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 struct import_data_st {
  32     EVP_KEYMGMT *keymgmt;
  33     void *keydata;
  34
  35     int selection;
  36 };
  37
  38 static int try_import(const OSSL_PARAM params[], void *arg)
  39 {
  40     struct import_data_st *data = arg;
  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     /* Just in time creation of keydata, if needed */
  50     if (data->keydata == NULL
  51         && (data->keydata = evp_keymgmt_newdata(data->keymgmt)) == NULL) {
  52         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
  53         return 0;
  54     }
  55
  56     return evp_keymgmt_import(data->keymgmt, data->keydata, data->selection,
  57                               params);
  58 }
  59
  60 void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
  61 {
  62     struct import_data_st import_data;
  63     size_t i = 0;
  64
  65     /* Export to where? */
  66     if (keymgmt == NULL)
  67         return NULL;
  68
  69     /* If we have an unassigned key, give up */
  70     if (pk->keydata == NULL)
  71         return NULL;
  72
  73     /* If |keymgmt| matches the "origin" |keymgmt|, no more to do */
  74     if (pk->keymgmt == keymgmt)
  75         return pk->keydata;
  76
  77     /* If this key is already exported to |keymgmt|, no more to do */
  78     i = evp_keymgmt_util_find_operation_cache_index(pk, keymgmt);
  79     if (i < OSSL_NELEM(pk->operation_cache)
  80         && pk->operation_cache[i].keymgmt != NULL)
  81         return pk->operation_cache[i].keydata;
  82
  83     /* If the "origin" |keymgmt| doesn't support exporting, give up */
  84     /*
  85      * TODO(3.0) consider an evp_keymgmt_export() return value that indicates
  86      * that the method is unsupported.
  87      */
  88     if (pk->keymgmt->export == NULL)
  89         return NULL;
  90
  91     /* Check that we have found an empty slot in the export cache */
  92     /*
  93      * TODO(3.0) Right now, we assume we have ample space.  We will have to
  94      * think about a cache aging scheme, though, if |i| indexes outside the
  95      * array.
  96      */
  97     if (!ossl_assert(i < OSSL_NELEM(pk->operation_cache)))
  98         return NULL;
  99
 100     /*
 101      * Make sure that the type of the keymgmt to export to matches the type
 102      * of the "origin"
 103      */
 104     if (!ossl_assert(match_type(pk->keymgmt, keymgmt)))
 105         return NULL;
 106
 107     /*
 108      * We look at the already cached provider keys, and import from the
 109      * first that supports it (i.e. use its export function), and export
 110      * the imported data to the new provider.
 111      */
 112
 113     /* Setup for the export callback */
 114     import_data.keydata = NULL;  /* try_import will create it */
 115     import_data.keymgmt = keymgmt;
 116     import_data.selection = OSSL_KEYMGMT_SELECT_ALL;
 117
 118     /*
 119      * The export function calls the callback (try_import), which does the
 120      * import for us.  If successful, we're done.
