crypto/evp/keymgmt_lib.c

   1 /*
   2  * Copyright 2019-2020 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/core_names.h>
  11 #include "internal/cryptlib.h"
  12 #include "internal/nelem.h"
  13 #include "crypto/evp.h"
  14 #include "crypto/asn1.h"
  15 #include "internal/core.h"
  16 #include "internal/provider.h"
  17 #include "evp_local.h"
  18
  19 /*
  20  * match_type() checks if two EVP_KEYMGMT are matching key types.  This
  21  * function assumes that the caller has made all the necessary NULL checks.
  22  */
  23 static int match_type(const EVP_KEYMGMT *keymgmt1, const EVP_KEYMGMT *keymgmt2)
  24 {
  25     const OSSL_PROVIDER *prov2 = EVP_KEYMGMT_provider(keymgmt2);
  26     const char *name2 = evp_first_name(prov2, EVP_KEYMGMT_number(keymgmt2));
  27
  28     return EVP_KEYMGMT_is_a(keymgmt1, name2);
  29 }
  30
  31 int evp_keymgmt_util_try_import(const OSSL_PARAM params[], void *arg)
  32 {
  33     struct evp_keymgmt_util_try_import_data_st *data = arg;
  34
  35     /* Just in time creation of keydata */
  36     if (data->keydata == NULL
  37         && (data->keydata = evp_keymgmt_newdata(data->keymgmt)) == NULL) {
  38         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  39         return 0;
  40     }
  41
  42     /*
  43      * It's fine if there was no data to transfer, we just end up with an
  44      * empty destination key.
  45      */
  46     if (params[0].key == NULL)
  47         return 1;
  48
  49     return evp_keymgmt_import(data->keymgmt, data->keydata, data->selection,
  50                               params);
  51 }
  52
  53 int evp_keymgmt_util_assign_pkey(EVP_PKEY *pkey, EVP_KEYMGMT *keymgmt,
  54                                  void *keydata)
  55 {
  56     if (pkey == NULL || keymgmt == NULL || keydata == NULL
  57         || !EVP_PKEY_set_type_by_keymgmt(pkey, keymgmt)) {
  58         ERR_raise(ERR_LIB_EVP, ERR_R_INTERNAL_ERROR);
  59         return 0;
  60     }
  61     pkey->keydata = keydata;
  62     evp_keymgmt_util_cache_keyinfo(pkey);
  63     return 1;
  64 }
  65
  66 EVP_PKEY *evp_keymgmt_util_make_pkey(EVP_KEYMGMT *keymgmt, void *keydata)
  67 {
  68     EVP_PKEY *pkey = NULL;
  69
  70     if (keymgmt == NULL
  71         || keydata == NULL
  72         || (pkey = EVP_PKEY_new()) == NULL
  73         || !evp_keymgmt_util_assign_pkey(pkey, keymgmt, keydata)) {
  74         EVP_PKEY_free(pkey);
  75         return NULL;
  76     }
  77     return pkey;
  78 }
  79
  80 int evp_keymgmt_util_export(const EVP_PKEY *pk, int selection,
  81                             OSSL_CALLBACK *export_cb, void *export_cbarg)
  82 {
  83     return evp_keymgmt_export(pk->keymgmt, pk->keydata, selection,
  84                               export_cb, export_cbarg);
  85 }
  86
  87 void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
  88 {
  89     struct evp_keymgmt_util_try_import_data_st import_data;
  90     size_t i = 0;
  91
  92     /* Export to where? */
  93     if (keymgmt == NULL)
  94         return NULL;
  95
  96     /* If we have an unassigned key, give up */
  97     if (pk->keydata == NULL)
  98         return NULL;
  99
 100     /* If |keymgmt| matches the "origin" |keymgmt|, no more to do */
 101     if (pk->keymgmt == keymgmt)
 102         return pk->keydata;
 103
 104     CRYPTO_THREAD_read_lock(pk->lock);
 105     /*
 106      * If the provider native "origin" hasn't changed since last time, we
 107      * try to find our keymgmt in the operation cache.  If it has changed,
 108      * |i| remains zero, and we will clear the cache further down.
