crypto/dh/dh_ameth.c

   1 /*
   2  * Copyright 2006-2016 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 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/x509.h>
  13 #include <openssl/asn1.h>
  14 #include "dh_locl.h"
  15 #include <openssl/bn.h>
  16 #include "internal/asn1_int.h"
  17 #include "internal/evp_int.h"
  18 #include <openssl/cms.h>
  19
  20 /*
  21  * i2d/d2i like DH parameter functions which use the appropriate routine for
  22  * PKCS#3 DH or X9.42 DH.
  23  */
  24
  25 static DH *d2i_dhp(const EVP_PKEY *pkey, const unsigned char **pp,
  26                    long length)
  27 {
  28     if (pkey->ameth == &dhx_asn1_meth)
  29         return d2i_DHxparams(NULL, pp, length);
  30     return d2i_DHparams(NULL, pp, length);
  31 }
  32
  33 static int i2d_dhp(const EVP_PKEY *pkey, const DH *a, unsigned char **pp)
  34 {
  35     if (pkey->ameth == &dhx_asn1_meth)
  36         return i2d_DHxparams(a, pp);
  37     return i2d_DHparams(a, pp);
  38 }
  39
  40 static void int_dh_free(EVP_PKEY *pkey)
  41 {
  42     DH_free(pkey->pkey.dh);
  43 }
  44
  45 static int dh_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
  46 {
  47     const unsigned char *p, *pm;
  48     int pklen, pmlen;
  49     int ptype;
  50     const void *pval;
  51     const ASN1_STRING *pstr;
  52     X509_ALGOR *palg;
  53     ASN1_INTEGER *public_key = NULL;
  54
  55     DH *dh = NULL;
  56
  57     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
  58         return 0;
  59     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
  60
  61     if (ptype != V_ASN1_SEQUENCE) {
  62         DHerr(DH_F_DH_PUB_DECODE, DH_R_PARAMETER_ENCODING_ERROR);
  63         goto err;
  64     }
  65
  66     pstr = pval;
  67     pm = pstr->data;
  68     pmlen = pstr->length;
  69
  70     if ((dh = d2i_dhp(pkey, &pm, pmlen)) == NULL) {
  71         DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
  72         goto err;
  73     }
  74
  75     if ((public_key = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL) {
  76         DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
  77         goto err;
  78     }
  79
  80     /* We have parameters now set public key */
  81     if ((dh->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL) {
  82         DHerr(DH_F_DH_PUB_DECODE, DH_R_BN_DECODE_ERROR);
  83         goto err;
  84     }
  85
  86     ASN1_INTEGER_free(public_key);
  87     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
  88     return 1;
  89
  90  err:
  91     ASN1_INTEGER_free(public_key);
  92     DH_free(dh);
  93     return 0;
  94
  95 }
  96
  97 static int dh_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  98 {
  99     DH *dh;
 100     int ptype;
 101     unsigned char *penc = NULL;
 102     int penclen;
 103     ASN1_STRING *str;
 104     ASN1_INTEGER *pub_key = NULL;
 105
 106     dh = pkey->pkey.dh;
 107
 108     str = ASN1_STRING_new();
 109     if (str == NULL) {
 110         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 111         goto err;
 112     }
 113     str->length = i2d_dhp(pkey, dh, &str->data);
 114     if (str->length <= 0) {
 115         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 116         goto err;
 117     }
 118     ptype = V_ASN1_SEQUENCE;
 119
 120     pub_key = BN_to_ASN1_INTEGER(dh->pub_key, NULL);
 121     if (!pub_key)
 122         goto err;
 123
 124     penclen = i2d_ASN1_INTEGER(pub_key, &penc);
 125
 126     ASN1_INTEGER_free(pub_key);
 127
 128     if (penclen <= 0) {
 129         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 130         goto err;
 131     }
 132
 133     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(pkey->ameth->pkey_id),
 134                                ptype, str, penc, penclen))
 135         return 1;
 136
 137  err:
 138     OPENSSL_free(penc);
 139     ASN1_STRING_free(str);
 140
 141     return 0;
 142 }
 143
 144 /*
 145  * PKCS#8 DH is defined in PKCS#11 of all places. It is similar to DH in that
 146  * the AlgorithmIdentifier contains the parameters, the private key is
 147  * explicitly included and the pubkey must be recalculated.
