crypto/ec/ec_ameth.c

   1 /*
   2  * Copyright 2006-2021 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/asn1t.h>
  22 #include "crypto/asn1.h"
  23 #include "crypto/evp.h"
  24 #include "crypto/x509.h"
  25 #include <openssl/core_names.h>
  26 #include "openssl/param_build.h"
  27 #include "ec_local.h"
  28
  29 static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key)
  30 {
  31     const EC_GROUP *group;
  32     int nid;
  33
  34     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  35         ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS);
  36         return 0;
  37     }
  38     if (EC_GROUP_get_asn1_flag(group)
  39         && (nid = EC_GROUP_get_curve_name(group)))
  40         /* we have a 'named curve' => just set the OID */
  41     {
  42         ASN1_OBJECT *asn1obj = OBJ_nid2obj(nid);
  43
  44         if (asn1obj == NULL || OBJ_length(asn1obj) == 0) {
  45             ASN1_OBJECT_free(asn1obj);
  46             ERR_raise(ERR_LIB_EC, EC_R_MISSING_OID);
  47             return 0;
  48         }
  49         *ppval = asn1obj;
  50         *pptype = V_ASN1_OBJECT;
  51     } else {                    /* explicit parameters */
  52
  53         ASN1_STRING *pstr = NULL;
  54         pstr = ASN1_STRING_new();
  55         if (pstr == NULL)
  56             return 0;
  57         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  58         if (pstr->length <= 0) {
  59             ASN1_STRING_free(pstr);
  60             ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
  61             return 0;
  62         }
  63         *ppval = pstr;
  64         *pptype = V_ASN1_SEQUENCE;
  65     }
  66     return 1;
  67 }
  68
  69 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  70 {
  71     const EC_KEY *ec_key = pkey->pkey.ec;
  72     void *pval = NULL;
  73     int ptype;
  74     unsigned char *penc = NULL, *p;
  75     int penclen;
  76
  77     if (!eckey_param2type(&ptype, &pval, ec_key)) {
  78         ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
  79         return 0;
  80     }
  81     penclen = i2o_ECPublicKey(ec_key, NULL);
  82     if (penclen <= 0)
  83         goto err;
  84     penc = OPENSSL_malloc(penclen);
  85     if (penc == NULL)
  86         goto err;
  87     p = penc;
  88     penclen = i2o_ECPublicKey(ec_key, &p);
  89     if (penclen <= 0)
  90         goto err;
  91     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
  92                                ptype, pval, penc, penclen))
  93         return 1;
  94  err:
  95     if (ptype == V_ASN1_OBJECT)
  96         ASN1_OBJECT_free(pval);
  97     else
  98         ASN1_STRING_free(pval);
  99     OPENSSL_free(penc);
 100     return 0;
 101 }
 102
 103 static EC_KEY *eckey_type2param(int ptype, const void *pval,
 104                                 OSSL_LIB_CTX *libctx, const char *propq)
 105 {
 106     EC_KEY *eckey = NULL;
 107     EC_GROUP *group = NULL;
 108
 109     if ((eckey = EC_KEY_new_ex(libctx, propq)) == NULL) {
 110         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
 111         goto ecerr;
 112     }
 113
 114     if (ptype == V_ASN1_SEQUENCE) {
 115         const ASN1_STRING *pstr = pval;
 116         const unsigned char *pm = pstr->data;
 117         int pmlen = pstr->length;
 118
 119
 120         if (d2i_ECParameters(&eckey, &pm, pmlen) == NULL) {
 121             ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR);
 122             goto ecerr;
 123         }
 124     } else if (ptype == V_ASN1_OBJECT) {
 125         const ASN1_OBJECT *poid = pval;
 126
 127         /*
 128          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 129          */
 130
 131         group = EC_GROUP_new_by_curve_name_ex(libctx, propq, OBJ_obj2nid(poid));
 132         if (group == NULL)
 133             goto ecerr;
 134         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 135         if (EC_KEY_set_group(eckey, group) == 0)
 136             goto ecerr;
 137         EC_GROUP_free(group);
 138     } else {
 139         ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR);
 140         goto ecerr;
 141     }
 142
 143     return eckey;
 144
 145  ecerr:
 146     EC_KEY_free(eckey);
 147     EC_GROUP_free(group);
