crypto/evp/kem.c

   1 /*
   2  * Copyright 2020-2021 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 <stdlib.h>
  12 #include <openssl/objects.h>
  13 #include <openssl/evp.h>
  14 #include "internal/cryptlib.h"
  15 #include "internal/provider.h"
  16 #include "internal/core.h"
  17 #include "crypto/evp.h"
  18 #include "evp_local.h"
  19
  20 static int evp_kem_init(EVP_PKEY_CTX *ctx, int operation,
  21                         const OSSL_PARAM params[])
  22 {
  23     int ret = 0;
  24     EVP_KEM *kem = NULL;
  25     EVP_KEYMGMT *tmp_keymgmt = NULL;
  26     const OSSL_PROVIDER *tmp_prov = NULL;
  27     void *provkey = NULL;
  28     const char *supported_kem = NULL;
  29     int iter;
  30
  31     if (ctx == NULL || ctx->keytype == NULL) {
  32         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  33         return 0;
  34     }
  35
  36     evp_pkey_ctx_free_old_ops(ctx);
  37     ctx->operation = operation;
  38
  39     if (ctx->pkey == NULL) {
  40         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
  41         goto err;
  42     }
  43
  44     /*
  45      * Try to derive the supported kem from |ctx->keymgmt|.
  46      */
  47     if (!ossl_assert(ctx->pkey->keymgmt == NULL
  48                      || ctx->pkey->keymgmt == ctx->keymgmt)) {
  49         ERR_raise(ERR_LIB_EVP, ERR_R_INTERNAL_ERROR);
  50         goto err;
  51     }
  52     supported_kem = evp_keymgmt_util_query_operation_name(ctx->keymgmt,
  53                                                           OSSL_OP_KEM);
  54     if (supported_kem == NULL) {
  55         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  56         goto err;
  57     }
  58
  59     /*
  60      * Because we cleared out old ops, we shouldn't need to worry about
  61      * checking if kem is already there.
  62      * We perform two iterations:
  63      *
  64      * 1.  Do the normal kem fetch, using the fetching data given by
  65      *     the EVP_PKEY_CTX.
  66      * 2.  Do the provider specific kem fetch, from the same provider
  67      *     as |ctx->keymgmt|
  68      *
  69      * We then try to fetch the keymgmt from the same provider as the
  70      * kem, and try to export |ctx->pkey| to that keymgmt (when this
  71      * keymgmt happens to be the same as |ctx->keymgmt|, the export is
  72      * a no-op, but we call it anyway to not complicate the code even
  73      * more).
  74      * If the export call succeeds (returns a non-NULL provider key pointer),
  75      * we're done and can perform the operation itself.  If not, we perform
  76      * the second iteration, or jump to legacy.
  77      */
  78     for (iter = 1, provkey = NULL; iter < 3 && provkey == NULL; iter++) {
  79         EVP_KEYMGMT *tmp_keymgmt_tofree = NULL;
  80
  81         /*
  82          * If we're on the second iteration, free the results from the first.
  83          * They are NULL on the first iteration, so no need to check what
  84          * iteration we're on.
  85          */
  86         EVP_KEM_free(kem);
  87         EVP_KEYMGMT_free(tmp_keymgmt);
  88
  89         switch (iter) {
  90         case 1:
  91             kem = EVP_KEM_fetch(ctx->libctx, supported_kem, ctx->propquery);
  92             if (kem != NULL)
  93                 tmp_prov = EVP_KEM_get0_provider(kem);
  94             break;
  95         case 2:
  96             tmp_prov = EVP_KEYMGMT_get0_provider(ctx->keymgmt);
  97             kem = evp_kem_fetch_from_prov((OSSL_PROVIDER *)tmp_prov,
  98                                           supported_kem, ctx->propquery);
  99
 100             if (kem == NULL) {
 101                 ERR_raise(ERR_LIB_EVP,
 102                           EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 103                 ret = -2;
 104                 goto err;
 105             }
 106         }
 107         if (kem == NULL)
 108             continue;
 109
 110         /*
 111          * Ensure that the key is provided, either natively, or as a cached
 112          * export.  We start by fetching the keymgmt with the same name as
 113          * |ctx->pkey|, but from the provider of the kem method, using the
 114          * same property query as when fetching the kem method.
