crypto/property/property.c

   1 /*
   2  * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 #include <string.h>
  12 #include <stdio.h>
  13 #include <stdarg.h>
  14 #include <openssl/crypto.h>
  15 #include "internal/core.h"
  16 #include "internal/property.h"
  17 #include "internal/provider.h"
  18 #include "crypto/ctype.h"
  19 #include <openssl/lhash.h>
  20 #include <openssl/rand.h>
  21 #include "internal/thread_once.h"
  22 #include "crypto/lhash.h"
  23 #include "crypto/sparse_array.h"
  24 #include "property_local.h"
  25
  26 /*
  27  * The number of elements in the query cache before we initiate a flush.
  28  * If reducing this, also ensure the stochastic test in test/property_test.c
  29  * isn't likely to fail.
  30  */
  31 #define IMPL_CACHE_FLUSH_THRESHOLD  500
  32
  33 typedef struct {
  34     void *method;
  35     int (*up_ref)(void *);
  36     void (*free)(void *);
  37 } METHOD;
  38
  39 typedef struct {
  40     const OSSL_PROVIDER *provider;
  41     OSSL_PROPERTY_LIST *properties;
  42     METHOD method;
  43 } IMPLEMENTATION;
  44
  45 DEFINE_STACK_OF(IMPLEMENTATION)
  46
  47 typedef struct {
  48     const char *query;
  49     METHOD method;
  50     char body[1];
  51 } QUERY;
  52
  53 DEFINE_LHASH_OF(QUERY);
  54
  55 typedef struct {
  56     int nid;
  57     STACK_OF(IMPLEMENTATION) *impls;
  58     LHASH_OF(QUERY) *cache;
  59 } ALGORITHM;
  60
  61 struct ossl_method_store_st {
  62     OSSL_LIB_CTX *ctx;
  63     size_t nelem;
  64     SPARSE_ARRAY_OF(ALGORITHM) *algs;
  65     int need_flush;
  66     CRYPTO_RWLOCK *lock;
  67 };
  68
  69 typedef struct {
  70     LHASH_OF(QUERY) *cache;
  71     size_t nelem;
  72     uint32_t seed;
  73 } IMPL_CACHE_FLUSH;
  74
  75 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);
  76
  77 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);
  78
  79 /* Global properties are stored per library context */
  80 static void ossl_ctx_global_properties_free(void *vstore)
  81 {
  82     OSSL_PROPERTY_LIST **plp = vstore;
  83
  84     if (plp != NULL) {
  85         ossl_property_free(*plp);
  86         OPENSSL_free(plp);
  87     }
  88 }
  89
  90 static void *ossl_ctx_global_properties_new(OSSL_LIB_CTX *ctx)
  91 {
  92     return OPENSSL_zalloc(sizeof(OSSL_PROPERTY_LIST **));
  93 }
  94
  95
  96 static const OSSL_LIB_CTX_METHOD ossl_ctx_global_properties_method = {
  97     ossl_ctx_global_properties_new,
  98     ossl_ctx_global_properties_free,
  99 };
 100
 101 OSSL_PROPERTY_LIST **ossl_ctx_global_properties(OSSL_LIB_CTX *libctx,
 102                                                 int loadconfig)
 103 {
 104 #ifndef FIPS_MODULE
 105     if (loadconfig && !OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
 106         return NULL;
 107 #endif
 108     return ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES,
 109                                  &ossl_ctx_global_properties_method);
 110 }
 111
 112 static int ossl_method_up_ref(METHOD *method)
 113 {
 114     return (*method->up_ref)(method->method);
 115 }
 116
 117 static void ossl_method_free(METHOD *method)
 118 {
 119     (*method->free)(method->method);
 120 }
 121
 122 static __owur int ossl_property_read_lock(OSSL_METHOD_STORE *p)
 123 {
 124     return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
 125 }
 126
 127 static __owur int ossl_property_write_lock(OSSL_METHOD_STORE *p)
 128 {
 129     return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
 130 }
 131
 132 static int ossl_property_unlock(OSSL_METHOD_STORE *p)
