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_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     /*
 205      * TODO when we stop falling back to legacy, this and the ERR_pop_to_mark()
 206      * calls can be removed.
 207      */
 208     ERR_set_mark();
 209
 210     if (evp_pkey_ctx_is_legacy(ctx))
 211         goto legacy;
 212
 213     /*
 214      * Ensure that the key is provided, either natively, or as a cached export.
 215      * If not, goto legacy
 216      */
 217     tmp_keymgmt = ctx->keymgmt;
 218     if (ctx->pkey == NULL) {
 219         /*
 220          * Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
 221          * a blank one.
 222          */
 223         EVP_PKEY *pkey = EVP_PKEY_new();
 224
 225         if (pkey == NULL || !EVP_PKEY_set_type_by_keymgmt(pkey, tmp_keymgmt)) {
 226             ERR_clear_last_mark();
 227             EVP_PKEY_free(pkey);
 228             ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 229             goto err;
 230         }
 231         provkey = pkey->keydata = evp_keymgmt_newdata(tmp_keymgmt);
 232         if (provkey == NULL)
 233             EVP_PKEY_free(pkey);
 234         else
 235             ctx->pkey = pkey;
 236     } else {
 237         provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 238                                             &tmp_keymgmt, ctx->propquery);
 239     }
 240     if (provkey == NULL)
 241         goto legacy;
 242     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 243         ERR_clear_last_mark();
 244         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 245         goto err;
 246     }
 247     EVP_KEYMGMT_free(ctx->keymgmt);
 248     ctx->keymgmt = tmp_keymgmt;
 249
 250     if (ctx->keymgmt->query_operation_name != NULL)
 251         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 252
 253     /*
 254      * If we didn't get a supported exch, assume there is one with the
 255      * same name as the key type.
 256      */
 257     if (supported_exch == NULL)
 258         supported_exch = ctx->keytype;
 259
 260     /*
 261      * Because we cleared out old ops, we shouldn't need to worry about
 262      * checking if exchange is already there.
 263      */
 264     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 265
 266     if (exchange == NULL
 267         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 268             != EVP_KEYEXCH_provider(exchange))) {
 269         /*
 270          * We don't need to free ctx->keymgmt here, as it's not necessarily
 271          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 272          */
 273         EVP_KEYEXCH_free(exchange);
 274         goto legacy;
 275     }
 276
 277     /*
 278      * TODO remove this when legacy is gone
 279      * If we don't have the full support we need with provided methods,
 280      * let's go see if legacy does.
 281      */
 282     ERR_pop_to_mark();
 283
 284     /* No more legacy from here down to legacy: */
 285
 286     ctx->op.kex.exchange = exchange;
 287     ctx->op.kex.algctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 288     if (ctx->op.kex.algctx == NULL) {
 289         /* The provider key can stay in the cache */
 290         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 291         goto err;
 292     }
 293     ret = exchange->init(ctx->op.kex.algctx, provkey, params);
 294
 295     return ret ? 1 : 0;
 296  err:
 297     evp_pkey_ctx_free_old_ops(ctx);
 298     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 299     return 0;
 300
 301  legacy:
 302     /*
 303      * TODO remove this when legacy is gone
 304      * If we don't have the full support we need with provided methods,
 305      * let's go see if legacy does.
