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_local.h"
  15 #include <openssl/bn.h>
  16 #include "crypto/asn1.h"
  17 #include "crypto/evp.h"
  18 #include <openssl/cms.h>
  19 #include <openssl/core_names.h>
  20 #include "internal/param_build.h"
  21
  22 /*
  23  * i2d/d2i like DH parameter functions which use the appropriate routine for
  24  * PKCS#3 DH or X9.42 DH.
  25  */
  26
  27 static DH *d2i_dhp(const EVP_PKEY *pkey, const unsigned char **pp,
  28                    long length)
  29 {
  30     if (pkey->ameth == &dhx_asn1_meth)
  31         return d2i_DHxparams(NULL, pp, length);
  32     return d2i_DHparams(NULL, pp, length);
  33 }
  34
  35 static int i2d_dhp(const EVP_PKEY *pkey, const DH *a, unsigned char **pp)
  36 {
  37     if (pkey->ameth == &dhx_asn1_meth)
  38         return i2d_DHxparams(a, pp);
  39     return i2d_DHparams(a, pp);
  40 }
  41
  42 static void int_dh_free(EVP_PKEY *pkey)
  43 {
  44     DH_free(pkey->pkey.dh);
  45 }
  46
  47 static int dh_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
  48 {
  49     const unsigned char *p, *pm;
  50     int pklen, pmlen;
  51     int ptype;
  52     const void *pval;
  53     const ASN1_STRING *pstr;
  54     X509_ALGOR *palg;
  55     ASN1_INTEGER *public_key = NULL;
  56
  57     DH *dh = NULL;
  58
  59     if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
  60         return 0;
  61     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
  62
  63     if (ptype != V_ASN1_SEQUENCE) {
  64         DHerr(DH_F_DH_PUB_DECODE, DH_R_PARAMETER_ENCODING_ERROR);
  65         goto err;
  66     }
  67
  68     pstr = pval;
  69     pm = pstr->data;
  70     pmlen = pstr->length;
  71
  72     if ((dh = d2i_dhp(pkey, &pm, pmlen)) == NULL) {
  73         DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
  74         goto err;
  75     }
  76
  77     if ((public_key = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL) {
  78         DHerr(DH_F_DH_PUB_DECODE, DH_R_DECODE_ERROR);
  79         goto err;
  80     }
  81
  82     /* We have parameters now set public key */
  83     if ((dh->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL) {
  84         DHerr(DH_F_DH_PUB_DECODE, DH_R_BN_DECODE_ERROR);
  85         goto err;
  86     }
  87
  88     ASN1_INTEGER_free(public_key);
  89     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
  90     return 1;
  91
  92  err:
  93     ASN1_INTEGER_free(public_key);
  94     DH_free(dh);
  95     return 0;
  96
  97 }
  98
  99 static int dh_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
 100 {
 101     DH *dh;
 102     int ptype;
 103     unsigned char *penc = NULL;
 104     int penclen;
 105     ASN1_STRING *str;
 106     ASN1_INTEGER *pub_key = NULL;
 107
 108     dh = pkey->pkey.dh;
 109
 110     str = ASN1_STRING_new();
 111     if (str == NULL) {
 112         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 113         goto err;
 114     }
 115     str->length = i2d_dhp(pkey, dh, &str->data);
 116     if (str->length <= 0) {
 117         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 118         goto err;
 119     }
 120     ptype = V_ASN1_SEQUENCE;
 121
 122     pub_key = BN_to_ASN1_INTEGER(dh->pub_key, NULL);
 123     if (pub_key == NULL)
 124         goto err;
 125
 126     penclen = i2d_ASN1_INTEGER(pub_key, &penc);
 127
 128     ASN1_INTEGER_free(pub_key);
 129
 130     if (penclen <= 0) {
 131         DHerr(DH_F_DH_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
 132         goto err;
 133     }
 134
 135     if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(pkey->ameth->pkey_id),
 136                                ptype, str, penc, penclen))
 137         return 1;
 138
 139  err:
 140     OPENSSL_free(penc);
 141     ASN1_STRING_free(str);
 142
 143     return 0;
 144 }
 145
 146 /*
 147  * PKCS#8 DH is defined in PKCS#11 of all places. It is similar to DH in that
 148  * the AlgorithmIdentifier contains the parameters, the private key is
 149  * explicitly included and the pubkey must be recalculated.