 109      */
 110     if (pk->dirty_cnt == pk->dirty_cnt_copy) {
 111         /* If this key is already exported to |keymgmt|, no more to do */
 112         i = evp_keymgmt_util_find_operation_cache_index(pk, keymgmt);
 113         if (i < OSSL_NELEM(pk->operation_cache)
 114             && pk->operation_cache[i].keymgmt != NULL) {
 115             void *ret = pk->operation_cache[i].keydata;
 116
 117             CRYPTO_THREAD_unlock(pk->lock);
 118             return ret;
 119         }
 120     }
 121     CRYPTO_THREAD_unlock(pk->lock);
 122
 123     /* If the "origin" |keymgmt| doesn't support exporting, give up */
 124     /*
 125      * TODO(3.0) consider an evp_keymgmt_export() return value that indicates
 126      * that the method is unsupported.
 127      */
 128     if (pk->keymgmt->export == NULL)
 129         return NULL;
 130
 131     /* Check that we have found an empty slot in the export cache */
 132     /*
 133      * TODO(3.0) Right now, we assume we have ample space.  We will have to
 134      * think about a cache aging scheme, though, if |i| indexes outside the
 135      * array.
 136      */
 137     if (!ossl_assert(i < OSSL_NELEM(pk->operation_cache)))
 138         return NULL;
 139
 140     /*
 141      * Make sure that the type of the keymgmt to export to matches the type
 142      * of the "origin"
 143      */
 144     if (!ossl_assert(match_type(pk->keymgmt, keymgmt)))
 145         return NULL;
 146
 147     /*
 148      * We look at the already cached provider keys, and import from the
 149      * first that supports it (i.e. use its export function), and export
 150      * the imported data to the new provider.
 151      */
 152
 153     /* Setup for the export callback */
 154     import_data.keydata = NULL;  /* evp_keymgmt_util_try_import will create it */
 155     import_data.keymgmt = keymgmt;
 156     import_data.selection = OSSL_KEYMGMT_SELECT_ALL;
 157
 158     /*
 159      * The export function calls the callback (evp_keymgmt_util_try_import),
 160      * which does the import for us.  If successful, we're done.
 161      */
 162     if (!evp_keymgmt_util_export(pk, OSSL_KEYMGMT_SELECT_ALL,
 163                                  &evp_keymgmt_util_try_import, &import_data)) {
 164         /* If there was an error, bail out */
 165         evp_keymgmt_freedata(keymgmt, import_data.keydata);
 166         return NULL;
 167     }
 168
 169     CRYPTO_THREAD_write_lock(pk->lock);
 170     /* Check to make sure some other thread didn't get there first */
 171     i = evp_keymgmt_util_find_operation_cache_index(pk, keymgmt);
 172     if (i < OSSL_NELEM(pk->operation_cache)
 173         && pk->operation_cache[i].keymgmt != NULL) {
 174         void *ret = pk->operation_cache[i].keydata;
 175
 176         CRYPTO_THREAD_unlock(pk->lock);
 177
 178         /*
 179          * Another thread seemms to have already exported this so we abandon
 180          * all the work we just did.
 181          */
 182         evp_keymgmt_freedata(keymgmt, import_data.keydata);
 183
 184         return ret;
 185     }
 186
 187     /*
 188      * If the dirty counter changed since last time, then clear the
 189      * operation cache.  In that case, we know that |i| is zero.