 148     return NULL;
 149 }
 150
 151 static int eckey_pub_decode(EVP_PKEY *pkey, const X509_PUBKEY *pubkey)
 152 {
 153     const unsigned char *p = NULL;
 154     const void *pval;
 155     int ptype, pklen;
 156     EC_KEY *eckey = NULL;
 157     X509_ALGOR *palg;
 158     OSSL_LIB_CTX *libctx = NULL;
 159     const char *propq = NULL;
 160
 161     if (!X509_PUBKEY_get0_libctx(&libctx, &propq, pubkey)
 162         || !X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 163         return 0;
 164     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 165
 166     eckey = eckey_type2param(ptype, pval, libctx, propq);
 167
 168     if (!eckey)
 169         return 0;
 170
 171     /* We have parameters now set public key */
 172     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 173         ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR);
 174         goto ecerr;
 175     }
 176
 177     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 178     return 1;
 179
 180  ecerr:
 181     EC_KEY_free(eckey);
 182     return 0;
 183 }
 184
 185 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 186 {
 187     int r;
 188     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 189     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 190         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 191
 192     if (group == NULL || pa == NULL || pb == NULL)
 193         return -2;
 194     r = EC_POINT_cmp(group, pa, pb, NULL);
 195     if (r == 0)
 196         return 1;
 197     if (r == 1)
 198         return 0;
 199     return -2;
 200 }
 201
 202 static int eckey_priv_decode_ex(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8,
 203                                 OSSL_LIB_CTX *libctx, const char *propq)
 204 {
 205     const unsigned char *p = NULL;
 206     const void *pval;
 207     int ptype, pklen;
 208     EC_KEY *eckey = NULL;
 209     const X509_ALGOR *palg;
 210
 211     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 212         return 0;
 213     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 214
 215     eckey = eckey_type2param(ptype, pval, libctx, propq);
 216     if (eckey == NULL)
 217         goto err;
 218
 219     /* We have parameters now set private key */
 220     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 221         ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR);
 222         goto err;
 223     }
 224
 225     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 226     return 1;
 227
 228  err:
 229     EC_KEY_free(eckey);
 230     return 0;
 231 }
 232
 233 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 234 {
 235     EC_KEY ec_key = *(pkey->pkey.ec);
 236     unsigned char *ep, *p;
 237     int eplen, ptype;
 238     void *pval;
 239     unsigned int old_flags;
 240
 241     if (!eckey_param2type(&ptype, &pval, &ec_key)) {
 242         ERR_raise(ERR_LIB_EC, EC_R_DECODE_ERROR);
 243         return 0;
 244     }
 245
 246     /* set the private key */
 247
 248     /*
 249      * do not include the parameters in the SEC1 private key see PKCS#11
 250      * 12.11
 251      */
 252     old_flags = EC_KEY_get_enc_flags(&ec_key);
 253     EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS);
 254
 255     eplen = i2d_ECPrivateKey(&ec_key, NULL);
 256     if (!eplen) {
 257         ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
 258         return 0;
 259     }
 260     ep = OPENSSL_malloc(eplen);
 261     if (ep == NULL) {
 262         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
 263         return 0;
 264     }
 265     p = ep;
 266     if (!i2d_ECPrivateKey(&ec_key, &p)) {
 267         OPENSSL_free(ep);
 268         ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
 269         return 0;
 270     }
 271
 272     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 273                          ptype, pval, ep, eplen)) {
 274         OPENSSL_free(ep);
 275         return 0;
 276     }
 277
 278     return 1;
 279 }
 280
 281 static int int_ec_size(const EVP_PKEY *pkey)
 282 {
 283     return ECDSA_size(pkey->pkey.ec);
 284 }
 285
 286 static int ec_bits(const EVP_PKEY *pkey)
 287 {
 288     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 289 }
