crypto/ec/ec_ameth.c

   1 /*
   2  * Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/x509.h>
  13 #include <openssl/ec.h>
  14 #include <openssl/bn.h>
  15 #include <openssl/cms.h>
  16 #include <openssl/asn1t.h>
  17 #include "internal/asn1_int.h"
  18 #include "internal/evp_int.h"
  19
  20 #ifndef OPENSSL_NO_CMS
  21 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  22 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  23 #endif
  24
  25 static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
  26 {
  27     const EC_GROUP *group;
  28     int nid;
  29     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  30         ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
  31         return 0;
  32     }
  33     if (EC_GROUP_get_asn1_flag(group)
  34         && (nid = EC_GROUP_get_curve_name(group)))
  35         /* we have a 'named curve' => just set the OID */
  36     {
  37         *ppval = OBJ_nid2obj(nid);
  38         *pptype = V_ASN1_OBJECT;
  39     } else {                    /* explicit parameters */
  40
  41         ASN1_STRING *pstr = NULL;
  42         pstr = ASN1_STRING_new();
  43         if (pstr == NULL)
  44             return 0;
  45         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  46         if (pstr->length <= 0) {
  47             ASN1_STRING_free(pstr);
  48             ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
  49             return 0;
  50         }
  51         *ppval = pstr;
  52         *pptype = V_ASN1_SEQUENCE;
  53     }
  54     return 1;
  55 }
  56
  57 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  58 {
  59     EC_KEY *ec_key = pkey->pkey.ec;
  60     void *pval = NULL;
  61     int ptype;
  62     unsigned char *penc = NULL, *p;
  63     int penclen;
  64
  65     if (!eckey_param2type(&ptype, &pval, ec_key)) {
  66         ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
  67         return 0;
  68     }
  69     penclen = i2o_ECPublicKey(ec_key, NULL);
  70     if (penclen <= 0)
  71         goto err;
  72     penc = OPENSSL_malloc(penclen);
  73     if (penc == NULL)
  74         goto err;
  75     p = penc;
  76     penclen = i2o_ECPublicKey(ec_key, &p);
  77     if (penclen <= 0)
  78         goto err;
  79     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
  80                                ptype, pval, penc, penclen))
  81         return 1;
  82  err:
  83     if (ptype == V_ASN1_OBJECT)
  84         ASN1_OBJECT_free(pval);
  85     else
  86         ASN1_STRING_free(pval);
  87     OPENSSL_free(penc);
  88     return 0;
  89 }
  90
  91 static EC_KEY *eckey_type2param(int ptype, void *pval)
  92 {
  93     EC_KEY *eckey = NULL;
  94     if (ptype == V_ASN1_SEQUENCE) {
  95         ASN1_STRING *pstr = pval;
  96         const unsigned char *pm = NULL;
  97         int pmlen;
  98         pm = pstr->data;
  99         pmlen = pstr->length;
 100         if ((eckey = d2i_ECParameters(NULL, &pm, pmlen)) == NULL) {
 101             ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 102             goto ecerr;
 103         }
 104     } else if (ptype == V_ASN1_OBJECT) {
 105         ASN1_OBJECT *poid = pval;
 106         EC_GROUP *group;
 107
 108         /*
 109          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 110          */
 111         if ((eckey = EC_KEY_new()) == NULL) {
 112             ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
 113             goto ecerr;
 114         }
 115         group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
 116         if (group == NULL)
 117             goto ecerr;
 118         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 119         if (EC_KEY_set_group(eckey, group) == 0)
 120             goto ecerr;
 121         EC_GROUP_free(group);
 122     } else {
 123         ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 124         goto ecerr;
 125     }
 126
 127     return eckey;
 128
 129  ecerr:
 130     EC_KEY_free(eckey);
 131     return NULL;
 132 }
 133
 134 static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
 135 {
 136     const unsigned char *p = NULL;
 137     void *pval;
 138     int ptype, pklen;
 139     EC_KEY *eckey = NULL;
 140     X509_ALGOR *palg;
 141
 142     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 143         return 0;
 144     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 145
 146     eckey = eckey_type2param(ptype, pval);
 147
 148     if (!eckey) {
 149         ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
 150         return 0;
 151     }
 152
 153     /* We have parameters now set public key */
 154     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 155         ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
 156         goto ecerr;
 157     }
 158
 159     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 160     return 1;
 161
 162  ecerr:
 163     EC_KEY_free(eckey);
 164     return 0;
 165 }
 166
 167 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 168 {
 169     int r;
 170     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 171     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 172         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 173     r = EC_POINT_cmp(group, pa, pb, NULL);
 174     if (r == 0)
 175         return 1;
 176     if (r == 1)
