crypto/ec/ec_ameth.c

   1 /*
   2  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   3  * 2006.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59 #include <stdio.h>
  60 #include "internal/cryptlib.h"
  61 #include <openssl/x509.h>
  62 #include <openssl/ec.h>
  63 #include <openssl/bn.h>
  64 #ifndef OPENSSL_NO_CMS
  65 # include <openssl/cms.h>
  66 #endif
  67 #include <openssl/asn1t.h>
  68 #include "internal/asn1_int.h"
  69 #include "internal/evp_int.h"
  70
  71 #ifndef OPENSSL_NO_CMS
  72 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  73 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  74 #endif
  75
  76 static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
  77 {
  78     const EC_GROUP *group;
  79     int nid;
  80     if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
  81         ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
  82         return 0;
  83     }
  84     if (EC_GROUP_get_asn1_flag(group)
  85         && (nid = EC_GROUP_get_curve_name(group)))
  86         /* we have a 'named curve' => just set the OID */
  87     {
  88         *ppval = OBJ_nid2obj(nid);
  89         *pptype = V_ASN1_OBJECT;
  90     } else {                    /* explicit parameters */
  91
  92         ASN1_STRING *pstr = NULL;
  93         pstr = ASN1_STRING_new();
  94         if (pstr == NULL)
  95             return 0;
  96         pstr->length = i2d_ECParameters(ec_key, &pstr->data);
  97         if (pstr->length <= 0) {
  98             ASN1_STRING_free(pstr);
  99             ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
 100             return 0;
 101         }
 102         *ppval = pstr;
 103         *pptype = V_ASN1_SEQUENCE;
 104     }
 105     return 1;
 106 }
 107
 108 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
 109 {
 110     EC_KEY *ec_key = pkey->pkey.ec;
 111     void *pval = NULL;
 112     int ptype;
 113     unsigned char *penc = NULL, *p;
 114     int penclen;
 115
 116     if (!eckey_param2type(&ptype, &pval, ec_key)) {
 117         ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
 118         return 0;
 119     }
 120     penclen = i2o_ECPublicKey(ec_key, NULL);
 121     if (penclen <= 0)
 122         goto err;
 123     penc = OPENSSL_malloc(penclen);
 124     if (penc == NULL)
 125         goto err;
 126     p = penc;
 127     penclen = i2o_ECPublicKey(ec_key, &p);
 128     if (penclen <= 0)
 129         goto err;
 130     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
 131                                ptype, pval, penc, penclen))
 132         return 1;
 133  err:
 134     if (ptype == V_ASN1_OBJECT)
 135         ASN1_OBJECT_free(pval);
 136     else
 137         ASN1_STRING_free(pval);
 138     OPENSSL_free(penc);
 139     return 0;
 140 }
 141
 142 static EC_KEY *eckey_type2param(int ptype, void *pval)
 143 {
 144     EC_KEY *eckey = NULL;
 145     if (ptype == V_ASN1_SEQUENCE) {
 146         ASN1_STRING *pstr = pval;
 147         const unsigned char *pm = NULL;
 148         int pmlen;
 149         pm = pstr->data;
 150         pmlen = pstr->length;
 151         if ((eckey = d2i_ECParameters(NULL, &pm, pmlen)) == NULL) {
 152             ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 153             goto ecerr;
 154         }
 155     } else if (ptype == V_ASN1_OBJECT) {
 156         ASN1_OBJECT *poid = pval;
 157         EC_GROUP *group;
 158
 159         /*
 160          * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
 161          */
 162         if ((eckey = EC_KEY_new()) == NULL) {
 163             ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
 164             goto ecerr;
 165         }
 166         group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
 167         if (group == NULL)
 168             goto ecerr;
 169         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
 170         if (EC_KEY_set_group(eckey, group) == 0)
 171             goto ecerr;
 172         EC_GROUP_free(group);
 173     } else {
 174         ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
 175         goto ecerr;
 176     }
 177
 178     return eckey;
 179
 180  ecerr:
 181     EC_KEY_free(eckey);
 182     return NULL;
 183 }
 184
 185 static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
 186 {
 187     const unsigned char *p = NULL;
 188     void *pval;
 189     int ptype, pklen;
 190     EC_KEY *eckey = NULL;
 191     X509_ALGOR *palg;
 192
 193     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
