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