crypto/evp/kem.c

   1 /*
   2  * Copyright 2020-2021 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 <stdio.h>
  11 #include <stdlib.h>
  12 #include <openssl/objects.h>
  13 #include <openssl/evp.h>
  14 #include "internal/cryptlib.h"
  15 #include "internal/provider.h"
  16 #include "internal/core.h"
  17 #include "crypto/evp.h"
  18 #include "evp_local.h"
  19
  20 static int evp_kem_init(EVP_PKEY_CTX *ctx, int operation,
  21                         const OSSL_PARAM params[])
  22 {
  23     int ret = 0;
  24     EVP_KEM *kem = NULL;
  25     EVP_KEYMGMT *tmp_keymgmt = NULL;
  26     void *provkey = NULL;
  27     const char *supported_kem = NULL;
  28
  29     if (ctx == NULL || ctx->keytype == NULL) {
  30         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  31         return 0;
  32     }
  33
  34     evp_pkey_ctx_free_old_ops(ctx);
  35     ctx->operation = operation;
  36
  37     /*
  38      * Ensure that the key is provided, either natively, or as a cached export.
  39      */
  40     tmp_keymgmt = ctx->keymgmt;
  41     provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
  42                                           &tmp_keymgmt, ctx->propquery);
  43     if (provkey == NULL
  44         || !EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
  45         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  46         goto err;
  47     }
  48     EVP_KEYMGMT_free(ctx->keymgmt);
  49     ctx->keymgmt = tmp_keymgmt;
  50
  51     if (ctx->keymgmt->query_operation_name != NULL)
  52         supported_kem = ctx->keymgmt->query_operation_name(OSSL_OP_KEM);
  53
  54     /*
  55      * If we didn't get a supported kem, assume there is one with the
  56      * same name as the key type.
  57      */
  58     if (supported_kem == NULL)
  59         supported_kem = ctx->keytype;
  60
  61     kem = EVP_KEM_fetch(ctx->libctx, supported_kem, ctx->propquery);
  62     if (kem == NULL
  63         || (EVP_KEYMGMT_get0_provider(ctx->keymgmt) != EVP_KEM_get0_provider(kem))) {
  64         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
  65         ret = -2;
  66         goto err;
  67     }
  68
  69     ctx->op.encap.kem = kem;
  70     ctx->op.encap.algctx = kem->newctx(ossl_provider_ctx(kem->prov));
  71     if (ctx->op.encap.algctx == NULL) {
  72         /* The provider key can stay in the cache */
  73         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  74         goto err;
  75     }
  76
  77     switch (operation) {
  78     case EVP_PKEY_OP_ENCAPSULATE:
  79         if (kem->encapsulate_init == NULL) {
  80             ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
  81             ret = -2;
  82             goto err;
  83         }
  84         ret = kem->encapsulate_init(ctx->op.encap.algctx, provkey, params);
  85         break;
  86     case EVP_PKEY_OP_DECAPSULATE:
  87         if (kem->decapsulate_init == NULL) {
  88             ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
  89             ret = -2;
  90             goto err;
  91         }
  92         ret = kem->decapsulate_init(ctx->op.encap.algctx, provkey, params);
  93         break;
  94     default:
  95         ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
  96         goto err;
  97     }
  98
  99     if (ret > 0)
 100         return 1;
 101  err:
 102     if (ret <= 0) {
 103         evp_pkey_ctx_free_old_ops(ctx);
 104         ctx->operation = EVP_PKEY_OP_UNDEFINED;
 105     }
 106     return ret;
 107 }
 108
 109 int EVP_PKEY_encapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 110 {
 111     return evp_kem_init(ctx, EVP_PKEY_OP_ENCAPSULATE, params);
 112 }
 113
 114 int EVP_PKEY_encapsulate(EVP_PKEY_CTX *ctx,
 115                          unsigned char *out, size_t *outlen,
 116                          unsigned char *secret, size_t *secretlen)
 117 {
 118     if (ctx == NULL)
 119         return 0;
 120
 121     if (ctx->operation != EVP_PKEY_OP_ENCAPSULATE) {
 122         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 123         return -1;
 124     }
 125
 126     if (ctx->op.encap.algctx == NULL) {
 127         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 128         return -2;
 129     }
 130
 131     if (out != NULL && secret == NULL)
 132         return 0;
 133
 134     return ctx->op.encap.kem->encapsulate(ctx->op.encap.algctx,
 135                                           out, outlen, secret, secretlen);
 136 }
 137
 138 int EVP_PKEY_decapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[])
 139 {
 140     return evp_kem_init(ctx, EVP_PKEY_OP_DECAPSULATE, params);
 141 }
 142
 143 int EVP_PKEY_decapsulate(EVP_PKEY_CTX *ctx,
 144                          unsigned char *secret, size_t *secretlen,
 145                          const unsigned char *in, size_t inlen)
 146 {
 147     if (ctx == NULL
 148         || (in == NULL || inlen == 0)
 149         || (secret == NULL && secretlen == NULL))
 150         return 0;
 151
 152     if (ctx->operation != EVP_PKEY_OP_DECAPSULATE) {
 153         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_INITIALIZED);
 154         return -1;
 155     }
 156
 157     if (ctx->op.encap.algctx == NULL) {
 158         ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
