crypto/evp/exchange.c

   1 /*
   2  * Copyright 2019-2021 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 <openssl/crypto.h>
  11 #include <openssl/evp.h>
  12 #include <openssl/err.h>
  13 #include "internal/cryptlib.h"
  14 #include "internal/refcount.h"
  15 #include "internal/provider.h"
  16 #include "internal/core.h"
  17 #include "internal/numbers.h"   /* includes SIZE_MAX */
  18 #include "crypto/evp.h"
  19 #include "evp_local.h"
  20
  21 static EVP_KEYEXCH *evp_keyexch_new(OSSL_PROVIDER *prov)
  22 {
  23     EVP_KEYEXCH *exchange = OPENSSL_zalloc(sizeof(EVP_KEYEXCH));
  24
  25     if (exchange == NULL) {
  26         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  27         return NULL;
  28     }
  29
  30     exchange->lock = CRYPTO_THREAD_lock_new();
  31     if (exchange->lock == NULL) {
  32         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  33         OPENSSL_free(exchange);
  34         return NULL;
  35     }
  36     exchange->prov = prov;
  37     ossl_provider_up_ref(prov);
  38     exchange->refcnt = 1;
  39
  40     return exchange;
  41 }
  42
  43 static void *evp_keyexch_from_algorithm(int name_id,
  44                                         const OSSL_ALGORITHM *algodef,
  45                                         OSSL_PROVIDER *prov)
  46 {
  47     const OSSL_DISPATCH *fns = algodef->implementation;
  48     EVP_KEYEXCH *exchange = NULL;
  49     int fncnt = 0, sparamfncnt = 0, gparamfncnt = 0;
  50
  51     if ((exchange = evp_keyexch_new(prov)) == NULL) {
  52         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  53         goto err;
  54     }
  55
  56     exchange->name_id = name_id;
  57     if ((exchange->type_name = ossl_algorithm_get1_first_name(algodef)) == NULL)
  58         goto err;
  59     exchange->description = algodef->algorithm_description;
  60
  61     for (; fns->function_id != 0; fns++) {
  62         switch (fns->function_id) {
  63         case OSSL_FUNC_KEYEXCH_NEWCTX:
  64             if (exchange->newctx != NULL)
  65                 break;
  66             exchange->newctx = OSSL_FUNC_keyexch_newctx(fns);
  67             fncnt++;
  68             break;
  69         case OSSL_FUNC_KEYEXCH_INIT:
  70             if (exchange->init != NULL)
  71                 break;
  72             exchange->init = OSSL_FUNC_keyexch_init(fns);
  73             fncnt++;
  74             break;
  75         case OSSL_FUNC_KEYEXCH_SET_PEER:
  76             if (exchange->set_peer != NULL)
  77                 break;
  78             exchange->set_peer = OSSL_FUNC_keyexch_set_peer(fns);
  79             break;
  80         case OSSL_FUNC_KEYEXCH_DERIVE:
  81             if (exchange->derive != NULL)
  82                 break;
  83             exchange->derive = OSSL_FUNC_keyexch_derive(fns);
  84             fncnt++;
  85             break;
  86         case OSSL_FUNC_KEYEXCH_FREECTX:
  87             if (exchange->freectx != NULL)
  88                 break;
  89             exchange->freectx = OSSL_FUNC_keyexch_freectx(fns);
  90             fncnt++;
  91             break;
  92         case OSSL_FUNC_KEYEXCH_DUPCTX:
  93             if (exchange->dupctx != NULL)
  94                 break;
  95             exchange->dupctx = OSSL_FUNC_keyexch_dupctx(fns);
  96             break;
  97         case OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS:
  98             if (exchange->get_ctx_params != NULL)
  99                 break;
 100             exchange->get_ctx_params = OSSL_FUNC_keyexch_get_ctx_params(fns);
 101             gparamfncnt++;
 102             break;
 103         case OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS:
 104             if (exchange->gettable_ctx_params != NULL)
 105                 break;
 106             exchange->gettable_ctx_params
 107                 = OSSL_FUNC_keyexch_gettable_ctx_params(fns);
 108             gparamfncnt++;
 109             break;
 110         case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
 111             if (exchange->set_ctx_params != NULL)
 112                 break;
 113             exchange->set_ctx_params = OSSL_FUNC_keyexch_set_ctx_params(fns);
 114             sparamfncnt++;
 115             break;
 116         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
 117             if (exchange->settable_ctx_params != NULL)
 118                 break;
 119             exchange->settable_ctx_params
 120                 = OSSL_FUNC_keyexch_settable_ctx_params(fns);
 121             sparamfncnt++;
 122             break;
 123         }
 124     }
 125     if (fncnt != 4
 126             || (gparamfncnt != 0 && gparamfncnt != 2)
 127             || (sparamfncnt != 0 && sparamfncnt != 2)) {
 128         /*
 129          * In order to be a consistent set of functions we must have at least
 130          * a complete set of "exchange" functions: init, derive, newctx,
 131          * and freectx. The set_ctx_params and settable_ctx_params functions are
 132          * optional, but if one of them is present then the other one must also
 133          * be present. Same goes for get_ctx_params and gettable_ctx_params.