 148  */
 149
 150 static int dh_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 151 {
 152     const unsigned char *p, *pm;
 153     int pklen, pmlen;
 154     int ptype;
 155     const void *pval;
 156     const ASN1_STRING *pstr;
 157     const X509_ALGOR *palg;
 158     ASN1_INTEGER *privkey = NULL;
 159
 160     DH *dh = NULL;
 161
 162     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 163         return 0;
 164
 165     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 166
 167     if (ptype != V_ASN1_SEQUENCE)
 168         goto decerr;
 169     if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
 170         goto decerr;
 171
 172     pstr = pval;
 173     pm = pstr->data;
 174     pmlen = pstr->length;
 175     if ((dh = d2i_dhp(pkey, &pm, pmlen)) == NULL)
 176         goto decerr;
 177
 178     /* We have parameters now set private key */
 179     if ((dh->priv_key = BN_secure_new()) == NULL
 180         || !ASN1_INTEGER_to_BN(privkey, dh->priv_key)) {
 181         DHerr(DH_F_DH_PRIV_DECODE, DH_R_BN_ERROR);
 182         goto dherr;
 183     }
 184     /* Calculate public key */
 185     if (!DH_generate_key(dh))
 186         goto dherr;
 187
 188     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
 189
 190     ASN1_STRING_clear_free(privkey);
 191
 192     return 1;
 193
 194  decerr:
 195     DHerr(DH_F_DH_PRIV_DECODE, EVP_R_DECODE_ERROR);
 196  dherr:
 197     DH_free(dh);
 198     ASN1_STRING_clear_free(privkey);
 199     return 0;
 200 }
 201
 202 static int dh_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 203 {
 204     ASN1_STRING *params = NULL;
 205     ASN1_INTEGER *prkey = NULL;
 206     unsigned char *dp = NULL;
 207     int dplen;
 208
 209     params = ASN1_STRING_new();
 210
 211     if (params == NULL) {
 212         DHerr(DH_F_DH_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 213         goto err;
 214     }
 215
 216     params->length = i2d_dhp(pkey, pkey->pkey.dh, &params->data);
 217     if (params->length <= 0) {
 218         DHerr(DH_F_DH_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 219         goto err;
 220     }
 221     params->type = V_ASN1_SEQUENCE;
 222
 223     /* Get private key into integer */
 224     prkey = BN_to_ASN1_INTEGER(pkey->pkey.dh->priv_key, NULL);
 225
 226     if (!prkey) {
 227         DHerr(DH_F_DH_PRIV_ENCODE, DH_R_BN_ERROR);
 228         goto err;
 229     }
 230
 231     dplen = i2d_ASN1_INTEGER(prkey, &dp);
 232
 233     ASN1_STRING_clear_free(prkey);
 234     prkey = NULL;
 235
 236     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(pkey->ameth->pkey_id), 0,
 237                          V_ASN1_SEQUENCE, params, dp, dplen))
 238         goto err;
 239
 240     return 1;
 241
 242  err:
 243     OPENSSL_free(dp);
 244     ASN1_STRING_free(params);
 245     ASN1_STRING_clear_free(prkey);
 246     return 0;
 247 }
 248
 249 static int dh_param_decode(EVP_PKEY *pkey,
 250                            const unsigned char **pder, int derlen)
 251 {
 252     DH *dh;
 253
 254     if ((dh = d2i_dhp(pkey, pder, derlen)) == NULL) {
 255         DHerr(DH_F_DH_PARAM_DECODE, ERR_R_DH_LIB);
 256         return 0;
 257     }
 258     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
 259     return 1;
 260 }
 261
 262 static int dh_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 263 {
 264     return i2d_dhp(pkey, pkey->pkey.dh, pder);
 265 }
 266
 267 static int do_dh_print(BIO *bp, const DH *x, int indent, int ptype)