 150  */
 151
 152 static int dh_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 153 {
 154     const unsigned char *p, *pm;
 155     int pklen, pmlen;
 156     int ptype;
 157     const void *pval;
 158     const ASN1_STRING *pstr;
 159     const X509_ALGOR *palg;
 160     ASN1_INTEGER *privkey = NULL;
 161     DH *dh = NULL;
 162
 163     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
 164         return 0;
 165
 166     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
 167
 168     if (ptype != V_ASN1_SEQUENCE)
 169         goto decerr;
 170     if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
 171         goto decerr;
 172
 173     pstr = pval;
 174     pm = pstr->data;
 175     pmlen = pstr->length;
 176     if ((dh = d2i_dhp(pkey, &pm, pmlen)) == NULL)
 177         goto decerr;
 178
 179     /* We have parameters now set private key */
 180     if ((dh->priv_key = BN_secure_new()) == NULL
 181         || !ASN1_INTEGER_to_BN(privkey, dh->priv_key)) {
 182         DHerr(DH_F_DH_PRIV_DECODE, DH_R_BN_ERROR);
 183         goto dherr;
 184     }
 185     /* Calculate public key, increments dirty_cnt */
 186     if (!DH_generate_key(dh))
 187         goto dherr;
 188
 189     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
 190
 191     ASN1_STRING_clear_free(privkey);
 192
 193     return 1;
 194
 195  decerr:
 196     DHerr(DH_F_DH_PRIV_DECODE, EVP_R_DECODE_ERROR);
 197  dherr:
 198     DH_free(dh);
 199     ASN1_STRING_clear_free(privkey);
 200     return 0;
 201 }
 202
 203 static int dh_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
 204 {
 205     ASN1_STRING *params = NULL;
 206     ASN1_INTEGER *prkey = NULL;
 207     unsigned char *dp = NULL;
 208     int dplen;
 209
 210     params = ASN1_STRING_new();
 211
 212     if (params == NULL) {
 213         DHerr(DH_F_DH_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 214         goto err;
 215     }
 216
 217     params->length = i2d_dhp(pkey, pkey->pkey.dh, &params->data);
 218     if (params->length <= 0) {
 219         DHerr(DH_F_DH_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
 220         goto err;
 221     }
 222     params->type = V_ASN1_SEQUENCE;
 223
 224     /* Get private key into integer */
 225     prkey = BN_to_ASN1_INTEGER(pkey->pkey.dh->priv_key, NULL);
 226
 227     if (prkey == NULL) {
 228         DHerr(DH_F_DH_PRIV_ENCODE, DH_R_BN_ERROR);
 229         goto err;
 230     }
 231
 232     dplen = i2d_ASN1_INTEGER(prkey, &dp);
 233
 234     ASN1_STRING_clear_free(prkey);
 235     prkey = NULL;
 236
 237     if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(pkey->ameth->pkey_id), 0,
 238                          V_ASN1_SEQUENCE, params, dp, dplen))
 239         goto err;
 240
 241     return 1;
 242
 243  err:
 244     OPENSSL_free(dp);
 245     ASN1_STRING_free(params);
 246     ASN1_STRING_clear_free(prkey);
 247     return 0;
 248 }
 249
 250 static int dh_param_decode(EVP_PKEY *pkey,
 251                            const unsigned char **pder, int derlen)
 252 {
 253     DH *dh;
 254
 255     if ((dh = d2i_dhp(pkey, pder, derlen)) == NULL) {
 256         DHerr(DH_F_DH_PARAM_DECODE, ERR_R_DH_LIB);
 257         return 0;
 258     }
 259     dh->dirty_cnt++;
 260     EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);
 261     return 1;
 262 }
 263
 264 static int dh_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
 265 {
 266     return i2d_dhp(pkey, pkey->pkey.dh, pder);
 267 }
 268
 269 static int do_dh_print(BIO *bp, const DH *x, int indent, int ptype)
 270 {
 271     int reason = ERR_R_BUF_LIB;
 272     const char *ktype = NULL;
 273     BIGNUM *priv_key, *pub_key;
 274
 275     if (ptype == 2)
 276         priv_key = x->priv_key;
 277     else
 278         priv_key = NULL;
 279
 280     if (ptype > 0)
 281         pub_key = x->pub_key;
 282     else
 283         pub_key = NULL;
 284
