758          * The ECDH Cofactor Mode is defined only if the EC_KEY actually
 759          * contains a private key, so we check for the flag and export it only
 760          * in this case.
 761          */
 762         ecdh_cofactor_mode =
 763             (EC_KEY_get_flags(eckey) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 764
 765         /* Export the ECDH_COFACTOR_MODE parameter */
 766         if (!OSSL_PARAM_BLD_push_int(tmpl,
 767                                      OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 768                                      ecdh_cofactor_mode))
 769             goto err;
 770         selection |= OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS;
 771     }
 772
 773     params = OSSL_PARAM_BLD_to_param(tmpl);
 774
 775     /* We export, the provider imports */
 776     rv = evp_keymgmt_import(to_keymgmt, to_keydata, selection, params);
 777
 778  err:
 779     OSSL_PARAM_BLD_free(tmpl);
 780     OSSL_PARAM_BLD_free_params(params);
 781     OPENSSL_free(pub_key_buf);
 782     BN_CTX_free(bnctx);
 783     return rv;
 784 }
 785
 786 static int ec_pkey_import_from(const OSSL_PARAM params[], void *vpctx)
 787 {
 788     EVP_PKEY_CTX *pctx = vpctx;
 789     EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 790     EC_KEY *ec = EC_KEY_new_with_libctx(pctx->libctx, pctx->propquery);
 791
 792     if (ec == NULL) {
 793         ERR_raise(ERR_LIB_DH, ERR_R_MALLOC_FAILURE);
 794         return 0;
 795     }
 796
 797     if (!ec_key_domparams_fromdata(ec, params)
 798         || !ec_key_otherparams_fromdata(ec, params)
 799         || !ec_key_fromdata(ec, params, 1)
 800         || !EVP_PKEY_assign_EC_KEY(pkey, ec)) {
 801         EC_KEY_free(ec);
 802         return 0;
 803     }
 804     return 1;
 805 }
 806
 807 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 808     EVP_PKEY_EC,
 809     EVP_PKEY_EC,
 810     0,
 811     "EC",
 812     "OpenSSL EC algorithm",
 813
 814     eckey_pub_decode,
 815     eckey_pub_encode,
 816     eckey_pub_cmp,
 817     eckey_pub_print,
 818
 819     NULL,
 820     eckey_priv_encode,
 821     eckey_priv_print,
 822
 823     int_ec_size,
 824     ec_bits,
 825     ec_security_bits,
 826
 827     eckey_param_decode,
 828     eckey_param_encode,
 829     ec_missing_parameters,
 830     ec_copy_parameters,
 831     ec_cmp_parameters,
 832     eckey_param_print,
 833     0,
 834
 835     int_ec_free,
 836     ec_pkey_ctrl,
 837     old_ec_priv_decode,
 838     old_ec_priv_encode,
 839
 840     0, 0, 0,
 841
 842     ec_pkey_check,
 843     ec_pkey_public_check,
 844     ec_pkey_param_check,
 845
 846     0, /* set_priv_key */
 847     0, /* set_pub_key */
 848     0, /* get_priv_key */
 849     0, /* get_pub_key */
 850
 851     ec_pkey_dirty_cnt,
 852     ec_pkey_export_to,
 853     ec_pkey_import_from,
 854     eckey_priv_decode_with_libctx
 855 };
 856
 857 #if !defined(OPENSSL_NO_SM2)
 858 const EVP_PKEY_ASN1_METHOD sm2_asn1_meth = {
 859    EVP_PKEY_SM2,
 860    EVP_PKEY_EC,
 861    ASN1_PKEY_ALIAS
 862 };
 863 #endif
 864
 865 int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
 866 {
 867     int private = EC_KEY_get0_private_key(x) != NULL;
 868
 869     return do_EC_KEY_print(bp, x, off,
 870                 private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC);
 871 }
 872
 873 int ECParameters_print(BIO *bp, const EC_KEY *x)
 874 {
 875     return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM);
 876 }
 877
 878 #ifndef OPENSSL_NO_CMS
 879
 880 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 881                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 882 {
 883     const ASN1_OBJECT *aoid;
 884     int atype;
 885     const void *aval;
 886     int rv = 0;
 887     EVP_PKEY *pkpeer = NULL;
 888     EC_KEY *ecpeer = NULL;
 889     const unsigned char *p;
 890     int plen;
 891
 892     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 893     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
 894         goto err;
 895     /* If absent parameters get group from main key */
 896     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
 897         const EC_GROUP *grp;
 898         EVP_PKEY *pk;
 899         pk = EVP_PKEY_CTX_get0_pkey(pctx);
 900         if (pk == NULL)
 901             goto err;
 902         grp = EC_KEY_get0_group(pk->pkey.ec);
 903         ecpeer = EC_KEY_new();
 904         if (ecpeer == NULL)
 905             goto err;
 906         if (!EC_KEY_set_group(ecpeer, grp))
 907             goto err;
 908     } else {
 909         ecpeer = eckey_type2param(atype, aval, pctx->libctx, pctx->propquery);
 910         if (!ecpeer)
 911             goto err;
 912     }
 913     /* We have parameters now set public key */