 268 {
 269     int reason = ERR_R_BUF_LIB;
 270     const char *ktype = NULL;
 271     BIGNUM *priv_key, *pub_key;
 272
 273     if (ptype == 2)
 274         priv_key = x->priv_key;
 275     else
 276         priv_key = NULL;
 277
 278     if (ptype > 0)
 279         pub_key = x->pub_key;
 280     else
 281         pub_key = NULL;
 282
 283     if (x->p == NULL || (ptype == 2 && priv_key == NULL)
 284             || (ptype > 0 && pub_key == NULL)) {
 285         reason = ERR_R_PASSED_NULL_PARAMETER;
 286         goto err;
 287     }
 288
 289     if (ptype == 2)
 290         ktype = "DH Private-Key";
 291     else if (ptype == 1)
 292         ktype = "DH Public-Key";
 293     else
 294         ktype = "DH Parameters";
 295
 296     BIO_indent(bp, indent, 128);
 297     if (BIO_printf(bp, "%s: (%d bit)\n", ktype, BN_num_bits(x->p)) <= 0)
 298         goto err;
 299     indent += 4;
 300
 301     if (!ASN1_bn_print(bp, "private-key:", priv_key, NULL, indent))
 302         goto err;
 303     if (!ASN1_bn_print(bp, "public-key:", pub_key, NULL, indent))
 304         goto err;
 305
 306     if (!ASN1_bn_print(bp, "prime:", x->p, NULL, indent))
 307         goto err;
 308     if (!ASN1_bn_print(bp, "generator:", x->g, NULL, indent))
 309         goto err;
 310     if (x->q && !ASN1_bn_print(bp, "subgroup order:", x->q, NULL, indent))
 311         goto err;
 312     if (x->j && !ASN1_bn_print(bp, "subgroup factor:", x->j, NULL, indent))
 313         goto err;
 314     if (x->seed) {
 315         int i;
 316         BIO_indent(bp, indent, 128);
 317         BIO_puts(bp, "seed:");
 318         for (i = 0; i < x->seedlen; i++) {
 319             if ((i % 15) == 0) {
 320                 if (BIO_puts(bp, "\n") <= 0
 321                     || !BIO_indent(bp, indent + 4, 128))
 322                     goto err;
 323             }
 324             if (BIO_printf(bp, "%02x%s", x->seed[i],
 325                            ((i + 1) == x->seedlen) ? "" : ":") <= 0)
 326                 goto err;
 327         }
 328         if (BIO_write(bp, "\n", 1) <= 0)
 329             return 0;
 330     }
 331     if (x->counter && !ASN1_bn_print(bp, "counter:", x->counter, NULL, indent))
 332         goto err;
 333     if (x->length != 0) {
 334         BIO_indent(bp, indent, 128);
 335         if (BIO_printf(bp, "recommended-private-length: %d bits\n",
 336                        (int)x->length) <= 0)
 337             goto err;
 338     }
 339
 340     return 1;
 341
 342  err:
 343     DHerr(DH_F_DO_DH_PRINT, reason);
 344     return 0;
 345 }
 346
 347 static int int_dh_size(const EVP_PKEY *pkey)
 348 {
 349     return DH_size(pkey->pkey.dh);
 350 }
 351
 352 static int dh_bits(const EVP_PKEY *pkey)
 353 {
 354     return BN_num_bits(pkey->pkey.dh->p);
 355 }
 356
 357 static int dh_security_bits(const EVP_PKEY *pkey)
 358 {
 359     return DH_security_bits(pkey->pkey.dh);
 360 }
 361
 362 static int dh_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 363 {
 364     if (BN_cmp(a->pkey.dh->p, b->pkey.dh->p) ||
 365         BN_cmp(a->pkey.dh->g, b->pkey.dh->g))
 366         return 0;
 367     else if (a->ameth == &dhx_asn1_meth) {
 368         if (BN_cmp(a->pkey.dh->q, b->pkey.dh->q))
 369             return 0;
 370     }
 371     return 1;
 372 }
 373
 374 static int int_dh_bn_cpy(BIGNUM **dst, const BIGNUM *src)
 375 {
 376     BIGNUM *a;
 377
 378     /*
 379      * If source is read only just copy the pointer, so
 380      * we don't have to reallocate it.