 194         return 0;
 195     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 196
 197     eckey = eckey_type2param(ptype, pval);
 198
 199     if (!eckey) {
 200         ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
 201         return 0;
 202     }
 203
 204     /* We have parameters now set public key */
 205     if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
 206         ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
 207         goto ecerr;
 208     }
 209
 210     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 211     return 1;
 212
 213  ecerr:
 214     EC_KEY_free(eckey);
 215     return 0;
 216 }
 217
 218 static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 219 {
 220     int r;
 221     const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
 222     const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
 223         *pb = EC_KEY_get0_public_key(b->pkey.ec);
 224     r = EC_POINT_cmp(group, pa, pb, NULL);
 225     if (r == 0)
 226         return 1;
 227     if (r == 1)
 228         return 0;
 229     return -2;
 230 }
 231
 232 static int eckey_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
 233 {
 234     const unsigned char *p = NULL;
 235     void *pval;
 236     int ptype, pklen;
 237     EC_KEY *eckey = NULL;
 238     X509_ALGOR *palg;
 239
 240     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 241         return 0;
 242     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 243
 244     eckey = eckey_type2param(ptype, pval);
 245
 246     if (!eckey)
 247         goto ecliberr;
 248
 249     /* We have parameters now set private key */
 250     if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
 251         ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
 252         goto ecerr;
 253     }
 254
 255     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 256     return 1;
 257
 258  ecliberr:
 259     ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
 260  ecerr:
 261     EC_KEY_free(eckey);
 262     return 0;
 263 }
 264
 265 static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 266 {
 267     EC_KEY *ec_key;
 268     unsigned char *ep, *p;
 269     int eplen, ptype;
 270     void *pval;
 271     unsigned int tmp_flags, old_flags;
 272
 273     ec_key = pkey->pkey.ec;
 274
 275     if (!eckey_param2type(&ptype, &pval, ec_key)) {
 276         ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
 277         return 0;
 278     }
 279
 280     /* set the private key */
 281
 282     /*
 283      * do not include the parameters in the SEC1 private key see PKCS#11
 284      * 12.11
 285      */
 286     old_flags = EC_KEY_get_enc_flags(ec_key);
 287     tmp_flags = old_flags | EC_PKEY_NO_PARAMETERS;
 288     EC_KEY_set_enc_flags(ec_key, tmp_flags);
 289     eplen = i2d_ECPrivateKey(ec_key, NULL);
 290     if (!eplen) {
 291         EC_KEY_set_enc_flags(ec_key, old_flags);
 292         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 293         return 0;
 294     }
 295     ep = OPENSSL_malloc(eplen);
 296     if (ep == NULL) {
 297         EC_KEY_set_enc_flags(ec_key, old_flags);
 298         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 299         return 0;
 300     }
 301     p = ep;
 302     if (!i2d_ECPrivateKey(ec_key, &p)) {
 303         EC_KEY_set_enc_flags(ec_key, old_flags);
 304         OPENSSL_free(ep);
 305         ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
 306         return 0;
 307     }
 308     /* restore old encoding flags */
 309     EC_KEY_set_enc_flags(ec_key, old_flags);
 310
 311     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
 312                          ptype, pval, ep, eplen))
 313         return 0;
 314
 315     return 1;
 316 }
 317
 318 static int int_ec_size(const EVP_PKEY *pkey)
 319 {
 320     return ECDSA_size(pkey->pkey.ec);
 321 }
 322
 323 static int ec_bits(const EVP_PKEY *pkey)
 324 {
 325     return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
 326 }
 327
 328 static int ec_security_bits(const EVP_PKEY *pkey)
 329 {
 330     int ecbits = ec_bits(pkey);
 331     if (ecbits >= 512)
 332         return 256;
 333     if (ecbits >= 384)
 334         return 192;
 335     if (ecbits >= 256)
 336         return 128;
 337     if (ecbits >= 224)
 338         return 112;
 339     if (ecbits >= 160)
 340         return 80;
 341     return ecbits / 2;
 342 }
 343
 344 static int ec_missing_parameters(const EVP_PKEY *pkey)
 345 {
