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     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, paramfncnt = 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_SET_CTX_PARAMS:
  92             if (exchange->set_ctx_params != NULL)
  93                 break;
  94             exchange->set_ctx_params = OSSL_get_OP_keyexch_set_ctx_params(fns);
  95             paramfncnt++;
  96             break;
  97         case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
  98             if (exchange->settable_ctx_params != NULL)
  99                 break;
 100             exchange->settable_ctx_params
 101                 = OSSL_get_OP_keyexch_settable_ctx_params(fns);
 102             paramfncnt++;
 103             break;
 104         }
 105     }
 106     if (fncnt != 4 || (paramfncnt != 0 && paramfncnt != 2)) {
 107         /*
 108          * In order to be a consistent set of functions we must have at least
 109          * a complete set of "exchange" functions: init, derive, newctx,
 110          * and freectx. The set_ctx_params and settable_ctx_params functions are
 111          * optional, but if one of them is present then the other one must also
 112          * be present. The dupctx and set_peer functions are optional.
 113          */
 114         EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,
 115                EVP_R_INVALID_PROVIDER_FUNCTIONS);
 116         goto err;
 117     }
 118
 119     return exchange;
 120
 121  err:
 122     EVP_KEYEXCH_free(exchange);
 123     return NULL;
 124 }
 125
 126 void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
 127 {
 128     if (exchange != NULL) {
 129         int i;
 130
 131         CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
 132         if (i > 0)
 133             return;
 134         ossl_provider_free(exchange->prov);
 135         CRYPTO_THREAD_lock_free(exchange->lock);
 136         OPENSSL_free(exchange);
 137     }
 138 }
 139
 140 int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
 141 {
 142     int ref = 0;
 143
 144     CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
 145     return 1;
 146 }
 147
 148 OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
 149 {
 150     return exchange->prov;
 151 }
 152
 153 EVP_KEYEXCH *EVP_KEYEXCH_fetch(OPENSSL_CTX *ctx, const char *algorithm,
 154                                const char *properties)
 155 {
 156     return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
 157                              evp_keyexch_from_dispatch,
 158                              (int (*)(void *))EVP_KEYEXCH_up_ref,
 159                              (void (*)(void *))EVP_KEYEXCH_free);
 160 }
 161
 162 int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
 163 {
 164     int ret;
 165     void *provkey = NULL;
 166     EVP_KEYEXCH *exchange = NULL;
 167     EVP_KEYMGMT *tmp_keymgmt = NULL;
 168     const char *supported_exch = NULL;
 169
 170     if (ctx == NULL) {
 171         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 172         return -2;
 173     }
 174
 175     evp_pkey_ctx_free_old_ops(ctx);
 176     ctx->operation = EVP_PKEY_OP_DERIVE;
 177
 178     if (ctx->engine != NULL || ctx->keytype == NULL)
 179         goto legacy;
 180
 181     /* Ensure that the key is provided.  If not, go legacy */
 182     tmp_keymgmt = ctx->keymgmt;
 183     provkey = evp_pkey_make_provided(ctx->pkey, ctx->libctx,
 184                                      &tmp_keymgmt, ctx->propquery, 0);
 185     if (provkey == NULL)
 186         goto legacy;
 187     if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
 188         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
 189         goto err;
 190     }
 191     EVP_KEYMGMT_free(ctx->keymgmt);
 192     ctx->keymgmt = tmp_keymgmt;
 193
 194     if (ctx->keymgmt->query_operation_name != NULL)
 195         supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
 196
 197     /*
 198      * If we didn't get a supported exch, assume there is one with the
 199      * same name as the key type.
 200      */
 201     if (supported_exch == NULL)
 202         supported_exch = ctx->keytype;
 203
 204     /*
 205      * Because we cleared out old ops, we shouldn't need to worry about
 206      * checking if exchange is already there.
 207      */
 208     exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
 209
 210     if (exchange == NULL
 211         || (EVP_KEYMGMT_provider(ctx->keymgmt)
 212             != EVP_KEYEXCH_provider(exchange))) {
 213         /*
 214          * We don't have the full support we need with provided methods,
 215          * let's go see if legacy does.  Also, we don't need to free
 216          * ctx->keymgmt here, as it's not necessarily tied to this
 217          * operation.  It will be freed by EVP_PKEY_CTX_free().