 914     plen = ASN1_STRING_length(pubkey);
 915     p = ASN1_STRING_get0_data(pubkey);
 916     if (p == NULL || plen == 0)
 917         goto err;
 918     if (!o2i_ECPublicKey(&ecpeer, &p, plen))
 919         goto err;
 920     pkpeer = EVP_PKEY_new();
 921     if (pkpeer == NULL)
 922         goto err;
 923     EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
 924     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 925         rv = 1;
 926  err:
 927     EC_KEY_free(ecpeer);
 928     EVP_PKEY_free(pkpeer);
 929     return rv;
 930 }
 931
 932 /* Set KDF parameters based on KDF NID */
 933 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 934 {
 935     int kdf_nid, kdfmd_nid, cofactor;
 936     const EVP_MD *kdf_md;
 937     if (eckdf_nid == NID_undef)
 938         return 0;
 939
 940     /* Lookup KDF type, cofactor mode and digest */
 941     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 942         return 0;
 943
 944     if (kdf_nid == NID_dh_std_kdf)
 945         cofactor = 0;
 946     else if (kdf_nid == NID_dh_cofactor_kdf)
 947         cofactor = 1;
 948     else
 949         return 0;
 950
 951     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 952         return 0;
 953
 954     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
 955         return 0;
 956
 957     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 958     if (!kdf_md)
 959         return 0;
 960
 961     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 962         return 0;
 963     return 1;
 964 }
 965
 966 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 967 {
 968     int rv = 0;
 969
 970     X509_ALGOR *alg, *kekalg = NULL;
 971     ASN1_OCTET_STRING *ukm;
 972     const unsigned char *p;
 973     unsigned char *der = NULL;
 974     int plen, keylen;
 975     EVP_CIPHER *kekcipher = NULL;
 976     EVP_CIPHER_CTX *kekctx;
 977     const char *name;
 978
 979     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 980         return 0;
 981
 982     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 983         ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
 984         return 0;
 985     }
 986
 987     if (alg->parameter->type != V_ASN1_SEQUENCE)
 988         return 0;
 989
 990     p = alg->parameter->value.sequence->data;
 991     plen = alg->parameter->value.sequence->length;
 992     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 993     if (kekalg == NULL)
 994         goto err;
 995     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 996     if (kekctx == NULL)
 997         goto err;
 998     name = OBJ_nid2sn(OBJ_obj2nid(kekalg->algorithm));
 999     kekcipher = EVP_CIPHER_fetch(pctx->libctx, name, NULL);
1000     if (kekcipher == NULL || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
1001         goto err;
1002     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
1003         goto err;
1004     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
1005         goto err;
1006
1007     keylen = EVP_CIPHER_CTX_key_length(kekctx);
1008     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
1009         goto err;
1010
1011     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
1012
1013     if (!plen)
1014         goto err;
1015
1016     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
1017         goto err;
1018     der = NULL;
1019
1020     rv = 1;
1021  err:
1022     EVP_CIPHER_free(kekcipher);
1023     X509_ALGOR_free(kekalg);
1024     OPENSSL_free(der);
1025     return rv;
1026 }
1027
1028 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
1029 {
1030     EVP_PKEY_CTX *pctx;
1031
1032     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
1033     if (pctx == NULL)
1034         return 0;
1035     /* See if we need to set peer key */
1036     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
1037         X509_ALGOR *alg;
1038         ASN1_BIT_STRING *pubkey;
1039
1040         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
1041                                                  NULL, NULL, NULL))
1042             return 0;
1043         if (!alg || !pubkey)
1044             return 0;
1045         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
1046             ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
1047             return 0;
1048         }
1049     }
1050     /* Set ECDH derivation parameters and initialise unwrap context */
1051     if (!ecdh_cms_set_shared_info(pctx, ri)) {
1052         ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
1053         return 0;
1054     }
1055     return 1;
1056 }
1057
1058 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
1059 {
1060     EVP_PKEY_CTX *pctx;
1061     EVP_PKEY *pkey;