 133 {
 134     return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
 135 }
 136
 137 static unsigned long query_hash(const QUERY *a)
 138 {
 139     return OPENSSL_LH_strhash(a->query);
 140 }
 141
 142 static int query_cmp(const QUERY *a, const QUERY *b)
 143 {
 144     return strcmp(a->query, b->query);
 145 }
 146
 147 static void impl_free(IMPLEMENTATION *impl)
 148 {
 149     if (impl != NULL) {
 150         ossl_method_free(&impl->method);
 151         OPENSSL_free(impl);
 152     }
 153 }
 154
 155 static void impl_cache_free(QUERY *elem)
 156 {
 157     if (elem != NULL) {
 158         ossl_method_free(&elem->method);
 159         OPENSSL_free(elem);
 160     }
 161 }
 162
 163 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
 164 {
 165     if (a != NULL) {
 166         sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
 167         lh_QUERY_doall(a->cache, &impl_cache_free);
 168         lh_QUERY_free(a->cache);
 169         OPENSSL_free(a);
 170     }
 171 }
 172
 173 /*
 174  * The OSSL_LIB_CTX param here allows access to underlying property data needed
 175  * for computation
 176  */
 177 OSSL_METHOD_STORE *ossl_method_store_new(OSSL_LIB_CTX *ctx)
 178 {
 179     OSSL_METHOD_STORE *res;
 180
 181     res = OPENSSL_zalloc(sizeof(*res));
 182     if (res != NULL) {
 183         res->ctx = ctx;
 184         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
 185             OPENSSL_free(res);
 186             return NULL;
 187         }
 188         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
 189             ossl_sa_ALGORITHM_free(res->algs);
 190             OPENSSL_free(res);
 191             return NULL;
 192         }
 193     }
 194     return res;
 195 }
 196
 197 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 198 {
 199     if (store != NULL) {
 200         ossl_sa_ALGORITHM_doall(store->algs, &alg_cleanup);
 201         ossl_sa_ALGORITHM_free(store->algs);
 202         CRYPTO_THREAD_lock_free(store->lock);
 203         OPENSSL_free(store);
 204     }
 205 }
 206
 207 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 208 {
 209     return ossl_sa_ALGORITHM_get(store->algs, nid);
 210 }
 211
 212 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 213 {
 214         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 215 }
 216
 217 int ossl_method_store_add(OSSL_METHOD_STORE *store, const OSSL_PROVIDER *prov,
 218                           int nid, const char *properties, void *method,
 219                           int (*method_up_ref)(void *),
 220                           void (*method_destruct)(void *))
 221 {
 222     ALGORITHM *alg = NULL;
 223     IMPLEMENTATION *impl;
 224     int ret = 0;
 225     int i;
 226
 227     if (nid <= 0 || method == NULL || store == NULL)
 228         return 0;
 229     if (properties == NULL)
 230         properties = "";
 231
 232     /* Create new entry */
 233     impl = OPENSSL_malloc(sizeof(*impl));
 234     if (impl == NULL)
 235         return 0;
 236     impl->method.method = method;
 237     impl->method.up_ref = method_up_ref;
 238     impl->method.free = method_destruct;
 239     if (!ossl_method_up_ref(&impl->method)) {
 240         OPENSSL_free(impl);
 241         return 0;
 242     }
 243     impl->provider = prov;
 244
 245     /*
 246      * Insert into the hash table if required.
 247      *
 248      * A write lock is used unconditionally because we wend our way down to the
 249      * property string code which isn't locking friendly.