 159         return -2;
 160     }
 161     return ctx->op.encap.kem->decapsulate(ctx->op.encap.algctx,
 162                                           secret, secretlen, in, inlen);
 163 }
 164
 165 static EVP_KEM *evp_kem_new(OSSL_PROVIDER *prov)
 166 {
 167     EVP_KEM *kem = OPENSSL_zalloc(sizeof(EVP_KEM));
 168
 169     if (kem == NULL) {
 170         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 171         return NULL;
 172     }
 173
 174     kem->lock = CRYPTO_THREAD_lock_new();
 175     if (kem->lock == NULL) {
 176         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 177         OPENSSL_free(kem);
 178         return NULL;
 179     }
 180     kem->prov = prov;
 181     ossl_provider_up_ref(prov);
 182     kem->refcnt = 1;
 183
 184     return kem;
 185 }
 186
 187 static void *evp_kem_from_algorithm(int name_id, const OSSL_ALGORITHM *algodef,
 188                                     OSSL_PROVIDER *prov)
 189 {
 190     const OSSL_DISPATCH *fns = algodef->implementation;
 191     EVP_KEM *kem = NULL;
 192     int ctxfncnt = 0, encfncnt = 0, decfncnt = 0;
 193     int gparamfncnt = 0, sparamfncnt = 0;
 194
 195     if ((kem = evp_kem_new(prov)) == NULL) {
 196         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 197         goto err;
 198     }
 199
 200     kem->name_id = name_id;
 201     if ((kem->type_name = ossl_algorithm_get1_first_name(algodef)) == NULL)
 202         goto err;
 203     kem->description = algodef->algorithm_description;
 204
 205     for (; fns->function_id != 0; fns++) {
 206         switch (fns->function_id) {
 207         case OSSL_FUNC_KEM_NEWCTX:
 208             if (kem->newctx != NULL)
 209                 break;
 210             kem->newctx = OSSL_FUNC_kem_newctx(fns);
 211             ctxfncnt++;
 212             break;
 213         case OSSL_FUNC_KEM_ENCAPSULATE_INIT:
 214             if (kem->encapsulate_init != NULL)
 215                 break;
 216             kem->encapsulate_init = OSSL_FUNC_kem_encapsulate_init(fns);
 217             encfncnt++;
 218             break;
 219         case OSSL_FUNC_KEM_ENCAPSULATE:
 220             if (kem->encapsulate != NULL)
 221                 break;
 222             kem->encapsulate = OSSL_FUNC_kem_encapsulate(fns);
 223             encfncnt++;
 224             break;
 225         case OSSL_FUNC_KEM_DECAPSULATE_INIT:
 226             if (kem->decapsulate_init != NULL)
 227                 break;
 228             kem->decapsulate_init = OSSL_FUNC_kem_decapsulate_init(fns);
 229             decfncnt++;
 230             break;
 231         case OSSL_FUNC_KEM_DECAPSULATE:
 232             if (kem->decapsulate != NULL)
 233                 break;
 234             kem->decapsulate = OSSL_FUNC_kem_decapsulate(fns);
 235             decfncnt++;
 236             break;
 237         case OSSL_FUNC_KEM_FREECTX:
 238             if (kem->freectx != NULL)
 239                 break;
 240             kem->freectx = OSSL_FUNC_kem_freectx(fns);
 241             ctxfncnt++;
 242             break;
 243         case OSSL_FUNC_KEM_DUPCTX:
 244             if (kem->dupctx != NULL)
 245                 break;
 246             kem->dupctx = OSSL_FUNC_kem_dupctx(fns);
 247             break;
 248         case OSSL_FUNC_KEM_GET_CTX_PARAMS:
 249             if (kem->get_ctx_params != NULL)
 250                 break;
 251             kem->get_ctx_params
 252                 = OSSL_FUNC_kem_get_ctx_params(fns);
 253             gparamfncnt++;
 254             break;
 255         case OSSL_FUNC_KEM_GETTABLE_CTX_PARAMS:
 256             if (kem->gettable_ctx_params != NULL)
 257                 break;
 258             kem->gettable_ctx_params
 259                 = OSSL_FUNC_kem_gettable_ctx_params(fns);
 260             gparamfncnt++;
 261             break;
 262         case OSSL_FUNC_KEM_SET_CTX_PARAMS:
 263             if (kem->set_ctx_params != NULL)
 264                 break;
 265             kem->set_ctx_params
 266                 = OSSL_FUNC_kem_set_ctx_params(fns);
 267             sparamfncnt++;
 268             break;
 269         case OSSL_FUNC_KEM_SETTABLE_CTX_PARAMS:
 270             if (kem->settable_ctx_params != NULL)
 271                 break;
 272             kem->settable_ctx_params
 273                 = OSSL_FUNC_kem_settable_ctx_params(fns);
 274             sparamfncnt++;
 275             break;
 276         }
 277     }
 278     if (ctxfncnt != 2
 279         || (encfncnt != 0 && encfncnt != 2)
 280         || (decfncnt != 0 && decfncnt != 2)
 281         || (encfncnt != 2 && decfncnt != 2)
 282         || (gparamfncnt != 0 && gparamfncnt != 2)
 283         || (sparamfncnt != 0 && sparamfncnt != 2)) {
 284         /*
 285          * In order to be a consistent set of functions we must have at least
 286          * a set of context functions (newctx and freectx) as well as a pair of
 287          * "kem" functions: (encapsulate_init, encapsulate) or
 288          * (decapsulate_init, decapsulate). set_ctx_params and settable_ctx_params are
 289          * optional, but if one of them is present then the other one must also
 290          * be present. The same applies to get_ctx_params and
 291          * gettable_ctx_params. The dupctx function is optional.
