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 = evp_keymgmt_export_to_provider(ctx->pkey, exchange->keymgmt);
 228         if (provkey == NULL) {
 229             EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX, EVP_R_INITIALIZATION_ERROR);
 230             goto err;
 231         }
 232     }
 233     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 234     if (ctx->op.kex.exchprovctx == NULL) {
 235         /* The provider key can stay in the cache */
 236         EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX, EVP_R_INITIALIZATION_ERROR);
 237         goto err;
 238     }
 239     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 240
 241     return ret ? 1 : 0;
 242  err:
 243     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 244     return 0;
 245
 246  legacy:
 247     if (ctx == NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 248         EVPerr(EVP_F_EVP_PKEY_DERIVE_INIT_EX,
 249                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 250         return -2;
 251     }
 252
 253     if (ctx->pmeth->derive_init == NULL)
 254         return 1;
 255     ret = ctx->pmeth->derive_init(ctx);
 256     if (ret <= 0)
 257         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 258     return ret;
 259 }
 260
 261 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 262 {
 263     return EVP_PKEY_derive_init_ex(ctx, NULL);
 264 }
 265
 266 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 267 {
 268     int ret;
 269     void *provkey = NULL;
 270
 271     if (ctx == NULL) {
 272         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 273                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 274         return -2;
 275     }
 276
 277     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 278         goto legacy;
 279
 280     if (ctx->op.kex.exchange->set_peer == NULL) {
 281         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 282                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 283         return -2;
 284     }
 285
 286     provkey = evp_keymgmt_export_to_provider(peer,
 287                                              ctx->op.kex.exchange->keymgmt);
 288     if (provkey == NULL) {
 289         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, ERR_R_INTERNAL_ERROR);
 290         return 0;
 291     }
 292     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 293
 294  legacy:
 295     if (ctx->pmeth == NULL
 296         || !(ctx->pmeth->derive != NULL
 297              || ctx->pmeth->encrypt != NULL
 298              || ctx->pmeth->decrypt != NULL)
 299         || ctx->pmeth->ctrl == NULL) {
 300         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 301                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 302         return -2;
 303     }
 304     if (ctx->operation != EVP_PKEY_OP_DERIVE
 305         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 306         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 307         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 308                EVP_R_OPERATON_NOT_INITIALIZED);
 309         return -1;
 310     }
 311
 312     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 313
 314     if (ret <= 0)
 315         return ret;
 316
 317     if (ret == 2)
 318         return 1;
 319
 320     if (ctx->pkey == NULL) {
 321         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 322         return -1;
 323     }
 324
 325     if (ctx->pkey->type != peer->type) {
 326         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 327         return -1;
 328     }
 329
 330     /*
 331      * For clarity.  The error is if parameters in peer are
 332      * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return
 333      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 334      * (different key types) is impossible here because it is checked earlier.
 335      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 336      */
 337     if (!EVP_PKEY_missing_parameters(peer) &&
 338         !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {
 339         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 340         return -1;
 341     }
 342
 343     EVP_PKEY_free(ctx->peerkey);
 344     ctx->peerkey = peer;
 345
 346     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 347
 348     if (ret <= 0) {
 349         ctx->peerkey = NULL;
 350         return ret;
 351     }
 352
 353     EVP_PKEY_up_ref(peer);
 354     return 1;
 355 }
 356
 357 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 358 {
 359     int ret;
 360
 361     if (ctx == NULL) {
 362         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 363                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 364         return -2;
 365     }
 366
 367     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 368         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 369         return -1;
 370     }
 371
 372     if (ctx->op.kex.exchprovctx == NULL)
 373         goto legacy;
 374
 375     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 376                                        SIZE_MAX);
 377
 378     return ret;
 379  legacy:
 380     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 381         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 382                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 383         return -2;
 384     }
 385
 386     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 387         return ctx->pmeth->derive(ctx, key, pkeylen);
 388 }