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 #include "ec_lcl.h"
  20
  21 #ifndef OPENSSL_NO_CMS
  22 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  23 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  24 #endif
  25
  26 static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
  27 {
  28     const EC_GROUP *group;
  29     int nid;
  30     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  31         ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
  32         return 0;
  33     }
  34     if (EC_GROUP_get_asn1_flag(group)
  35         && (nid = EC_GROUP_get_curve_name(group)))
  36         /* we have a 'named curve' => just set the OID */
  37     {
  38         *ppval = OBJ_nid2obj(nid);
  39         *pptype = V_ASN1_OBJECT;
  40     } else {                    /* explicit parameters */
  41
  42         ASN1_STRING *pstr = NULL;
  43         pstr = ASN1_STRING_new();
  44         if (pstr == NULL)
  45             return 0;
  46         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  47         if (pstr->length <= 0) {
  48             ASN1_STRING_free(pstr);
  49             ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
  50             return 0;
  51         }
  52         *ppval = pstr;
  53         *pptype = V_ASN1_SEQUENCE;
  54     }
  55     return 1;
  56 }
  57
  58 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  59 {
  60     EC_KEY *ec_key = pkey->pkey.ec;
  61     void *pval = NULL;
  62     int ptype;
  63     unsigned char *penc = NULL, *p;
  64     int penclen;
  65
  66     if (!eckey_param2type(&ptype, &pval, ec_key)) {
  67         ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
  68         return 0;
  69     }
  70     penclen = i2o_ECPublicKey(ec_key, NULL);
  71     if (penclen <= 0)
  72         goto err;
  73     penc = OPENSSL_malloc(penclen);
  74     if (penc == NULL)
  75         goto err;
  76     p = penc;
  77     penclen = i2o_ECPublicKey(ec_key, &p);
  78     if (penclen <= 0)
  79         goto err;
  80     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
  81                                ptype, pval, penc, penclen))
  82         return 1;
  83  err:
  84     if (ptype == V_ASN1_OBJECT)
  85         ASN1_OBJECT_free(pval);
  86     else
  87         ASN1_STRING_free(pval);
  88     OPENSSL_free(penc);
  89     return 0;
  90 }
  91
  92 static EC_KEY *eckey_type2param(int ptype, const void *pval)
  93 {
  94     EC_KEY *eckey = NULL;
  95     if (ptype == V_ASN1_SEQUENCE) {
  96         const ASN1_STRING *pstr = pval;
  97         const unsigned char *pm = NULL;
  98         int pmlen;
  99         pm = pstr->data;
 100         pmlen = pstr->length;
 101         if ((eckey = d2i_ECParameters(NULL, &pm, pmlen)) == NULL) {
 102             ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 103             goto ecerr;
 104         }
 105     } else if (ptype == V_ASN1_OBJECT) {
 106         const ASN1_OBJECT *poid = pval;
 107         EC_GROUP *group;
 108
 109         /*
 110          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 111          */
 112         if ((eckey = EC_KEY_new()) == NULL) {
 113             ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
 114             goto ecerr;
 115         }
 116         group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
 117         if (group == NULL)
 118             goto ecerr;
 119         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 120         if (EC_KEY_set_group(eckey, group) == 0)
 121             goto ecerr;
 122         EC_GROUP_free(group);
 123     } else {
 124         ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 125         goto ecerr;
 126     }
 127
 128     return eckey;
 129
 130  ecerr:
 131     EC_KEY_free(eckey);
 132     return NULL;
 133 }
 134
 135 static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
 136 {
 137     const unsigned char *p = NULL;
 138     const void *pval;
 139     int ptype, pklen;
 140     EC_KEY *eckey = NULL;
 141     X509_ALGOR *palg;
 142
 143     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 144         return 0;
 145     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 146
 147     eckey = eckey_type2param(ptype, pval);
 148
 149     if (!eckey) {
 150         ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
 151         return 0;
 152     }
 153
 154     /* We have parameters now set public key */
 155     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 156         ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
 157         goto ecerr;
 158     }
