crypto/evp/exchange.c

   1 /*
   2  * Copyright 2019-2020 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 <openssl/crypto.h>
  11 #include <openssl/evp.h>
  12 #include <openssl/err.h>
  13 #include "internal/refcount.h"
  14 #include "crypto/evp.h"
  15 #include "internal/provider.h"
  16 #include "internal/numbers.h"   /* includes SIZE_MAX */
  17 #include "evp_local.h"
  18
  19 static EVP_KEYEXCH *evp_keyexch_new(OSSL_PROVIDER *prov)
  20 {
  21     EVP_KEYEXCH *exchange = OPENSSL_zalloc(sizeof(EVP_KEYEXCH));
  22
  23     if (exchange == NULL) {
  24         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  25         return NULL;
  26     }
  27
  28     exchange->lock = CRYPTO_THREAD_lock_new();
  29     if (exchange->lock == NULL) {
  30         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  31         OPENSSL_free(exchange);
  32         return NULL;
  33     }
  34     exchange->prov = prov;
  35     ossl_provider_up_ref(prov);
  36     exchange->refcnt = 1;
  37
  38     return exchange;
  39 }
  40
  41 static void *evp_keyexch_from_dispatch(int name_id,
  42                                        const OSSL_DISPATCH *fns,
  43                                        OSSL_PROVIDER *prov)
  44 {
  45     EVP_KEYEXCH *exchange = NULL;
  46     int fncnt = 0, sparamfncnt = 0, gparamfncnt = 0;
  47
  48     if ((exchange = evp_keyexch_new(prov)) == NULL) {
  49         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  50         goto err;
  51     }
  52
  53     exchange->name_id = name_id;
  54
  55     for (; fns->function_id != 0; fns++) {
  56         switch (fns->function_id) {
  57         case OSSL_FUNC_KEYEXCH_NEWCTX:
  58             if (exchange->newctx != NULL)
  59                 break;
  60             exchange->newctx = OSSL_FUNC_keyexch_newctx(fns);
  61             fncnt++;
  62             break;
  63         case OSSL_FUNC_KEYEXCH_INIT:
  64             if (exchange->init != NULL)
  65                 break;
  66             exchange->init = OSSL_FUNC_keyexch_init(fns);
  67             fncnt++;
  68             break;
  69         case OSSL_FUNC_KEYEXCH_SET_PEER:
  70             if (exchange->set_peer != NULL)
  71                 break;
  72             exchange->set_peer = OSSL_FUNC_keyexch_set_peer(fns);
  73             break;
  74         case OSSL_FUNC_KEYEXCH_DERIVE:
  75             if (exchange->derive != NULL)
  76                 break;
  77             exchange->derive = OSSL_FUNC_keyexch_derive(fns);
  78             fncnt++;
  79             break;
  80         case OSSL_FUNC_KEYEXCH_FREECTX:
  81             if (exchange->freectx != NULL)
  82                 break;
  83             exchange->freectx = OSSL_FUNC_keyexch_freectx(fns);
  84             fncnt++;
  85             break;
  86         case OSSL_FUNC_KEYEXCH_DUPCTX:
  87             if (exchange->dupctx != NULL)
  88                 break;
  89             exchange->dupctx = OSSL_FUNC_keyexch_dupctx(fns);
  90             break;
  91         case OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS:
  92             if (exchange->get_ctx_params != NULL)
  93                 break;
  94             exchange->get_ctx_params = OSSL_FUNC_keyexch_get_ctx_params(fns);
  95             gparamfncnt++;
  96             break;
  97         case OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS:
  98             if (exchange->gettable_ctx_params != NULL)
  99                 break;
 100             exchange->gettable_ctx_params
 101                 = OSSL_FUNC_keyexch_gettable_ctx_params(fns);
 102             gparamfncnt++;
 103             break;
 104         case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
 105             if (exchange->set_ctx_params != NULL)
 106                 break;
 107             exchange->set_ctx_params = OSSL_FUNC_keyexch_set_ctx_params(fns);
 108             sparamfncnt++;
 109             break;
 110         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
 111             if (exchange->settable_ctx_params != NULL)
 112                 break;
 113             exchange->settable_ctx_params
 114                 = OSSL_FUNC_keyexch_settable_ctx_params(fns);
 115             sparamfncnt++;
 116             break;
 117         }
 118     }
 119     if (fncnt != 4
 120             || (gparamfncnt != 0 && gparamfncnt != 2)
 121             || (sparamfncnt != 0 && sparamfncnt != 2)) {
 122         /*
 123          * In order to be a consistent set of functions we must have at least
 124          * a complete set of "exchange" functions: init, derive, newctx,
 125          * and freectx. The set_ctx_params and settable_ctx_params functions are
 126          * optional, but if one of them is present then the other one must also
 127          * be present. Same goes for get_ctx_params and gettable_ctx_params.
