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         ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_PROVIDER_FUNCTIONS);
 131         goto err;
 132     }
 133
 134     return exchange;
 135
 136  err:
 137     EVP_KEYEXCH_free(exchange);
 138     return NULL;
 139 }
 140
 141 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 142 {
 143     if (exchange != NULL) {
 144         int i;
 145
 146         CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 147         if (i > 0)
 148             return;
 149         ossl_provider_free(exchange->prov);
 150         CRYPTO_THREAD_lock_free(exchange->lock);
 151         OPENSSL_free(exchange);
 152     }
 153 }
 154
 155 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 156 {
 157     int ref = 0;
 158
 159     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 160     return 1;
 161 }
 162
 163 OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
 164 {
 165     return exchange->prov;
 166 }
 167
 168 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 169                                const char *properties)
 170 {
 171     return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 172                              evp_keyexch_from_dispatch,
 173                              (int (*)(void *))EVP_KEYEXCH_up_ref,
 174                              (void (*)(void *))EVP_KEYEXCH_free);
 175 }
 176
 177 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 178 {
 179     int ret;
 180     void *provkey = NULL;
 181     EVP_KEYEXCH *exchange = NULL;
 182     EVP_KEYMGMT *tmp_keymgmt = NULL;
 183     const char *supported_exch = NULL;
 184
 185     if (ctx == NULL) {
 186         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 187         return -2;
 188     }
 189
 190     evp_pkey_ctx_free_old_ops(ctx);
 191     ctx->operation = EVP_PKEY_OP_DERIVE;
 192
 193     /*
 194      * TODO when we stop falling back to legacy, this and the ERR_pop_to_mark()
 195      * calls can be removed.
 196      */
 197     ERR_set_mark();
 198
 199     if (evp_pkey_ctx_is_legacy(ctx))
 200         goto legacy;
 201
 202     /*
 203      * Ensure that the key is provided, either natively, or as a cached export.
 204      * If not, goto legacy
 205      */
 206     tmp_keymgmt = ctx->keymgmt;
 207     if (ctx->pkey == NULL) {
 208         /*
 209          * Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
 210          * a blank one.
 211          */
 212         EVP_PKEY *pkey = EVP_PKEY_new();
 213
 214         if (pkey == NULL || !EVP_PKEY_set_type_by_keymgmt(pkey, tmp_keymgmt)) {
 215             ERR_clear_last_mark();
 216             EVP_PKEY_free(pkey);
 217             ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 218             goto err;
 219         }
 220         provkey = pkey->keydata = evp_keymgmt_newdata(tmp_keymgmt);
 221         if (provkey == NULL)
 222             EVP_PKEY_free(pkey);
 223         else
 224             ctx->pkey = pkey;
 225     } else {
 226         provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 227                                             &tmp_keymgmt, ctx->propquery);
 228     }
 229     if (provkey == NULL)
 230         goto legacy;
 231     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 232         ERR_clear_last_mark();
 233         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 234         goto err;
 235     }
 236     EVP_KEYMGMT_free(ctx->keymgmt);
 237     ctx->keymgmt = tmp_keymgmt;
 238
 239     if (ctx->keymgmt->query_operation_name != NULL)
 240         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 241
 242     /*
 243      * If we didn't get a supported exch, assume there is one with the
 244      * same name as the key type.
 245      */
 246     if (supported_exch == NULL)
 247         supported_exch = ctx->keytype;
 248
 249     /*
 250      * Because we cleared out old ops, we shouldn't need to worry about
 251      * checking if exchange is already there.
 252      */
 253     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 254
 255     if (exchange == NULL
 256         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 257             != EVP_KEYEXCH_provider(exchange))) {
 258         /*
 259          * We don't need to free ctx->keymgmt here, as it's not necessarily
 260          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 261          */
 262         EVP_KEYEXCH_free(exchange);
 263         goto legacy;
 264     }
 265
 266     /*
 267      * TODO remove this when legacy is gone
 268      * If we don't have the full support we need with provided methods,
 269      * let's go see if legacy does.
 270      */
 271     ERR_pop_to_mark();
 272
 273     /* No more legacy from here down to legacy: */
 274
 275     ctx->op.kex.exchange = exchange;
 276     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 277     if (ctx->op.kex.exchprovctx == NULL) {
 278         /* The provider key can stay in the cache */
 279         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 280         goto err;
 281     }
 282     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 283
 284     return ret ? 1 : 0;
 285  err:
 286     evp_pkey_ctx_free_old_ops(ctx);
 287     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 288     return 0;
 289
 290  legacy:
 291     /*
 292      * TODO remove this when legacy is gone
 293      * If we don't have the full support we need with provided methods,
 294      * let's go see if legacy does.