 134          * The dupctx and set_peer functions are optional.
 135          */
 136         ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_PROVIDER_FUNCTIONS);
 137         goto err;
 138     }
 139
 140     return exchange;
 141
 142  err:
 143     EVP_KEYEXCH_free(exchange);
 144     return NULL;
 145 }
 146
 147 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 148 {
 149     int i;
 150
 151     if (exchange == NULL)
 152         return;
 153     CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 154     if (i > 0)
 155         return;
 156     OPENSSL_free(exchange->type_name);
 157     ossl_provider_free(exchange->prov);
 158     CRYPTO_THREAD_lock_free(exchange->lock);
 159     OPENSSL_free(exchange);
 160 }
 161
 162 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 163 {
 164     int ref = 0;
 165
 166     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 167     return 1;
 168 }
 169
 170 OSSL_PROVIDER *EVP_KEYEXCH_get0_provider(const EVP_KEYEXCH *exchange)
 171 {
 172     return exchange->prov;
 173 }
 174
 175 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 176                                const char *properties)
 177 {
 178     return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 179                              evp_keyexch_from_algorithm,
 180                              (int (*)(void *))EVP_KEYEXCH_up_ref,
 181                              (void (*)(void *))EVP_KEYEXCH_free);
 182 }
 183
 184 EVP_KEYEXCH *evp_keyexch_fetch_from_prov(OSSL_PROVIDER *prov,
 185                                          const char *algorithm,
 186                                          const char *properties)
 187 {
 188     return evp_generic_fetch_from_prov(prov, OSSL_OP_KEYEXCH,
 189                                        algorithm, properties,
 190                                        evp_keyexch_from_algorithm,
 191                                        (int (*)(void *))EVP_KEYEXCH_up_ref,
 192                                        (void (*)(void *))EVP_KEYEXCH_free);
 193 }
 194
 195 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 196 {
 197     return EVP_PKEY_derive_init_ex(ctx, NULL);
 198 }
 199
 200 int EVP_PKEY_derive_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 201 {
 202     int ret;
 203     void *provkey = NULL;
 204     EVP_KEYEXCH *exchange = NULL;
 205     EVP_KEYMGMT *tmp_keymgmt = NULL;
 206     const char *supported_exch = NULL;
 207
 208     if (ctx == NULL) {
 209         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 210         return -2;
 211     }
 212
 213     evp_pkey_ctx_free_old_ops(ctx);
 214     ctx->operation = EVP_PKEY_OP_DERIVE;
 215
 216     ERR_set_mark();
 217
 218     if (evp_pkey_ctx_is_legacy(ctx))
 219         goto legacy;
 220
 221     /*
 222      * Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
 223      * a blank one.
 224      */
 225     if (ctx->pkey == NULL) {
 226         EVP_PKEY *pkey = EVP_PKEY_new();
 227
 228         if (pkey == NULL
 229             || !EVP_PKEY_set_type_by_keymgmt(pkey, ctx->keymgmt)
 230             || (pkey->keydata = evp_keymgmt_newdata(ctx->keymgmt)) == NULL) {
 231             ERR_clear_last_mark();
 232             EVP_PKEY_free(pkey);
 233             ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 234             goto err;
 235         }
 236         ctx->pkey = pkey;
 237     }
 238
 239     /*
 240      * Try to derive the supported exch from |ctx->keymgmt|.