 381      */
 382     if (src == NULL)
 383         a = NULL;
 384     else if (BN_get_flags(src, BN_FLG_STATIC_DATA)
 385                 && !BN_get_flags(src, BN_FLG_MALLOCED))
 386         a = (BIGNUM *)src;
 387     else if ((a = BN_dup(src)) == NULL)
 388         return 0;
 389     BN_clear_free(*dst);
 390     *dst = a;
 391     return 1;
 392 }
 393
 394 static int int_dh_param_copy(DH *to, const DH *from, int is_x942)
 395 {
 396     if (is_x942 == -1)
 397         is_x942 = ! !from->q;
 398     if (!int_dh_bn_cpy(&to->p, from->p))
 399         return 0;
 400     if (!int_dh_bn_cpy(&to->g, from->g))
 401         return 0;
 402     if (is_x942) {
 403         if (!int_dh_bn_cpy(&to->q, from->q))
 404             return 0;
 405         if (!int_dh_bn_cpy(&to->j, from->j))
 406             return 0;
 407         OPENSSL_free(to->seed);
 408         to->seed = NULL;
 409         to->seedlen = 0;
 410         if (from->seed) {
 411             to->seed = OPENSSL_memdup(from->seed, from->seedlen);
 412             if (!to->seed)
 413                 return 0;
 414             to->seedlen = from->seedlen;
 415         }
 416     } else
 417         to->length = from->length;
 418     return 1;
 419 }
 420
 421 DH *DHparams_dup(DH *dh)
 422 {
 423     DH *ret;
 424     ret = DH_new();
 425     if (ret == NULL)
 426         return NULL;
 427     if (!int_dh_param_copy(ret, dh, -1)) {
 428         DH_free(ret);
 429         return NULL;
 430     }
 431     return ret;
 432 }
 433
 434 static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 435 {
 436     if (to->pkey.dh == NULL) {
 437         to->pkey.dh = DH_new();
 438         if (to->pkey.dh == NULL)
 439             return 0;
 440     }
 441     return int_dh_param_copy(to->pkey.dh, from->pkey.dh,
 442                              from->ameth == &dhx_asn1_meth);
 443 }
 444
 445 static int dh_missing_parameters(const EVP_PKEY *a)
 446 {
 447     if (a->pkey.dh == NULL || a->pkey.dh->p == NULL || a->pkey.dh->g == NULL)
 448         return 1;
 449     return 0;
 450 }
 451
 452 static int dh_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 453 {
 454     if (dh_cmp_parameters(a, b) == 0)
 455         return 0;
 456     if (BN_cmp(b->pkey.dh->pub_key, a->pkey.dh->pub_key) != 0)
 457         return 0;
 458     else
 459         return 1;
 460 }
 461
 462 static int dh_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 463                           ASN1_PCTX *ctx)
 464 {
 465     return do_dh_print(bp, pkey->pkey.dh, indent, 0);
 466 }
 467
 468 static int dh_public_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 469                            ASN1_PCTX *ctx)
 470 {
 471     return do_dh_print(bp, pkey->pkey.dh, indent, 1);
 472 }
 473
 474 static int dh_private_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 475                             ASN1_PCTX *ctx)
 476 {
 477     return do_dh_print(bp, pkey->pkey.dh, indent, 2);
 478 }
 479
 480 int DHparams_print(BIO *bp, const DH *x)
 481 {
 482     return do_dh_print(bp, x, 4, 0);
 483 }
 484
 485 #ifndef OPENSSL_NO_CMS
 486 static int dh_cms_decrypt(CMS_RecipientInfo *ri);
 487 static int dh_cms_encrypt(CMS_RecipientInfo *ri);
 488 #endif
 489
 490 static int dh_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 491 {
 492     switch (op) {
 493 #ifndef OPENSSL_NO_CMS
 494
 495     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 496         if (arg1 == 1)
 497             return dh_cms_decrypt(arg2);
 498         else if (arg1 == 0)
 499             return dh_cms_encrypt(arg2);
 500         return -2;
 501
 502     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 503         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 504         return 1;
 505 #endif
 506     default:
 507         return -2;
 508     }
 509
 510 }
 511
 512 static int dh_pkey_public_check(const EVP_PKEY *pkey)
 513 {
 514     DH *dh = pkey->pkey.dh;
 515
 516     if (dh->pub_key == NULL) {
 517         DHerr(DH_F_DH_PKEY_PUBLIC_CHECK, DH_R_MISSING_PUBKEY);
 518         return 0;
 519     }
 520
 521     return DH_check_pub_key_ex(dh, dh->pub_key);
 522 }
 523
 524 static int dh_pkey_param_check(const EVP_PKEY *pkey)
 525 {
