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 *vkeymgmt_data)
  39 {
  40     /*
  41      * Key exchange cannot work without a key, and key management
  42      * from the same provider to manage its keys.  We therefore fetch
  43      * a key management method using the same algorithm and properties
  44      * and pass that down to evp_generic_fetch to be passed on to our
  45      * evp_keyexch_from_dispatch, which will attach the key management
  46      * method to the newly created key exchange method as long as the
  47      * provider matches.
  48      */
  49     struct keymgmt_data_st *keymgmt_data = vkeymgmt_data;
  50     EVP_KEYMGMT *keymgmt =
  51         evp_keymgmt_fetch_by_number(keymgmt_data->ctx, name_id,
  52                                     keymgmt_data->properties);
  53     EVP_KEYEXCH *exchange = NULL;
  54     int fncnt = 0, paramfncnt = 0;
  55
  56     if (keymgmt == NULL || EVP_KEYMGMT_provider(keymgmt) != prov) {
  57         ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEYMGMT_AVAILABLE);
  58         goto err;
  59     }
  60
  61     if ((exchange = evp_keyexch_new(prov)) == NULL) {
  62         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  63         goto err;
  64     }
  65
  66     exchange->name_id = name_id;
  67     exchange->keymgmt = keymgmt;
  68     keymgmt = NULL;              /* avoid double free on failure below */
  69
  70     for (; fns->function_id != 0; fns++) {
  71         switch (fns->function_id) {
  72         case OSSL_FUNC_KEYEXCH_NEWCTX:
  73             if (exchange->newctx != NULL)
  74                 break;
  75             exchange->newctx = OSSL_get_OP_keyexch_newctx(fns);
  76             fncnt++;
  77             break;
  78         case OSSL_FUNC_KEYEXCH_INIT:
  79             if (exchange->init != NULL)
  80                 break;
  81             exchange->init = OSSL_get_OP_keyexch_init(fns);
  82             fncnt++;
  83             break;
  84         case OSSL_FUNC_KEYEXCH_SET_PEER:
  85             if (exchange->set_peer != NULL)
  86                 break;
  87             exchange->set_peer = OSSL_get_OP_keyexch_set_peer(fns);
  88             break;
  89         case OSSL_FUNC_KEYEXCH_DERIVE:
  90             if (exchange->derive != NULL)
  91                 break;
  92             exchange->derive = OSSL_get_OP_keyexch_derive(fns);
  93             fncnt++;
  94             break;
  95         case OSSL_FUNC_KEYEXCH_FREECTX:
  96             if (exchange->freectx != NULL)
  97                 break;
  98             exchange->freectx = OSSL_get_OP_keyexch_freectx(fns);
  99             fncnt++;
 100             break;
 101         case OSSL_FUNC_KEYEXCH_DUPCTX:
 102             if (exchange->dupctx != NULL)
 103                 break;
 104             exchange->dupctx = OSSL_get_OP_keyexch_dupctx(fns);
 105             break;
 106         case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
 107             if (exchange->set_ctx_params != NULL)
 108                 break;
 109             exchange->set_ctx_params = OSSL_get_OP_keyexch_set_ctx_params(fns);
 110             paramfncnt++;
 111             break;
 112         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
 113             if (exchange->settable_ctx_params != NULL)
 114                 break;
 115             exchange->settable_ctx_params
 116                 = OSSL_get_OP_keyexch_settable_ctx_params(fns);
 117             paramfncnt++;
 118             break;
 119         }
 120     }
 121     if (fncnt != 4 || (paramfncnt != 0 && paramfncnt != 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. The dupctx and set_peer functions are optional.
 128          */
 129         EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,
 130                EVP_R_INVALID_PROVIDER_FUNCTIONS);
 131         goto err;
 132     }
 133
 134     return exchange;
 135
 136  err:
 137     EVP_KEYEXCH_free(exchange);
 138     EVP_KEYMGMT_free(keymgmt);
 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         EVP_KEYMGMT_free(exchange->keymgmt);
 151         ossl_provider_free(exchange->prov);
 152         CRYPTO_THREAD_lock_free(exchange->lock);
 153         OPENSSL_free(exchange);
 154     }
 155 }
 156
 157 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 158 {
 159     int ref = 0;
 160
 161     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 162     return 1;
 163 }
 164
 165 OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
 166 {
 167     return exchange->prov;
 168 }
 169
 170 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OPENSSL_CTX *ctx, const char *algorithm,
 171                                const char *properties)
 172 {
 173     EVP_KEYEXCH *keyexch = NULL;
 174     struct keymgmt_data_st keymgmt_data;
 175
 176     keymgmt_data.ctx = ctx;
 177     keymgmt_data.properties = properties;
 178     keyexch = evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 179                                 evp_keyexch_from_dispatch, &keymgmt_data,
 180                                 (int (*)(void *))EVP_KEYEXCH_up_ref,
 181                                 (void (*)(void *))EVP_KEYEXCH_free);
 182
 183     return keyexch;
 184 }
 185
 186 int EVP_PKEY_derive_init_ex(EVP_PKEY_CTX *ctx, EVP_KEYEXCH *exchange)
 187 {
 188     int ret;
 189     void *provkey = NULL;
 190
 191     evp_pkey_ctx_free_old_ops(ctx);
 192     ctx->operation = EVP_PKEY_OP_DERIVE;
 193
 194     if (ctx->engine != NULL)
 195         goto legacy;
 196
 197     if (exchange != NULL) {
 198         if (!EVP_KEYEXCH_up_ref(exchange))
 199             goto err;
 200     } else {
 201         int nid = ctx->pkey != NULL ? ctx->pkey->type : ctx->pmeth->pkey_id;
 202
 203         /*
 204          * TODO(3.0): Check for legacy handling. Remove this once all all
 205          * algorithms are moved to providers.
