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     exchange->lock = CRYPTO_THREAD_lock_new();
  24     if (exchange->lock == NULL) {
  25         OPENSSL_free(exchange);
  26         return NULL;
  27     }
  28     exchange->prov = prov;
  29     ossl_provider_up_ref(prov);
  30     exchange->refcnt = 1;
  31
  32     return exchange;
  33 }
  34
  35 static void *evp_keyexch_from_dispatch(int name_id,
  36                                        const OSSL_DISPATCH *fns,
  37                                        OSSL_PROVIDER *prov,
  38                                        void *unused)
  39 {
  40     EVP_KEYEXCH *exchange = NULL;
  41     int fncnt = 0, paramfncnt = 0;
  42
  43     if ((exchange = evp_keyexch_new(prov)) == NULL) {
  44         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  45         goto err;
  46     }
  47
  48     exchange->name_id = name_id;
  49
  50     for (; fns->function_id != 0; fns++) {
  51         switch (fns->function_id) {
  52         case OSSL_FUNC_KEYEXCH_NEWCTX:
  53             if (exchange->newctx != NULL)
  54                 break;
  55             exchange->newctx = OSSL_get_OP_keyexch_newctx(fns);
  56             fncnt++;
  57             break;
  58         case OSSL_FUNC_KEYEXCH_INIT:
  59             if (exchange->init != NULL)
  60                 break;
  61             exchange->init = OSSL_get_OP_keyexch_init(fns);
  62             fncnt++;
  63             break;
  64         case OSSL_FUNC_KEYEXCH_SET_PEER:
  65             if (exchange->set_peer != NULL)
  66                 break;
  67             exchange->set_peer = OSSL_get_OP_keyexch_set_peer(fns);
  68             break;
  69         case OSSL_FUNC_KEYEXCH_DERIVE:
  70             if (exchange->derive != NULL)
  71                 break;
  72             exchange->derive = OSSL_get_OP_keyexch_derive(fns);
  73             fncnt++;
  74             break;
  75         case OSSL_FUNC_KEYEXCH_FREECTX:
  76             if (exchange->freectx != NULL)
  77                 break;
  78             exchange->freectx = OSSL_get_OP_keyexch_freectx(fns);
  79             fncnt++;
  80             break;
  81         case OSSL_FUNC_KEYEXCH_DUPCTX:
  82             if (exchange->dupctx != NULL)
  83                 break;
  84             exchange->dupctx = OSSL_get_OP_keyexch_dupctx(fns);
  85             break;
  86         case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
  87             if (exchange->set_ctx_params != NULL)
  88                 break;
  89             exchange->set_ctx_params = OSSL_get_OP_keyexch_set_ctx_params(fns);
  90             paramfncnt++;
  91             break;
  92         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
  93             if (exchange->settable_ctx_params != NULL)
  94                 break;
  95             exchange->settable_ctx_params
  96                 = OSSL_get_OP_keyexch_settable_ctx_params(fns);
  97             paramfncnt++;
  98             break;
  99         }
 100     }
 101     if (fncnt != 4 || (paramfncnt != 0 && paramfncnt != 2)) {
 102         /*
 103          * In order to be a consistent set of functions we must have at least
 104          * a complete set of "exchange" functions: init, derive, newctx,
 105          * and freectx. The set_ctx_params and settable_ctx_params functions are
 106          * optional, but if one of them is present then the other one must also
 107          * be present. The dupctx and set_peer functions are optional.
 108          */
 109         EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,
 110                EVP_R_INVALID_PROVIDER_FUNCTIONS);
 111         goto err;
 112     }
 113
 114     return exchange;
 115
 116  err:
 117     EVP_KEYEXCH_free(exchange);
 118     return NULL;
 119 }
 120
 121 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 122 {
 123     if (exchange != NULL) {
 124         int i;
 125
 126         CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 127         if (i > 0)
 128             return;
 129         ossl_provider_free(exchange->prov);
 130         CRYPTO_THREAD_lock_free(exchange->lock);
 131         OPENSSL_free(exchange);
 132     }
 133 }
 134
 135 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 136 {
 137     int ref = 0;
 138
 139     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 140     return 1;
 141 }
 142
 143 OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
 144 {
 145     return exchange->prov;
 146 }
 147
 148 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OPENSSL_CTX *ctx, const char *algorithm,
 149                                const char *properties)
 150 {
 151     EVP_KEYEXCH *keyexch = NULL;
 152
 153     keyexch = evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 154                                 evp_keyexch_from_dispatch, NULL,
 155                                 (int (*)(void *))EVP_KEYEXCH_up_ref,
 156                                 (void (*)(void *))EVP_KEYEXCH_free);
 157
 158     return keyexch;
 159 }
 160
 161 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 162 {
 163     int ret;
 164     void *provkey = NULL;
 165     EVP_KEYEXCH *exchange = NULL;
 166
 167     if (ctx == NULL) {
 168         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 169         return -2;
 170     }
 171
 172     evp_pkey_ctx_free_old_ops(ctx);
 173     ctx->operation = EVP_PKEY_OP_DERIVE;
 174
 175     if (ctx->engine != NULL || ctx->algorithm == NULL)
 176         goto legacy;
 177
 178     /*
 179      * Because we cleared out old ops, we shouldn't need to worry about
 180      * checking if exchange is already there.  Keymgmt is a different
 181      * matter, as it isn't tied to a specific EVP_PKEY op.