 121      */
 122     if (!evp_keymgmt_export(pk->keymgmt, pk->keydata, OSSL_KEYMGMT_SELECT_ALL,
 123                             &try_import, &import_data)) {
 124         /* If there was an error, bail out */
 125         evp_keymgmt_freedata(keymgmt, import_data.keydata);
 126         return NULL;
 127     }
 128
 129     /* Add the new export to the operation cache */
 130     if (!evp_keymgmt_util_cache_keydata(pk, i, keymgmt, import_data.keydata)) {
 131         evp_keymgmt_freedata(keymgmt, import_data.keydata);
 132         return NULL;
 133     }
 134
 135     return import_data.keydata;
 136 }
 137
 138 void evp_keymgmt_util_clear_operation_cache(EVP_PKEY *pk)
 139 {
 140     size_t i, end = OSSL_NELEM(pk->operation_cache);
 141
 142     if (pk != NULL) {
 143         for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
 144             EVP_KEYMGMT *keymgmt = pk->operation_cache[i].keymgmt;
 145             void *keydata = pk->operation_cache[i].keydata;
 146
 147             pk->operation_cache[i].keymgmt = NULL;
 148             pk->operation_cache[i].keydata = NULL;
 149             evp_keymgmt_freedata(keymgmt, keydata);
 150             EVP_KEYMGMT_free(keymgmt);
 151         }
 152     }
 153 }
 154
 155 size_t evp_keymgmt_util_find_operation_cache_index(EVP_PKEY *pk,
 156                                                    EVP_KEYMGMT *keymgmt)
 157 {
 158     size_t i, end = OSSL_NELEM(pk->operation_cache);
 159
 160     for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
 161         if (keymgmt == pk->operation_cache[i].keymgmt)
 162             break;
 163     }
 164
 165     return i;
 166 }
 167
 168 int evp_keymgmt_util_cache_keydata(EVP_PKEY *pk, size_t index,
 169                                    EVP_KEYMGMT *keymgmt, void *keydata)
 170 {
 171     if (keydata != NULL) {
 172         if (!EVP_KEYMGMT_up_ref(keymgmt))
 173             return 0;
 174         pk->operation_cache[index].keydata = keydata;
 175         pk->operation_cache[index].keymgmt = keymgmt;
 176     }
 177     return 1;
 178 }
 179
 180 void evp_keymgmt_util_cache_keyinfo(EVP_PKEY *pk)
 181 {
 182     /*
 183      * Cache information about the provider "origin" key.
 184      *
 185      * This services functions like EVP_PKEY_size, EVP_PKEY_bits, etc
 186      */
 187     if (pk->keydata != NULL) {
 188         int bits = 0;
 189         int security_bits = 0;
 190         int size = 0;
 191         OSSL_PARAM params[4];
 192
 193         params[0] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_BITS, &bits);
 194         params[1] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_SECURITY_BITS,
 195                                              &security_bits);
 196         params[2] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_MAX_SIZE, &size);
 197         params[3] = OSSL_PARAM_construct_end();
 198         if (evp_keymgmt_get_params(pk->keymgmt, pk->keydata, params)) {
 199             pk->cache.size = size;
 200             pk->cache.bits = bits;
 201             pk->cache.security_bits = security_bits;
 202         }
 203     }
 204 }
 205
 206 void *evp_keymgmt_util_fromdata(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
 207                                 int selection, const OSSL_PARAM params[])
 208 {
 209     void *keydata = NULL;
 210
 211     if ((keydata = evp_keymgmt_newdata(keymgmt)) == NULL
 212         || !evp_keymgmt_import(keymgmt, keydata, selection, params)
 213         || !EVP_PKEY_set_type_by_keymgmt(target, keymgmt)) {
 214         evp_keymgmt_freedata(keymgmt, keydata);
 215         keydata = NULL;
 216     }
 217     if (keydata != NULL) {
 218         target->keydata = keydata;
 219         evp_keymgmt_util_cache_keyinfo(target);
 220     }
 221
 222     return keydata;
 223 }
 224
 225 int evp_keymgmt_util_has(EVP_PKEY *pk, int selection)
 226 {
 227     /* Check if key is even assigned */
 228     if (pk->keymgmt == NULL)
 229         return 0;
 230
 231     return evp_keymgmt_has(pk->keymgmt, pk->keydata, selection);
 232 }
 233
 234 /*
 235  * evp_keymgmt_util_match() doesn't just look at the provider side "origin",
 236  * but also in the operation cache to see if there's any common keymgmt that
 237  * supplies OP_keymgmt_match.