 290
 291 static int ec_security_bits(const EVP_PKEY *pkey)
 292 {
 293     int ecbits = ec_bits(pkey);
 294
 295     if (ecbits >= 512)
 296         return 256;
 297     if (ecbits >= 384)
 298         return 192;
 299     if (ecbits >= 256)
 300         return 128;
 301     if (ecbits >= 224)
 302         return 112;
 303     if (ecbits >= 160)
 304         return 80;
 305     return ecbits / 2;
 306 }
 307
 308 static int ec_missing_parameters(const EVP_PKEY *pkey)
 309 {
 310     if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 311         return 1;
 312     return 0;
 313 }
 314
 315 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 316 {
 317     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 318
 319     if (group == NULL)
 320         return 0;
 321     if (to->pkey.ec == NULL) {
 322         to->pkey.ec = EC_KEY_new();
 323         if (to->pkey.ec == NULL)
 324             goto err;
 325     }
 326     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 327         goto err;
 328     EC_GROUP_free(group);
 329     return 1;
 330  err:
 331     EC_GROUP_free(group);
 332     return 0;
 333 }
 334
 335 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 336 {
 337     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 338         *group_b = EC_KEY_get0_group(b->pkey.ec);
 339
 340     if (group_a == NULL || group_b == NULL)
 341         return -2;
 342     if (EC_GROUP_cmp(group_a, group_b, NULL))
 343         return 0;
 344     else
 345         return 1;
 346 }
 347
 348 static void int_ec_free(EVP_PKEY *pkey)
 349 {
 350     EC_KEY_free(pkey->pkey.ec);
 351 }
 352
 353 typedef enum {
 354     EC_KEY_PRINT_PRIVATE,
 355     EC_KEY_PRINT_PUBLIC,
 356     EC_KEY_PRINT_PARAM
 357 } ec_print_t;
 358
 359 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 360 {
 361     const char *ecstr;
 362     unsigned char *priv = NULL, *pub = NULL;
 363     size_t privlen = 0, publen = 0;
 364     int ret = 0;
 365     const EC_GROUP *group;
 366
 367     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 368         ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
 369         return 0;
 370     }
 371
 372     if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) {
 373         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 374         if (publen == 0)
 375             goto err;
 376     }
 377
 378     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 379         privlen = EC_KEY_priv2buf(x, &priv);
 380         if (privlen == 0)
 381             goto err;
 382     }
 383
 384     if (ktype == EC_KEY_PRINT_PRIVATE)
 385         ecstr = "Private-Key";
 386     else if (ktype == EC_KEY_PRINT_PUBLIC)
 387         ecstr = "Public-Key";
 388     else
 389         ecstr = "ECDSA-Parameters";
 390
 391     if (!BIO_indent(bp, off, 128))
 392         goto err;
 393     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 394                    EC_GROUP_order_bits(group)) <= 0)
 395         goto err;
 396
 397     if (privlen != 0) {
 398         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 399             goto err;
 400         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 401             goto err;
 402     }
 403
 404     if (publen != 0) {
 405         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 406             goto err;
 407         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 408             goto err;
 409     }
 410
 411     if (!ECPKParameters_print(bp, group, off))
 412         goto err;
 413     ret = 1;
 414  err:
 415     if (!ret)
 416         ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
 417     OPENSSL_clear_free(priv, privlen);
 418     OPENSSL_free(pub);
 419     return ret;
 420 }
 421
 422 static int eckey_param_decode(EVP_PKEY *pkey,
 423                               const unsigned char **pder, int derlen)
 424 {
 425     EC_KEY *eckey;
 426
 427     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL)
 428         return 0;
 429     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 430     return 1;
 431 }
 432
 433 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 434 {
 435     return i2d_ECParameters(pkey->pkey.ec, pder);
 436 }
 437