 206          */
 207         if (ctx->pkey != NULL) {
 208             switch (ctx->pkey->type) {
 209             case EVP_PKEY_DH:
 210                 break;
 211             default:
 212                 goto legacy;
 213             }
 214             exchange = EVP_KEYEXCH_fetch(NULL, OBJ_nid2sn(nid), NULL);
 215         } else {
 216             goto legacy;
 217         }
 218
 219         if (exchange == NULL) {
 220             EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX, EVP_R_INITIALIZATION_ERROR);
 221             goto err;
 222         }
 223     }
 224
 225     ctx->op.kex.exchange = exchange;
 226     if (ctx->pkey != NULL) {
 227         provkey =
 228             evp_keymgmt_export_to_provider(ctx->pkey, exchange->keymgmt, 0);
 229         if (provkey == NULL) {
 230             EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX, EVP_R_INITIALIZATION_ERROR);
 231             goto err;
 232         }
 233     }
 234     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 235     if (ctx->op.kex.exchprovctx == NULL) {
 236         /* The provider key can stay in the cache */
 237         EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX, EVP_R_INITIALIZATION_ERROR);
 238         goto err;
 239     }
 240     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 241
 242     return ret ? 1 : 0;
 243  err:
 244     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 245     return 0;
 246
 247  legacy:
 248     if (ctx == NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 249         EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX,
 250                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 251         return -2;
 252     }
 253
 254     if (ctx->pmeth->derive_init == NULL)
 255         return 1;
 256     ret = ctx->pmeth->derive_init(ctx);
 257     if (ret <= 0)
 258         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 259     return ret;
 260 }
 261
 262 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 263 {
 264     return EVP_PKEY_derive_init_ex(ctx, NULL);
 265 }
 266
 267 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 268 {
 269     int ret;
 270     void *provkey = NULL;
 271
 272     if (ctx == NULL) {
 273         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 274                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 275         return -2;
 276     }
 277
 278     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 279         goto legacy;
 280
 281     if (ctx->op.kex.exchange->set_peer == NULL) {
 282         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 283                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 284         return -2;
 285     }
 286
 287     provkey =
 288         evp_keymgmt_export_to_provider(peer, ctx->op.kex.exchange->keymgmt, 0);
 289     if (provkey == NULL) {
 290         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, ERR_R_INTERNAL_ERROR);
 291         return 0;
 292     }
 293     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 294
 295  legacy:
 296     if (ctx->pmeth == NULL
 297         || !(ctx->pmeth->derive != NULL
 298              || ctx->pmeth->encrypt != NULL
 299              || ctx->pmeth->decrypt != NULL)
 300         || ctx->pmeth->ctrl == NULL) {
 301         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 302                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 303         return -2;
 304     }
 305     if (ctx->operation != EVP_PKEY_OP_DERIVE
 306         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 307         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 308         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 309                EVP_R_OPERATON_NOT_INITIALIZED);
 310         return -1;
 311     }
 312
 313     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 314
 315     if (ret <= 0)
 316         return ret;
 317
 318     if (ret == 2)
 319         return 1;
 320
 321     if (ctx->pkey == NULL) {
 322         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 323         return -1;
 324     }
 325
 326     if (ctx->pkey->type != peer->type) {
 327         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 328         return -1;
 329     }
 330
 331     /*
 332      * For clarity.  The error is if parameters in peer are
 333      * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return
 334      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 335      * (different key types) is impossible here because it is checked earlier.
 336      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 337      */
 338     if (!EVP_PKEY_missing_parameters(peer) &&
 339         !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {
 340         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 341         return -1;
 342     }
 343
 344     EVP_PKEY_free(ctx->peerkey);
 345     ctx->peerkey = peer;
 346
 347     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 348
 349     if (ret <= 0) {
 350         ctx->peerkey = NULL;
 351         return ret;
 352     }
 353
 354     EVP_PKEY_up_ref(peer);
 355     return 1;
 356 }
 357
 358 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 359 {
 360     int ret;
 361
 362     if (ctx == NULL) {
 363         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 364                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 365         return -2;
 366     }
 367
 368     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 369         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 370         return -1;
 371     }
 372
 373     if (ctx->op.kex.exchprovctx == NULL)
 374         goto legacy;
 375
 376     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 377                                        SIZE_MAX);
 378
 379     return ret;
 380  legacy:
 381     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 382         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 383                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 384         return -2;
 385     }
 386
 387     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 388         return ctx->pmeth->derive(ctx, key, pkeylen);
 389 }
 390
 391 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 392 {
 393     return keyexch->name_id;
 394 }
 395
 396 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 397 {
 398     return evp_is_a(keyexch->prov, keyexch->name_id, name);
 399 }
 400
 401 void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,
 402                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 403                                  void *arg)
 404 {
 405     struct keymgmt_data_st keymgmt_data;
 406
 407     keymgmt_data.ctx = libctx;
 408     keymgmt_data.properties = NULL;
 409     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 410                        (void (*)(void *, void *))fn, arg,
 411                        evp_keyexch_from_dispatch, &keymgmt_data,
 412                        (void (*)(void *))EVP_KEYEXCH_free);
 413 }
 414
 415 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 416                               void (*fn)(const char *name, void *data),
 417                               void *data)
 418 {
 419     if (keyexch->prov != NULL)
 420         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 421 }