 128          * The dupctx and set_peer functions are optional.
 129          */
 130         EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,
 131                EVP_R_INVALID_PROVIDER_FUNCTIONS);
 132         goto err;
 133     }
 134
 135     return exchange;
 136
 137  err:
 138     EVP_KEYEXCH_free(exchange);
 139     return NULL;
 140 }
 141
 142 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 143 {
 144     if (exchange != NULL) {
 145         int i;
 146
 147         CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 148         if (i > 0)
 149             return;
 150         ossl_provider_free(exchange->prov);
 151         CRYPTO_THREAD_lock_free(exchange->lock);
 152         OPENSSL_free(exchange);
 153     }
 154 }
 155
 156 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 157 {
 158     int ref = 0;
 159
 160     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 161     return 1;
 162 }
 163
 164 OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
 165 {
 166     return exchange->prov;
 167 }
 168
 169 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 170                                const char *properties)
 171 {
 172     return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 173                              evp_keyexch_from_dispatch,
 174                              (int (*)(void *))EVP_KEYEXCH_up_ref,
 175                              (void (*)(void *))EVP_KEYEXCH_free);
 176 }
 177
 178 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 179 {
 180     int ret;
 181     void *provkey = NULL;
 182     EVP_KEYEXCH *exchange = NULL;
 183     EVP_KEYMGMT *tmp_keymgmt = NULL;
 184     const char *supported_exch = NULL;
 185
 186     if (ctx == NULL) {
 187         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 188         return -2;
 189     }
 190
 191     evp_pkey_ctx_free_old_ops(ctx);
 192     ctx->operation = EVP_PKEY_OP_DERIVE;
 193
 194     /*
 195      * TODO when we stop falling back to legacy, this and the ERR_pop_to_mark()
 196      * calls can be removed.
 197      */
 198     ERR_set_mark();
 199
 200     if (evp_pkey_ctx_is_legacy(ctx))
 201         goto legacy;
 202
 203     /*
 204      * Ensure that the key is provided, either natively, or as a cached export.
 205      * If not, goto legacy
 206      */
 207     tmp_keymgmt = ctx->keymgmt;
 208     if (ctx->pkey == NULL) {
 209         /*
 210          * Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
 211          * a blank one.
 212          */
 213         EVP_PKEY *pkey = EVP_PKEY_new();
 214
 215         if (pkey == NULL || !EVP_PKEY_set_type_by_keymgmt(pkey, tmp_keymgmt)) {
 216             ERR_clear_last_mark();
 217             EVP_PKEY_free(pkey);
 218             ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 219             goto err;
 220         }
 221         provkey = pkey->keydata = evp_keymgmt_newdata(tmp_keymgmt);
 222         if (provkey == NULL)
 223             EVP_PKEY_free(pkey);
 224         else
 225             ctx->pkey = pkey;
 226     } else {
 227         provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 228                                             &tmp_keymgmt, ctx->propquery);
 229     }
 230     if (provkey == NULL)
 231         goto legacy;
 232     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 233         ERR_clear_last_mark();
 234         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 235         goto err;
 236     }
 237     EVP_KEYMGMT_free(ctx->keymgmt);
 238     ctx->keymgmt = tmp_keymgmt;
 239
 240     if (ctx->keymgmt->query_operation_name != NULL)
 241         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 242
 243     /*
 244      * If we didn't get a supported exch, assume there is one with the
 245      * same name as the key type.
 246      */
 247     if (supported_exch == NULL)
 248         supported_exch = ctx->keytype;
 249
 250     /*
 251      * Because we cleared out old ops, we shouldn't need to worry about
 252      * checking if exchange is already there.
 253      */
 254     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 255
 256     if (exchange == NULL
 257         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 258             != EVP_KEYEXCH_provider(exchange))) {
 259         /*
 260          * We don't need to free ctx->keymgmt here, as it's not necessarily
 261          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 262          */
 263         EVP_KEYEXCH_free(exchange);
 264         goto legacy;
 265     }
 266
 267     /*
 268      * TODO remove this when legacy is gone
 269      * If we don't have the full support we need with provided methods,
 270      * let's go see if legacy does.
 271      */
 272     ERR_pop_to_mark();
 273
 274     /* No more legacy from here down to legacy: */
 275
 276     ctx->op.kex.exchange = exchange;
 277     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 278     if (ctx->op.kex.exchprovctx == NULL) {
 279         /* The provider key can stay in the cache */
 280         EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 281         goto err;
 282     }
 283     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 284
 285     return ret ? 1 : 0;
 286  err:
 287     evp_pkey_ctx_free_old_ops(ctx);
 288     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 289     return 0;
 290
 291  legacy:
 292     /*
 293      * TODO remove this when legacy is gone
 294      * If we don't have the full support we need with provided methods,
 295      * let's go see if legacy does.