 292          */
 293         ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_PROVIDER_FUNCTIONS);
 294         goto err;
 295     }
 296
 297     return kem;
 298  err:
 299     EVP_KEM_free(kem);
 300     return NULL;
 301 }
 302
 303 void EVP_KEM_free(EVP_KEM *kem)
 304 {
 305     int i;
 306
 307     if (kem == NULL)
 308         return;
 309
 310     CRYPTO_DOWN_REF(&kem->refcnt, &i, kem->lock);
 311     if (i > 0)
 312         return;
 313     OPENSSL_free(kem->type_name);
 314     ossl_provider_free(kem->prov);
 315     CRYPTO_THREAD_lock_free(kem->lock);
 316     OPENSSL_free(kem);
 317 }
 318
 319 int EVP_KEM_up_ref(EVP_KEM *kem)
 320 {
 321     int ref = 0;
 322
 323     CRYPTO_UP_REF(&kem->refcnt, &ref, kem->lock);
 324     return 1;
 325 }
 326
 327 OSSL_PROVIDER *EVP_KEM_get0_provider(const EVP_KEM *kem)
 328 {
 329     return kem->prov;
 330 }
 331
 332 EVP_KEM *EVP_KEM_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
 333                        const char *properties)
 334 {
 335     return evp_generic_fetch(ctx, OSSL_OP_KEM, algorithm, properties,
 336                              evp_kem_from_algorithm,
 337                              (int (*)(void *))EVP_KEM_up_ref,
 338                              (void (*)(void *))EVP_KEM_free);
 339 }
 340
 341 int EVP_KEM_is_a(const EVP_KEM *kem, const char *name)
 342 {
 343     return evp_is_a(kem->prov, kem->name_id, NULL, name);
 344 }
 345
 346 int EVP_KEM_get_number(const EVP_KEM *kem)
 347 {
 348     return kem->name_id;
 349 }
 350
 351 const char *EVP_KEM_get0_name(const EVP_KEM *kem)
 352 {
 353     return kem->type_name;
 354 }
 355
 356 const char *EVP_KEM_get0_description(const EVP_KEM *kem)
 357 {
 358     return kem->description;
 359 }
 360
 361 void EVP_KEM_do_all_provided(OSSL_LIB_CTX *libctx,
 362                              void (*fn)(EVP_KEM *kem, void *arg),
 363                              void *arg)
 364 {
 365     evp_generic_do_all(libctx, OSSL_OP_KEM, (void (*)(void *, void *))fn, arg,
 366                        evp_kem_from_algorithm,
 367                        (void (*)(void *))EVP_KEM_free);
 368 }
 369
 370 int EVP_KEM_names_do_all(const EVP_KEM *kem,
 371                          void (*fn)(const char *name, void *data),
 372                          void *data)
 373 {
 374     if (kem->prov != NULL)
 375         return evp_names_do_all(kem->prov, kem->name_id, fn, data);
 376
 377     return 1;
 378 }
 379
 380 const OSSL_PARAM *EVP_KEM_gettable_ctx_params(const EVP_KEM *kem)
 381 {
 382     void *provctx;
 383
 384     if (kem == NULL || kem->gettable_ctx_params == NULL)
 385         return NULL;
 386
 387     provctx = ossl_provider_ctx(EVP_KEM_get0_provider(kem));
 388     return kem->gettable_ctx_params(NULL, provctx);
 389 }
 390
 391 const OSSL_PARAM *EVP_KEM_settable_ctx_params(const EVP_KEM *kem)
 392 {
 393     void *provctx;
 394
 395     if (kem == NULL || kem->settable_ctx_params == NULL)
 396         return NULL;
 397
 398     provctx = ossl_provider_ctx(EVP_KEM_get0_provider(kem));
 399     return kem->settable_ctx_params(NULL, provctx);
 400 }