 250      */
 251     if (!ossl_property_write_lock(store)) {
 252         OPENSSL_free(impl);
 253         return 0;
 254     }
 255     ossl_method_cache_flush(store, nid);
 256     if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
 257         impl->properties = ossl_parse_property(store->ctx, properties);
 258         if (impl->properties == NULL)
 259             goto err;
 260         ossl_prop_defn_set(store->ctx, properties, impl->properties);
 261     }
 262
 263     alg = ossl_method_store_retrieve(store, nid);
 264     if (alg == NULL) {
 265         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 266                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 267                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 268             goto err;
 269         alg->nid = nid;
 270         if (!ossl_method_store_insert(store, alg))
 271             goto err;
 272     }
 273
 274     /* Push onto stack if there isn't one there already */
 275     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 276         const IMPLEMENTATION *tmpimpl = sk_IMPLEMENTATION_value(alg->impls, i);
 277
 278         if (tmpimpl->provider == impl->provider
 279             && tmpimpl->properties == impl->properties)
 280             break;
 281     }
 282     if (i == sk_IMPLEMENTATION_num(alg->impls)
 283         && sk_IMPLEMENTATION_push(alg->impls, impl))
 284         ret = 1;
 285     ossl_property_unlock(store);
 286     if (ret == 0)
 287         impl_free(impl);
 288     return ret;
 289
 290 err:
 291     ossl_property_unlock(store);
 292     alg_cleanup(0, alg);
 293     impl_free(impl);
 294     return 0;
 295 }
 296
 297 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 298                              const void *method)
 299 {
 300     ALGORITHM *alg = NULL;
 301     int i;
 302
 303     if (nid <= 0 || method == NULL || store == NULL)
 304         return 0;
 305
 306     if (!ossl_property_write_lock(store))
 307         return 0;
 308     ossl_method_cache_flush(store, nid);
 309     alg = ossl_method_store_retrieve(store, nid);
 310     if (alg == NULL) {
 311         ossl_property_unlock(store);
 312         return 0;
 313     }
 314
 315     /*
 316      * A sorting find then a delete could be faster but these stacks should be
 317      * relatively small, so we avoid the overhead.  Sorting could also surprise
 318      * users when result orderings change (even though they are not guaranteed).
 319      */
 320     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 321         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 322
 323         if (impl->method.method == method) {
 324             impl_free(impl);
 325             (void)sk_IMPLEMENTATION_delete(alg->impls, i);
 326             ossl_property_unlock(store);
 327             return 1;
 328         }
 329     }
 330     ossl_property_unlock(store);
 331     return 0;
 332 }
 333
 334 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 335                             const char *prop_query,
 336                             void **method)
 337 {
 338     OSSL_PROPERTY_LIST **plp;
 339     ALGORITHM *alg;
 340     IMPLEMENTATION *impl;
 341     OSSL_PROPERTY_LIST *pq = NULL, *p2 = NULL;
 342     METHOD *best_method = NULL;
 343     int ret = 0;
 344     int j, best = -1, score, optional;
 345
 346 #ifndef FIPS_MODULE
 347     if (!OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
 348         return 0;
 349 #endif
 350
 351     if (nid <= 0 || method == NULL || store == NULL)
 352         return 0;
 353
 354     /*
 355      * This only needs to be a read lock, because queries never create property
 356      * names or value and thus don't modify any of the property string layer.
 357      */
 358     if (!ossl_property_read_lock(store))
 359         return 0;
 360     alg = ossl_method_store_retrieve(store, nid);
 361     if (alg == NULL) {
 362         ossl_property_unlock(store);
 363         return 0;
 364     }
 365
 366     if (prop_query != NULL)
 367         p2 = pq = ossl_parse_query(store->ctx, prop_query, 0);
 368     plp = ossl_ctx_global_properties(store->ctx, 0);
 369     if (plp != NULL && *plp != NULL) {
 370         if (pq == NULL) {
 371             pq = *plp;
 372         } else {
 373             p2 = ossl_property_merge(pq, *plp);
 374             ossl_property_free(pq);
 375             if (p2 == NULL)
 376                 goto fin;
 377             pq = p2;
 378         }
 379     }
 380
 381     if (pq == NULL) {
 382         if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
 383             best_method = &impl->method;
 384             ret = 1;
 385         }
 386         goto fin;
 387     }
 388     optional = ossl_property_has_optional(pq);
 389     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 390         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 391         score = ossl_property_match_count(pq, impl->properties);
 392         if (score > best) {
 393             best_method = &impl->method;
 394             best = score;
 395             ret = 1;
 396             if (!optional)
 397                 goto fin;
 398         }
 399     }
 400 fin:
 401     if (ret && ossl_method_up_ref(best_method))
 402         *method = best_method->method;
 403     else
 404         ret = 0;
 405     ossl_property_unlock(store);
 406     ossl_property_free(p2);
 407     return ret;
 408 }
 409
 410 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg, void *arg)
 411 {
 412     SPARSE_ARRAY_OF(ALGORITHM) *algs = arg;
 413
 414     lh_QUERY_doall(alg->cache, &impl_cache_free);
 415     if (algs != NULL) {
 416         sk_IMPLEMENTATION_pop_free(alg->impls, &impl_free);
 417         lh_QUERY_free(alg->cache);
 418         OPENSSL_free(alg);
 419         ossl_sa_ALGORITHM_set(algs, idx, NULL);
 420     } else {
 421         lh_QUERY_flush(alg->cache);
 422     }
 423 }
 424
 425 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 426 {
 427     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
 428
 429     if (alg != NULL) {
 430         ossl_provider_clear_all_operation_bits(store->ctx);
 431         store->nelem -= lh_QUERY_num_items(alg->cache);
 432         impl_cache_flush_alg(0, alg, NULL);
 433     }
 434 }
 435
 436 int ossl_method_store_flush_cache(OSSL_METHOD_STORE *store, int all)
 437 {
 438     void *arg = (all != 0 ? store->algs : NULL);
 439
 440     if (!ossl_property_write_lock(store))
 441         return 0;
 442     ossl_provider_clear_all_operation_bits(store->ctx);
 443     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_alg, arg);
 444     store->nelem = 0;
 445     ossl_property_unlock(store);
 446     return 1;
 447 }
 448
 449 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
 450
 451 /*
 452  * Flush an element from the query cache (perhaps).