 438 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 439                              ASN1_PCTX *ctx)
 440 {
 441     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 442 }
 443
 444 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 445                            ASN1_PCTX *ctx)
 446 {
 447     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 448 }
 449
 450 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 451                             ASN1_PCTX *ctx)
 452 {
 453     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 454 }
 455
 456 static int old_ec_priv_decode(EVP_PKEY *pkey,
 457                               const unsigned char **pder, int derlen)
 458 {
 459     EC_KEY *ec;
 460
 461     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL)
 462         return 0;
 463     EVP_PKEY_assign_EC_KEY(pkey, ec);
 464     return 1;
 465 }
 466
 467 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 468 {
 469     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 470 }
 471
 472 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 473 {
 474     switch (op) {
 475     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 476         if (EVP_PKEY_id(pkey) == EVP_PKEY_SM2) {
 477             /* For SM2, the only valid digest-alg is SM3 */
 478             *(int *)arg2 = NID_sm3;
 479             return 2;            /* Make it mandatory */
 480         }
 481         *(int *)arg2 = NID_sha256;
 482         return 1;
 483
 484     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
 485         return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
 486
 487     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
 488         return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
 489                               POINT_CONVERSION_UNCOMPRESSED, arg2, NULL);
 490
 491     default:
 492         return -2;
 493     }
 494 }
 495
 496 static int ec_pkey_check(const EVP_PKEY *pkey)
 497 {
 498     EC_KEY *eckey = pkey->pkey.ec;
 499
 500     /* stay consistent to what EVP_PKEY_check demands */
 501     if (eckey->priv_key == NULL) {
 502         ERR_raise(ERR_LIB_EC, EC_R_MISSING_PRIVATE_KEY);
 503         return 0;
 504     }
 505
 506     return EC_KEY_check_key(eckey);
 507 }
 508
 509 static int ec_pkey_public_check(const EVP_PKEY *pkey)
 510 {
 511     EC_KEY *eckey = pkey->pkey.ec;
 512
 513     /*
 514      * Note: it unnecessary to check eckey->pub_key here since
 515      * it will be checked in EC_KEY_check_key(). In fact, the
 516      * EC_KEY_check_key() mainly checks the public key, and checks
 517      * the private key optionally (only if there is one). So if
 518      * someone passes a whole EC key (public + private), this
 519      * will also work...
 520      */
 521
 522     return EC_KEY_check_key(eckey);
 523 }
 524
 525 static int ec_pkey_param_check(const EVP_PKEY *pkey)
 526 {
 527     EC_KEY *eckey = pkey->pkey.ec;
 528
 529     /* stay consistent to what EVP_PKEY_check demands */
 530     if (eckey->group == NULL) {
 531         ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS);
 532         return 0;
 533     }
 534
 535     return EC_GROUP_check(eckey->group, NULL);
 536 }
 537
 538 static
 539 size_t ec_pkey_dirty_cnt(const EVP_PKEY *pkey)
 540 {
 541     return pkey->pkey.ec->dirty_cnt;
 542 }
 543
 544 static
 545 int ec_pkey_export_to(const EVP_PKEY *from, void *to_keydata,
 546                       EVP_KEYMGMT *to_keymgmt, OSSL_LIB_CTX *libctx,
 547                       const char *propq)
 548 {
 549     const EC_KEY *eckey = NULL;
 550     const EC_GROUP *ecg = NULL;
 551     unsigned char *pub_key_buf = NULL, *gen_buf = NULL;
 552     size_t pub_key_buflen;
 553     OSSL_PARAM_BLD *tmpl;
 554     OSSL_PARAM *params = NULL;
 555     const BIGNUM *priv_key = NULL;
 556     const EC_POINT *pub_point = NULL;
 557     int selection = 0;
 558     int rv = 0;
 559     BN_CTX *bnctx = NULL;
 560
 561     if (from == NULL
 562             || (eckey = from->pkey.ec) == NULL
 563             || (ecg = EC_KEY_get0_group(eckey)) == NULL)
 564         return 0;
 565
 566     /*
 567      * If the EC_KEY method is foreign, then we can't be sure of anything,
 568      * and can therefore not export or pretend to export.