 159
 160     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 161     return 1;
 162
 163  ecerr:
 164     EC_KEY_free(eckey);
 165     return 0;
 166 }
 167
 168 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 169 {
 170     int r;
 171     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 172     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 173         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 174     if (group == NULL || pa == NULL || pb == NULL)
 175         return -2;
 176     r = EC_POINT_cmp(group, pa, pb, NULL);
 177     if (r == 0)
 178         return 1;
 179     if (r == 1)
 180         return 0;
 181     return -2;
 182 }
 183
 184 static int eckey_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 185 {
 186     const unsigned char *p = NULL;
 187     const void *pval;
 188     int ptype, pklen;
 189     EC_KEY *eckey = NULL;
 190     const X509_ALGOR *palg;
 191
 192     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 193         return 0;
 194     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 195
 196     eckey = eckey_type2param(ptype, pval);
 197
 198     if (!eckey)
 199         goto ecliberr;
 200
 201     /* We have parameters now set private key */
 202     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 203         ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
 204         goto ecerr;
 205     }
 206
 207     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 208     return 1;
 209
 210  ecliberr:
 211     ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
 212  ecerr:
 213     EC_KEY_free(eckey);
 214     return 0;
 215 }
 216
 217 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 218 {
 219     EC_KEY ec_key = *(pkey->pkey.ec);
 220     unsigned char *ep, *p;
 221     int eplen, ptype;
 222     void *pval;
 223     unsigned int old_flags;
 224
 225     if (!eckey_param2type(&ptype, &pval, &ec_key)) {
 226         ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
 227         return 0;
 228     }
 229
 230     /* set the private key */
 231
 232     /*
 233      * do not include the parameters in the SEC1 private key see PKCS#11
 234      * 12.11
 235      */
 236     old_flags = EC_KEY_get_enc_flags(&ec_key);
 237     EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS);
 238
 239     eplen = i2d_ECPrivateKey(&ec_key, NULL);
 240     if (!eplen) {
 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         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 247         return 0;
 248     }
 249     p = ep;
 250     if (!i2d_ECPrivateKey(&ec_key, &p)) {
 251         OPENSSL_free(ep);
 252         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 253         return 0;
 254     }
 255
 256     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 257                          ptype, pval, ep, eplen)) {
 258         OPENSSL_free(ep);
 259         return 0;
 260     }
 261
 262     return 1;
 263 }
 264
 265 static int int_ec_size(const EVP_PKEY *pkey)
 266 {
 267     return ECDSA_size(pkey->pkey.ec);
 268 }
 269
 270 static int ec_bits(const EVP_PKEY *pkey)
 271 {
 272     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 273 }
 274
 275 static int ec_security_bits(const EVP_PKEY *pkey)
 276 {
 277     int ecbits = ec_bits(pkey);
 278     if (ecbits >= 512)
 279         return 256;
 280     if (ecbits >= 384)
 281         return 192;
 282     if (ecbits >= 256)
 283         return 128;
 284     if (ecbits >= 224)
 285         return 112;
 286     if (ecbits >= 160)
 287         return 80;
 288     return ecbits / 2;
 289 }
 290
 291 static int ec_missing_parameters(const EVP_PKEY *pkey)
 292 {
 293     if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 294         return 1;
 295     return 0;
 296 }
 297
 298 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 299 {
 300     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 301
 302     if (group == NULL)
 303         return 0;
 304     if (to->pkey.ec == NULL) {
 305         to->pkey.ec = EC_KEY_new();
 306         if (to->pkey.ec == NULL)
 307             goto err;
 308     }
 309     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 310         goto err;
 311     EC_GROUP_free(group);
 312     return 1;
 313  err:
 314     EC_GROUP_free(group);
 315     return 0;
 316 }
 317
 318 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 319 {
 320     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 321         *group_b = EC_KEY_get0_group(b->pkey.ec);
 322     if (group_a == NULL || group_b == NULL)
 323         return -2;
