crypto/evp/exchange.c

   1 /*
   2  * Copyright 2019 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_get_OP_keyexch_newctx(fns);
  61             fncnt++;
  62             break;
  63         case OSSL_FUNC_KEYEXCH_INIT:
  64             if (exchange->init != NULL)
  65                 break;
  66             exchange->init = OSSL_get_OP_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_get_OP_keyexch_set_peer(fns);
  73             break;
  74         case OSSL_FUNC_KEYEXCH_DERIVE:
  75             if (exchange->derive != NULL)
  76                 break;
  77             exchange->derive = OSSL_get_OP_keyexch_derive(fns);
  78             fncnt++;
  79             break;
  80         case OSSL_FUNC_KEYEXCH_FREECTX:
  81             if (exchange->freectx != NULL)
  82                 break;
  83             exchange->freectx = OSSL_get_OP_keyexch_freectx(fns);
  84             fncnt++;
  85             break;
  86         case OSSL_FUNC_KEYEXCH_DUPCTX:
  87             if (exchange->dupctx != NULL)
  88                 break;
  89             exchange->dupctx = OSSL_get_OP_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_get_OP_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_get_OP_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_get_OP_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_get_OP_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(OPENSSL_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 (ctx->engine != NULL || ctx->keytype == NULL)
 201         goto legacy;
 202
 203     /* Ensure that the key is provided.  If not, go legacy */
 204     tmp_keymgmt = ctx->keymgmt;
 205     provkey = evp_pkey_make_provided(ctx->pkey, ctx->libctx,
 206                                      &tmp_keymgmt, ctx->propquery);
 207     if (provkey == NULL)
 208         goto legacy;
 209     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 210         ERR_clear_last_mark();
 211         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 212         goto err;
 213     }
 214     EVP_KEYMGMT_free(ctx->keymgmt);
 215     ctx->keymgmt = tmp_keymgmt;
 216
 217     if (ctx->keymgmt->query_operation_name != NULL)
 218         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 219
 220     /*
 221      * If we didn't get a supported exch, assume there is one with the
 222      * same name as the key type.
 223      */
 224     if (supported_exch == NULL)
 225         supported_exch = ctx->keytype;
 226
 227     /*
 228      * Because we cleared out old ops, we shouldn't need to worry about
 229      * checking if exchange is already there.
 230      */
 231     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 232
 233     if (exchange == NULL
 234         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 235             != EVP_KEYEXCH_provider(exchange))) {
 236         /*
 237          * We don't need to free ctx->keymgmt here, as it's not necessarily
 238          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 239          */
 240         EVP_KEYEXCH_free(exchange);
 241         goto legacy;
 242     }
 243
 244     /*
 245      * TODO remove this when legacy is gone
 246      * If we don't have the full support we need with provided methods,
 247      * let's go see if legacy does.
 248      */
 249     ERR_pop_to_mark();
 250
 251     /* No more legacy from here down to legacy: */
 252
 253     ctx->op.kex.exchange = exchange;
 254     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 255     if (ctx->op.kex.exchprovctx == NULL) {
 256         /* The provider key can stay in the cache */
 257         EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 258         goto err;
 259     }
 260     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 261
 262     return ret ? 1 : 0;
 263  err:
 264     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 265     return 0;
 266
 267  legacy:
 268     /*
 269      * TODO remove this when legacy is gone
 270      * If we don't have the full support we need with provided methods,
 271      * let's go see if legacy does.
 272      */
 273     ERR_pop_to_mark();
 274
 275 #ifdef FIPS_MODE
 276     return 0;
 277 #else
 278     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 279         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 280         return -2;
 281     }
 282
 283     if (ctx->pmeth->derive_init == NULL)
 284         return 1;
 285     ret = ctx->pmeth->derive_init(ctx);
 286     if (ret <= 0)
 287         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 288     return ret;
 289 #endif
 290 }
 291
 292 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 293 {
 294     int ret = 0;
 295     void *provkey = NULL;
 296
 297     if (ctx == NULL) {
 298         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 299                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 300         return -2;
 301     }
 302
 303     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 304         goto legacy;
 305
 306     if (ctx->op.kex.exchange->set_peer == NULL) {
 307         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 308                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 309         return -2;
 310     }
 311
 312     provkey = evp_pkey_make_provided(peer, ctx->libctx, &ctx->keymgmt,
 313                                      ctx->propquery);
 314     /*
 315      * If making the key provided wasn't possible, legacy may be able to pick
 316      * it up
 317      */
 318     if (provkey == NULL)
 319         goto legacy;
 320     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 321
 322  legacy:
 323 #ifdef FIPS_MODE
 324     return ret;
 325 #else
 326     /*
 327      * TODO(3.0) investigate the case where the operation is deemed legacy,
 328      * but the given peer key is provider only.
 329      */
 330     if (ctx->pmeth == NULL
 331         || !(ctx->pmeth->derive != NULL
 332              || ctx->pmeth->encrypt != NULL
 333              || ctx->pmeth->decrypt != NULL)
 334         || ctx->pmeth->ctrl == NULL) {
 335         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 336                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 337         return -2;
 338     }
 339     if (ctx->operation != EVP_PKEY_OP_DERIVE
 340         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 341         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 342         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 343                EVP_R_OPERATON_NOT_INITIALIZED);
 344         return -1;
 345     }
 346
 347     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 348
 349     if (ret <= 0)
 350         return ret;
 351
 352     if (ret == 2)
 353         return 1;
 354
 355     if (ctx->pkey == NULL) {
 356         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 357         return -1;
 358     }
 359
 360     if (ctx->pkey->type != peer->type) {
 361         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 362         return -1;
 363     }
 364
 365     /*
 366      * For clarity.  The error is if parameters in peer are
 367      * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return
 368      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 369      * (different key types) is impossible here because it is checked earlier.
 370      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 371      */
 372     if (!EVP_PKEY_missing_parameters(peer) &&
 373         !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {
 374         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 375         return -1;
 376     }
 377
 378     EVP_PKEY_free(ctx->peerkey);
 379     ctx->peerkey = peer;
 380
 381     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 382
 383     if (ret <= 0) {
 384         ctx->peerkey = NULL;
 385         return ret;
 386     }
 387
 388     EVP_PKEY_up_ref(peer);
 389     return 1;
 390 #endif
 391 }
 392
 393 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 394 {
 395     int ret;
 396
 397     if (ctx == NULL) {
 398         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 399                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 400         return -2;
 401     }
 402
 403     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 404         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 405         return -1;
 406     }
 407
 408     if (ctx->op.kex.exchprovctx == NULL)
 409         goto legacy;
 410
 411     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 412                                        SIZE_MAX);
 413
 414     return ret;
 415  legacy:
 416     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 417         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 418                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 419         return -2;
 420     }
 421
 422     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 423         return ctx->pmeth->derive(ctx, key, pkeylen);
 424 }
 425
 426 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 427 {
 428     return keyexch->name_id;
 429 }
 430
 431 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 432 {
 433     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 434 }
 435
 436 void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,
 437                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 438                                  void *arg)
 439 {
 440     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 441                        (void (*)(void *, void *))fn, arg,
 442                        evp_keyexch_from_dispatch,
 443                        (void (*)(void *))EVP_KEYEXCH_free);
 444 }
 445
 446 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 447                               void (*fn)(const char *name, void *data),
 448                               void *data)
 449 {
 450     if (keyexch->prov != NULL)
 451         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 452 }