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/refcount.h"
  14 #include "internal/provider.h"
  15 #include "internal/core.h"
  16 #include "internal/numbers.h"   /* includes SIZE_MAX */
  17 #include "crypto/evp.h"
  18 #include "evp_local.h"
  19
  20 static EVP_KEYEXCH *evp_keyexch_new(OSSL_PROVIDER *prov)
  21 {
  22     EVP_KEYEXCH *exchange = OPENSSL_zalloc(sizeof(EVP_KEYEXCH));
  23
  24     if (exchange == NULL) {
  25         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  26         return NULL;
  27     }
  28
  29     exchange->lock = CRYPTO_THREAD_lock_new();
  30     if (exchange->lock == NULL) {
  31         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  32         OPENSSL_free(exchange);
  33         return NULL;
  34     }
  35     exchange->prov = prov;
  36     ossl_provider_up_ref(prov);
  37     exchange->refcnt = 1;
  38
  39     return exchange;
  40 }
  41
  42 static void *evp_keyexch_from_algorithm(int name_id,
  43                                         const OSSL_ALGORITHM *algodef,
  44                                         OSSL_PROVIDER *prov)
  45 {
  46     const OSSL_DISPATCH *fns = algodef->implementation;
  47     EVP_KEYEXCH *exchange = NULL;
  48     int fncnt = 0, sparamfncnt = 0, gparamfncnt = 0;
  49
  50     if ((exchange = evp_keyexch_new(prov)) == NULL) {
  51         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  52         goto err;
  53     }
  54
  55     exchange->name_id = name_id;
  56     if ((exchange->type_name = ossl_algorithm_get1_first_name(algodef)) == NULL)
  57         goto err;
  58     exchange->description = algodef->algorithm_description;
  59
  60     for (; fns->function_id != 0; fns++) {
  61         switch (fns->function_id) {
  62         case OSSL_FUNC_KEYEXCH_NEWCTX:
  63             if (exchange->newctx != NULL)
  64                 break;
  65             exchange->newctx = OSSL_FUNC_keyexch_newctx(fns);
  66             fncnt++;
  67             break;
  68         case OSSL_FUNC_KEYEXCH_INIT:
  69             if (exchange->init != NULL)
  70                 break;
  71             exchange->init = OSSL_FUNC_keyexch_init(fns);
  72             fncnt++;
  73             break;
  74         case OSSL_FUNC_KEYEXCH_SET_PEER:
  75             if (exchange->set_peer != NULL)
  76                 break;
  77             exchange->set_peer = OSSL_FUNC_keyexch_set_peer(fns);
  78             break;
  79         case OSSL_FUNC_KEYEXCH_DERIVE:
  80             if (exchange->derive != NULL)
  81                 break;
  82             exchange->derive = OSSL_FUNC_keyexch_derive(fns);
  83             fncnt++;
  84             break;
  85         case OSSL_FUNC_KEYEXCH_FREECTX:
  86             if (exchange->freectx != NULL)
  87                 break;
  88             exchange->freectx = OSSL_FUNC_keyexch_freectx(fns);
  89             fncnt++;
  90             break;
  91         case OSSL_FUNC_KEYEXCH_DUPCTX:
  92             if (exchange->dupctx != NULL)
  93                 break;
  94             exchange->dupctx = OSSL_FUNC_keyexch_dupctx(fns);
  95             break;
  96         case OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS:
  97             if (exchange->get_ctx_params != NULL)
  98                 break;
  99             exchange->get_ctx_params = OSSL_FUNC_keyexch_get_ctx_params(fns);
 100             gparamfncnt++;
 101             break;
 102         case OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS:
 103             if (exchange->gettable_ctx_params != NULL)
 104                 break;
 105             exchange->gettable_ctx_params
 106                 = OSSL_FUNC_keyexch_gettable_ctx_params(fns);
 107             gparamfncnt++;
 108             break;
 109         case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
 110             if (exchange->set_ctx_params != NULL)
 111                 break;
 112             exchange->set_ctx_params = OSSL_FUNC_keyexch_set_ctx_params(fns);
 113             sparamfncnt++;
 114             break;
 115         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
 116             if (exchange->settable_ctx_params != NULL)
 117                 break;
 118             exchange->settable_ctx_params
 119                 = OSSL_FUNC_keyexch_settable_ctx_params(fns);
 120             sparamfncnt++;
 121             break;
 122         }
 123     }
 124     if (fncnt != 4
 125             || (gparamfncnt != 0 && gparamfncnt != 2)
 126             || (sparamfncnt != 0 && sparamfncnt != 2)) {
 127         /*
 128          * In order to be a consistent set of functions we must have at least
 129          * a complete set of "exchange" functions: init, derive, newctx,
 130          * and freectx. The set_ctx_params and settable_ctx_params functions are
 131          * optional, but if one of them is present then the other one must also
 132          * be present. Same goes for get_ctx_params and gettable_ctx_params.