 177         return 0;
 178     return -2;
 179 }
 180
 181 static int eckey_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
 182 {
 183     const unsigned char *p = NULL;
 184     void *pval;
 185     int ptype, pklen;
 186     EC_KEY *eckey = NULL;
 187     X509_ALGOR *palg;
 188
 189     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 190         return 0;
 191     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 192
 193     eckey = eckey_type2param(ptype, pval);
 194
 195     if (!eckey)
 196         goto ecliberr;
 197
 198     /* We have parameters now set private key */
 199     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 200         ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
 201         goto ecerr;
 202     }
 203
 204     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 205     return 1;
 206
 207  ecliberr:
 208     ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
 209  ecerr:
 210     EC_KEY_free(eckey);
 211     return 0;
 212 }
 213
 214 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 215 {
 216     EC_KEY *ec_key;
 217     unsigned char *ep, *p;
 218     int eplen, ptype;
 219     void *pval;
 220     unsigned int tmp_flags, old_flags;
 221
 222     ec_key = pkey->pkey.ec;
 223
 224     if (!eckey_param2type(&ptype, &pval, ec_key)) {
 225         ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
 226         return 0;
 227     }
 228
 229     /* set the private key */
 230
 231     /*
 232      * do not include the parameters in the SEC1 private key see PKCS#11
 233      * 12.11
 234      */
 235     old_flags = EC_KEY_get_enc_flags(ec_key);
 236     tmp_flags = old_flags | EC_PKEY_NO_PARAMETERS;
 237     EC_KEY_set_enc_flags(ec_key, tmp_flags);
 238     eplen = i2d_ECPrivateKey(ec_key, NULL);
 239     if (!eplen) {
 240         EC_KEY_set_enc_flags(ec_key, old_flags);
 241         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 242         return 0;
 243     }
 244     ep = OPENSSL_malloc(eplen);
 245     if (ep == NULL) {
 246         EC_KEY_set_enc_flags(ec_key, old_flags);
 247         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 248         return 0;
 249     }
 250     p = ep;
 251     if (!i2d_ECPrivateKey(ec_key, &p)) {
 252         EC_KEY_set_enc_flags(ec_key, old_flags);
 253         OPENSSL_free(ep);
 254         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 255         return 0;
 256     }
 257     /* restore old encoding flags */
 258     EC_KEY_set_enc_flags(ec_key, old_flags);
 259
 260     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 261                          ptype, pval, ep, eplen))
 262         return 0;
 263
 264     return 1;
 265 }
 266
 267 static int int_ec_size(const EVP_PKEY *pkey)
 268 {
 269     return ECDSA_size(pkey->pkey.ec);
 270 }
 271
 272 static int ec_bits(const EVP_PKEY *pkey)
 273 {
 274     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 275 }
 276
 277 static int ec_security_bits(const EVP_PKEY *pkey)
 278 {
 279     int ecbits = ec_bits(pkey);
 280     if (ecbits >= 512)
 281         return 256;
 282     if (ecbits >= 384)
 283         return 192;
 284     if (ecbits >= 256)
 285         return 128;
 286     if (ecbits >= 224)
 287         return 112;
 288     if (ecbits >= 160)
 289         return 80;
 290     return ecbits / 2;
 291 }
 292
 293 static int ec_missing_parameters(const EVP_PKEY *pkey)
 294 {
 295     if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 296         return 1;
 297     return 0;
 298 }
 299
 300 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 301 {
 302     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 303     if (group == NULL)
 304         return 0;
 305     if (to->pkey.ec == NULL) {
 306         to->pkey.ec = EC_KEY_new();
 307         if (to->pkey.ec == NULL)
 308             return 0;
 309     }
 310     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 311         return 0;
 312     EC_GROUP_free(group);
 313     return 1;
 314 }
 315
 316 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 317 {
 318     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 319         *group_b = EC_KEY_get0_group(b->pkey.ec);
 320     if (EC_GROUP_cmp(group_a, group_b, NULL))
 321         return 0;
 322     else
 323         return 1;
 324 }
 325
 326 static void int_ec_free(EVP_PKEY *pkey)
 327 {
 328     EC_KEY_free(pkey->pkey.ec);
 329 }
 330
 331 typedef enum {
 332     EC_KEY_PRINT_PRIVATE,
 333     EC_KEY_PRINT_PUBLIC,
 334     EC_KEY_PRINT_PARAM
 335 } ec_print_t;
 336
 337 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 338 {
 339     const char *ecstr;
 340     unsigned char *priv = NULL, *pub = NULL;
 341     size_t privlen = 0, publen = 0;
 342     int ret = 0;
 343     const EC_GROUP *group;
 344
 345     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 346         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
 347         return 0;
 348     }
 349
 350     if (ktype != EC_KEY_PRINT_PARAM) {
 351         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 352         if (publen == 0)
 353             goto err;
 354     }
 355
 356     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 357         privlen = EC_KEY_priv2buf(x, &priv);
 358         if (privlen == 0)
 359             goto err;
 360     }
 361