 526     DH *dh = pkey->pkey.dh;
 527
 528     return DH_check_ex(dh);
 529 }
 530
 531 const EVP_PKEY_ASN1_METHOD dh_asn1_meth = {
 532     EVP_PKEY_DH,
 533     EVP_PKEY_DH,
 534     0,
 535
 536     "DH",
 537     "OpenSSL PKCS#3 DH method",
 538
 539     dh_pub_decode,
 540     dh_pub_encode,
 541     dh_pub_cmp,
 542     dh_public_print,
 543
 544     dh_priv_decode,
 545     dh_priv_encode,
 546     dh_private_print,
 547
 548     int_dh_size,
 549     dh_bits,
 550     dh_security_bits,
 551
 552     dh_param_decode,
 553     dh_param_encode,
 554     dh_missing_parameters,
 555     dh_copy_parameters,
 556     dh_cmp_parameters,
 557     dh_param_print,
 558     0,
 559
 560     int_dh_free,
 561     0,
 562
 563     0, 0, 0, 0, 0,
 564
 565     0,
 566     dh_pkey_public_check,
 567     dh_pkey_param_check
 568 };
 569
 570 const EVP_PKEY_ASN1_METHOD dhx_asn1_meth = {
 571     EVP_PKEY_DHX,
 572     EVP_PKEY_DHX,
 573     0,
 574
 575     "X9.42 DH",
 576     "OpenSSL X9.42 DH method",
 577
 578     dh_pub_decode,
 579     dh_pub_encode,
 580     dh_pub_cmp,
 581     dh_public_print,
 582
 583     dh_priv_decode,
 584     dh_priv_encode,
 585     dh_private_print,
 586
 587     int_dh_size,
 588     dh_bits,
 589     dh_security_bits,
 590
 591     dh_param_decode,
 592     dh_param_encode,
 593     dh_missing_parameters,
 594     dh_copy_parameters,
 595     dh_cmp_parameters,
 596     dh_param_print,
 597     0,
 598
 599     int_dh_free,
 600     dh_pkey_ctrl,
 601
 602     0, 0, 0, 0, 0,
 603
 604     0,
 605     dh_pkey_public_check,
 606     dh_pkey_param_check
 607 };
 608
 609 #ifndef OPENSSL_NO_CMS
 610
 611 static int dh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 612                               X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 613 {
 614     const ASN1_OBJECT *aoid;
 615     int atype;
 616     const void *aval;
 617     ASN1_INTEGER *public_key = NULL;
 618     int rv = 0;
 619     EVP_PKEY *pkpeer = NULL, *pk = NULL;
 620     DH *dhpeer = NULL;
 621     const unsigned char *p;
 622     int plen;
 623
 624     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 625     if (OBJ_obj2nid(aoid) != NID_dhpublicnumber)
 626         goto err;
 627     /* Only absent parameters allowed in RFC XXXX */
 628     if (atype != V_ASN1_UNDEF && atype == V_ASN1_NULL)
 629         goto err;
 630
 631     pk = EVP_PKEY_CTX_get0_pkey(pctx);
 632     if (!pk)
 633         goto err;
 634     if (pk->type != EVP_PKEY_DHX)
 635         goto err;
 636     /* Get parameters from parent key */
 637     dhpeer = DHparams_dup(pk->pkey.dh);
 638     /* We have parameters now set public key */
 639     plen = ASN1_STRING_length(pubkey);
 640     p = ASN1_STRING_get0_data(pubkey);
 641     if (!p || !plen)
 642         goto err;
 643
 644     if ((public_key = d2i_ASN1_INTEGER(NULL, &p, plen)) == NULL) {
 645         DHerr(DH_F_DH_CMS_SET_PEERKEY, DH_R_DECODE_ERROR);
 646         goto err;
 647     }
 648
 649     /* We have parameters now set public key */
 650     if ((dhpeer->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL) {
 651         DHerr(DH_F_DH_CMS_SET_PEERKEY, DH_R_BN_DECODE_ERROR);
 652         goto err;
 653     }
 654
 655     pkpeer = EVP_PKEY_new();
 656     if (pkpeer == NULL)
 657         goto err;
 658     EVP_PKEY_assign(pkpeer, pk->ameth->pkey_id, dhpeer);
 659     dhpeer = NULL;
 660     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 661         rv = 1;
 662  err:
 663     ASN1_INTEGER_free(public_key);
 664     EVP_PKEY_free(pkpeer);
 665     DH_free(dhpeer);
 666     return rv;
 667 }
 668
 669 static int dh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 670 {
 671     int rv = 0;
 672
 673     X509_ALGOR *alg, *kekalg = NULL;
 674     ASN1_OCTET_STRING *ukm;
 675     const unsigned char *p;
 676     unsigned char *dukm = NULL;
 677     size_t dukmlen = 0;
 678     int keylen, plen;
 679     const EVP_CIPHER *kekcipher;
 680     EVP_CIPHER_CTX *kekctx;
 681
 682     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 683         goto err;
 684
 685     /*
 686      * For DH we only have one OID permissible. If ever any more get defined
 687      * we will need something cleverer.