 324     if (EC_GROUP_cmp(group_a, group_b, NULL))
 325         return 0;
 326     else
 327         return 1;
 328 }
 329
 330 static void int_ec_free(EVP_PKEY *pkey)
 331 {
 332     EC_KEY_free(pkey->pkey.ec);
 333 }
 334
 335 typedef enum {
 336     EC_KEY_PRINT_PRIVATE,
 337     EC_KEY_PRINT_PUBLIC,
 338     EC_KEY_PRINT_PARAM
 339 } ec_print_t;
 340
 341 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 342 {
 343     const char *ecstr;
 344     unsigned char *priv = NULL, *pub = NULL;
 345     size_t privlen = 0, publen = 0;
 346     int ret = 0;
 347     const EC_GROUP *group;
 348
 349     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 350         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
 351         return 0;
 352     }
 353
 354     if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) {
 355         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 356         if (publen == 0)
 357             goto err;
 358     }
 359
 360     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 361         privlen = EC_KEY_priv2buf(x, &priv);
 362         if (privlen == 0)
 363             goto err;
 364     }
 365
 366     if (ktype == EC_KEY_PRINT_PRIVATE)
 367         ecstr = "Private-Key";
 368     else if (ktype == EC_KEY_PRINT_PUBLIC)
 369         ecstr = "Public-Key";
 370     else
 371         ecstr = "ECDSA-Parameters";
 372
 373     if (!BIO_indent(bp, off, 128))
 374         goto err;
 375     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 376                    EC_GROUP_order_bits(group)) <= 0)
 377         goto err;
 378
 379     if (privlen != 0) {
 380         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 381             goto err;
 382         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 383             goto err;
 384     }
 385
 386     if (publen != 0) {
 387         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 388             goto err;
 389         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 390             goto err;
 391     }
 392
 393     if (!ECPKParameters_print(bp, group, off))
 394         goto err;
 395     ret = 1;
 396  err:
 397     if (!ret)
 398         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
 399     OPENSSL_clear_free(priv, privlen);
 400     OPENSSL_free(pub);
 401     return ret;
 402 }
 403
 404 static int eckey_param_decode(EVP_PKEY *pkey,
 405                               const unsigned char **pder, int derlen)
 406 {
 407     EC_KEY *eckey;
 408
 409     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
 410         ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
 411         return 0;
 412     }
 413     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 414     return 1;
 415 }
 416
 417 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 418 {
 419     return i2d_ECParameters(pkey->pkey.ec, pder);
 420 }
 421
 422 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 423                              ASN1_PCTX *ctx)
 424 {
 425     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 426 }
 427
 428 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 429                            ASN1_PCTX *ctx)
 430 {
 431     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 432 }
 433
 434 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 435                             ASN1_PCTX *ctx)
 436 {
 437     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 438 }
 439
 440 static int old_ec_priv_decode(EVP_PKEY *pkey,
 441                               const unsigned char **pder, int derlen)
 442 {
 443     EC_KEY *ec;
 444
 445     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
 446         ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
 447         return 0;
 448     }
 449     EVP_PKEY_assign_EC_KEY(pkey, ec);
 450     return 1;
 451 }
 452
 453 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 454 {
 455     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 456 }
 457
 458 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 459 {
 460     switch (op) {
 461     case ASN1_PKEY_CTRL_PKCS7_SIGN:
 462         if (arg1 == 0) {
 463             int snid, hnid;
 464             X509_ALGOR *alg1, *alg2;
 465             PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
 466             if (alg1 == NULL || alg1->algorithm == NULL)
 467                 return -1;
 468             hnid = OBJ_obj2nid(alg1->algorithm);
 469             if (hnid == NID_undef)
 470                 return -1;
 471             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 472                 return -1;