 346     if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
 347         return 1;
 348     return 0;
 349 }
 350
 351 static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 352 {
 353     EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
 354     if (group == NULL)
 355         return 0;
 356     if (to->pkey.ec == NULL) {
 357         to->pkey.ec = EC_KEY_new();
 358         if (to->pkey.ec == NULL)
 359             return 0;
 360     }
 361     if (EC_KEY_set_group(to->pkey.ec, group) == 0)
 362         return 0;
 363     EC_GROUP_free(group);
 364     return 1;
 365 }
 366
 367 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 368 {
 369     const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
 370         *group_b = EC_KEY_get0_group(b->pkey.ec);
 371     if (EC_GROUP_cmp(group_a, group_b, NULL))
 372         return 0;
 373     else
 374         return 1;
 375 }
 376
 377 static void int_ec_free(EVP_PKEY *pkey)
 378 {
 379     EC_KEY_free(pkey->pkey.ec);
 380 }
 381
 382 typedef enum {
 383     EC_KEY_PRINT_PRIVATE,
 384     EC_KEY_PRINT_PUBLIC,
 385     EC_KEY_PRINT_PARAM
 386 } ec_print_t;
 387
 388 static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
 389 {
 390     const char *ecstr;
 391     unsigned char *priv = NULL, *pub = NULL;
 392     size_t privlen = 0, publen = 0;
 393     int ret = 0;
 394     const EC_GROUP *group;
 395
 396     if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
 397         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
 398         return 0;
 399     }
 400
 401     if (ktype != EC_KEY_PRINT_PARAM) {
 402         publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
 403         if (publen == 0)
 404             goto err;
 405     }
 406
 407     if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
 408         privlen = EC_KEY_priv2buf(x, &priv);
 409         if (privlen == 0)
 410             goto err;
 411     }
 412
 413     if (ktype == EC_KEY_PRINT_PRIVATE)
 414         ecstr = "Private-Key";
 415     else if (ktype == EC_KEY_PRINT_PUBLIC)
 416         ecstr = "Public-Key";
 417     else
 418         ecstr = "ECDSA-Parameters";
 419
 420     if (!BIO_indent(bp, off, 128))
 421         goto err;
 422     if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
 423                    EC_GROUP_order_bits(group)) <= 0)
 424         goto err;
 425
 426     if (privlen != 0) {
 427         if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
 428             goto err;
 429         if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
 430             goto err;
 431     }
 432
 433     if (publen != 0) {
 434         if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
 435             goto err;
 436         if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
 437             goto err;
 438     }
 439
 440     if (!ECPKParameters_print(bp, group, off))
 441         goto err;
 442     ret = 1;
 443  err:
 444     if (!ret)
 445         ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
 446     OPENSSL_clear_free(priv, privlen);
 447     OPENSSL_free(pub);
 448     return ret;
 449 }
 450
 451 static int eckey_param_decode(EVP_PKEY *pkey,
 452                               const unsigned char **pder, int derlen)
 453 {
 454     EC_KEY *eckey;
 455
 456     if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
 457         ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
 458         return 0;
 459     }
 460     EVP_PKEY_assign_EC_KEY(pkey, eckey);
 461     return 1;
 462 }
 463
 464 static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 465 {
 466     return i2d_ECParameters(pkey->pkey.ec, pder);
 467 }
 468
 469 static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 470                              ASN1_PCTX *ctx)
 471 {
 472     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
 473 }
 474
 475 static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 476                            ASN1_PCTX *ctx)
 477 {
 478     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
 479 }
 480
 481 static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 482                             ASN1_PCTX *ctx)
 483 {
 484     return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
 485 }
 486
 487 static int old_ec_priv_decode(EVP_PKEY *pkey,
 488                               const unsigned char **pder, int derlen)
 489 {
 490     EC_KEY *ec;
 491
 492     if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
