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_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->keymgmt == NULL)
 201         goto legacy;
 202
 203     /*
 204      * Ensure that the key is provided, either natively, or as a cached export.
 205      *  If not, go legacy
 206      */
 207     tmp_keymgmt = ctx->keymgmt;
 208     provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
 209                                           &tmp_keymgmt, ctx->propquery);
 210     if (provkey == NULL)
 211         goto legacy;
 212     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 213         ERR_clear_last_mark();
 214         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 215         goto err;
 216     }
 217     EVP_KEYMGMT_free(ctx->keymgmt);
 218     ctx->keymgmt = tmp_keymgmt;
 219
 220     if (ctx->keymgmt->query_operation_name != NULL)
 221         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 222
 223     /*
 224      * If we didn't get a supported exch, assume there is one with the
 225      * same name as the key type.
 226      */
 227     if (supported_exch == NULL)
 228         supported_exch = ctx->keytype;
 229
 230     /*
 231      * Because we cleared out old ops, we shouldn't need to worry about
 232      * checking if exchange is already there.
 233      */
 234     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 235
 236     if (exchange == NULL
 237         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 238             != EVP_KEYEXCH_provider(exchange))) {
 239         /*
 240          * We don't need to free ctx->keymgmt here, as it's not necessarily
 241          * tied to this operation.  It will be freed by EVP_PKEY_CTX_free().
 242          */
 243         EVP_KEYEXCH_free(exchange);
 244         goto legacy;
 245     }
 246
 247     /*
 248      * TODO remove this when legacy is gone
 249      * If we don't have the full support we need with provided methods,
 250      * let's go see if legacy does.
 251      */
 252     ERR_pop_to_mark();
 253
 254     /* No more legacy from here down to legacy: */
 255
 256     ctx->op.kex.exchange = exchange;
 257     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 258     if (ctx->op.kex.exchprovctx == NULL) {
 259         /* The provider key can stay in the cache */
 260         EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 261         goto err;
 262     }
 263     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 264
 265     return ret ? 1 : 0;
 266  err:
 267     evp_pkey_ctx_free_old_ops(ctx);
 268     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 269     return 0;
 270
 271  legacy:
 272     /*
 273      * TODO remove this when legacy is gone
 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 #ifdef FIPS_MODULE
 280     return 0;
 281 #else
 282     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 283         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 284         return -2;
 285     }
 286
 287     if (ctx->pmeth->derive_init == NULL)
 288         return 1;
 289     ret = ctx->pmeth->derive_init(ctx);
 290     if (ret <= 0)
 291         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 292     return ret;
 293 #endif
 294 }
 295
 296 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 297 {
 298     int ret = 0;
 299     void *provkey = NULL;
 300
 301     if (ctx == NULL) {
 302         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 303                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 304         return -2;
 305     }
 306
 307     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 308         goto legacy;
 309
 310     if (ctx->op.kex.exchange->set_peer == NULL) {
 311         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 312                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 313         return -2;
 314     }
 315
 316     provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
 317                                           ctx->propquery);
 318     /*
 319      * If making the key provided wasn't possible, legacy may be able to pick
 320      * it up
 321      */
 322     if (provkey == NULL)
 323         goto legacy;
 324     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 325
 326  legacy:
 327 #ifdef FIPS_MODULE
 328     return ret;
 329 #else
 330     /*
 331      * TODO(3.0) investigate the case where the operation is deemed legacy,
 332      * but the given peer key is provider only.
 333      */
 334     if (ctx->pmeth == NULL
 335         || !(ctx->pmeth->derive != NULL
 336              || ctx->pmeth->encrypt != NULL
 337              || ctx->pmeth->decrypt != NULL)
 338         || ctx->pmeth->ctrl == NULL) {
 339         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 340                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 341         return -2;
 342     }
 343     if (ctx->operation != EVP_PKEY_OP_DERIVE
 344         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 345         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 346         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 347                EVP_R_OPERATON_NOT_INITIALIZED);
 348         return -1;
 349     }
 350
 351     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 352
 353     if (ret <= 0)
 354         return ret;
 355
 356     if (ret == 2)
 357         return 1;
 358
 359     if (ctx->pkey == NULL) {
 360         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 361         return -1;
 362     }
 363
 364     if (ctx->pkey->type != peer->type) {
 365         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 366         return -1;
 367     }
 368
 369     /*
 370      * For clarity.  The error is if parameters in peer are
 371      * present (!missing) but don't match.  EVP_PKEY_parameters_eq may return
 372      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 373      * (different key types) is impossible here because it is checked earlier.
 374      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 375      */
 376     if (!EVP_PKEY_missing_parameters(peer) &&
 377         !EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
 378         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 379         return -1;
 380     }
 381
 382     EVP_PKEY_free(ctx->peerkey);
 383     ctx->peerkey = peer;
 384
 385     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 386
 387     if (ret <= 0) {
 388         ctx->peerkey = NULL;
 389         return ret;
 390     }
 391
 392     EVP_PKEY_up_ref(peer);
 393     return 1;
 394 #endif
 395 }
 396
 397 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 398 {
 399     int ret;
 400
 401     if (ctx == NULL) {
 402         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 403                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 404         return -2;
 405     }
 406
 407     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 408         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 409         return -1;
 410     }
 411
 412     if (ctx->op.kex.exchprovctx == NULL)
 413         goto legacy;
 414
 415     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 416                                        SIZE_MAX);
 417
 418     return ret;
 419  legacy:
 420     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 421         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 422                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 423         return -2;
 424     }
 425
 426     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 427         return ctx->pmeth->derive(ctx, key, pkeylen);
 428 }
 429
 430 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 431 {
 432     return keyexch->name_id;
 433 }
 434
 435 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 436 {
 437     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 438 }
 439
 440 void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,
 441                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 442                                  void *arg)
 443 {
 444     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 445                        (void (*)(void *, void *))fn, arg,
 446                        evp_keyexch_from_dispatch,
 447                        (void (*)(void *))EVP_KEYEXCH_free);
 448 }
 449
 450 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 451                               void (*fn)(const char *name, void *data),
 452                               void *data)
 453 {
 454     if (keyexch->prov != NULL)
 455         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 456 }