 285     if (x->params.p == NULL || (ptype == 2 && priv_key == NULL)
 286             || (ptype > 0 && pub_key == NULL)) {
 287         reason = ERR_R_PASSED_NULL_PARAMETER;
 288         goto err;
 289     }
 290
 291     if (ptype == 2)
 292         ktype = "DH Private-Key";
 293     else if (ptype == 1)
 294         ktype = "DH Public-Key";
 295     else
 296         ktype = "DH Parameters";
 297
 298     if (!BIO_indent(bp, indent, 128)
 299             || BIO_printf(bp, "%s: (%d bit)\n", ktype, DH_bits(x)) <= 0)
 300         goto err;
 301     indent += 4;
 302
 303     if (!ASN1_bn_print(bp, "private-key:", priv_key, NULL, indent))
 304         goto err;
 305     if (!ASN1_bn_print(bp, "public-key:", pub_key, NULL, indent))
 306         goto err;
 307
 308     if (!ffc_params_print(bp, &x->params, indent))
 309         goto err;
 310
 311     if (x->length != 0) {
 312         if (!BIO_indent(bp, indent, 128)
 313                 || BIO_printf(bp, "recommended-private-length: %d bits\n",
 314                               (int)x->length) <= 0)
 315             goto err;
 316     }
 317
 318     return 1;
 319
 320  err:
 321     DHerr(DH_F_DO_DH_PRINT, reason);
 322     return 0;
 323 }
 324
 325 static int int_dh_size(const EVP_PKEY *pkey)
 326 {
 327     return DH_size(pkey->pkey.dh);
 328 }
 329
 330 static int dh_bits(const EVP_PKEY *pkey)
 331 {
 332     return DH_bits(pkey->pkey.dh);
 333 }
 334
 335 static int dh_security_bits(const EVP_PKEY *pkey)
 336 {
 337     return DH_security_bits(pkey->pkey.dh);
 338 }
 339
 340 static int dh_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
 341 {
 342     return ffc_params_cmp(&a->pkey.dh->params, &a->pkey.dh->params,
 343                           a->ameth != &dhx_asn1_meth);
 344 }
 345
 346 static int int_dh_param_copy(DH *to, const DH *from, int is_x942)
 347 {
 348     if (is_x942 == -1)
 349         is_x942 = (from->params.q != NULL);
 350     if (!ffc_params_copy(&to->params, &from->params))
 351         return 0;
 352     if (!is_x942)
 353         to->length = from->length;
 354     to->dirty_cnt++;
 355     return 1;
 356 }
 357
 358 DH *DHparams_dup(const DH *dh)
 359 {
 360     DH *ret;
 361     ret = DH_new();
 362     if (ret == NULL)
 363         return NULL;
 364     if (!int_dh_param_copy(ret, dh, -1)) {
 365         DH_free(ret);
 366         return NULL;
 367     }
 368     return ret;
 369 }
 370
 371 static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 372 {
 373     if (to->pkey.dh == NULL) {
 374         to->pkey.dh = DH_new();
 375         if (to->pkey.dh == NULL)
 376             return 0;
 377     }
 378     return int_dh_param_copy(to->pkey.dh, from->pkey.dh,
 379                              from->ameth == &dhx_asn1_meth);
 380 }
 381
 382 static int dh_missing_parameters(const EVP_PKEY *a)
 383 {
 384     return a->pkey.dh == NULL
 385         || a->pkey.dh->params.p == NULL
 386         || a->pkey.dh->params.g == NULL;
 387 }
 388
 389 static int dh_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
 390 {
 391     if (dh_cmp_parameters(a, b) == 0)
 392         return 0;
 393     if (BN_cmp(b->pkey.dh->pub_key, a->pkey.dh->pub_key) != 0)
 394         return 0;
 395     else
 396         return 1;
 397 }
 398
 399 static int dh_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 400                           ASN1_PCTX *ctx)
 401 {
 402     return do_dh_print(bp, pkey->pkey.dh, indent, 0);
 403 }
 404
 405 static int dh_public_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 406                            ASN1_PCTX *ctx)
 407 {
 408     return do_dh_print(bp, pkey->pkey.dh, indent, 1);
 409 }
 410
 411 static int dh_private_print(BIO *bp, const EVP_PKEY *pkey, int indent,
 412                             ASN1_PCTX *ctx)
 413 {
 414     return do_dh_print(bp, pkey->pkey.dh, indent, 2);
 415 }
 416
 417 int DHparams_print(BIO *bp, const DH *x)