 182      */
 183     exchange = EVP_KEYEXCH_fetch(ctx->libctx, ctx->algorithm, ctx->propquery);
 184     if (exchange != NULL && ctx->keymgmt == NULL) {
 185         int name_id = EVP_KEYEXCH_number(exchange);
 186
 187         ctx->keymgmt =
 188             evp_keymgmt_fetch_by_number(ctx->libctx, name_id, ctx->propquery);
 189     }
 190
 191     if (ctx->keymgmt == NULL
 192         || exchange == NULL
 193         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 194             != EVP_KEYEXCH_provider(exchange))) {
 195         /*
 196          * We don't have the full support we need with provided methods,
 197          * let's go see if legacy does.  Also, we don't need to free
 198          * ctx->keymgmt here, as it's not necessarily tied to this
 199          * operation.  It will be freed by EVP_PKEY_CTX_free().
 200          */
 201         EVP_KEYEXCH_free(exchange);
 202         goto legacy;
 203     }
 204
 205
 206     ctx->op.kex.exchange = exchange;
 207
 208     if (ctx->pkey != NULL) {
 209         provkey = evp_keymgmt_export_to_provider(ctx->pkey, ctx->keymgmt, 0);
 210         if (provkey == NULL) {
 211             EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 212             goto err;
 213         }
 214     }
 215     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 216     if (ctx->op.kex.exchprovctx == NULL) {
 217         /* The provider key can stay in the cache */
 218         EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 219         goto err;
 220     }
 221     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 222
 223     return ret ? 1 : 0;
 224  err:
 225     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 226     return 0;
 227
 228  legacy:
 229     if (ctx == NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 230         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 231         return -2;
 232     }
 233
 234     if (ctx->pmeth->derive_init == NULL)
 235         return 1;
 236     ret = ctx->pmeth->derive_init(ctx);
 237     if (ret <= 0)
 238         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 239     return ret;
 240 }
 241
 242 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 243 {
 244     int ret;
 245     void *provkey = NULL;
 246
 247     if (ctx == NULL) {
 248         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 249                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 250         return -2;
 251     }
 252
 253     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 254         goto legacy;
 255
 256     if (ctx->op.kex.exchange->set_peer == NULL) {
 257         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 258                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 259         return -2;
 260     }
 261
 262     provkey = evp_keymgmt_export_to_provider(peer, ctx->keymgmt, 0);
 263     if (provkey == NULL) {
 264         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, ERR_R_INTERNAL_ERROR);
 265         return 0;
 266     }
 267     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 268
 269  legacy:
 270     if (ctx->pmeth == NULL
 271         || !(ctx->pmeth->derive != NULL
 272              || ctx->pmeth->encrypt != NULL
 273              || ctx->pmeth->decrypt != NULL)
 274         || ctx->pmeth->ctrl == NULL) {
 275         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 276                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 277         return -2;
 278     }
 279     if (ctx->operation != EVP_PKEY_OP_DERIVE
 280         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 281         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 282         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 283                EVP_R_OPERATON_NOT_INITIALIZED);
 284         return -1;
 285     }
 286
 287     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 288
 289     if (ret <= 0)
 290         return ret;
 291
 292     if (ret == 2)
 293         return 1;
 294
 295     if (ctx->pkey == NULL) {
 296         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 297         return -1;
 298     }
 299
 300     if (ctx->pkey->type != peer->type) {
 301         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 302         return -1;
 303     }
 304
 305     /*
 306      * For clarity.  The error is if parameters in peer are
 307      * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return
 308      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 309      * (different key types) is impossible here because it is checked earlier.
 310      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 311      */
 312     if (!EVP_PKEY_missing_parameters(peer) &&
 313         !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {
 314         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 315         return -1;
 316     }
 317
 318     EVP_PKEY_free(ctx->peerkey);
 319     ctx->peerkey = peer;
 320
 321     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 322
 323     if (ret <= 0) {
 324         ctx->peerkey = NULL;
 325         return ret;
 326     }
 327
 328     EVP_PKEY_up_ref(peer);
 329     return 1;
 330 }
 331
 332 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 333 {
 334     int ret;
 335
 336     if (ctx == NULL) {
 337         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 338                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 339         return -2;
 340     }
 341
 342     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 343         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 344         return -1;
 345     }
 346
 347     if (ctx->op.kex.exchprovctx == NULL)
 348         goto legacy;
 349
 350     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 351                                        SIZE_MAX);
 352
 353     return ret;
 354  legacy:
 355     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 356         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 357                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 358         return -2;
 359     }
 360
 361     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 362         return ctx->pmeth->derive(ctx, key, pkeylen);
 363 }
 364
 365 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 366 {
 367     return keyexch->name_id;
 368 }
 369
 370 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 371 {
 372     return evp_is_a(keyexch->prov, keyexch->name_id, name);
 373 }
 374
 375 void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,
 376                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 377                                  void *arg)
 378 {
 379     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 380                        (void (*)(void *, void *))fn, arg,
 381                        evp_keyexch_from_dispatch, NULL,
 382                        (void (*)(void *))EVP_KEYEXCH_free);
 383 }
 384
 385 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 386                               void (*fn)(const char *name, void *data),
 387                               void *data)
 388 {
 389     if (keyexch->prov != NULL)
 390         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 391 }