 133          * The dupctx and set_peer functions are optional.
 134          */
 135         ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_PROVIDER_FUNCTIONS);
 136         goto err;
 137     }
 138
 139     return exchange;
 140
 141  err:
 142     EVP_KEYEXCH_free(exchange);
 143     return NULL;
 144 }
 145
 146 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 147 {
 148     int i;
 149
 150     if (exchange == NULL)
 151         return;
 152     CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 153     if (i > 0)
 154         return;
 155     OPENSSL_free(exchange->type_name);
 156     ossl_provider_free(exchange->prov);
 157     CRYPTO_THREAD_lock_free(exchange->lock);
 158     OPENSSL_free(exchange);
 159 }
 160
 161 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 162 {
 163     int ref = 0;
 164
 165     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 166     return 1;
 167 }
 168
 169 OSSL_PROVIDER *EVP_KEYEXCH_get0_provider(const EVP_KEYEXCH *exchange)
 170 {
 171     return exchange->prov;
 172 }
 173
 174 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 175                                const char *properties)
 176 {
 177     return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 178                              evp_keyexch_from_algorithm,
 179                              (int (*)(void *))EVP_KEYEXCH_up_ref,
 180                              (void (*)(void *))EVP_KEYEXCH_free);
 181 }
 182
 183 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 184 {
 185     return EVP_PKEY_derive_init_ex(ctx, NULL);
 186 }
 187
 188 int EVP_PKEY_derive_init_ex(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 189 {
 190     int ret;
 191     void *provkey = NULL;
 192     EVP_KEYEXCH *exchange = NULL;
 193     EVP_KEYMGMT *tmp_keymgmt = NULL;
 194     const char *supported_exch = NULL;
 195
 196     if (ctx == NULL) {
 197         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 198         return -2;
 199     }
 200
 201     evp_pkey_ctx_free_old_ops(ctx);
 202     ctx->operation = EVP_PKEY_OP_DERIVE;
 203
 204     ERR_set_mark();
 205
 206     if (evp_pkey_ctx_is_legacy(ctx))
 207         goto legacy;
 208
 209     /*
 210      * Ensure that the key is provided, either natively, or as a cached export.
 211      * If not, goto legacy
 212      */
 213     tmp_keymgmt = ctx->keymgmt;
 214     if (ctx->pkey == NULL) {
 215         /*
 216          * Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
 217          * a blank one.
 218          */
 219         EVP_PKEY *pkey = EVP_PKEY_new();
 220
 221         if (pkey == NULL || !EVP_PKEY_set_type_by_keymgmt(pkey, tmp_keymgmt)) {
 222             ERR_clear_last_mark();
 223             EVP_PKEY_free(pkey);
 224             ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 225             goto err;
 226         }
 227         provkey = pkey->keydata = evp_keymgmt_newdata(tmp_keymgmt);
 228         if (provkey == NULL)
 229             EVP_PKEY_free(pkey);
 230         else
 231             ctx->pkey = pkey;
 232     } else {
 233         provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 234                                             &tmp_keymgmt, ctx->propquery);
 235     }
 236     if (provkey == NULL)
 237         goto legacy;
 238     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 239         ERR_clear_last_mark();
 240         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 241         goto err;
 242     }
 243     EVP_KEYMGMT_free(ctx->keymgmt);
 244     ctx->keymgmt = tmp_keymgmt;
 245
 246     if (ctx->keymgmt->query_operation_name != NULL)
 247         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 248
 249     /*
 250      * If we didn't get a supported exch, assume there is one with the
 251      * same name as the key type.