 115          * With the keymgmt we found (if we did), we try to export |ctx->pkey|
 116          * to it (evp_pkey_export_to_provider() is smart enough to only actually
 117
 118          * export it if |tmp_keymgmt| is different from |ctx->pkey|'s keymgmt)
 119          */
 120         tmp_keymgmt_tofree = tmp_keymgmt =
 121             evp_keymgmt_fetch_from_prov((OSSL_PROVIDER *)tmp_prov,
 122                                         EVP_KEYMGMT_get0_name(ctx->keymgmt),
 123                                         ctx->propquery);
 124         if (tmp_keymgmt != NULL)
 125             provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 126                                                   &tmp_keymgmt, ctx->propquery);
 127         if (tmp_keymgmt == NULL)
 128             EVP_KEYMGMT_free(tmp_keymgmt_tofree);
 129     }
 130
 131     if (provkey == NULL) {
 132         EVP_KEM_free(kem);
 133         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 134         goto err;
 135     }
 136
 137     ctx->op.encap.kem = kem;
 138     ctx->op.encap.algctx = kem->newctx(ossl_provider_ctx(kem->prov));
 139     if (ctx->op.encap.algctx == NULL) {
 140         /* The provider key can stay in the cache */
 141         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 142         goto err;
 143     }
 144
 145     switch (operation) {
 146     case EVP_PKEY_OP_ENCAPSULATE:
 147         if (kem->encapsulate_init == NULL) {
 148             ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 149             ret = -2;
 150             goto err;
 151         }
 152         ret = kem->encapsulate_init(ctx->op.encap.algctx, provkey, params);
 153         break;
 154     case EVP_PKEY_OP_DECAPSULATE:
 155         if (kem->decapsulate_init == NULL) {
 156             ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 157             ret = -2;
 158             goto err;
 159         }
 160         ret = kem->decapsulate_init(ctx->op.encap.algctx, provkey, params);
 161         break;
 162     default:
 163         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 164         goto err;
 165     }
 166
 167     EVP_KEYMGMT_free(tmp_keymgmt);
 168     tmp_keymgmt = NULL;
 169
 170     if (ret > 0)
 171         return 1;
 172  err:
 173     if (ret <= 0) {
 174         evp_pkey_ctx_free_old_ops(ctx);
 175         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 176     }
 177     EVP_KEYMGMT_free(tmp_keymgmt);
 178     return ret;
 179 }
 180
 181 int EVP_PKEY_encapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 182 {
 183     return evp_kem_init(ctx, EVP_PKEY_OP_ENCAPSULATE, params);
 184 }
 185
 186 int EVP_PKEY_encapsulate(EVP_PKEY_CTX *ctx,
 187                          unsigned char *out, size_t *outlen,
 188                          unsigned char *secret, size_t *secretlen)
 189 {
 190     if (ctx == NULL)
 191         return 0;
 192
 193     if (ctx->operation != EVP_PKEY_OP_ENCAPSULATE) {
 194         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 195         return -1;
 196     }
 197
 198     if (ctx->op.encap.algctx == NULL) {
 199         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 200         return -2;
 201     }
 202
 203     if (out != NULL && secret == NULL)
 204         return 0;
 205
 206     return ctx->op.encap.kem->encapsulate(ctx->op.encap.algctx,
 207                                           out, outlen, secret, secretlen);
 208 }
 209
 210 int EVP_PKEY_decapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 211 {
 212     return evp_kem_init(ctx, EVP_PKEY_OP_DECAPSULATE, params);
 213 }
 214
 215 int EVP_PKEY_decapsulate(EVP_PKEY_CTX *ctx,
 216                          unsigned char *secret, size_t *secretlen,
 217                          const unsigned char *in, size_t inlen)
 218 {
 219     if (ctx == NULL
 220         || (in == NULL || inlen == 0)
 221         || (secret == NULL && secretlen == NULL))
 222         return 0;
 223
 224     if (ctx->operation != EVP_PKEY_OP_DECAPSULATE) {
 225         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 226         return -1;
 227     }
 228
 229     if (ctx->op.encap.algctx == NULL) {
 230         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 231         return -2;
 232     }
 233     return ctx->op.encap.kem->decapsulate(ctx->op.encap.algctx,
 234                                           secret, secretlen, in, inlen);
 235 }
 236
 237 static EVP_KEM *evp_kem_new(OSSL_PROVIDER *prov)
 238 {
 239     EVP_KEM *kem = OPENSSL_zalloc(sizeof(EVP_KEM));
 240
 241     if (kem == NULL) {
 242         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 243         return NULL;
 244     }
 245
 246     kem->lock = CRYPTO_THREAD_lock_new();
