crypto/cms/cms_ec.c

   1 /*
   2  * Copyright 2006-2020 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 <assert.h>
  11 #include <openssl/cms.h>
  12 #include <openssl/err.h>
  13 #include <openssl/decoder.h>
  14 #include "cms_local.h"
  15 #include "crypto/evp.h"
  16
  17 #ifndef OPENSSL_NO_EC
  18 static EVP_PKEY *pkey_type2param(int ptype, const void *pval,
  19                                  OSSL_LIB_CTX *libctx, const char *propq)
  20 {
  21     EVP_PKEY *pkey = NULL;
  22     EVP_PKEY_CTX *pctx = NULL;
  23
  24     if (ptype == V_ASN1_SEQUENCE) {
  25         const ASN1_STRING *pstr = pval;
  26         const unsigned char *pm = pstr->data;
  27         size_t pmlen = (size_t)pstr->length;
  28         OSSL_DECODER_CTX *ctx = NULL;
  29         int selection = OSSL_KEYMGMT_SELECT_ALL_PARAMETERS;
  30
  31         ctx = OSSL_DECODER_CTX_new_by_EVP_PKEY(&pkey, "DER", NULL, "EC",
  32                                                selection, libctx, propq);
  33         if (ctx == NULL)
  34             goto err;
  35
  36         OSSL_DECODER_from_data(ctx, &pm, &pmlen);
  37         OSSL_DECODER_CTX_free(ctx);
  38     } else if (ptype == V_ASN1_OBJECT) {
  39         const ASN1_OBJECT *poid = pval;
  40         const char *groupname;
  41
  42         /* type == V_ASN1_OBJECT => the parameters are given by an asn1 OID */
  43         pctx = EVP_PKEY_CTX_new_from_name(libctx, "EC", propq);
  44         if (pctx == NULL || EVP_PKEY_paramgen_init(pctx) <= 0)
  45             goto err;
  46         groupname = OBJ_nid2sn(OBJ_obj2nid(poid));
  47         if (groupname == NULL
  48                 || !EVP_PKEY_CTX_set_group_name(pctx, groupname)) {
  49             ERR_raise(ERR_LIB_CMS, CMS_R_DECODE_ERROR);
  50             goto err;
  51         }
  52         if (EVP_PKEY_paramgen(pctx, &pkey) <= 0)
  53             goto err;
  54     } else {
  55         ERR_raise(ERR_LIB_CMS, CMS_R_DECODE_ERROR);
  56         goto err;
  57     }
  58
  59     return pkey;
  60
  61  err:
  62     EVP_PKEY_free(pkey);
  63     EVP_PKEY_CTX_free(pctx);
  64     return NULL;
  65 }
  66
  67 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
  68                                 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
  69 {
  70     const ASN1_OBJECT *aoid;
  71     int atype;
  72     const void *aval;
  73     int rv = 0;
  74     EVP_PKEY *pkpeer = NULL;
  75     const unsigned char *p;
  76     int plen;
  77
  78     X509_ALGOR_get0(&aoid, &atype, &aval, alg);
  79     if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
  80         goto err;
  81
  82     /* If absent parameters get group from main key */
  83     if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
  84         EVP_PKEY *pk;
  85
  86         pk = EVP_PKEY_CTX_get0_pkey(pctx);
  87         if (pk == NULL)
  88             goto err;
  89
  90         pkpeer = EVP_PKEY_new();
  91         if (pkpeer == NULL)
  92             goto err;
  93         if (!EVP_PKEY_copy_parameters(pkpeer, pk))
  94             goto err;
  95     } else {
  96         pkpeer = pkey_type2param(atype, aval,
  97                                  EVP_PKEY_CTX_get0_libctx(pctx),
  98                                  EVP_PKEY_CTX_get0_propq(pctx));
  99         if (pkpeer == NULL)
 100             goto err;
 101     }
 102     /* We have parameters now set public key */
 103     plen = ASN1_STRING_length(pubkey);
 104     p = ASN1_STRING_get0_data(pubkey);
 105     if (p == NULL || plen == 0)
 106         goto err;
 107
 108     if (!EVP_PKEY_set1_encoded_public_key(pkpeer, p, plen))
 109         goto err;
 110
 111     if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
 112         rv = 1;
 113  err:
 114     EVP_PKEY_free(pkpeer);
 115     return rv;
 116 }
 117
 118 /* Set KDF parameters based on KDF NID */
 119 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
 120 {
 121     int kdf_nid, kdfmd_nid, cofactor;
 122     const EVP_MD *kdf_md;
 123
 124     if (eckdf_nid == NID_undef)
 125         return 0;
 126
 127     /* Lookup KDF type, cofactor mode and digest */
 128     if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
 129         return 0;
 130
 131     if (kdf_nid == NID_dh_std_kdf)
 132         cofactor = 0;
 133     else if (kdf_nid == NID_dh_cofactor_kdf)
 134         cofactor = 1;
 135     else
 136         return 0;
 137
 138     if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
 139         return 0;
 140