 252      */
 253     if (supported_exch == NULL)
 254         supported_exch = ctx->keytype;
 255
 256     /*
 257      * Because we cleared out old ops, we shouldn't need to worry about
 258      * checking if exchange is already there.
 259      */
 260     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 261
 262     if (exchange == NULL
 263         || (EVP_KEYMGMT_get0_provider(ctx->keymgmt)
 264             != EVP_KEYEXCH_get0_provider(exchange))) {
 265         /*
 266          * We don't need to free ctx->keymgmt here, as it's not necessarily
 267          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 268          */
 269         EVP_KEYEXCH_free(exchange);
 270         goto legacy;
 271     }
 272
 273     /*
 274      * If we don't have the full support we need with provided methods,
 275      * let's go see if legacy does.
 276      */
 277     ERR_pop_to_mark();
 278
 279     /* No more legacy from here down to legacy: */
 280
 281     ctx->op.kex.exchange = exchange;
 282     ctx->op.kex.algctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 283     if (ctx->op.kex.algctx == NULL) {
 284         /* The provider key can stay in the cache */
 285         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 286         goto err;
 287     }
 288     ret = exchange->init(ctx->op.kex.algctx, provkey, params);
 289
 290     return ret ? 1 : 0;
 291  err:
 292     evp_pkey_ctx_free_old_ops(ctx);
 293     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 294     return 0;
 295
 296  legacy:
 297     /*
 298      * If we don't have the full support we need with provided methods,
 299      * let's go see if legacy does.
 300      */
 301     ERR_pop_to_mark();
 302
 303 #ifdef FIPS_MODULE
 304     return 0;
 305 #else
 306     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 307         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 308         return -2;
 309     }
 310
 311     if (ctx->pmeth->derive_init == NULL)
 312         return 1;
 313     ret = ctx->pmeth->derive_init(ctx);
 314     if (ret <= 0)
 315         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 316     return ret;
 317 #endif
 318 }
 319
 320 int EVP_PKEY_derive_set_peer_ex(EVP_PKEY_CTX *ctx, EVP_PKEY *peer,
 321                                 int validate_peer)
 322 {
 323     int ret = 0, check;
 324     void *provkey = NULL;
 325     EVP_PKEY_CTX *check_ctx = NULL;
 326
 327     if (ctx == NULL) {
 328         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 329         return -1;
 330     }
 331
 332     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.algctx == NULL)
 333         goto legacy;
 334
 335     if (ctx->op.kex.exchange->set_peer == NULL) {
 336         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 337         return -2;
 338     }
 339
 340     if (validate_peer) {
 341         check_ctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx, peer, ctx->propquery);
 342         if (check_ctx == NULL)
 343             return -1;
 344         check = EVP_PKEY_public_check(check_ctx);
 345         EVP_PKEY_CTX_free(check_ctx);
 346         if (check <= 0)
 347             return -1;
 348     }
 349
 350     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 351                                           ctx->propquery);
 352     /*
 353      * If making the key provided wasn't possible, legacy may be able to pick
 354      * it up
 355      */
 356     if (provkey == NULL)
 357         goto legacy;
 358     return ctx->op.kex.exchange->set_peer(ctx->op.kex.algctx, provkey);
 359
 360  legacy:
 361 #ifdef FIPS_MODULE
 362     return ret;
 363 #else
 364     if (ctx->pmeth == NULL
 365         || !(ctx->pmeth->derive != NULL
 366              || ctx->pmeth->encrypt != NULL
 367              || ctx->pmeth->decrypt != NULL)
 368         || ctx->pmeth->ctrl == NULL) {
 369         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 370         return -2;
 371     }
 372     if (ctx->operation != EVP_PKEY_OP_DERIVE
 373         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 374         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 375         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 376         return -1;
 377     }
 378
 379     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 380
 381     if (ret <= 0)
 382         return ret;
 383
 384     if (ret == 2)
 385         return 1;
 386
 387     if (ctx->pkey == NULL) {
 388         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
 389         return -1;
 390     }
 391
 392     if (ctx->pkey->type != peer->type) {
 393         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 394         return -1;
 395     }
 396
 397     /*
 398      * For clarity.  The error is if parameters in peer are
 399      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 400      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 401      * (different key types) is impossible here because it is checked earlier.