 190      */
 191     if (pk->dirty_cnt != pk->dirty_cnt_copy)
 192         evp_keymgmt_util_clear_operation_cache(pk, 0);
 193
 194     /* Add the new export to the operation cache */
 195     if (!evp_keymgmt_util_cache_keydata(pk, i, keymgmt, import_data.keydata)) {
 196         evp_keymgmt_freedata(keymgmt, import_data.keydata);
 197         return NULL;
 198     }
 199
 200     /* Synchronize the dirty count */
 201     pk->dirty_cnt_copy = pk->dirty_cnt;
 202
 203     CRYPTO_THREAD_unlock(pk->lock);
 204
 205     return import_data.keydata;
 206 }
 207
 208 int evp_keymgmt_util_clear_operation_cache(EVP_PKEY *pk, int locking)
 209 {
 210     size_t i, end = OSSL_NELEM(pk->operation_cache);
 211
 212     if (pk != NULL) {
 213         if (locking && pk->lock != NULL && !CRYPTO_THREAD_write_lock(pk->lock))
 214             return 0;
 215         for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
 216             EVP_KEYMGMT *keymgmt = pk->operation_cache[i].keymgmt;
 217             void *keydata = pk->operation_cache[i].keydata;
 218
 219             pk->operation_cache[i].keymgmt = NULL;
 220             pk->operation_cache[i].keydata = NULL;
 221             evp_keymgmt_freedata(keymgmt, keydata);
 222             EVP_KEYMGMT_free(keymgmt);
 223         }
 224         if (locking && pk->lock != NULL)
 225             CRYPTO_THREAD_unlock(pk->lock);
 226     }
 227
 228     return 1;
 229 }
 230
 231 size_t evp_keymgmt_util_find_operation_cache_index(EVP_PKEY *pk,
 232                                                    EVP_KEYMGMT *keymgmt)
 233 {
 234     size_t i, end = OSSL_NELEM(pk->operation_cache);
 235
 236     for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
 237         if (keymgmt == pk->operation_cache[i].keymgmt)
 238             break;
 239     }
 240
 241     return i;
 242 }
 243
 244 int evp_keymgmt_util_cache_keydata(EVP_PKEY *pk, size_t index,
 245                                    EVP_KEYMGMT *keymgmt, void *keydata)
 246 {
 247     if (keydata != NULL) {
 248         if (!EVP_KEYMGMT_up_ref(keymgmt))
 249             return 0;
 250
 251         pk->operation_cache[index].keydata = keydata;
 252         pk->operation_cache[index].keymgmt = keymgmt;
 253     }
 254     return 1;
 255 }
 256
 257 void evp_keymgmt_util_cache_keyinfo(EVP_PKEY *pk)
 258 {
 259     /*
 260      * Cache information about the provider "origin" key.
 261      *
 262      * This services functions like EVP_PKEY_size, EVP_PKEY_bits, etc
 263      */
 264     if (pk->keydata != NULL) {
 265         int bits = 0;
 266         int security_bits = 0;
 267         int size = 0;
 268         OSSL_PARAM params[4];
 269
 270         params[0] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_BITS, &bits);
 271         params[1] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_SECURITY_BITS,
 272                                              &security_bits);
 273         params[2] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_MAX_SIZE, &size);
 274         params[3] = OSSL_PARAM_construct_end();
 275         if (evp_keymgmt_get_params(pk->keymgmt, pk->keydata, params)) {
 276             pk->cache.size = size;
 277             pk->cache.bits = bits;
 278             pk->cache.security_bits = security_bits;
 279         }
 280     }
 281 }
 282
 283 void *evp_keymgmt_util_fromdata(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
 284                                 int selection, const OSSL_PARAM params[])
 285 {
 286     void *keydata = NULL;
 287
 288     if ((keydata = evp_keymgmt_newdata(keymgmt)) == NULL
 289         || !evp_keymgmt_import(keymgmt, keydata, selection, params)
 290         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
 291         evp_keymgmt_freedata(keymgmt, keydata);
 292         keydata = NULL;
 293     }
 294     return keydata;
 295 }
 296
 297 int evp_keymgmt_util_has(EVP_PKEY *pk, int selection)
 298 {
 299     /* Check if key is even assigned */
 300     if (pk->keymgmt == NULL)
 301         return 0;
 302
 303     return evp_keymgmt_has(pk->keymgmt, pk->keydata, selection);
 304 }
 305
 306 /*
 307  * evp_keymgmt_util_match() doesn't just look at the provider side "origin",
 308  * but also in the operation cache to see if there's any common keymgmt that
 309  * supplies OP_keymgmt_match.