 418 {
 419     return do_dh_print(bp, x, 4, 0);
 420 }
 421
 422 #ifndef OPENSSL_NO_CMS
 423 static int dh_cms_decrypt(CMS_RecipientInfo *ri);
 424 static int dh_cms_encrypt(CMS_RecipientInfo *ri);
 425 #endif
 426
 427 static int dh_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 428 {
 429     switch (op) {
 430     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
 431         return dh_buf2key(EVP_PKEY_get0_DH(pkey), arg2, arg1);
 432     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
 433         return dh_key2buf(EVP_PKEY_get0_DH(pkey), arg2);
 434     default:
 435         return -2;
 436     }
 437 }
 438
 439 static int dhx_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 440 {
 441     switch (op) {
 442 #ifndef OPENSSL_NO_CMS
 443
 444     case ASN1_PKEY_CTRL_CMS_ENVELOPE:
 445         if (arg1 == 1)
 446             return dh_cms_decrypt(arg2);
 447         else if (arg1 == 0)
 448             return dh_cms_encrypt(arg2);
 449         return -2;
 450
 451     case ASN1_PKEY_CTRL_CMS_RI_TYPE:
 452         *(int *)arg2 = CMS_RECIPINFO_AGREE;
 453         return 1;
 454 #endif
 455     default:
 456         return -2;
 457     }
 458
 459 }
 460
 461 static int dh_pkey_public_check(const EVP_PKEY *pkey)
 462 {
 463     DH *dh = pkey->pkey.dh;
 464
 465     if (dh->pub_key == NULL) {
 466         DHerr(DH_F_DH_PKEY_PUBLIC_CHECK, DH_R_MISSING_PUBKEY);
 467         return 0;
 468     }
 469
 470     return DH_check_pub_key_ex(dh, dh->pub_key);
 471 }
 472
 473 static int dh_pkey_param_check(const EVP_PKEY *pkey)
 474 {
 475     DH *dh = pkey->pkey.dh;
 476
 477     return DH_check_ex(dh);
 478 }
 479
 480 static size_t dh_pkey_dirty_cnt(const EVP_PKEY *pkey)
 481 {
 482     return pkey->pkey.dh->dirty_cnt;
 483 }
 484
 485 static void *dh_pkey_export_to(const EVP_PKEY *pk, EVP_KEYMGMT *keymgmt,
 486                                int want_domainparams)
 487 {
 488     DH *dh = pk->pkey.dh;
 489     OSSL_PARAM_BLD tmpl;
 490     const BIGNUM *p = DH_get0_p(dh), *g = DH_get0_g(dh), *q = DH_get0_q(dh);
 491     const BIGNUM *pub_key = DH_get0_pub_key(dh);
 492     const BIGNUM *priv_key = DH_get0_priv_key(dh);
 493     OSSL_PARAM *params;
 494     void *provdata = NULL;
 495
 496     if (p == NULL || g == NULL)
 497         return NULL;
 498
 499     ossl_param_bld_init(&tmpl);
 500     if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_P, p)
 501         || !ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_G, g))
 502         return NULL;
 503     if (q != NULL) {
 504         if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_Q, q))
 505             return NULL;
 506     }
 507
 508     if (!want_domainparams) {
 509         /* A key must at least have a public part. */
 510         if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_PUB_KEY,
 511                                     pub_key))
 512             return NULL;
 513
 514         if (priv_key != NULL) {
 515             if (!ossl_param_bld_push_BN(&tmpl, OSSL_PKEY_PARAM_DH_PRIV_KEY,
 516                                         priv_key))
 517                 return NULL;
 518         }
 519     }
 520
 521     params = ossl_param_bld_to_param(&tmpl);
 522
 523     /* We export, the provider imports */
 524     provdata = want_domainparams
 525         ? evp_keymgmt_importdomparams(keymgmt, params)
 526         : evp_keymgmt_importkey(keymgmt, params);
 527
 528     ossl_param_bld_free(params);
 529     return provdata;
 530 }
 531
 532 const EVP_PKEY_ASN1_METHOD dh_asn1_meth = {
 533     EVP_PKEY_DH,
 534     EVP_PKEY_DH,
 535     0,
 536
 537     "DH",
 538     "OpenSSL PKCS#3 DH method",
 539
 540     dh_pub_decode,
 541     dh_pub_encode,
 542     dh_pub_cmp,
 543     dh_public_print,
 544
 545     dh_priv_decode,
 546     dh_priv_encode,
 547     dh_private_print,
 548
 549     int_dh_size,