 473             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 474         }
 475         return 1;
 476 #ifndef OPENSSL_NO_CMS
 477     case ASN1_PKEY_CTRL_CMS_SIGN:
 478         if (arg1 == 0) {
 479             int snid, hnid;
 480             X509_ALGOR *alg1, *alg2;
 481             CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
 482             if (alg1 == NULL || alg1->algorithm == NULL)
 483                 return -1;
 484             hnid = OBJ_obj2nid(alg1->algorithm);
 485             if (hnid == NID_undef)
 486                 return -1;
 487             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 488                 return -1;
 489             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 490         }
 491         return 1;
 492
 493     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 494         if (arg1 == 1)
 495             return ecdh_cms_decrypt(arg2);
 496         else if (arg1 == 0)
 497             return ecdh_cms_encrypt(arg2);
 498         return -2;
 499
 500     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 501         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 502         return 1;
 503 #endif
 504
 505     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 506         *(int *)arg2 = NID_sha256;
 507         return 2;
 508
 509     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
 510         return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
 511
 512     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
 513         return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
 514                               POINT_CONVERSION_UNCOMPRESSED, arg2, NULL);
 515
 516     default:
 517         return -2;
 518
 519     }
 520
 521 }
 522
 523 static int ec_pkey_check(const EVP_PKEY *pkey)
 524 {
 525     EC_KEY *eckey = pkey->pkey.ec;
 526
 527     /* stay consistent to what EVP_PKEY_check demands */
 528     if (eckey->priv_key == NULL) {
 529         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_MISSING_PRIVATE_KEY);
 530         return 0;
 531     }
 532
 533     return EC_KEY_check_key(eckey);
 534 }
 535
 536 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 537     EVP_PKEY_EC,
 538     EVP_PKEY_EC,
 539     0,
 540     "EC",
 541     "OpenSSL EC algorithm",
 542
 543     eckey_pub_decode,
 544     eckey_pub_encode,
 545     eckey_pub_cmp,
 546     eckey_pub_print,
 547
 548     eckey_priv_decode,
 549     eckey_priv_encode,
 550     eckey_priv_print,
 551
 552     int_ec_size,
 553     ec_bits,
 554     ec_security_bits,
 555
 556     eckey_param_decode,
 557     eckey_param_encode,
 558     ec_missing_parameters,
 559     ec_copy_parameters,
 560     ec_cmp_parameters,
 561     eckey_param_print,
 562     0,
 563
 564     int_ec_free,
 565     ec_pkey_ctrl,
 566     old_ec_priv_decode,
 567     old_ec_priv_encode,
 568
 569     0, 0, 0,
 570
 571     ec_pkey_check
 572 };
 573
 574 int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
 575 {
 576     int private = EC_KEY_get0_private_key(x) != NULL;
 577
 578     return do_EC_KEY_print(bp, x, off,
 579                 private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC);
 580 }
 581
 582 int ECParameters_print(BIO *bp, const EC_KEY *x)
 583 {
 584     return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM);
 585 }
 586
 587 #ifndef OPENSSL_NO_CMS
 588
 589 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 590                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 591 {
 592     const ASN1_OBJECT *aoid;
 593     int atype;
 594     const void *aval;
 595     int rv = 0;
 596     EVP_PKEY *pkpeer = NULL;
 597     EC_KEY *ecpeer = NULL;
 598     const unsigned char *p;
 599     int plen;
 600     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 601     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
 602         goto err;
 603     /* If absent parameters get group from main key */
 604     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
 605         const EC_GROUP *grp;
 606         EVP_PKEY *pk;
 607         pk = EVP_PKEY_CTX_get0_pkey(pctx);
 608         if (!pk)
 609             goto err;
 610         grp = EC_KEY_get0_group(pk->pkey.ec);
 611         ecpeer = EC_KEY_new();
 612         if (ecpeer == NULL)
 613             goto err;
 614         if (!EC_KEY_set_group(ecpeer, grp))
 615             goto err;
 616     } else {
 617         ecpeer = eckey_type2param(atype, aval);
 618         if (!ecpeer)
 619             goto err;
 620     }
 621     /* We have parameters now set public key */
 622     plen = ASN1_STRING_length(pubkey);