 362     if (ktype == EC_KEY_PRINT_PRIVATE)
 363         ecstr = "Private-Key";
 364     else if (ktype == EC_KEY_PRINT_PUBLIC)
 365         ecstr = "Public-Key";
 366     else
 367         ecstr = "ECDSA-Parameters";
 368
 369     if (!BIO_indent(bp, off, 128))
 370         goto err;
 371     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 372                    EC_GROUP_order_bits(group)) <= 0)
 373         goto err;
 374
 375     if (privlen != 0) {
 376         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 377             goto err;
 378         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 379             goto err;
 380     }
 381
 382     if (publen != 0) {
 383         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 384             goto err;
 385         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 386             goto err;
 387     }
 388
 389     if (!ECPKParameters_print(bp, group, off))
 390         goto err;
 391     ret = 1;
 392  err:
 393     if (!ret)
 394         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
 395     OPENSSL_clear_free(priv, privlen);
 396     OPENSSL_free(pub);
 397     return ret;
 398 }
 399
 400 static int eckey_param_decode(EVP_PKEY *pkey,
 401                               const unsigned char **pder, int derlen)
 402 {
 403     EC_KEY *eckey;
 404
 405     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
 406         ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
 407         return 0;
 408     }
 409     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 410     return 1;
 411 }
 412
 413 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 414 {
 415     return i2d_ECParameters(pkey->pkey.ec, pder);
 416 }
 417
 418 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 419                              ASN1_PCTX *ctx)
 420 {
 421     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 422 }
 423
 424 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 425                            ASN1_PCTX *ctx)
 426 {
 427     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 428 }
 429
 430 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 431                             ASN1_PCTX *ctx)
 432 {
 433     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 434 }
 435
 436 static int old_ec_priv_decode(EVP_PKEY *pkey,
 437                               const unsigned char **pder, int derlen)
 438 {
 439     EC_KEY *ec;
 440
 441     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
 442         ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
 443         return 0;
 444     }
 445     EVP_PKEY_assign_EC_KEY(pkey, ec);
 446     return 1;
 447 }
 448
 449 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 450 {
 451     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 452 }
 453
 454 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 455 {
 456     switch (op) {
 457     case ASN1_PKEY_CTRL_PKCS7_SIGN:
 458         if (arg1 == 0) {
 459             int snid, hnid;
 460             X509_ALGOR *alg1, *alg2;
 461             PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
 462             if (alg1 == NULL || alg1->algorithm == NULL)
 463                 return -1;
 464             hnid = OBJ_obj2nid(alg1->algorithm);
 465             if (hnid == NID_undef)
 466                 return -1;
 467             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 468                 return -1;
 469             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 470         }
 471         return 1;
 472 #ifndef OPENSSL_NO_CMS
 473     case ASN1_PKEY_CTRL_CMS_SIGN:
 474         if (arg1 == 0) {
 475             int snid, hnid;
 476             X509_ALGOR *alg1, *alg2;
 477             CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
 478             if (alg1 == NULL || alg1->algorithm == NULL)
 479                 return -1;
 480             hnid = OBJ_obj2nid(alg1->algorithm);
 481             if (hnid == NID_undef)
 482                 return -1;
 483             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 484                 return -1;
 485             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 486         }
 487         return 1;
 488
 489     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 490         if (arg1 == 1)
 491             return ecdh_cms_decrypt(arg2);
 492         else if (arg1 == 0)
 493             return ecdh_cms_encrypt(arg2);
 494         return -2;
 495
 496     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 497         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 498         return 1;
 499 #endif
 500
 501     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 502         *(int *)arg2 = NID_sha256;
 503         return 2;
 504
 505     default:
 506         return -2;
 507
 508     }
 509
 510 }
 511
 512 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 513     EVP_PKEY_EC,
 514     EVP_PKEY_EC,
 515     0,
 516     "EC",
 517     "OpenSSL EC algorithm",
 518
 519     eckey_pub_decode,
 520     eckey_pub_encode,
 521     eckey_pub_cmp,
 522     eckey_pub_print,
 523
 524     eckey_priv_decode,
 525     eckey_priv_encode,
 526     eckey_priv_print,
 527
 528     int_ec_size,
 529     ec_bits,
 530     ec_security_bits,
 531
 532     eckey_param_decode,
 533     eckey_param_encode,