1062     EVP_CIPHER_CTX *ctx;
1063     int keylen;
1064     X509_ALGOR *talg, *wrap_alg = NULL;
1065     const ASN1_OBJECT *aoid;
1066     ASN1_BIT_STRING *pubkey;
1067     ASN1_STRING *wrap_str;
1068     ASN1_OCTET_STRING *ukm;
1069     unsigned char *penc = NULL;
1070     int penclen;
1071     int rv = 0;
1072     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
1073     const EVP_MD *kdf_md;
1074
1075     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
1076     if (pctx == NULL)
1077         return 0;
1078     /* Get ephemeral key */
1079     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
1080     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
1081                                              NULL, NULL, NULL))
1082         goto err;
1083     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
1084     /* Is everything uninitialised? */
1085     if (aoid == OBJ_nid2obj(NID_undef)) {
1086
1087         EC_KEY *eckey = pkey->pkey.ec;
1088         /* Set the key */
1089         unsigned char *p;
1090
1091         penclen = i2o_ECPublicKey(eckey, NULL);
1092         if (penclen <= 0)
1093             goto err;
1094         penc = OPENSSL_malloc(penclen);
1095         if (penc == NULL)
1096             goto err;
1097         p = penc;
1098         penclen = i2o_ECPublicKey(eckey, &p);
1099         if (penclen <= 0)
1100             goto err;
1101         ASN1_STRING_set0(pubkey, penc, penclen);
1102         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
1103         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
1104
1105         penc = NULL;
1106         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
1107                         V_ASN1_UNDEF, NULL);
1108     }
1109
1110     /* See if custom parameters set */
1111     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
1112     if (kdf_type <= 0)
1113         goto err;
1114     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
1115         goto err;
1116     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
1117     if (ecdh_nid < 0)
1118         goto err;
1119     else if (ecdh_nid == 0)
1120         ecdh_nid = NID_dh_std_kdf;
1121     else if (ecdh_nid == 1)
1122         ecdh_nid = NID_dh_cofactor_kdf;
1123
1124     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
1125         kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
1126         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
1127             goto err;
1128     } else
1129         /* Unknown KDF */
1130         goto err;
1131     if (kdf_md == NULL) {
1132         /* Fixme later for better MD */
1133         kdf_md = EVP_sha1();
1134         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
1135             goto err;
1136     }
1137
1138     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
1139         goto err;
1140
1141     /* Lookup NID for KDF+cofactor+digest */
1142
1143     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
1144         goto err;
1145     /* Get wrap NID */
1146     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
1147     wrap_nid = EVP_CIPHER_CTX_type(ctx);
1148     keylen = EVP_CIPHER_CTX_key_length(ctx);
1149
1150     /* Package wrap algorithm in an AlgorithmIdentifier */
1151
1152     wrap_alg = X509_ALGOR_new();
1153     if (wrap_alg == NULL)
1154         goto err;
1155     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
1156     wrap_alg->parameter = ASN1_TYPE_new();
1157     if (wrap_alg->parameter == NULL)
1158         goto err;
1159     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
1160         goto err;
1161     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
1162         ASN1_TYPE_free(wrap_alg->parameter);
1163         wrap_alg->parameter = NULL;
1164     }
1165
1166     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
1167         goto err;
1168
1169     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
1170
1171     if (!penclen)
1172         goto err;
1173
1174     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
1175         goto err;
1176     penc = NULL;
1177
1178     /*
1179      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
1180      * of another AlgorithmIdentifier.
1181      */
1182     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
1183     if (!penc || !penclen)
1184         goto err;
1185     wrap_str = ASN1_STRING_new();
1186     if (wrap_str == NULL)
1187         goto err;
1188     ASN1_STRING_set0(wrap_str, penc, penclen);
1189     penc = NULL;
1190     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
1191
1192     rv = 1;
1193
1194  err:
1195     OPENSSL_free(penc);
1196     X509_ALGOR_free(wrap_alg);
1197     return rv;
1198 }
1199
1200 #endif