 247     if (kem->lock == NULL) {
 248         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 249         OPENSSL_free(kem);
 250         return NULL;
 251     }
 252     kem->prov = prov;
 253     ossl_provider_up_ref(prov);
 254     kem->refcnt = 1;
 255
 256     return kem;
 257 }
 258
 259 static void *evp_kem_from_algorithm(int name_id, const OSSL_ALGORITHM *algodef,
 260                                     OSSL_PROVIDER *prov)
 261 {
 262     const OSSL_DISPATCH *fns = algodef->implementation;
 263     EVP_KEM *kem = NULL;
 264     int ctxfncnt = 0, encfncnt = 0, decfncnt = 0;
 265     int gparamfncnt = 0, sparamfncnt = 0;
 266
 267     if ((kem = evp_kem_new(prov)) == NULL) {
 268         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 269         goto err;
 270     }
 271
 272     kem->name_id = name_id;
 273     if ((kem->type_name = ossl_algorithm_get1_first_name(algodef)) == NULL)
 274         goto err;
 275     kem->description = algodef->algorithm_description;
 276
 277     for (; fns->function_id != 0; fns++) {
 278         switch (fns->function_id) {
 279         case OSSL_FUNC_KEM_NEWCTX:
 280             if (kem->newctx != NULL)
 281                 break;
 282             kem->newctx = OSSL_FUNC_kem_newctx(fns);
 283             ctxfncnt++;
 284             break;
 285         case OSSL_FUNC_KEM_ENCAPSULATE_INIT:
 286             if (kem->encapsulate_init != NULL)
 287                 break;
 288             kem->encapsulate_init = OSSL_FUNC_kem_encapsulate_init(fns);
 289             encfncnt++;
 290             break;
 291         case OSSL_FUNC_KEM_ENCAPSULATE:
 292             if (kem->encapsulate != NULL)
 293                 break;
 294             kem->encapsulate = OSSL_FUNC_kem_encapsulate(fns);
 295             encfncnt++;
 296             break;
 297         case OSSL_FUNC_KEM_DECAPSULATE_INIT:
 298             if (kem->decapsulate_init != NULL)
 299                 break;
 300             kem->decapsulate_init = OSSL_FUNC_kem_decapsulate_init(fns);
 301             decfncnt++;
 302             break;
 303         case OSSL_FUNC_KEM_DECAPSULATE:
 304             if (kem->decapsulate != NULL)
 305                 break;
 306             kem->decapsulate = OSSL_FUNC_kem_decapsulate(fns);
 307             decfncnt++;
 308             break;
 309         case OSSL_FUNC_KEM_FREECTX:
 310             if (kem->freectx != NULL)
 311                 break;
 312             kem->freectx = OSSL_FUNC_kem_freectx(fns);
 313             ctxfncnt++;
 314             break;
 315         case OSSL_FUNC_KEM_DUPCTX:
 316             if (kem->dupctx != NULL)
 317                 break;
 318             kem->dupctx = OSSL_FUNC_kem_dupctx(fns);
 319             break;
 320         case OSSL_FUNC_KEM_GET_CTX_PARAMS:
 321             if (kem->get_ctx_params != NULL)
 322                 break;
 323             kem->get_ctx_params
 324                 = OSSL_FUNC_kem_get_ctx_params(fns);
 325             gparamfncnt++;
 326             break;
 327         case OSSL_FUNC_KEM_GETTABLE_CTX_PARAMS:
 328             if (kem->gettable_ctx_params != NULL)
 329                 break;
 330             kem->gettable_ctx_params
 331                 = OSSL_FUNC_kem_gettable_ctx_params(fns);
 332             gparamfncnt++;
 333             break;
 334         case OSSL_FUNC_KEM_SET_CTX_PARAMS:
 335             if (kem->set_ctx_params != NULL)
 336                 break;
 337             kem->set_ctx_params
 338                 = OSSL_FUNC_kem_set_ctx_params(fns);
 339             sparamfncnt++;
 340             break;
 341         case OSSL_FUNC_KEM_SETTABLE_CTX_PARAMS:
 342             if (kem->settable_ctx_params != NULL)
 343                 break;
 344             kem->settable_ctx_params
 345                 = OSSL_FUNC_kem_settable_ctx_params(fns);
 346             sparamfncnt++;
 347             break;
 348         }
 349     }
 350     if (ctxfncnt != 2
 351         || (encfncnt != 0 && encfncnt != 2)
 352         || (decfncnt != 0 && decfncnt != 2)
 353         || (encfncnt != 2 && decfncnt != 2)
 354         || (gparamfncnt != 0 && gparamfncnt != 2)
 355         || (sparamfncnt != 0 && sparamfncnt != 2)) {
 356         /*
 357          * In order to be a consistent set of functions we must have at least
 358          * a set of context functions (newctx and freectx) as well as a pair of
 359          * "kem" functions: (encapsulate_init, encapsulate) or
 360          * (decapsulate_init, decapsulate). set_ctx_params and settable_ctx_params are
 361          * optional, but if one of them is present then the other one must also
 362          * be present. The same applies to get_ctx_params and
 363          * gettable_ctx_params. The dupctx function is optional.