 688      */
 689     if (OBJ_obj2nid(alg->algorithm) != NID_id_smime_alg_ESDH) {
 690         DHerr(DH_F_DH_CMS_SET_SHARED_INFO, DH_R_KDF_PARAMETER_ERROR);
 691         goto err;
 692     }
 693
 694     if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, EVP_PKEY_DH_KDF_X9_42) <= 0)
 695         goto err;
 696
 697     if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, EVP_sha1()) <= 0)
 698         goto err;
 699
 700     if (alg->parameter->type != V_ASN1_SEQUENCE)
 701         goto err;
 702
 703     p = alg->parameter->value.sequence->data;
 704     plen = alg->parameter->value.sequence->length;
 705     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 706     if (!kekalg)
 707         goto err;
 708     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 709     if (!kekctx)
 710         goto err;
 711     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 712     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 713         goto err;
 714     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 715         goto err;
 716     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 717         goto err;
 718
 719     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 720     if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
 721         goto err;
 722     /* Use OBJ_nid2obj to ensure we use built in OID that isn't freed */
 723     if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx,
 724                                      OBJ_nid2obj(EVP_CIPHER_type(kekcipher)))
 725         <= 0)
 726         goto err;
 727
 728     if (ukm) {
 729         dukmlen = ASN1_STRING_length(ukm);
 730         dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
 731         if (!dukm)
 732             goto err;
 733     }
 734
 735     if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
 736         goto err;
 737     dukm = NULL;
 738
 739     rv = 1;
 740  err:
 741     X509_ALGOR_free(kekalg);
 742     OPENSSL_free(dukm);
 743     return rv;
 744 }
 745
 746 static int dh_cms_decrypt(CMS_RecipientInfo *ri)
 747 {
 748     EVP_PKEY_CTX *pctx;
 749     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 750     if (!pctx)
 751         return 0;
 752     /* See if we need to set peer key */
 753     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 754         X509_ALGOR *alg;
 755         ASN1_BIT_STRING *pubkey;
 756         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 757                                                  NULL, NULL, NULL))
 758             return 0;
 759         if (!alg || !pubkey)
 760             return 0;
 761         if (!dh_cms_set_peerkey(pctx, alg, pubkey)) {
 762             DHerr(DH_F_DH_CMS_DECRYPT, DH_R_PEER_KEY_ERROR);
 763             return 0;
 764         }
 765     }
 766     /* Set DH derivation parameters and initialise unwrap context */
 767     if (!dh_cms_set_shared_info(pctx, ri)) {
 768         DHerr(DH_F_DH_CMS_DECRYPT, DH_R_SHARED_INFO_ERROR);
 769         return 0;
 770     }
 771     return 1;
 772 }
 773
 774 static int dh_cms_encrypt(CMS_RecipientInfo *ri)
 775 {
 776     EVP_PKEY_CTX *pctx;
 777     EVP_PKEY *pkey;
 778     EVP_CIPHER_CTX *ctx;
 779     int keylen;
 780     X509_ALGOR *talg, *wrap_alg = NULL;
 781     const ASN1_OBJECT *aoid;
 782     ASN1_BIT_STRING *pubkey;
 783     ASN1_STRING *wrap_str;
 784     ASN1_OCTET_STRING *ukm;
 785     unsigned char *penc = NULL, *dukm = NULL;
 786     int penclen;
 787     size_t dukmlen = 0;
 788     int rv = 0;
 789     int kdf_type, wrap_nid;
 790     const EVP_MD *kdf_md;
 791     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 792     if (!pctx)
 793         return 0;
 794     /* Get ephemeral key */
 795     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 796     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 797                                              NULL, NULL, NULL))