 306      */
 307     ERR_pop_to_mark();
 308
 309 #ifdef FIPS_MODULE
 310     return 0;
 311 #else
 312     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 313         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 314         return -2;
 315     }
 316
 317     if (ctx->pmeth->derive_init == NULL)
 318         return 1;
 319     ret = ctx->pmeth->derive_init(ctx);
 320     if (ret <= 0)
 321         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 322     return ret;
 323 #endif
 324 }
 325
 326 int EVP_PKEY_derive_set_peer_ex(EVP_PKEY_CTX *ctx, EVP_PKEY *peer,
 327                                 int validate_peer)
 328 {
 329     int ret = 0, check;
 330     void *provkey = NULL;
 331     EVP_PKEY_CTX *check_ctx = NULL;
 332
 333     if (ctx == NULL) {
 334         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 335         return -1;
 336     }
 337
 338     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.algctx == NULL)
 339         goto legacy;
 340
 341     if (ctx->op.kex.exchange->set_peer == NULL) {
 342         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 343         return -2;
 344     }
 345
 346     if (validate_peer) {
 347         check_ctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx, peer, ctx->propquery);
 348         if (check_ctx == NULL)
 349             return -1;
 350         check = EVP_PKEY_public_check(check_ctx);
 351         EVP_PKEY_CTX_free(check_ctx);
 352         if (check <= 0)
 353             return -1;
 354     }
 355
 356     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 357                                           ctx->propquery);
 358     /*
 359      * If making the key provided wasn't possible, legacy may be able to pick
 360      * it up
 361      */
 362     if (provkey == NULL)
 363         goto legacy;
 364     return ctx->op.kex.exchange->set_peer(ctx->op.kex.algctx, provkey);
 365
 366  legacy:
 367 #ifdef FIPS_MODULE
 368     return ret;
 369 #else
 370     if (ctx->pmeth == NULL
 371         || !(ctx->pmeth->derive != NULL
 372              || ctx->pmeth->encrypt != NULL
 373              || ctx->pmeth->decrypt != NULL)
 374         || ctx->pmeth->ctrl == NULL) {
 375         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 376         return -2;
 377     }
 378     if (ctx->operation != EVP_PKEY_OP_DERIVE
 379         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 380         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 381         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 382         return -1;
 383     }
 384
 385     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 386
 387     if (ret <= 0)
 388         return ret;
 389
 390     if (ret == 2)
 391         return 1;
 392
 393     if (ctx->pkey == NULL) {
 394         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
 395         return -1;
 396     }
 397
 398     if (ctx->pkey->type != peer->type) {
 399         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 400         return -1;
 401     }
 402
 403     /*
 404      * For clarity.  The error is if parameters in peer are
 405      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 406      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 407      * (different key types) is impossible here because it is checked earlier.
 408      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 409      */
 410     if (!EVP_PKEY_missing_parameters(peer) &&
 411         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 412         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_PARAMETERS);
 413         return -1;
 414     }
 415
 416     EVP_PKEY_free(ctx->peerkey);
 417     ctx->peerkey = peer;
 418
 419     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 420
 421     if (ret <= 0) {
 422         ctx->peerkey = NULL;
 423         return ret;
 424     }
 425
 426     EVP_PKEY_up_ref(peer);
 427     return 1;
 428 #endif
 429 }
 430
 431 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 432 {
 433     return EVP_PKEY_derive_set_peer_ex(ctx, peer, 1);
 434 }
 435
 436 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 437 {
 438     int ret;
 439
 440     if (ctx == NULL || pkeylen == NULL) {
 441         ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_NULL_PARAMETER);
 442         return -1;
 443     }
 444
 445     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 446         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 447         return -1;
 448     }
 449
 450     if (ctx->op.kex.algctx == NULL)
 451         goto legacy;
 452
 453     ret = ctx->op.kex.exchange->derive(ctx->op.kex.algctx, key, pkeylen,
 454                                        key != NULL ? *pkeylen : 0);
 455
 456     return ret;
 457  legacy:
 458     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 459         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 460         return -2;
 461     }
 462
 463     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 464         return ctx->pmeth->derive(ctx, key, pkeylen);
 465 }
 466
 467 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 468 {
 469     return keyexch->name_id;
 470 }
 471
 472 const char *EVP_KEYEXCH_name(const EVP_KEYEXCH *keyexch)
 473 {
 474     return keyexch->type_name;
 475 }
 476
 477 const char *EVP_KEYEXCH_description(const EVP_KEYEXCH *keyexch)
 478 {
 479     return keyexch->description;
 480 }
 481
 482 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 483 {
 484     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 485 }
 486
 487 void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
 488                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 489                                  void *arg)
 490 {
 491     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 492                        (void (*)(void *, void *))fn, arg,
 493                        evp_keyexch_from_algorithm,
 494                        (void (*)(void *))EVP_KEYEXCH_free);
 495 }
 496
 497 int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 498                              void (*fn)(const char *name, void *data),
 499                              void *data)
 500 {
 501     if (keyexch->prov != NULL)
 502         return evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 503
 504     return 1;
 505 }
 506
 507 const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
 508 {
 509     void *provctx;
 510
 511     if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
 512         return NULL;
 513
 514     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 515     return keyexch->gettable_ctx_params(NULL, provctx);
 516 }
 517
 518 const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
 519 {
 520     void *provctx;
 521
 522     if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
 523         return NULL;
 524     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 525     return keyexch->settable_ctx_params(NULL, provctx);
 526 }