 218          */
 219         EVP_KEYEXCH_free(exchange);
 220         goto legacy;
 221     }
 222
 223
 224     ctx->op.kex.exchange = exchange;
 225     ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
 226     if (ctx->op.kex.exchprovctx == NULL) {
 227         /* The provider key can stay in the cache */
 228         EVPerr(0, EVP_R_INITIALIZATION_ERROR);
 229         goto err;
 230     }
 231     ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
 232
 233     return ret ? 1 : 0;
 234  err:
 235     ctx->operation = EVP_PKEY_OP_UNDEFINED;
 236     return 0;
 237
 238  legacy:
 239     if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 240         EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 241         return -2;
 242     }
 243
 244     if (ctx->pmeth->derive_init == NULL)
 245         return 1;
 246     ret = ctx->pmeth->derive_init(ctx);
 247     if (ret <= 0)
 248         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 249     return ret;
 250 }
 251
 252 int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
 253 {
 254     int ret;
 255     void *provkey = NULL;
 256
 257     if (ctx == NULL) {
 258         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 259                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 260         return -2;
 261     }
 262
 263     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
 264         goto legacy;
 265
 266     if (ctx->op.kex.exchange->set_peer == NULL) {
 267         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 268                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 269         return -2;
 270     }
 271
 272     provkey = evp_keymgmt_export_to_provider(peer, ctx->keymgmt, 0);
 273     /* If export failed, legacy may be able to pick it up */
 274     if (provkey == NULL)
 275         goto legacy;
 276     return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
 277
 278  legacy:
 279     if (ctx->pmeth == NULL
 280         || !(ctx->pmeth->derive != NULL
 281              || ctx->pmeth->encrypt != NULL
 282              || ctx->pmeth->decrypt != NULL)
 283         || ctx->pmeth->ctrl == NULL) {
 284         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 285                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 286         return -2;
 287     }
 288     if (ctx->operation != EVP_PKEY_OP_DERIVE
 289         && ctx->operation != EVP_PKEY_OP_ENCRYPT
 290         && ctx->operation != EVP_PKEY_OP_DECRYPT) {
 291         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
 292                EVP_R_OPERATON_NOT_INITIALIZED);
 293         return -1;
 294     }
 295
 296     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
 297
 298     if (ret <= 0)
 299         return ret;
 300
 301     if (ret == 2)
 302         return 1;
 303
 304     if (ctx->pkey == NULL) {
 305         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
 306         return -1;
 307     }
 308
 309     if (ctx->pkey->type != peer->type) {
 310         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
 311         return -1;
 312     }
 313
 314     /*
 315      * For clarity.  The error is if parameters in peer are
 316      * present (!missing) but don't match.  EVP_PKEY_cmp_parameters may return
 317      * 1 (match), 0 (don't match) and -2 (comparison is not defined).  -1
 318      * (different key types) is impossible here because it is checked earlier.
 319      * -2 is OK for us here, as well as 1, so we can check for 0 only.
 320      */
 321     if (!EVP_PKEY_missing_parameters(peer) &&
 322         !EVP_PKEY_cmp_parameters(ctx->pkey, peer)) {
 323         EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
 324         return -1;
 325     }
 326
 327     EVP_PKEY_free(ctx->peerkey);
 328     ctx->peerkey = peer;
 329
 330     ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
 331
 332     if (ret <= 0) {
 333         ctx->peerkey = NULL;
 334         return ret;
 335     }
 336
 337     EVP_PKEY_up_ref(peer);
 338     return 1;
 339 }
 340
 341 int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
 342 {
 343     int ret;
 344
 345     if (ctx == NULL) {
 346         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 347                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 348         return -2;
 349     }
 350
 351     if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
 352         EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
 353         return -1;
 354     }
 355
 356     if (ctx->op.kex.exchprovctx == NULL)
 357         goto legacy;
 358
 359     ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
 360                                        SIZE_MAX);
 361
 362     return ret;
 363  legacy:
 364     if (ctx ==  NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
 365         EVPerr(EVP_F_EVP_PKEY_DERIVE,
 366                EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 367         return -2;
 368     }
 369
 370     M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
 371         return ctx->pmeth->derive(ctx, key, pkeylen);
 372 }
 373
 374 int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
 375 {
 376     return keyexch->name_id;
 377 }
 378
 379 int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
 380 {
 381     return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
 382 }
 383
 384 void EVP_KEYEXCH_do_all_provided(OPENSSL_CTX *libctx,
 385                                  void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
 386                                  void *arg)
 387 {
 388     evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
 389                        (void (*)(void *, void *))fn, arg,
 390                        evp_keyexch_from_dispatch,
 391                        (void (*)(void *))EVP_KEYEXCH_free);
 392 }
 393
 394 void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
 395                               void (*fn)(const char *name, void *data),
 396                               void *data)
 397 {
 398     if (keyexch->prov != NULL)
 399         evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
 400 }