 569      */
 570     if (EC_KEY_get_method(eckey) != EC_KEY_OpenSSL())
 571         return 0;
 572
 573     tmpl = OSSL_PARAM_BLD_new();
 574     if (tmpl == NULL)
 575         return 0;
 576
 577     /*
 578      * EC_POINT_point2buf() can generate random numbers in some
 579      * implementations so we need to ensure we use the correct libctx.
 580      */
 581     bnctx = BN_CTX_new_ex(libctx);
 582     if (bnctx == NULL)
 583         goto err;
 584     BN_CTX_start(bnctx);
 585
 586     /* export the domain parameters */
 587     if (!ossl_ec_group_todata(ecg, tmpl, NULL, libctx, propq, bnctx, &gen_buf))
 588         goto err;
 589     selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS;
 590
 591     priv_key = EC_KEY_get0_private_key(eckey);
 592     pub_point = EC_KEY_get0_public_key(eckey);
 593
 594     if (pub_point != NULL) {
 595         /* convert pub_point to a octet string according to the SECG standard */
 596         if ((pub_key_buflen = EC_POINT_point2buf(ecg, pub_point,
 597                                                  POINT_CONVERSION_COMPRESSED,
 598                                                  &pub_key_buf, bnctx)) == 0
 599             || !OSSL_PARAM_BLD_push_octet_string(tmpl,
 600                                                  OSSL_PKEY_PARAM_PUB_KEY,
 601                                                  pub_key_buf,
 602                                                  pub_key_buflen))
 603             goto err;
 604         selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY;
 605     }
 606
 607     if (priv_key != NULL) {
 608         size_t sz;
 609         int ecbits;
 610         int ecdh_cofactor_mode;
 611
 612         /*
 613          * Key import/export should never leak the bit length of the secret
 614          * scalar in the key.
 615          *
 616          * For this reason, on export we use padded BIGNUMs with fixed length.
 617          *
 618          * When importing we also should make sure that, even if short lived,
 619          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 620          * soon as possible, so that any processing of this BIGNUM might opt for
 621          * constant time implementations in the backend.
 622          *
 623          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 624          * to preallocate the BIGNUM internal buffer to a fixed public size big
 625          * enough that operations performed during the processing never trigger
 626          * a realloc which would leak the size of the scalar through memory
 627          * accesses.
 628          *
 629          * Fixed Length
 630          * ------------
 631          *
 632          * The order of the large prime subgroup of the curve is our choice for
 633          * a fixed public size, as that is generally the upper bound for
 634          * generating a private key in EC cryptosystems and should fit all valid
 635          * secret scalars.
 636          *
 637          * For padding on export we just use the bit length of the order
 638          * converted to bytes (rounding up).
 639          *
 640          * For preallocating the BIGNUM storage we look at the number of "words"
 641          * required for the internal representation of the order, and we
 642          * preallocate 2 extra "words" in case any of the subsequent processing
 643          * might temporarily overflow the order length.
 644          */
 645         ecbits = EC_GROUP_order_bits(ecg);
 646         if (ecbits <= 0)
 647             goto err;
 648
 649         sz = (ecbits + 7 ) / 8;
 650         if (!OSSL_PARAM_BLD_push_BN_pad(tmpl,
 651                                         OSSL_PKEY_PARAM_PRIV_KEY,
 652                                         priv_key, sz))
 653             goto err;
 654         selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY;
 655
 656         /*
 657          * The ECDH Cofactor Mode is defined only if the EC_KEY actually
 658          * contains a private key, so we check for the flag and export it only
 659          * in this case.