 493         ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
 494         return 0;
 495     }
 496     EVP_PKEY_assign_EC_KEY(pkey, ec);
 497     return 1;
 498 }
 499
 500 static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
 501 {
 502     return i2d_ECPrivateKey(pkey->pkey.ec, pder);
 503 }
 504
 505 static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 506 {
 507     switch (op) {
 508     case ASN1_PKEY_CTRL_PKCS7_SIGN:
 509         if (arg1 == 0) {
 510             int snid, hnid;
 511             X509_ALGOR *alg1, *alg2;
 512             PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
 513             if (alg1 == NULL || alg1->algorithm == NULL)
 514                 return -1;
 515             hnid = OBJ_obj2nid(alg1->algorithm);
 516             if (hnid == NID_undef)
 517                 return -1;
 518             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 519                 return -1;
 520             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 521         }
 522         return 1;
 523 #ifndef OPENSSL_NO_CMS
 524     case ASN1_PKEY_CTRL_CMS_SIGN:
 525         if (arg1 == 0) {
 526             int snid, hnid;
 527             X509_ALGOR *alg1, *alg2;
 528             CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
 529             if (alg1 == NULL || alg1->algorithm == NULL)
 530                 return -1;
 531             hnid = OBJ_obj2nid(alg1->algorithm);
 532             if (hnid == NID_undef)
 533                 return -1;
 534             if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 535                 return -1;
 536             X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 537         }
 538         return 1;
 539
 540     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 541         if (arg1 == 1)
 542             return ecdh_cms_decrypt(arg2);
 543         else if (arg1 == 0)
 544             return ecdh_cms_encrypt(arg2);
 545         return -2;
 546
 547     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 548         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 549         return 1;
 550 #endif
 551
 552     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
 553         *(int *)arg2 = NID_sha256;
 554         return 2;
 555
 556     default:
 557         return -2;
 558
 559     }
 560
 561 }
 562
 563 const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
 564     EVP_PKEY_EC,
 565     EVP_PKEY_EC,
 566     0,
 567     "EC",
 568     "OpenSSL EC algorithm",
 569
 570     eckey_pub_decode,
 571     eckey_pub_encode,
 572     eckey_pub_cmp,
 573     eckey_pub_print,
 574
 575     eckey_priv_decode,
 576     eckey_priv_encode,
 577     eckey_priv_print,
 578
 579     int_ec_size,
 580     ec_bits,
 581     ec_security_bits,
 582
 583     eckey_param_decode,
 584     eckey_param_encode,
 585     ec_missing_parameters,
 586     ec_copy_parameters,
 587     ec_cmp_parameters,
 588     eckey_param_print,
 589     0,
 590
 591     int_ec_free,
 592     ec_pkey_ctrl,
 593     old_ec_priv_decode,
 594     old_ec_priv_encode
 595 };
 596
 597 #ifndef OPENSSL_NO_CMS
 598
 599 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 600                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 601 {
 602     ASN1_OBJECT *aoid;
 603     int atype;
 604     void *aval;
 605     int rv = 0;
 606     EVP_PKEY *pkpeer = NULL;
 607     EC_KEY *ecpeer = NULL;
 608     const unsigned char *p;
 609     int plen;
 610     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 611     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
 612         goto err;
 613     /* If absent parameters get group from main key */
 614     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
 615         const EC_GROUP *grp;
 616         EVP_PKEY *pk;
 617         pk = EVP_PKEY_CTX_get0_pkey(pctx);
 618         if (!pk)
 619             goto err;
 620         grp = EC_KEY_get0_group(pk->pkey.ec);
 621         ecpeer = EC_KEY_new();
 622         if (ecpeer == NULL)
 623             goto err;
 624         if (!EC_KEY_set_group(ecpeer, grp))
 625             goto err;
 626     } else {
 627         ecpeer = eckey_type2param(atype, aval);
 628         if (!ecpeer)
 629             goto err;
 630     }
 631     /* We have parameters now set public key */
 632     plen = ASN1_STRING_length(pubkey);
 633     p = ASN1_STRING_data(pubkey);
 634     if (!p || !plen)
 635         goto err;
 636     if (!o2i_ECPublicKey(&ecpeer, &p, plen))
 637         goto err;