 550     dh_bits,
 551     dh_security_bits,
 552
 553     dh_param_decode,
 554     dh_param_encode,
 555     dh_missing_parameters,
 556     dh_copy_parameters,
 557     dh_cmp_parameters,
 558     dh_param_print,
 559     0,
 560
 561     int_dh_free,
 562     dh_pkey_ctrl,
 563
 564     0, 0, 0, 0, 0,
 565
 566     0,
 567     dh_pkey_public_check,
 568     dh_pkey_param_check,
 569
 570     0, 0, 0, 0,
 571
 572     dh_pkey_dirty_cnt,
 573     dh_pkey_export_to,
 574 };
 575
 576 const EVP_PKEY_ASN1_METHOD dhx_asn1_meth = {
 577     EVP_PKEY_DHX,
 578     EVP_PKEY_DHX,
 579     0,
 580
 581     "X9.42 DH",
 582     "OpenSSL X9.42 DH method",
 583
 584     dh_pub_decode,
 585     dh_pub_encode,
 586     dh_pub_cmp,
 587     dh_public_print,
 588
 589     dh_priv_decode,
 590     dh_priv_encode,
 591     dh_private_print,
 592
 593     int_dh_size,
 594     dh_bits,
 595     dh_security_bits,
 596
 597     dh_param_decode,
 598     dh_param_encode,
 599     dh_missing_parameters,
 600     dh_copy_parameters,
 601     dh_cmp_parameters,
 602     dh_param_print,
 603     0,
 604
 605     int_dh_free,
 606     dhx_pkey_ctrl,
 607
 608     0, 0, 0, 0, 0,
 609
 610     0,
 611     dh_pkey_public_check,
 612     dh_pkey_param_check
 613 };
 614
 615 #ifndef OPENSSL_NO_CMS
 616
 617 static int dh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
 618                               X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
 619 {
 620     const ASN1_OBJECT *aoid;
 621     int atype;
 622     const void *aval;
 623     ASN1_INTEGER *public_key = NULL;
 624     int rv = 0;
 625     EVP_PKEY *pkpeer = NULL, *pk = NULL;
 626     DH *dhpeer = NULL;
 627     const unsigned char *p;
 628     int plen;
 629
 630     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
 631     if (OBJ_obj2nid(aoid) != NID_dhpublicnumber)
 632         goto err;
 633     /* Only absent parameters allowed in RFC XXXX */
 634     if (atype != V_ASN1_UNDEF && atype == V_ASN1_NULL)
 635         goto err;
 636
 637     pk = EVP_PKEY_CTX_get0_pkey(pctx);
 638     if (pk == NULL)
 639         goto err;
 640     if (pk->type != EVP_PKEY_DHX)
 641         goto err;
 642     /* Get parameters from parent key */
 643     dhpeer = DHparams_dup(pk->pkey.dh);
 644     /* We have parameters now set public key */
 645     plen = ASN1_STRING_length(pubkey);
 646     p = ASN1_STRING_get0_data(pubkey);
 647     if (p == NULL || plen == 0)
 648         goto err;
 649
 650     if ((public_key = d2i_ASN1_INTEGER(NULL, &p, plen)) == NULL) {
 651         DHerr(DH_F_DH_CMS_SET_PEERKEY, DH_R_DECODE_ERROR);
 652         goto err;
 653     }
 654
 655     /* We have parameters now set public key */
 656     if ((dhpeer->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL) {
 657         DHerr(DH_F_DH_CMS_SET_PEERKEY, DH_R_BN_DECODE_ERROR);
 658         goto err;
 659     }
 660
 661     pkpeer = EVP_PKEY_new();
 662     if (pkpeer == NULL)
 663         goto err;
 664     EVP_PKEY_assign(pkpeer, pk->ameth->pkey_id, dhpeer);
 665     dhpeer = NULL;
 666     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 667         rv = 1;
 668  err:
 669     ASN1_INTEGER_free(public_key);
 670     EVP_PKEY_free(pkpeer);
 671     DH_free(dhpeer);
 672     return rv;
 673 }
 674
 675 static int dh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 676 {
 677     int rv = 0;
 678
 679     X509_ALGOR *alg, *kekalg = NULL;
 680     ASN1_OCTET_STRING *ukm;
 681     const unsigned char *p;
 682     unsigned char *dukm = NULL;
 683     size_t dukmlen = 0;
 684     int keylen, plen;
 685     const EVP_CIPHER *kekcipher;
 686     EVP_CIPHER_CTX *kekctx;
 687
 688     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 689         goto err;
 690
 691     /*
 692      * For DH we only have one OID permissible. If ever any more get defined
 693      * we will need something cleverer.