 141     if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
 142         return 0;
 143
 144     kdf_md = EVP_get_digestbynid(kdfmd_nid);
 145     if (!kdf_md)
 146         return 0;
 147
 148     if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 149         return 0;
 150     return 1;
 151 }
 152
 153 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
 154 {
 155     int rv = 0;
 156     X509_ALGOR *alg, *kekalg = NULL;
 157     ASN1_OCTET_STRING *ukm;
 158     const unsigned char *p;
 159     unsigned char *der = NULL;
 160     int plen, keylen;
 161     EVP_CIPHER *kekcipher = NULL;
 162     EVP_CIPHER_CTX *kekctx;
 163     const char *name;
 164
 165     if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
 166         return 0;
 167
 168     if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
 169         ERR_raise(ERR_LIB_CMS, CMS_R_KDF_PARAMETER_ERROR);
 170         return 0;
 171     }
 172
 173     if (alg->parameter->type != V_ASN1_SEQUENCE)
 174         return 0;
 175
 176     p = alg->parameter->value.sequence->data;
 177     plen = alg->parameter->value.sequence->length;
 178     kekalg = d2i_X509_ALGOR(NULL, &p, plen);
 179     if (kekalg == NULL)
 180         goto err;
 181     kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 182     if (kekctx == NULL)
 183         goto err;
 184     name = OBJ_nid2sn(OBJ_obj2nid(kekalg->algorithm));
 185     kekcipher = EVP_CIPHER_fetch(pctx->libctx, name, pctx->propquery);
 186     if (kekcipher == NULL || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
 187         goto err;
 188     if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
 189         goto err;
 190     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
 191         goto err;
 192
 193     keylen = EVP_CIPHER_CTX_key_length(kekctx);
 194     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 195         goto err;
 196
 197     plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
 198
 199     if (plen <= 0)
 200         goto err;
 201
 202     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
 203         goto err;
 204     der = NULL;
 205
 206     rv = 1;
 207  err:
 208     EVP_CIPHER_free(kekcipher);
 209     X509_ALGOR_free(kekalg);
 210     OPENSSL_free(der);
 211     return rv;
 212 }
 213
 214 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
 215 {
 216     EVP_PKEY_CTX *pctx;
 217
 218     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 219     if (pctx == NULL)
 220         return 0;
 221     /* See if we need to set peer key */
 222     if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
 223         X509_ALGOR *alg;
 224         ASN1_BIT_STRING *pubkey;
 225
 226         if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
 227                                                  NULL, NULL, NULL))
 228             return 0;
 229         if (alg == NULL || pubkey == NULL)
 230             return 0;
 231         if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
 232             ERR_raise(ERR_LIB_CMS, CMS_R_PEER_KEY_ERROR);
 233             return 0;
 234         }
 235     }
 236     /* Set ECDH derivation parameters and initialise unwrap context */
 237     if (!ecdh_cms_set_shared_info(pctx, ri)) {
 238         ERR_raise(ERR_LIB_CMS, CMS_R_SHARED_INFO_ERROR);
 239         return 0;
 240     }
 241     return 1;
 242 }
 243
 244 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
 245 {
 246     EVP_PKEY_CTX *pctx;
 247     EVP_PKEY *pkey;
 248     EVP_CIPHER_CTX *ctx;
 249     int keylen;
 250     X509_ALGOR *talg, *wrap_alg = NULL;
 251     const ASN1_OBJECT *aoid;
 252     ASN1_BIT_STRING *pubkey;
 253     ASN1_STRING *wrap_str;
 254     ASN1_OCTET_STRING *ukm;
 255     unsigned char *penc = NULL;
 256     size_t penclen;
 257     int rv = 0;
 258     int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
 259     const EVP_MD *kdf_md;
 260
 261     pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
 262     if (pctx == NULL)
 263         return 0;
 264     /* Get ephemeral key */
 265     pkey = EVP_PKEY_CTX_get0_pkey(pctx);
 266     if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
 267                                              NULL, NULL, NULL))
 268         goto err;
 269     X509_ALGOR_get0(&aoid, NULL, NULL, talg);
 270     /* Is everything uninitialised? */
 271     if (aoid == OBJ_nid2obj(NID_undef)) {
 272         /* Set the key */
 273
 274         penclen = EVP_PKEY_get1_encoded_public_key(pkey, &penc);