 238  *
 239  * evp_keymgmt_util_match() adheres to the return values that EVP_PKEY_cmp()
 240  * and EVP_PKEY_cmp_parameters() return, i.e.:
 241  *
 242  *  1   same key
 243  *  0   not same key
 244  * -1   not same key type
 245  * -2   unsupported operation
 246  */
 247 int evp_keymgmt_util_match(EVP_PKEY *pk1, EVP_PKEY *pk2, int selection)
 248 {
 249     EVP_KEYMGMT *keymgmt1 = NULL, *keymgmt2 = NULL;
 250     void *keydata1 = NULL, *keydata2 = NULL;
 251
 252     if (pk1 == NULL || pk2 == NULL) {
 253         if (pk1 == NULL && pk2 == NULL)
 254             return 1;
 255         return 0;
 256     }
 257
 258     keymgmt1 = pk1->keymgmt;
 259     keydata1 = pk1->keydata;
 260     keymgmt2 = pk2->keymgmt;
 261     keydata2 = pk2->keydata;
 262
 263     if (keymgmt1 != keymgmt2) {
 264         /*
 265          * The condition for a successful cross export is that the
 266          * keydata to be exported is NULL (typed, but otherwise empty
 267          * EVP_PKEY), or that it was possible to export it with
 268          * evp_keymgmt_util_export_to_provider().
 269          *
 270          * We use |ok| to determine if it's ok to cross export one way,
 271          * but also to determine if we should attempt a cross export
 272          * the other way.  There's no point doing it both ways.
 273          */
 274         int ok = 1;
 275
 276         /* Complex case, where the keymgmt differ */
 277         if (keymgmt1 != NULL
 278             && keymgmt2 != NULL
 279             && !match_type(keymgmt1, keymgmt2)) {
 280             ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 281             return -1;           /* Not the same type */
 282         }
 283
 284         /*
 285          * The key types are determined to match, so we try cross export,
 286          * but only to keymgmt's that supply a matching function.
 287          */
 288         if (keymgmt2 != NULL
 289             && keymgmt2->match != NULL) {
 290             void *tmp_keydata = NULL;
 291
 292             ok = 1;
 293             if (keydata1 != NULL) {
 294                 tmp_keydata =
 295                     evp_keymgmt_util_export_to_provider(pk1, keymgmt2);
 296                 ok = (tmp_keydata != NULL);
 297             }
 298             if (ok) {
 299                 keymgmt1 = keymgmt2;
 300                 keydata1 = tmp_keydata;
 301             }
 302         }
 303         /*
 304          * If we've successfully cross exported one way, there's no point
 305          * doing it the other way, hence the |!ok| check.
 306          */
 307         if (!ok
 308             && keymgmt1 != NULL
 309             && keymgmt1->match != NULL) {
 310             void *tmp_keydata = NULL;
 311
 312             ok = 1;
 313             if (keydata2 != NULL) {
 314                 tmp_keydata =
 315                     evp_keymgmt_util_export_to_provider(pk2, keymgmt1);
 316                 ok = (tmp_keydata != NULL);
 317             }
 318             if (ok) {
 319                 keymgmt2 = keymgmt1;
 320                 keydata2 = tmp_keydata;
 321             }
 322         }
 323     }
 324
 325     /* If we still don't have matching keymgmt implementations, we give up */
 326     if (keymgmt1 != keymgmt2)
 327         return -2;
 328
 329     /* If both keydata are NULL, then they're the same key */
 330     if (keydata1 == NULL && keydata2 == NULL)
 331         return 1;
 332     /* If only one of the keydata is NULL, then they're different keys */
 333     if (keydata1 == NULL || keydata2 == NULL)
 334         return 0;
 335     /* If both keydata are non-NULL, we let the backend decide */
 336     return evp_keymgmt_match(keymgmt1, keydata1, keydata2, selection);
 337 }
 338
 339 int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
 340 {
 341     /* Save copies of pointers we want to play with without affecting |to| */
 342     EVP_KEYMGMT *to_keymgmt = to->keymgmt;
 343     void *to_keydata = to->keydata, *alloc_keydata = NULL;
 344
 345     /* An unassigned key can't be copied */
 346     if (from == NULL || from->keydata == NULL)
 347         return 0;
 348
 349     if (to_keymgmt == from->keymgmt && to_keymgmt->copy != NULL) {
 350         /* Make sure there's somewhere to copy to */
 351         if (to_keydata == NULL
 352             && (to_keydata = evp_keymgmt_newdata(to_keymgmt)) == NULL) {
 353             ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 354             return 0;
 355         }
 356
 357         /*
 358          * |to| and |from| have the same keymgmt, and the copy function is
 359          * implemented, so just copy and be done
 360          */
 361         if (!evp_keymgmt_copy(to_keymgmt, to_keydata, from->keydata,
 362                               selection))
 363             return 0;
 364     } else if (match_type(to_keymgmt, from->keymgmt)) {
 365         struct import_data_st import_data;
 366
 367         import_data.keymgmt = to_keymgmt;
 368         import_data.keydata = to_keydata;
 369         import_data.selection = selection;
 370
 371         if (!evp_keymgmt_export(from->keymgmt, from->keydata, selection,
 372                                 &try_import, &import_data)) {
 373             evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
 374             return 0;
 375         }
 376
 377         /*
 378          * In this case to_keydata was previously unallocated, try_import()
 379          * may have created it for us.