 694      */
 695     if (OBJ_obj2nid(alg->algorithm) != NID_id_smime_alg_ESDH) {
 696         DHerr(DH_F_DH_CMS_SET_SHARED_INFO, DH_R_KDF_PARAMETER_ERROR);
 697         goto err;
 698     }
 699
 700     if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, EVP_PKEY_DH_KDF_X9_42) <= 0)
 701         goto err;
 702
 703     if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, EVP_sha1()) <= 0)
 704         goto err;
 705
 706     if (alg->parameter->type != V_ASN1_SEQUENCE)
 707         goto err;
 708
 709     p = alg->parameter->value.sequence->data;
 710     plen = alg->parameter->value.sequence->length;
 711     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 712     if (!kekalg)
 713         goto err;
 714     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 715     if (!kekctx)
 716         goto err;
 717     kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
 718     if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 719         goto err;
 720     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 721         goto err;
 722     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 723         goto err;
 724
 725     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 726     if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
 727         goto err;
 728     /* Use OBJ_nid2obj to ensure we use built in OID that isn't freed */
 729     if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx,
 730                                      OBJ_nid2obj(EVP_CIPHER_type(kekcipher)))
 731         <= 0)
 732         goto err;
 733
 734     if (ukm) {
 735         dukmlen = ASN1_STRING_length(ukm);
 736         dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
 737         if (!dukm)
 738             goto err;
 739     }
 740
 741     if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
 742         goto err;
 743     dukm = NULL;
 744
 745     rv = 1;
 746  err:
 747     X509_ALGOR_free(kekalg);
 748     OPENSSL_free(dukm);
 749     return rv;
 750 }
 751
 752 static int dh_cms_decrypt(CMS_RecipientInfo *ri)
 753 {
 754     EVP_PKEY_CTX *pctx;
 755
 756     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 757
 758     if (pctx == NULL)
 759         return 0;
 760     /* See if we need to set peer key */
 761     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 762         X509_ALGOR *alg;
 763         ASN1_BIT_STRING *pubkey;
 764         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 765                                                  NULL, NULL, NULL))
 766             return 0;
 767         if (!alg || !pubkey)
 768             return 0;
 769         if (!dh_cms_set_peerkey(pctx, alg, pubkey)) {
 770             DHerr(DH_F_DH_CMS_DECRYPT, DH_R_PEER_KEY_ERROR);
 771             return 0;
 772         }
 773     }
 774     /* Set DH derivation parameters and initialise unwrap context */
 775     if (!dh_cms_set_shared_info(pctx, ri)) {
 776         DHerr(DH_F_DH_CMS_DECRYPT, DH_R_SHARED_INFO_ERROR);
 777         return 0;
 778     }
 779     return 1;
 780 }
 781
 782 static int dh_cms_encrypt(CMS_RecipientInfo *ri)
 783 {
 784     EVP_PKEY_CTX *pctx;
 785     EVP_PKEY *pkey;
 786     EVP_CIPHER_CTX *ctx;
 787     int keylen;
 788     X509_ALGOR *talg, *wrap_alg = NULL;
 789     const ASN1_OBJECT *aoid;
 790     ASN1_BIT_STRING *pubkey;
 791     ASN1_STRING *wrap_str;
 792     ASN1_OCTET_STRING *ukm;
 793     unsigned char *penc = NULL, *dukm = NULL;
 794     int penclen;
 795     size_t dukmlen = 0;
 796     int rv = 0;
 797     int kdf_type, wrap_nid;
 798     const EVP_MD *kdf_md;
 799
 800     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 801     if (pctx == NULL)
 802         return 0;
 803     /* Get ephemeral key */
 804     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 805     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 806                                              NULL, NULL, NULL))