 638     pkpeer = EVP_PKEY_new();
 639     if (pkpeer == NULL)
 640         goto err;
 641     EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
 642     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 643         rv = 1;
 644  err:
 645     EC_KEY_free(ecpeer);
 646     EVP_PKEY_free(pkpeer);
 647     return rv;
 648 }
 649
 650 /* Set KDF parameters based on KDF NID */
 651 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 652 {
 653     int kdf_nid, kdfmd_nid, cofactor;
 654     const EVP_MD *kdf_md;
 655     if (eckdf_nid == NID_undef)
 656         return 0;
 657
 658     /* Lookup KDF type, cofactor mode and digest */
 659     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 660         return 0;
 661
 662     if (kdf_nid == NID_dh_std_kdf)
 663         cofactor = 0;
 664     else if (kdf_nid == NID_dh_cofactor_kdf)
 665         cofactor = 1;
 666     else
 667         return 0;
 668
 669     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 670         return 0;
 671
 672     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_62) <= 0)
 673         return 0;
 674
 675     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 676     if (!kdf_md)
 677         return 0;
 678
 679     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 680         return 0;
 681     return 1;
 682 }
 683
 684 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 685 {
 686     int rv = 0;
 687
 688     X509_ALGOR *alg, *kekalg = NULL;
 689     ASN1_OCTET_STRING *ukm;
 690     const unsigned char *p;
 691     unsigned char *der = NULL;
 692     int plen, keylen;
 693     const EVP_CIPHER *kekcipher;
 694     EVP_CIPHER_CTX *kekctx;
 695
 696     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 697         return 0;
 698
 699     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 700         ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
 701         return 0;
 702     }
 703
 704     if (alg->parameter->type != V_ASN1_SEQUENCE)
 705         return 0;
 706
 707     p = alg->parameter->value.sequence->data;
 708     plen = alg->parameter->value.sequence->length;
 709     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 710     if (!kekalg)
 711         goto err;
 712     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 713     if (!kekctx)
 714         goto err;
 715     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 716     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 717         goto err;
 718     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 719         goto err;
 720     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 721         goto err;
 722
 723     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 724     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 725         goto err;
 726
 727     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
 728
 729     if (!plen)
 730         goto err;
 731
 732     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
 733         goto err;
 734     der = NULL;
 735
 736     rv = 1;
 737  err:
 738     X509_ALGOR_free(kekalg);
 739     OPENSSL_free(der);
 740     return rv;
 741 }
 742
 743 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
 744 {
 745     EVP_PKEY_CTX *pctx;
 746     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 747     if (!pctx)
 748         return 0;
 749     /* See if we need to set peer key */
 750     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 751         X509_ALGOR *alg;
 752         ASN1_BIT_STRING *pubkey;
 753         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 754                                                  NULL, NULL, NULL))
 755             return 0;
 756         if (!alg || !pubkey)
 757             return 0;
 758         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
 759             ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
 760             return 0;
 761         }
 762     }
 763     /* Set ECDH derivation parameters and initialise unwrap context */
 764     if (!ecdh_cms_set_shared_info(pctx, ri)) {
 765         ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
 766         return 0;
 767     }
 768     return 1;
 769 }
 770
 771 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
 772 {
 773     EVP_PKEY_CTX *pctx;
 774     EVP_PKEY *pkey;
 775     EVP_CIPHER_CTX *ctx;
 776     int keylen;
 777     X509_ALGOR *talg, *wrap_alg = NULL;
 778     ASN1_OBJECT *aoid;
 779     ASN1_BIT_STRING *pubkey;
 780     ASN1_STRING *wrap_str;