 296      */
 297     ERR_pop_to_mark();
 298
 299 #ifdef FIPS_MODULE
 300     return 0;
 301 #else
 302     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 303         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 304         return -2;
 305     }
 306
 307     if (ctx->pmeth->derive_init == NULL)
 308         return 1;
 309     ret = ctx->pmeth->derive_init(ctx);
 310     if (ret <= 0)
 311         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 312     return ret;
 313 #endif
 314 }
 315
 316 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 317 {
 318     int ret = 0;
 319     void *provkey = NULL;
 320
 321     if (ctx == NULL) {
 322         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 323                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 324         return -2;
 325     }
 326
 327     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 328         goto legacy;
 329
 330     if (ctx->op.kex.exchange->set_peer == NULL) {
 331         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 332                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 333         return -2;
 334     }
 335
 336     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 337                                           ctx->propquery);
 338     /*
 339      * If making the key provided wasn't possible, legacy may be able to pick
 340      * it up
 341      */
 342     if (provkey == NULL)
 343         goto legacy;
 344     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 345
 346  legacy:
 347 #ifdef FIPS_MODULE
 348     return ret;
 349 #else
 350     /*
 351      * TODO(3.0) investigate the case where the operation is deemed legacy,
 352      * but the given peer key is provider only.
 353      */
 354     if (ctx->pmeth == NULL
 355         || !(ctx->pmeth->derive != NULL
 356              || ctx->pmeth->encrypt != NULL
 357              || ctx->pmeth->decrypt != NULL)
 358         || ctx->pmeth->ctrl == NULL) {
 359         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 360                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 361         return -2;
 362     }
 363     if (ctx->operation != EVP_PKEY_OP_DERIVE
 364         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 365         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 366         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 367                EVP_R_OPERATON_NOT_INITIALIZED);
 368         return -1;
 369     }
 370
 371     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 372
 373     if (ret <= 0)
 374         return ret;
 375
 376     if (ret == 2)
 377         return 1;
 378
 379     if (ctx->pkey == NULL) {
 380         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 381         return -1;
 382     }
 383
 384     if (ctx->pkey->type != peer->type) {
 385         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 386         return -1;
 387     }
 388
 389     /*
 390      * For clarity.  The error is if parameters in peer are
 391      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 392      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 393      * (different key types) is impossible here because it is checked earlier.
 394      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 395      */
 396     if (!EVP_PKEY_missing_parameters(peer) &&
 397         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 398         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 399         return -1;
 400     }
 401
 402     EVP_PKEY_free(ctx->peerkey);
 403     ctx->peerkey = peer;
 404
 405     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 406
 407     if (ret <= 0) {
 408         ctx->peerkey = NULL;
 409         return ret;
 410     }
 411
 412     EVP_PKEY_up_ref(peer);
 413     return 1;
 414 #endif
 415 }
 416
 417 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 418 {
 419     int ret;
 420
 421     if (ctx == NULL) {
 422         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 423                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 424         return -2;
 425     }
 426
 427     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 428         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 429         return -1;
 430     }
 431
 432     if (ctx->op.kex.exchprovctx == NULL)
 433         goto legacy;
 434
 435     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 436                                        SIZE_MAX);
 437
 438     return ret;
 439  legacy:
 440     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 441         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 442                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 443         return -2;
 444     }
 445
 446     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 447         return ctx->pmeth->derive(ctx, key, pkeylen);
 448 }
 449
 450 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 451 {
 452     return keyexch->name_id;
 453 }
 454
 455 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 456 {
 457     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 458 }
 459
 460 void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
 461                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 462                                  void *arg)
 463 {
 464     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 465                        (void (*)(void *, void *))fn, arg,
 466                        evp_keyexch_from_dispatch,
 467                        (void (*)(void *))EVP_KEYEXCH_free);
 468 }
 469
 470 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 471                               void (*fn)(const char *name, void *data),
 472                               void *data)
 473 {
 474     if (keyexch->prov != NULL)
 475         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 476 }
 477
 478 const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
 479 {
 480     void *provctx;
 481
 482     if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
 483         return NULL;
 484
 485     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 486     return keyexch->gettable_ctx_params(provctx);
 487 }
 488
 489 const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
 490 {
 491     void *provctx;
 492
 493     if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
 494         return NULL;
 495     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 496     return keyexch->settable_ctx_params(provctx);
 497 }