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