 241      */
 242     if (!ossl_assert(ctx->pkey->keymgmt == NULL
 243                      || ctx->pkey->keymgmt == ctx->keymgmt)) {
 244         ERR_clear_last_mark();
 245         ERR_raise(ERR_LIB_EVP, ERR_R_INTERNAL_ERROR);
 246         goto err;
 247     }
 248     supported_exch = evp_keymgmt_util_query_operation_name(ctx->keymgmt,
 249                                                            OSSL_OP_KEYEXCH);
 250     if (supported_exch == NULL) {
 251         ERR_clear_last_mark();
 252         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 253         goto err;
 254     }
 255
 256
 257     /*
 258      * Because we cleared out old ops, we shouldn't need to worry about
 259      * checking if exchange is already there.
 260      */
 261     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 262     if (exchange == NULL)
 263         goto legacy;
 264
 265     /*
 266      * Ensure that the key is provided, either natively, or as a cached export.
 267      * We start by fetching the keymgmt with the same name as |ctx->pkey|,
 268      * but from the provider of the exch method, using the same property
 269      * query as when fetching the exch method.
 270      * With the keymgmt we found (if we did), we try to export |ctx->pkey|
 271      * to it (evp_pkey_export_to_provider() is smart enough to only actually
 272
 273      * export it if |tmp_keymgmt| is different from |ctx->pkey|'s keymgmt)
 274      */
 275     tmp_keymgmt
 276         = evp_keymgmt_fetch_from_prov(EVP_KEYEXCH_get0_provider(exchange),
 277                                       EVP_KEYMGMT_get0_name(ctx->keymgmt),
 278                                       ctx->propquery);
 279     if (tmp_keymgmt != NULL)
 280         provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 281                                               &tmp_keymgmt, ctx->propquery);
 282     if (provkey == NULL)
 283         goto legacy;
 284
 285     ERR_pop_to_mark();
 286
 287     /* No more legacy from here down to legacy: */
 288
 289     ctx->op.kex.exchange = exchange;
 290     ctx->op.kex.algctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 291     if (ctx->op.kex.algctx == NULL) {
 292         /* The provider key can stay in the cache */
 293         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 294         goto err;
 295     }
 296     ret = exchange->init(ctx->op.kex.algctx, provkey, params);
 297
 298     EVP_KEYMGMT_free(tmp_keymgmt);
 299     return ret ? 1 : 0;
 300  err:
 301     evp_pkey_ctx_free_old_ops(ctx);
 302     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 303     EVP_KEYMGMT_free(tmp_keymgmt);
 304     return 0;
 305
 306  legacy:
 307     /*
 308      * If we don't have the full support we need with provided methods,
 309      * let's go see if legacy does.
 310      */
 311     ERR_pop_to_mark();
 312
 313 #ifdef FIPS_MODULE
 314     return 0;
 315 #else
 316     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 317         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 318         return -2;
 319     }
 320
 321     if (ctx->pmeth->derive_init == NULL)
 322         return 1;
 323     ret = ctx->pmeth->derive_init(ctx);
 324     if (ret <= 0)
 325         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 326     EVP_KEYMGMT_free(tmp_keymgmt);
 327     return ret;
 328 #endif
 329 }
 330
 331 int EVP_PKEY_derive_set_peer_ex(EVP_PKEY_CTX *ctx, EVP_PKEY *peer,
 332                                 int validate_peer)
 333 {
 334     int ret = 0, check;
 335     void *provkey = NULL;
 336     EVP_PKEY_CTX *check_ctx = NULL;
 337
 338     if (ctx == NULL) {
 339         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 340         return -1;
 341     }
 342
 343     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.algctx == NULL)
 344         goto legacy;
 345
 346     if (ctx->op.kex.exchange->set_peer == NULL) {
 347         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 348         return -2;
 349     }
 350
 351     if (validate_peer) {
 352         check_ctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx, peer, ctx->propquery);
 353         if (check_ctx == NULL)
 354             return -1;
 355         check = EVP_PKEY_public_check(check_ctx);
 356         EVP_PKEY_CTX_free(check_ctx);
 357         if (check <= 0)
 358             return -1;
 359     }
 360
 361     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 362                                           ctx->propquery);
 363     /*
 364      * If making the key provided wasn't possible, legacy may be able to pick
 365      * it up
 366      */
 367     if (provkey == NULL)
 368         goto legacy;
 369     return ctx->op.kex.exchange->set_peer(ctx->op.kex.algctx, provkey);
 370
 371  legacy:
 372 #ifdef FIPS_MODULE
 373     return ret;
 374 #else
 375     if (ctx->pmeth == NULL
 376         || !(ctx->pmeth->derive != NULL
 377              || ctx->pmeth->encrypt != NULL
 378              || ctx->pmeth->decrypt != NULL)
 379         || ctx->pmeth->ctrl == NULL) {
 380         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 381         return -2;
 382     }
 383     if (ctx->operation != EVP_PKEY_OP_DERIVE
 384         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 385         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 386         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 387         return -1;
 388     }
 389
 390     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 391
 392     if (ret <= 0)
 393         return ret;
 394
 395     if (ret == 2)
 396         return 1;
 397
 398     if (ctx->pkey == NULL) {
 399         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
 400         return -1;
 401     }
 402
 403     if (ctx->pkey->type != peer->type) {
 404         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 405         return -1;
 406     }
 407
 408     /*
 409      * For clarity.  The error is if parameters in peer are
 410      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 411      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 412      * (different key types) is impossible here because it is checked earlier.