 295      */
 296     ERR_pop_to_mark();
 297
 298 #ifdef FIPS_MODULE
 299     return 0;
 300 #else
 301     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 302         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 303         return -2;
 304     }
 305
 306     if (ctx->pmeth->derive_init == NULL)
 307         return 1;
 308     ret = ctx->pmeth->derive_init(ctx);
 309     if (ret <= 0)
 310         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 311     return ret;
 312 #endif
 313 }
 314
 315 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 316 {
 317     int ret = 0;
 318     void *provkey = NULL;
 319
 320     if (ctx == NULL) {
 321         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 322         return -2;
 323     }
 324
 325     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 326         goto legacy;
 327
 328     if (ctx->op.kex.exchange->set_peer == NULL) {
 329         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 330         return -2;
 331     }
 332
 333     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 334                                           ctx->propquery);
 335     /*
 336      * If making the key provided wasn't possible, legacy may be able to pick
 337      * it up
 338      */
 339     if (provkey == NULL)
 340         goto legacy;
 341     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 342
 343  legacy:
 344 #ifdef FIPS_MODULE
 345     return ret;
 346 #else
 347     /*
 348      * TODO(3.0) investigate the case where the operation is deemed legacy,
 349      * but the given peer key is provider only.
 350      */
 351     if (ctx->pmeth == NULL
 352         || !(ctx->pmeth->derive != NULL
 353              || ctx->pmeth->encrypt != NULL
 354              || ctx->pmeth->decrypt != NULL)
 355         || ctx->pmeth->ctrl == NULL) {
 356         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 357         return -2;
 358     }
 359     if (ctx->operation != EVP_PKEY_OP_DERIVE
 360         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 361         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 362         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATON_NOT_INITIALIZED);
 363         return -1;
 364     }
 365
 366     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 367
 368     if (ret <= 0)
 369         return ret;
 370
 371     if (ret == 2)
 372         return 1;
 373
 374     if (ctx->pkey == NULL) {
 375         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
 376         return -1;
 377     }
 378
 379     if (ctx->pkey->type != peer->type) {
 380         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 381         return -1;
 382     }
 383
 384     /*
 385      * For clarity.  The error is if parameters in peer are
 386      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 387      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 388      * (different key types) is impossible here because it is checked earlier.
 389      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 390      */
 391     if (!EVP_PKEY_missing_parameters(peer) &&
 392         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 393         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_PARAMETERS);
 394         return -1;
 395     }
 396
 397     EVP_PKEY_free(ctx->peerkey);
 398     ctx->peerkey = peer;
 399
 400     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 401
 402     if (ret <= 0) {
 403         ctx->peerkey = NULL;
 404         return ret;
 405     }
 406
 407     EVP_PKEY_up_ref(peer);
 408     return 1;
 409 #endif
 410 }
 411
 412 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 413 {
 414     int ret;
 415
 416     if (ctx == NULL) {
 417         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 418         return -2;
 419     }
 420
 421     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 422         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATON_NOT_INITIALIZED);
 423         return -1;
 424     }
 425
 426     if (ctx->op.kex.exchprovctx == NULL)
 427         goto legacy;
 428
 429     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 430                                        SIZE_MAX);
 431
 432     return ret;
 433  legacy:
 434     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 435         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 436         return -2;
 437     }
 438
 439     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 440         return ctx->pmeth->derive(ctx, key, pkeylen);
 441 }
 442
 443 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 444 {
 445     return keyexch->name_id;
 446 }
 447
 448 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 449 {
 450     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 451 }
 452
 453 void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
 454                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 455                                  void *arg)
 456 {
 457     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 458                        (void (*)(void *, void *))fn, arg,
 459                        evp_keyexch_from_dispatch,
 460                        (void (*)(void *))EVP_KEYEXCH_free);
 461 }
 462
 463 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 464                               void (*fn)(const char *name, void *data),
 465                               void *data)
 466 {
 467     if (keyexch->prov != NULL)
 468         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 469 }
 470
 471 const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
 472 {
 473     void *provctx;
 474
 475     if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
 476         return NULL;
 477
 478     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 479     return keyexch->gettable_ctx_params(provctx);
 480 }
 481
 482 const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
 483 {
 484     void *provctx;
 485
 486     if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
 487         return NULL;
 488     provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
 489     return keyexch->settable_ctx_params(provctx);
 490 }