 380          */
 381         to_keydata = import_data.keydata;
 382     } else {
 383         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
 384         return 0;
 385     }
 386
 387     if (to->keymgmt == NULL
 388         && !EVP_PKEY_set_type_by_keymgmt(to, to_keymgmt)) {
 389         evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
 390         return 0;
 391     }
 392     to->keydata = to_keydata;
 393     evp_keymgmt_util_cache_keyinfo(to);
 394
 395     return 1;
 396 }
 397
 398 void *evp_keymgmt_util_gen(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
 399                            void *genctx, OSSL_CALLBACK *cb, void *cbarg)
 400 {
 401     void *keydata = NULL;
 402
 403     if ((keydata = evp_keymgmt_gen(keymgmt, genctx, cb, cbarg)) == NULL
 404         || !EVP_PKEY_set_type_by_keymgmt(target, keymgmt)) {
 405         evp_keymgmt_freedata(keymgmt, keydata);
 406         keydata = NULL;
 407     }
 408     if (keydata != NULL) {
 409         target->keydata = keydata;
 410         evp_keymgmt_util_cache_keyinfo(target);
 411     }
 412
 413     return keydata;
 414 }
 415
 416 /*
 417  * Returns the same numbers as EVP_PKEY_get_default_digest_name()
 418  * When the string from the EVP_KEYMGMT implementation is "", we use
 419  * SN_undef, since that corresponds to what EVP_PKEY_get_default_nid()
 420  * returns for no digest.
 421  */
 422 int evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT *keymgmt,
 423                                            void *keydata,
 424                                            char *mdname, size_t mdname_sz)
 425 {
 426     OSSL_PARAM params[3];
 427     char mddefault[100] = "";
 428     char mdmandatory[100] = "";
 429     char *result = NULL;
 430     int rv = -2;
 431
 432     params[0] =
 433         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_DEFAULT_DIGEST,
 434                                          mddefault, sizeof(mddefault));
 435     params[1] =
 436         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_MANDATORY_DIGEST,
 437                                          mdmandatory,
 438                                          sizeof(mdmandatory));
 439     params[2] = OSSL_PARAM_construct_end();
 440
 441     if (!evp_keymgmt_get_params(keymgmt, keydata, params))
 442         return 0;
 443
 444     if (OSSL_PARAM_modified(params + 1)) {
 445         if (params[1].return_size <= 1) /* Only a NUL byte */
 446             result = SN_undef;
 447         else
 448             result = mdmandatory;
 449         rv = 2;
 450     } else if (OSSL_PARAM_modified(params)) {
 451         if (params[0].return_size <= 1) /* Only a NUL byte */
 452             result = SN_undef;
 453         else
 454             result = mddefault;
 455         rv = 1;
 456     }
 457     if (rv > 0)
 458         OPENSSL_strlcpy(mdname, result, mdname_sz);
 459     return rv;
 460 }