 623     p = ASN1_STRING_get0_data(pubkey);
 624     if (!p || !plen)
 625         goto err;
 626     if (!o2i_ECPublicKey(&ecpeer, &p, plen))
 627         goto err;
 628     pkpeer = EVP_PKEY_new();
 629     if (pkpeer == NULL)
 630         goto err;
 631     EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
 632     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 633         rv = 1;
 634  err:
 635     EC_KEY_free(ecpeer);
 636     EVP_PKEY_free(pkpeer);
 637     return rv;
 638 }
 639
 640 /* Set KDF parameters based on KDF NID */
 641 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 642 {
 643     int kdf_nid, kdfmd_nid, cofactor;
 644     const EVP_MD *kdf_md;
 645     if (eckdf_nid == NID_undef)
 646         return 0;
 647
 648     /* Lookup KDF type, cofactor mode and digest */
 649     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 650         return 0;
 651
 652     if (kdf_nid == NID_dh_std_kdf)
 653         cofactor = 0;
 654     else if (kdf_nid == NID_dh_cofactor_kdf)
 655         cofactor = 1;
 656     else
 657         return 0;
 658
 659     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 660         return 0;
 661
 662     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_62) <= 0)
 663         return 0;
 664
 665     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 666     if (!kdf_md)
 667         return 0;
 668
 669     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 670         return 0;
 671     return 1;
 672 }
 673
 674 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 675 {
 676     int rv = 0;
 677
 678     X509_ALGOR *alg, *kekalg = NULL;
 679     ASN1_OCTET_STRING *ukm;
 680     const unsigned char *p;
 681     unsigned char *der = NULL;
 682     int plen, keylen;
 683     const EVP_CIPHER *kekcipher;
 684     EVP_CIPHER_CTX *kekctx;
 685
 686     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 687         return 0;
 688
 689     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 690         ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
 691         return 0;
 692     }
 693
 694     if (alg->parameter->type != V_ASN1_SEQUENCE)
 695         return 0;
 696
 697     p = alg->parameter->value.sequence->data;
 698     plen = alg->parameter->value.sequence->length;
 699     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 700     if (!kekalg)
 701         goto err;
 702     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 703     if (!kekctx)
 704         goto err;
 705     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 706     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 707         goto err;
 708     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 709         goto err;
 710     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 711         goto err;
 712
 713     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 714     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 715         goto err;
 716
 717     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
 718
 719     if (!plen)
 720         goto err;
 721
 722     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
 723         goto err;
 724     der = NULL;
 725
 726     rv = 1;
 727  err:
 728     X509_ALGOR_free(kekalg);
 729     OPENSSL_free(der);
 730     return rv;
 731 }
 732
 733 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
 734 {
 735     EVP_PKEY_CTX *pctx;
 736     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 737     if (!pctx)
 738         return 0;
 739     /* See if we need to set peer key */
 740     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 741         X509_ALGOR *alg;
 742         ASN1_BIT_STRING *pubkey;
 743         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 744                                                  NULL, NULL, NULL))
 745             return 0;
 746         if (!alg || !pubkey)
 747             return 0;
 748         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
 749             ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
 750             return 0;
 751         }
 752     }
 753     /* Set ECDH derivation parameters and initialise unwrap context */
 754     if (!ecdh_cms_set_shared_info(pctx, ri)) {
 755         ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
 756         return 0;
 757     }
 758     return 1;
 759 }
 760
 761 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
 762 {
 763     EVP_PKEY_CTX *pctx;
 764     EVP_PKEY *pkey;
 765     EVP_CIPHER_CTX *ctx;
 766     int keylen;
 767     X509_ALGOR *talg, *wrap_alg = NULL;