 310  *
 311  * evp_keymgmt_util_match() adheres to the return values that EVP_PKEY_eq()
 312  * and EVP_PKEY_parameters_eq() return, i.e.:
 313  *
 314  *  1   same key
 315  *  0   not same key
 316  * -1   not same key type
 317  * -2   unsupported operation
 318  */
 319 int evp_keymgmt_util_match(EVP_PKEY *pk1, EVP_PKEY *pk2, int selection)
 320 {
 321     EVP_KEYMGMT *keymgmt1 = NULL, *keymgmt2 = NULL;
 322     void *keydata1 = NULL, *keydata2 = NULL;
 323
 324     if (pk1 == NULL || pk2 == NULL) {
 325         if (pk1 == NULL && pk2 == NULL)
 326             return 1;
 327         return 0;
 328     }
 329
 330     keymgmt1 = pk1->keymgmt;
 331     keydata1 = pk1->keydata;
 332     keymgmt2 = pk2->keymgmt;
 333     keydata2 = pk2->keydata;
 334
 335     if (keymgmt1 != keymgmt2) {
 336         /*
 337          * The condition for a successful cross export is that the
 338          * keydata to be exported is NULL (typed, but otherwise empty
 339          * EVP_PKEY), or that it was possible to export it with
 340          * evp_keymgmt_util_export_to_provider().
 341          *
 342          * We use |ok| to determine if it's ok to cross export one way,
 343          * but also to determine if we should attempt a cross export
 344          * the other way.  There's no point doing it both ways.
 345          */
 346         int ok = 1;
 347
 348         /* Complex case, where the keymgmt differ */
 349         if (keymgmt1 != NULL
 350             && keymgmt2 != NULL
 351             && !match_type(keymgmt1, keymgmt2)) {
 352             ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 353             return -1;           /* Not the same type */
 354         }
 355
 356         /*
 357          * The key types are determined to match, so we try cross export,
 358          * but only to keymgmt's that supply a matching function.
 359          */
 360         if (keymgmt2 != NULL
 361             && keymgmt2->match != NULL) {
 362             void *tmp_keydata = NULL;
 363
 364             ok = 1;
 365             if (keydata1 != NULL) {
 366                 tmp_keydata =
 367                     evp_keymgmt_util_export_to_provider(pk1, keymgmt2);
 368                 ok = (tmp_keydata != NULL);
 369             }
 370             if (ok) {
 371                 keymgmt1 = keymgmt2;
 372                 keydata1 = tmp_keydata;
 373             }
 374         }
 375         /*
 376          * If we've successfully cross exported one way, there's no point
 377          * doing it the other way, hence the |!ok| check.
 378          */
 379         if (!ok
 380             && keymgmt1 != NULL
 381             && keymgmt1->match != NULL) {
 382             void *tmp_keydata = NULL;
 383
 384             ok = 1;
 385             if (keydata2 != NULL) {
 386                 tmp_keydata =
 387                     evp_keymgmt_util_export_to_provider(pk2, keymgmt1);
 388                 ok = (tmp_keydata != NULL);
 389             }
 390             if (ok) {
 391                 keymgmt2 = keymgmt1;
 392                 keydata2 = tmp_keydata;
 393             }
 394         }
 395     }
 396
 397     /* If we still don't have matching keymgmt implementations, we give up */
 398     if (keymgmt1 != keymgmt2)
 399         return -2;
 400
 401     /* If both keydata are NULL, then they're the same key */
 402     if (keydata1 == NULL && keydata2 == NULL)
 403         return 1;
 404     /* If only one of the keydata is NULL, then they're different keys */
 405     if (keydata1 == NULL || keydata2 == NULL)
 406         return 0;
 407     /* If both keydata are non-NULL, we let the backend decide */
 408     return evp_keymgmt_match(keymgmt1, keydata1, keydata2, selection);
 409 }
 410
 411 int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
 412 {
 413     /* Save copies of pointers we want to play with without affecting |to| */
 414     EVP_KEYMGMT *to_keymgmt = to->keymgmt;
 415     void *to_keydata = to->keydata, *alloc_keydata = NULL;
 416
 417     /* An unassigned key can't be copied */
 418     if (from == NULL || from->keydata == NULL)
 419         return 0;
 420
 421     /*
 422      * If |to| is unassigned, ensure it gets the same KEYMGMT as |from|,
 423      * Note that the final setting of KEYMGMT is done further down, with
 424      * EVP_PKEY_set_type_by_keymgmt(); we don't want to do that prematurely.