 807         goto err;
 808     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 809     /* Is everything uninitialised? */
 810     if (aoid == OBJ_nid2obj(NID_undef)) {
 811         ASN1_INTEGER *pubk = BN_to_ASN1_INTEGER(pkey->pkey.dh->pub_key, NULL);
 812
 813         if (pubk == NULL)
 814             goto err;
 815         /* Set the key */
 816
 817         penclen = i2d_ASN1_INTEGER(pubk, &penc);
 818         ASN1_INTEGER_free(pubk);
 819         if (penclen <= 0)
 820             goto err;
 821         ASN1_STRING_set0(pubkey, penc, penclen);
 822         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 823         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 824
 825         penc = NULL;
 826         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_dhpublicnumber),
 827                         V_ASN1_UNDEF, NULL);
 828     }
 829
 830     /* See if custom parameters set */
 831     kdf_type = EVP_PKEY_CTX_get_dh_kdf_type(pctx);
 832     if (kdf_type <= 0)
 833         goto err;
 834     if (!EVP_PKEY_CTX_get_dh_kdf_md(pctx, &kdf_md))
 835         goto err;
 836
 837     if (kdf_type == EVP_PKEY_DH_KDF_NONE) {
 838         kdf_type = EVP_PKEY_DH_KDF_X9_42;
 839         if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, kdf_type) <= 0)
 840             goto err;
 841     } else if (kdf_type != EVP_PKEY_DH_KDF_X9_42)
 842         /* Unknown KDF */
 843         goto err;
 844     if (kdf_md == NULL) {
 845         /* Only SHA1 supported */
 846         kdf_md = EVP_sha1();
 847         if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, kdf_md) <= 0)
 848             goto err;
 849     } else if (EVP_MD_type(kdf_md) != NID_sha1)
 850         /* Unsupported digest */
 851         goto err;
 852
 853     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 854         goto err;
 855
 856     /* Get wrap NID */
 857     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 858     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 859     if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx, OBJ_nid2obj(wrap_nid)) <= 0)
 860         goto err;
 861     keylen = EVP_CIPHER_CTX_key_length(ctx);
 862
 863     /* Package wrap algorithm in an AlgorithmIdentifier */
 864
 865     wrap_alg = X509_ALGOR_new();
 866     if (wrap_alg == NULL)
 867         goto err;
 868     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 869     wrap_alg->parameter = ASN1_TYPE_new();
 870     if (wrap_alg->parameter == NULL)
 871         goto err;
 872     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 873         goto err;
 874     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 875         ASN1_TYPE_free(wrap_alg->parameter);
 876         wrap_alg->parameter = NULL;
 877     }
 878
 879     if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
 880         goto err;
 881
 882     if (ukm) {
 883         dukmlen = ASN1_STRING_length(ukm);
 884         dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
 885         if (!dukm)
 886             goto err;
 887     }
 888
 889     if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
 890         goto err;
 891     dukm = NULL;
 892
 893     /*
 894      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 895      * of another AlgorithmIdentifier.
 896      */
 897     penc = NULL;
 898     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 899     if (penc == NULL || penclen == 0)
 900         goto err;
 901     wrap_str = ASN1_STRING_new();
 902     if (wrap_str == NULL)
 903         goto err;
 904     ASN1_STRING_set0(wrap_str, penc, penclen);
 905     penc = NULL;
 906     X509_ALGOR_set0(talg, OBJ_nid2obj(NID_id_smime_alg_ESDH),
 907                     V_ASN1_SEQUENCE, wrap_str);
 908
 909     rv = 1;
 910
 911  err:
 912     OPENSSL_free(penc);
 913     X509_ALGOR_free(wrap_alg);
 914     OPENSSL_free(dukm);
 915     return rv;
 916 }
 917
 918 #endif