 781     ASN1_OCTET_STRING *ukm;
 782     unsigned char *penc = NULL;
 783     int penclen;
 784     int rv = 0;
 785     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
 786     const EVP_MD *kdf_md;
 787     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 788     if (!pctx)
 789         return 0;
 790     /* Get ephemeral key */
 791     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 792     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 793                                              NULL, NULL, NULL))
 794         goto err;
 795     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 796     /* Is everything uninitialised? */
 797     if (aoid == OBJ_nid2obj(NID_undef)) {
 798
 799         EC_KEY *eckey = pkey->pkey.ec;
 800         /* Set the key */
 801         unsigned char *p;
 802
 803         penclen = i2o_ECPublicKey(eckey, NULL);
 804         if (penclen <= 0)
 805             goto err;
 806         penc = OPENSSL_malloc(penclen);
 807         if (penc == NULL)
 808             goto err;
 809         p = penc;
 810         penclen = i2o_ECPublicKey(eckey, &p);
 811         if (penclen <= 0)
 812             goto err;
 813         ASN1_STRING_set0(pubkey, penc, penclen);
 814         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 815         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 816
 817         penc = NULL;
 818         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
 819                         V_ASN1_UNDEF, NULL);
 820     }
 821
 822     /* See if custom paraneters set */
 823     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
 824     if (kdf_type <= 0)
 825         goto err;
 826     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
 827         goto err;
 828     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
 829     if (ecdh_nid < 0)
 830         goto err;
 831     else if (ecdh_nid == 0)
 832         ecdh_nid = NID_dh_std_kdf;
 833     else if (ecdh_nid == 1)
 834         ecdh_nid = NID_dh_cofactor_kdf;
 835
 836     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
 837         kdf_type = EVP_PKEY_ECDH_KDF_X9_62;
 838         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
 839             goto err;
 840     } else
 841         /* Uknown KDF */
 842         goto err;
 843     if (kdf_md == NULL) {
 844         /* Fixme later for better MD */
 845         kdf_md = EVP_sha1();
 846         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 847             goto err;
 848     }
 849
 850     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 851         goto err;
 852
 853     /* Lookup NID for KDF+cofactor+digest */
 854
 855     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
 856         goto err;
 857     /* Get wrap NID */
 858     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 859     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 860     keylen = EVP_CIPHER_CTX_key_length(ctx);
 861
 862     /* Package wrap algorithm in an AlgorithmIdentifier */
 863
 864     wrap_alg = X509_ALGOR_new();
 865     if (wrap_alg == NULL)
 866         goto err;
 867     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 868     wrap_alg->parameter = ASN1_TYPE_new();
 869     if (wrap_alg->parameter == NULL)
 870         goto err;
 871     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 872         goto err;
 873     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 874         ASN1_TYPE_free(wrap_alg->parameter);
 875         wrap_alg->parameter = NULL;
 876     }
 877
 878     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 879         goto err;
 880
 881     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
 882
 883     if (!penclen)
 884         goto err;
 885
 886     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
 887         goto err;
 888     penc = NULL;
 889
 890     /*
 891      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 892      * of another AlgorithmIdentifier.
 893      */
 894     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 895     if (!penc || !penclen)
 896         goto err;
 897     wrap_str = ASN1_STRING_new();
 898     if (wrap_str == NULL)
 899         goto err;
 900     ASN1_STRING_set0(wrap_str, penc, penclen);
 901     penc = NULL;
 902     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
 903
 904     rv = 1;
 905
 906  err:
 907     OPENSSL_free(penc);
 908     X509_ALGOR_free(wrap_alg);
 909     return rv;
 910 }
 911
 912 #endif