 275         ASN1_STRING_set0(pubkey, penc, penclen);
 276         pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 277         pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 278
 279         penc = NULL;
 280         X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
 281                         V_ASN1_UNDEF, NULL);
 282     }
 283
 284     /* See if custom parameters set */
 285     kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
 286     if (kdf_type <= 0)
 287         goto err;
 288     if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
 289         goto err;
 290     ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
 291     if (ecdh_nid < 0)
 292         goto err;
 293     else if (ecdh_nid == 0)
 294         ecdh_nid = NID_dh_std_kdf;
 295     else if (ecdh_nid == 1)
 296         ecdh_nid = NID_dh_cofactor_kdf;
 297
 298     if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
 299         kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
 300         if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
 301             goto err;
 302     } else
 303         /* Unknown KDF */
 304         goto err;
 305     if (kdf_md == NULL) {
 306         /* Fixme later for better MD */
 307         kdf_md = EVP_sha1();
 308         if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
 309             goto err;
 310     }
 311
 312     if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
 313         goto err;
 314
 315     /* Lookup NID for KDF+cofactor+digest */
 316
 317     if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
 318         goto err;
 319     /* Get wrap NID */
 320     ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
 321     wrap_nid = EVP_CIPHER_CTX_type(ctx);
 322     keylen = EVP_CIPHER_CTX_key_length(ctx);
 323
 324     /* Package wrap algorithm in an AlgorithmIdentifier */
 325
 326     wrap_alg = X509_ALGOR_new();
 327     if (wrap_alg == NULL)
 328         goto err;
 329     wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
 330     wrap_alg->parameter = ASN1_TYPE_new();
 331     if (wrap_alg->parameter == NULL)
 332         goto err;
 333     if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
 334         goto err;
 335     if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
 336         ASN1_TYPE_free(wrap_alg->parameter);
 337         wrap_alg->parameter = NULL;
 338     }
 339
 340     if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
 341         goto err;
 342
 343     penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
 344
 345     if (penclen == 0)
 346         goto err;
 347
 348     if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
 349         goto err;
 350     penc = NULL;
 351
 352     /*
 353      * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
 354      * of another AlgorithmIdentifier.
 355      */
 356     penclen = i2d_X509_ALGOR(wrap_alg, &penc);
 357     if (penc == NULL || penclen == 0)
 358         goto err;
 359     wrap_str = ASN1_STRING_new();
 360     if (wrap_str == NULL)
 361         goto err;
 362     ASN1_STRING_set0(wrap_str, penc, penclen);
 363     penc = NULL;
 364     X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
 365
 366     rv = 1;
 367
 368  err:
 369     OPENSSL_free(penc);
 370     X509_ALGOR_free(wrap_alg);
 371     return rv;
 372 }
 373
 374 int cms_ecdh_envelope(CMS_RecipientInfo *ri, int decrypt)
 375 {
 376     assert(decrypt == 0 || decrypt == 1);
 377
 378     if (decrypt == 1)
 379         return ecdh_cms_decrypt(ri);
 380
 381     if (decrypt == 0)
 382         return ecdh_cms_encrypt(ri);
 383
 384     ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);
 385     return 0;
 386 }
 387 #endif
 388
 389 /* ECDSA and DSA implementation is the same */
 390 int cms_ecdsa_dsa_sign(CMS_SignerInfo *si, int verify)
 391 {
 392     assert(verify == 0 || verify == 1);
 393
 394     if (verify == 0) {
 395         int snid, hnid;
 396         X509_ALGOR *alg1, *alg2;
 397         EVP_PKEY *pkey = si->pkey;
 398
 399         CMS_SignerInfo_get0_algs(si, NULL, NULL, &alg1, &alg2);
 400         if (alg1 == NULL || alg1->algorithm == NULL)
 401             return -1;
 402         hnid = OBJ_obj2nid(alg1->algorithm);
 403         if (hnid == NID_undef)
 404             return -1;
 405         if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
 406             return -1;
 407         X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 408     }
 409     return 1;
 410 }