 768     const ASN1_OBJECT *aoid;
 769     ASN1_BIT_STRING *pubkey;
 770     ASN1_STRING *wrap_str;
 771     ASN1_OCTET_STRING *ukm;
 772     unsigned char *penc = NULL;
 773     int penclen;
 774     int rv = 0;
 775     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
 776     const EVP_MD *kdf_md;
 777     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 778     if (!pctx)
 779         return 0;
 780     /* Get ephemeral key */
 781     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 782     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 783                                              NULL, NULL, NULL))
 784         goto err;
 785     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 786     /* Is everything uninitialised? */
 787     if (aoid == OBJ_nid2obj(NID_undef)) {
 788
 789         EC_KEY *eckey = pkey->pkey.ec;
 790         /* Set the key */
 791         unsigned char *p;
 792
 793         penclen = i2o_ECPublicKey(eckey, NULL);
 794         if (penclen <= 0)
 795             goto err;
 796         penc = OPENSSL_malloc(penclen);
 797         if (penc == NULL)
 798             goto err;
 799         p = penc;
 800         penclen = i2o_ECPublicKey(eckey, &p);
 801         if (penclen <= 0)
 802             goto err;
 803         ASN1_STRING_set0(pubkey, penc, penclen);
 804         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 805         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 806
 807         penc = NULL;
 808         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
 809                         V_ASN1_UNDEF, NULL);
 810     }
 811
 812     /* See if custom parameters set */
 813     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
 814     if (kdf_type <= 0)
 815         goto err;
 816     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
 817         goto err;
 818     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
 819     if (ecdh_nid < 0)
 820         goto err;
 821     else if (ecdh_nid == 0)
 822         ecdh_nid = NID_dh_std_kdf;
 823     else if (ecdh_nid == 1)
 824         ecdh_nid = NID_dh_cofactor_kdf;
 825
 826     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
 827         kdf_type = EVP_PKEY_ECDH_KDF_X9_62;
 828         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
 829             goto err;
 830     } else
 831         /* Unknown KDF */
 832         goto err;
 833     if (kdf_md == NULL) {
 834         /* Fixme later for better MD */
 835         kdf_md = EVP_sha1();
 836         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 837             goto err;
 838     }
 839
 840     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 841         goto err;
 842
 843     /* Lookup NID for KDF+cofactor+digest */
 844
 845     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
 846         goto err;
 847     /* Get wrap NID */
 848     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 849     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 850     keylen = EVP_CIPHER_CTX_key_length(ctx);
 851
 852     /* Package wrap algorithm in an AlgorithmIdentifier */
 853
 854     wrap_alg = X509_ALGOR_new();
 855     if (wrap_alg == NULL)
 856         goto err;
 857     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 858     wrap_alg->parameter = ASN1_TYPE_new();
 859     if (wrap_alg->parameter == NULL)
 860         goto err;
 861     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 862         goto err;
 863     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 864         ASN1_TYPE_free(wrap_alg->parameter);
 865         wrap_alg->parameter = NULL;
 866     }
 867
 868     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 869         goto err;
 870
 871     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
 872
 873     if (!penclen)
 874         goto err;
 875
 876     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
 877         goto err;
 878     penc = NULL;
 879
 880     /*
 881      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 882      * of another AlgorithmIdentifier.
 883      */
 884     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 885     if (!penc || !penclen)
 886         goto err;
 887     wrap_str = ASN1_STRING_new();
 888     if (wrap_str == NULL)
 889         goto err;
 890     ASN1_STRING_set0(wrap_str, penc, penclen);
 891     penc = NULL;
 892     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
 893
 894     rv = 1;
 895
 896  err:
 897     OPENSSL_free(penc);
 898     X509_ALGOR_free(wrap_alg);
 899     return rv;
 900 }
 901
 902 #endif