 660          */
 661         ecdh_cofactor_mode =
 662             (EC_KEY_get_flags(eckey) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 663
 664         /* Export the ECDH_COFACTOR_MODE parameter */
 665         if (!OSSL_PARAM_BLD_push_int(tmpl,
 666                                      OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 667                                      ecdh_cofactor_mode))
 668             goto err;
 669         selection |= OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS;
 670     }
 671
 672     params = OSSL_PARAM_BLD_to_param(tmpl);
 673
 674     /* We export, the provider imports */
 675     rv = evp_keymgmt_import(to_keymgmt, to_keydata, selection, params);
 676
 677  err:
 678     OSSL_PARAM_BLD_free(tmpl);
 679     OSSL_PARAM_BLD_free_params(params);
 680     OPENSSL_free(pub_key_buf);
 681     OPENSSL_free(gen_buf);
 682     BN_CTX_end(bnctx);
 683     BN_CTX_free(bnctx);
 684     return rv;
 685 }
 686
 687 static int ec_pkey_import_from(const OSSL_PARAM params[], void *vpctx)
 688 {
 689     EVP_PKEY_CTX *pctx = vpctx;
 690     EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 691     EC_KEY *ec = EC_KEY_new_ex(pctx->libctx, pctx->propquery);
 692
 693     if (ec == NULL) {
 694         ERR_raise(ERR_LIB_DH, ERR_R_MALLOC_FAILURE);
 695         return 0;
 696     }
 697
 698     if (!ossl_ec_group_fromdata(ec, params)
 699         || !ossl_ec_key_otherparams_fromdata(ec, params)
 700         || !ossl_ec_key_fromdata(ec, params, 1)
 701         || !EVP_PKEY_assign_EC_KEY(pkey, ec)) {
 702         EC_KEY_free(ec);
 703         return 0;
 704     }
 705     return 1;
 706 }
 707
 708 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 709     EVP_PKEY_EC,
 710     EVP_PKEY_EC,
 711     0,
 712     "EC",
 713     "OpenSSL EC algorithm",
 714
 715     eckey_pub_decode,
 716     eckey_pub_encode,
 717     eckey_pub_cmp,
 718     eckey_pub_print,
 719
 720     NULL,
 721     eckey_priv_encode,
 722     eckey_priv_print,
 723
 724     int_ec_size,
 725     ec_bits,
 726     ec_security_bits,
 727
 728     eckey_param_decode,
 729     eckey_param_encode,
 730     ec_missing_parameters,
 731     ec_copy_parameters,
 732     ec_cmp_parameters,
 733     eckey_param_print,
 734     0,
 735
 736     int_ec_free,
 737     ec_pkey_ctrl,
 738     old_ec_priv_decode,
 739     old_ec_priv_encode,
 740
 741     0, 0, 0,
 742
 743     ec_pkey_check,
 744     ec_pkey_public_check,
 745     ec_pkey_param_check,
 746
 747     0, /* set_priv_key */
 748     0, /* set_pub_key */
 749     0, /* get_priv_key */
 750     0, /* get_pub_key */
 751
 752     ec_pkey_dirty_cnt,
 753     ec_pkey_export_to,
 754     ec_pkey_import_from,
 755     eckey_priv_decode_ex
 756 };
 757
 758 #if !defined(OPENSSL_NO_SM2)
 759 const EVP_PKEY_ASN1_METHOD sm2_asn1_meth = {
 760    EVP_PKEY_SM2,
 761    EVP_PKEY_EC,
 762    ASN1_PKEY_ALIAS
 763 };
 764 #endif
 765
 766 int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
 767 {
 768     int private = EC_KEY_get0_private_key(x) != NULL;
 769
 770     return do_EC_KEY_print(bp, x, off,
 771                 private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC);
 772 }
 773
 774 int ECParameters_print(BIO *bp, const EC_KEY *x)
 775 {
 776     return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM);
 777 }