 425      */
 426     if (to_keymgmt == NULL)
 427         to_keymgmt = from->keymgmt;
 428
 429     if (to_keymgmt == from->keymgmt && to_keymgmt->copy != NULL) {
 430         /* Make sure there's somewhere to copy to */
 431         if (to_keydata == NULL
 432             && ((to_keydata = alloc_keydata = evp_keymgmt_newdata(to_keymgmt))
 433                 == NULL)) {
 434             ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 435             return 0;
 436         }
 437
 438         /*
 439          * |to| and |from| have the same keymgmt, and the copy function is
 440          * implemented, so just copy and be done
 441          */
 442         if (!evp_keymgmt_copy(to_keymgmt, to_keydata, from->keydata,
 443                               selection))
 444             return 0;
 445     } else if (match_type(to_keymgmt, from->keymgmt)) {
 446         struct evp_keymgmt_util_try_import_data_st import_data;
 447
 448         import_data.keymgmt = to_keymgmt;
 449         import_data.keydata = to_keydata;
 450         import_data.selection = selection;
 451
 452         if (!evp_keymgmt_util_export(from, selection,
 453                                      &evp_keymgmt_util_try_import,
 454                                      &import_data)) {
 455             evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
 456             return 0;
 457         }
 458
 459         /*
 460          * In case to_keydata was previously unallocated,
 461          * evp_keymgmt_util_try_import() may have created it for us.
 462          */
 463         if (to_keydata == NULL)
 464             to_keydata = alloc_keydata = import_data.keydata;
 465     } else {
 466         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 467         return 0;
 468     }
 469
 470     /*
 471      * We only need to set the |to| type when its |keymgmt| isn't set.
 472      * We can then just set its |keydata| to what we have, which might
 473      * be exactly what it had when entering this function.
 474      * This is a bit different from using evp_keymgmt_util_assign_pkey(),
 475      * which isn't as careful with |to|'s original |keymgmt|, since it's
 476      * meant to forcibly reassign an EVP_PKEY no matter what, which is
 477      * why we don't use that one here.
 478      */
 479     if (to->keymgmt == NULL
 480         && !EVP_PKEY_set_type_by_keymgmt(to, to_keymgmt)) {
 481         evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
 482         return 0;
 483     }
 484     to->keydata = to_keydata;
 485     evp_keymgmt_util_cache_keyinfo(to);
 486
 487     return 1;
 488 }
 489
 490 void *evp_keymgmt_util_gen(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
 491                            void *genctx, OSSL_CALLBACK *cb, void *cbarg)
 492 {
 493     void *keydata = NULL;
 494
 495     if ((keydata = evp_keymgmt_gen(keymgmt, genctx, cb, cbarg)) == NULL
 496         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
 497         evp_keymgmt_freedata(keymgmt, keydata);
 498         keydata = NULL;
 499     }
 500
 501     return keydata;
 502 }
 503
 504 /*
 505  * Returns the same numbers as EVP_PKEY_get_default_digest_name()
 506  * When the string from the EVP_KEYMGMT implementation is "", we use
 507  * SN_undef, since that corresponds to what EVP_PKEY_get_default_nid()
 508  * returns for no digest.
 509  */
 510 int evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT *keymgmt,
 511                                            void *keydata,
 512                                            char *mdname, size_t mdname_sz)
 513 {
 514     OSSL_PARAM params[3];
 515     char mddefault[100] = "";
 516     char mdmandatory[100] = "";
 517     char *result = NULL;
 518     int rv = -2;
 519
 520     params[0] =
 521         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_DEFAULT_DIGEST,
 522                                          mddefault, sizeof(mddefault));
 523     params[1] =
 524         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_MANDATORY_DIGEST,
 525                                          mdmandatory,
 526                                          sizeof(mdmandatory));
 527     params[2] = OSSL_PARAM_construct_end();
 528
 529     if (!evp_keymgmt_get_params(keymgmt, keydata, params))
 530         return 0;
 531
 532     if (OSSL_PARAM_modified(params + 1)) {
 533         if (params[1].return_size <= 1) /* Only a NUL byte */
 534             result = SN_undef;
 535         else
 536             result = mdmandatory;
 537         rv = 2;
 538     } else if (OSSL_PARAM_modified(params)) {
 539         if (params[0].return_size <= 1) /* Only a NUL byte */
 540             result = SN_undef;
 541         else
 542             result = mddefault;
 543         rv = 1;
 544     }
 545     if (rv > 0)
 546         OPENSSL_strlcpy(mdname, result, mdname_sz);
 547     return rv;
 548 }