 364          */
 365         ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_PROVIDER_FUNCTIONS);
 366         goto err;
 367     }
 368
 369     return kem;
 370  err:
 371     EVP_KEM_free(kem);
 372     return NULL;
 373 }
 374
 375 void EVP_KEM_free(EVP_KEM *kem)
 376 {
 377     int i;
 378
 379     if (kem == NULL)
 380         return;
 381
 382     CRYPTO_DOWN_REF(&kem->refcnt, &i, kem->lock);
 383     if (i > 0)
 384         return;
 385     OPENSSL_free(kem->type_name);
 386     ossl_provider_free(kem->prov);
 387     CRYPTO_THREAD_lock_free(kem->lock);
 388     OPENSSL_free(kem);
 389 }
 390
 391 int EVP_KEM_up_ref(EVP_KEM *kem)
 392 {
 393     int ref = 0;
 394
 395     CRYPTO_UP_REF(&kem->refcnt, &ref, kem->lock);
 396     return 1;
 397 }
 398
 399 OSSL_PROVIDER *EVP_KEM_get0_provider(const EVP_KEM *kem)
 400 {
 401     return kem->prov;
 402 }
 403
 404 EVP_KEM *EVP_KEM_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 405                        const char *properties)
 406 {
 407     return evp_generic_fetch(ctx, OSSL_OP_KEM, algorithm, properties,
 408                              evp_kem_from_algorithm,
 409                              (int (*)(void *))EVP_KEM_up_ref,
 410                              (void (*)(void *))EVP_KEM_free);
 411 }
 412
 413 EVP_KEM *evp_kem_fetch_from_prov(OSSL_PROVIDER *prov, const char *algorithm,
 414                                  const char *properties)
 415 {
 416     return evp_generic_fetch_from_prov(prov, OSSL_OP_KEM, algorithm, properties,
 417                                        evp_kem_from_algorithm,
 418                                        (int (*)(void *))EVP_KEM_up_ref,
 419                                        (void (*)(void *))EVP_KEM_free);
 420 }
 421
 422 int EVP_KEM_is_a(const EVP_KEM *kem, const char *name)
 423 {
 424     return kem != NULL && evp_is_a(kem->prov, kem->name_id, NULL, name);
 425 }
 426
 427 int evp_kem_get_number(const EVP_KEM *kem)
 428 {
 429     return kem->name_id;
 430 }
 431
 432 const char *EVP_KEM_get0_name(const EVP_KEM *kem)
 433 {
 434     return kem->type_name;
 435 }
 436
 437 const char *EVP_KEM_get0_description(const EVP_KEM *kem)
 438 {
 439     return kem->description;
 440 }
 441
 442 void EVP_KEM_do_all_provided(OSSL_LIB_CTX *libctx,
 443                              void (*fn)(EVP_KEM *kem, void *arg),
 444                              void *arg)
 445 {
 446     evp_generic_do_all(libctx, OSSL_OP_KEM, (void (*)(void *, void *))fn, arg,
 447                        evp_kem_from_algorithm,
 448                        (int (*)(void *))EVP_KEM_up_ref,
 449                        (void (*)(void *))EVP_KEM_free);
 450 }
 451
 452 int EVP_KEM_names_do_all(const EVP_KEM *kem,
 453                          void (*fn)(const char *name, void *data),
 454                          void *data)
 455 {
 456     if (kem->prov != NULL)
 457         return evp_names_do_all(kem->prov, kem->name_id, fn, data);
 458
 459     return 1;
 460 }
 461
 462 const OSSL_PARAM *EVP_KEM_gettable_ctx_params(const EVP_KEM *kem)
 463 {
 464     void *provctx;
 465
 466     if (kem == NULL || kem->gettable_ctx_params == NULL)
 467         return NULL;
 468
 469     provctx = ossl_provider_ctx(EVP_KEM_get0_provider(kem));
 470     return kem->gettable_ctx_params(NULL, provctx);
 471 }
 472
 473 const OSSL_PARAM *EVP_KEM_settable_ctx_params(const EVP_KEM *kem)
 474 {
 475     void *provctx;
 476
 477     if (kem == NULL || kem->settable_ctx_params == NULL)
 478         return NULL;
 479
 480     provctx = ossl_provider_ctx(EVP_KEM_get0_provider(kem));
 481     return kem->settable_ctx_params(NULL, provctx);
 482 }