 798         goto err;
 799     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 800     /* Is everything uninitialised? */
 801     if (aoid == OBJ_nid2obj(NID_undef)) {
 802         ASN1_INTEGER *pubk = BN_to_ASN1_INTEGER(pkey->pkey.dh->pub_key, NULL);
 803         if (!pubk)
 804             goto err;
 805         /* Set the key */
 806
 807         penclen = i2d_ASN1_INTEGER(pubk, &penc);
 808         ASN1_INTEGER_free(pubk);
 809         if (penclen <= 0)
 810             goto err;
 811         ASN1_STRING_set0(pubkey, penc, penclen);
 812         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 813         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 814
 815         penc = NULL;
 816         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_dhpublicnumber),
 817                         V_ASN1_UNDEF, NULL);
 818     }
 819
 820     /* See if custom parameters set */
 821     kdf_type = EVP_PKEY_CTX_get_dh_kdf_type(pctx);
 822     if (kdf_type <= 0)
 823         goto err;
 824     if (!EVP_PKEY_CTX_get_dh_kdf_md(pctx, &kdf_md))
 825         goto err;
 826
 827     if (kdf_type == EVP_PKEY_DH_KDF_NONE) {
 828         kdf_type = EVP_PKEY_DH_KDF_X9_42;
 829         if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, kdf_type) <= 0)
 830             goto err;
 831     } else if (kdf_type != EVP_PKEY_DH_KDF_X9_42)
 832         /* Unknown KDF */
 833         goto err;
 834     if (kdf_md == NULL) {
 835         /* Only SHA1 supported */
 836         kdf_md = EVP_sha1();
 837         if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, kdf_md) <= 0)
 838             goto err;
 839     } else if (EVP_MD_type(kdf_md) != NID_sha1)
 840         /* Unsupported digest */
 841         goto err;
 842
 843     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 844         goto err;
 845
 846     /* Get wrap NID */
 847     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 848     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 849     if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx, OBJ_nid2obj(wrap_nid)) <= 0)
 850         goto err;
 851     keylen = EVP_CIPHER_CTX_key_length(ctx);
 852
 853     /* Package wrap algorithm in an AlgorithmIdentifier */
 854
 855     wrap_alg = X509_ALGOR_new();
 856     if (wrap_alg == NULL)
 857         goto err;
 858     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 859     wrap_alg->parameter = ASN1_TYPE_new();
 860     if (wrap_alg->parameter == NULL)
 861         goto err;
 862     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 863         goto err;
 864     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 865         ASN1_TYPE_free(wrap_alg->parameter);
 866         wrap_alg->parameter = NULL;
 867     }
 868
 869     if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
 870         goto err;
 871
 872     if (ukm) {
 873         dukmlen = ASN1_STRING_length(ukm);
 874         dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
 875         if (!dukm)
 876             goto err;
 877     }
 878
 879     if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
 880         goto err;
 881     dukm = NULL;
 882
 883     /*
 884      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 885      * of another AlgorithmIdentifier.
 886      */
 887     penc = NULL;
 888     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 889     if (!penc || !penclen)
 890         goto err;
 891     wrap_str = ASN1_STRING_new();
 892     if (wrap_str == NULL)
 893         goto err;
 894     ASN1_STRING_set0(wrap_str, penc, penclen);
 895     penc = NULL;
 896     X509_ALGOR_set0(talg, OBJ_nid2obj(NID_id_smime_alg_ESDH),
 897                     V_ASN1_SEQUENCE, wrap_str);
 898
 899     rv = 1;
 900
 901  err:
 902     OPENSSL_free(penc);
 903     X509_ALGOR_free(wrap_alg);
 904     return rv;
 905 }
 906
 907 #endif