 402      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 403      */
 404     if (!EVP_PKEY_missing_parameters(peer) &&
 405         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 406         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_PARAMETERS);
 407         return -1;
 408     }
 409
 410     EVP_PKEY_free(ctx->peerkey);
 411     ctx->peerkey = peer;
 412
 413     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 414
 415     if (ret <= 0) {
 416         ctx->peerkey = NULL;
 417         return ret;
 418     }
 419
 420     EVP_PKEY_up_ref(peer);
 421     return 1;
 422 #endif
 423 }
 424
 425 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 426 {
 427     return EVP_PKEY_derive_set_peer_ex(ctx, peer, 1);
 428 }
 429
 430 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 431 {
 432     int ret;
 433
 434     if (ctx == NULL || pkeylen == NULL) {
 435         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 436         return -1;
 437     }
 438
 439     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 440         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 441         return -1;
 442     }
 443
 444     if (ctx->op.kex.algctx == NULL)
 445         goto legacy;
 446
 447     ret = ctx->op.kex.exchange->derive(ctx->op.kex.algctx, key, pkeylen,
 448                                        key != NULL ? *pkeylen : 0);
 449
 450     return ret;
 451  legacy:
 452     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 453         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 454         return -2;
 455     }
 456
 457     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 458         return ctx->pmeth->derive(ctx, key, pkeylen);
 459 }
 460
 461 int evp_keyexch_get_number(const EVP_KEYEXCH *keyexch)
 462 {
 463     return keyexch->name_id;
 464 }
 465
 466 const char *EVP_KEYEXCH_get0_name(const EVP_KEYEXCH *keyexch)
 467 {
 468     return keyexch->type_name;
 469 }
 470
 471 const char *EVP_KEYEXCH_get0_description(const EVP_KEYEXCH *keyexch)
 472 {
 473     return keyexch->description;
 474 }
 475
 476 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 477 {
 478     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 479 }
 480
 481 void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
 482                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 483                                  void *arg)
 484 {
 485     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 486                        (void (*)(void *, void *))fn, arg,
 487                        evp_keyexch_from_algorithm,
 488                        (int (*)(void *))EVP_KEYEXCH_up_ref,
 489                        (void (*)(void *))EVP_KEYEXCH_free);
 490 }
 491
 492 int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 493                              void (*fn)(const char *name, void *data),
 494                              void *data)
 495 {
 496     if (keyexch->prov != NULL)
 497         return evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 498
 499     return 1;
 500 }
 501
 502 const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
 503 {
 504     void *provctx;
 505
 506     if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
 507         return NULL;
 508
 509     provctx = ossl_provider_ctx(EVP_KEYEXCH_get0_provider(keyexch));
 510     return keyexch->gettable_ctx_params(NULL, provctx);
 511 }
 512
 513 const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
 514 {
 515     void *provctx;
 516
 517     if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
 518         return NULL;
 519     provctx = ossl_provider_ctx(EVP_KEYEXCH_get0_provider(keyexch));
 520     return keyexch->settable_ctx_params(NULL, provctx);
 521 }