 534     ec_missing_parameters,
 535     ec_copy_parameters,
 536     ec_cmp_parameters,
 537     eckey_param_print,
 538     0,
 539
 540     int_ec_free,
 541     ec_pkey_ctrl,
 542     old_ec_priv_decode,
 543     old_ec_priv_encode
 544 };
 545
 546 #ifndef OPENSSL_NO_CMS
 547
 548 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 549                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 550 {
 551     ASN1_OBJECT *aoid;
 552     int atype;
 553     void *aval;
 554     int rv = 0;
 555     EVP_PKEY *pkpeer = NULL;
 556     EC_KEY *ecpeer = NULL;
 557     const unsigned char *p;
 558     int plen;
 559     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 560     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
 561         goto err;
 562     /* If absent parameters get group from main key */
 563     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
 564         const EC_GROUP *grp;
 565         EVP_PKEY *pk;
 566         pk = EVP_PKEY_CTX_get0_pkey(pctx);
 567         if (!pk)
 568             goto err;
 569         grp = EC_KEY_get0_group(pk->pkey.ec);
 570         ecpeer = EC_KEY_new();
 571         if (ecpeer == NULL)
 572             goto err;
 573         if (!EC_KEY_set_group(ecpeer, grp))
 574             goto err;
 575     } else {
 576         ecpeer = eckey_type2param(atype, aval);
 577         if (!ecpeer)
 578             goto err;
 579     }
 580     /* We have parameters now set public key */
 581     plen = ASN1_STRING_length(pubkey);
 582     p = ASN1_STRING_data(pubkey);
 583     if (!p || !plen)
 584         goto err;
 585     if (!o2i_ECPublicKey(&ecpeer, &p, plen))
 586         goto err;
 587     pkpeer = EVP_PKEY_new();
 588     if (pkpeer == NULL)
 589         goto err;
 590     EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
 591     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 592         rv = 1;
 593  err:
 594     EC_KEY_free(ecpeer);
 595     EVP_PKEY_free(pkpeer);
 596     return rv;
 597 }
 598
 599 /* Set KDF parameters based on KDF NID */
 600 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 601 {
 602     int kdf_nid, kdfmd_nid, cofactor;
 603     const EVP_MD *kdf_md;
 604     if (eckdf_nid == NID_undef)
 605         return 0;
 606
 607     /* Lookup KDF type, cofactor mode and digest */
 608     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 609         return 0;
 610
 611     if (kdf_nid == NID_dh_std_kdf)
 612         cofactor = 0;
 613     else if (kdf_nid == NID_dh_cofactor_kdf)
 614         cofactor = 1;
 615     else
 616         return 0;
 617
 618     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 619         return 0;
 620
 621     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_62) <= 0)
 622         return 0;
 623
 624     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 625     if (!kdf_md)
 626         return 0;
 627
 628     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 629         return 0;
 630     return 1;
 631 }
 632
 633 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 634 {
 635     int rv = 0;
 636
 637     X509_ALGOR *alg, *kekalg = NULL;
 638     ASN1_OCTET_STRING *ukm;
 639     const unsigned char *p;
 640     unsigned char *der = NULL;
 641     int plen, keylen;
 642     const EVP_CIPHER *kekcipher;
 643     EVP_CIPHER_CTX *kekctx;
 644
 645     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 646         return 0;
 647
 648     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 649         ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
 650         return 0;
 651     }
 652
 653     if (alg->parameter->type != V_ASN1_SEQUENCE)
 654         return 0;
 655
 656     p = alg->parameter->value.sequence->data;
 657     plen = alg->parameter->value.sequence->length;
 658     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 659     if (!kekalg)
 660         goto err;
 661     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 662     if (!kekctx)
 663         goto err;
 664     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 665     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 666         goto err;
 667     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 668         goto err;
 669     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 670         goto err;
 671
 672     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 673     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 674         goto err;
 675
 676     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
 677
 678     if (!plen)
 679         goto err;
 680
 681     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
 682         goto err;
 683     der = NULL;
 684
 685     rv = 1;
 686  err:
 687     X509_ALGOR_free(kekalg);
 688     OPENSSL_free(der);
 689     return rv;
 690 }
 691
 692 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
 693 {
 694     EVP_PKEY_CTX *pctx;
 695     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 696     if (!pctx)
 697         return 0;
 698     /* See if we need to set peer key */
 699     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 700         X509_ALGOR *alg;
 701         ASN1_BIT_STRING *pubkey;
 702         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 703                                                  NULL, NULL, NULL))