 413      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 414      */
 415     if (!EVP_PKEY_missing_parameters(peer) &&
 416         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 417         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_PARAMETERS);
 418         return -1;
 419     }
 420
 421     EVP_PKEY_free(ctx->peerkey);
 422     ctx->peerkey = peer;
 423
 424     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 425
 426     if (ret <= 0) {
 427         ctx->peerkey = NULL;
 428         return ret;
 429     }
 430
 431     EVP_PKEY_up_ref(peer);
 432     return 1;
 433 #endif
 434 }
 435
 436 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 437 {
 438     return EVP_PKEY_derive_set_peer_ex(ctx, peer, 1);
 439 }
 440
 441 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 442 {
 443     int ret;
 444
 445     if (ctx == NULL || pkeylen == NULL) {
 446         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 447         return -1;
 448     }
 449
 450     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 451         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 452         return -1;
 453     }
 454
 455     if (ctx->op.kex.algctx == NULL)
 456         goto legacy;
 457
 458     ret = ctx->op.kex.exchange->derive(ctx->op.kex.algctx, key, pkeylen,
 459                                        key != NULL ? *pkeylen : 0);
 460
 461     return ret;
 462  legacy:
 463     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 464         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 465         return -2;
 466     }
 467
 468     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 469         return ctx->pmeth->derive(ctx, key, pkeylen);
 470 }
 471
 472 int evp_keyexch_get_number(const EVP_KEYEXCH *keyexch)
 473 {
 474     return keyexch->name_id;
 475 }
 476
 477 const char *EVP_KEYEXCH_get0_name(const EVP_KEYEXCH *keyexch)
 478 {
 479     return keyexch->type_name;
 480 }
 481
 482 const char *EVP_KEYEXCH_get0_description(const EVP_KEYEXCH *keyexch)
 483 {
 484     return keyexch->description;
 485 }
 486
 487 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 488 {
 489     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 490 }
 491
 492 void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
 493                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 494                                  void *arg)
 495 {
 496     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 497                        (void (*)(void *, void *))fn, arg,
 498                        evp_keyexch_from_algorithm,
 499                        (int (*)(void *))EVP_KEYEXCH_up_ref,
 500                        (void (*)(void *))EVP_KEYEXCH_free);
 501 }
 502
 503 int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 504                              void (*fn)(const char *name, void *data),
 505                              void *data)
 506 {
 507     if (keyexch->prov != NULL)
 508         return evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 509
 510     return 1;
 511 }
 512
 513 const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
 514 {
 515     void *provctx;
 516
 517     if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
 518         return NULL;
 519
 520     provctx = ossl_provider_ctx(EVP_KEYEXCH_get0_provider(keyexch));
 521     return keyexch->gettable_ctx_params(NULL, provctx);
 522 }
 523
 524 const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
 525 {
 526     void *provctx;
 527
 528     if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
 529         return NULL;
 530     provctx = ossl_provider_ctx(EVP_KEYEXCH_get0_provider(keyexch));
 531     return keyexch->settable_ctx_params(NULL, provctx);
 532 }