 704             return 0;
 705         if (!alg || !pubkey)
 706             return 0;
 707         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
 708             ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
 709             return 0;
 710         }
 711     }
 712     /* Set ECDH derivation parameters and initialise unwrap context */
 713     if (!ecdh_cms_set_shared_info(pctx, ri)) {
 714         ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
 715         return 0;
 716     }
 717     return 1;
 718 }
 719
 720 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
 721 {
 722     EVP_PKEY_CTX *pctx;
 723     EVP_PKEY *pkey;
 724     EVP_CIPHER_CTX *ctx;
 725     int keylen;
 726     X509_ALGOR *talg, *wrap_alg = NULL;
 727     ASN1_OBJECT *aoid;
 728     ASN1_BIT_STRING *pubkey;
 729     ASN1_STRING *wrap_str;
 730     ASN1_OCTET_STRING *ukm;
 731     unsigned char *penc = NULL;
 732     int penclen;
 733     int rv = 0;
 734     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
 735     const EVP_MD *kdf_md;
 736     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 737     if (!pctx)
 738         return 0;
 739     /* Get ephemeral key */
 740     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 741     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 742                                              NULL, NULL, NULL))
 743         goto err;
 744     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 745     /* Is everything uninitialised? */
 746     if (aoid == OBJ_nid2obj(NID_undef)) {
 747
 748         EC_KEY *eckey = pkey->pkey.ec;
 749         /* Set the key */
 750         unsigned char *p;
 751
 752         penclen = i2o_ECPublicKey(eckey, NULL);
 753         if (penclen <= 0)
 754             goto err;
 755         penc = OPENSSL_malloc(penclen);
 756         if (penc == NULL)
 757             goto err;
 758         p = penc;
 759         penclen = i2o_ECPublicKey(eckey, &p);
 760         if (penclen <= 0)
 761             goto err;
 762         ASN1_STRING_set0(pubkey, penc, penclen);
 763         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 764         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 765
 766         penc = NULL;
 767         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
 768                         V_ASN1_UNDEF, NULL);
 769     }
 770
 771     /* See if custom parameters set */
 772     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
 773     if (kdf_type <= 0)
 774         goto err;
 775     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
 776         goto err;
 777     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
 778     if (ecdh_nid < 0)
 779         goto err;
 780     else if (ecdh_nid == 0)
 781         ecdh_nid = NID_dh_std_kdf;
 782     else if (ecdh_nid == 1)
 783         ecdh_nid = NID_dh_cofactor_kdf;
 784
 785     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
 786         kdf_type = EVP_PKEY_ECDH_KDF_X9_62;
 787         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
 788             goto err;
 789     } else
 790         /* Unknown KDF */
 791         goto err;
 792     if (kdf_md == NULL) {
 793         /* Fixme later for better MD */
 794         kdf_md = EVP_sha1();
 795         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 796             goto err;
 797     }
 798
 799     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 800         goto err;
 801
 802     /* Lookup NID for KDF+cofactor+digest */
 803
 804     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
 805         goto err;
 806     /* Get wrap NID */
 807     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 808     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 809     keylen = EVP_CIPHER_CTX_key_length(ctx);
 810
 811     /* Package wrap algorithm in an AlgorithmIdentifier */
 812
 813     wrap_alg = X509_ALGOR_new();
 814     if (wrap_alg == NULL)
 815         goto err;
 816     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 817     wrap_alg->parameter = ASN1_TYPE_new();
 818     if (wrap_alg->parameter == NULL)
 819         goto err;
 820     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 821         goto err;
 822     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 823         ASN1_TYPE_free(wrap_alg->parameter);
 824         wrap_alg->parameter = NULL;
 825     }
 826
 827     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 828         goto err;
 829
 830     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
 831
 832     if (!penclen)
 833         goto err;
 834
 835     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
 836         goto err;
 837     penc = NULL;
 838
 839     /*
 840      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 841      * of another AlgorithmIdentifier.
 842      */
 843     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 844     if (!penc || !penclen)
 845         goto err;
 846     wrap_str = ASN1_STRING_new();
 847     if (wrap_str == NULL)
 848         goto err;
 849     ASN1_STRING_set0(wrap_str, penc, penclen);
 850     penc = NULL;
 851     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
 852
 853     rv = 1;
 854
 855  err:
 856     OPENSSL_free(penc);
 857     X509_ALGOR_free(wrap_alg);
 858     return rv;
 859 }
 860
 861 #endif