 453  *
 454  * In order to avoid taking a write lock or using atomic operations
 455  * to keep accurate least recently used (LRU) or least frequently used
 456  * (LFU) information, the procedure used here is to stochastically
 457  * flush approximately half the cache.
 458  *
 459  * This procedure isn't ideal, LRU or LFU would be better.  However,
 460  * in normal operation, reaching a full cache would be unexpected.
 461  * It means that no steady state of algorithm queries has been reached.
 462  * That is, it is most likely an attack of some form.  A suboptimal clearance
 463  * strategy that doesn't degrade performance of the normal case is
 464  * preferable to a more refined approach that imposes a performance
 465  * impact.
 466  */
 467 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 468 {
 469     uint32_t n;
 470
 471     /*
 472      * Implement the 32 bit xorshift as suggested by George Marsaglia in:
 473      *      https://doi.org/10.18637/jss.v008.i14
 474      *
 475      * This is a very fast PRNG so there is no need to extract bits one at a
 476      * time and use the entire value each time.
 477      */
 478     n = state->seed;
 479     n ^= n << 13;
 480     n ^= n >> 17;
 481     n ^= n << 5;
 482     state->seed = n;
 483
 484     if ((n & 1) != 0)
 485         impl_cache_free(lh_QUERY_delete(state->cache, c));
 486     else
 487         state->nelem++;
 488 }
 489
 490 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
 491                                      void *v)
 492 {
 493     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 494
 495     state->cache = alg->cache;
 496     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 497                                     state);
 498 }
 499
 500 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 501 {
 502     IMPL_CACHE_FLUSH state;
 503
 504     state.nelem = 0;
 505     if ((state.seed = OPENSSL_rdtsc()) == 0)
 506         state.seed = 1;
 507     ossl_provider_clear_all_operation_bits(store->ctx);
 508     store->need_flush = 0;
 509     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 510     store->nelem = state.nelem;
 511 }
 512
 513 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
 514                                 const char *prop_query, void **method)
 515 {
 516     ALGORITHM *alg;
 517     QUERY elem, *r;
 518     int res = 0;
 519
 520     if (nid <= 0 || store == NULL)
 521         return 0;
 522
 523     if (!ossl_property_read_lock(store))
 524         return 0;
 525     alg = ossl_method_store_retrieve(store, nid);
 526     if (alg == NULL)
 527         goto err;
 528
 529     elem.query = prop_query != NULL ? prop_query : "";
 530     r = lh_QUERY_retrieve(alg->cache, &elem);
 531     if (r == NULL)
 532         goto err;
 533     if (ossl_method_up_ref(&r->method)) {
 534         *method = r->method.method;
 535         res = 1;
 536     }
 537 err:
 538     ossl_property_unlock(store);
 539     return res;
 540 }
 541
 542 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
 543                                 const char *prop_query, void *method,
 544                                 int (*method_up_ref)(void *),
 545                                 void (*method_destruct)(void *))
 546 {
 547     QUERY elem, *old, *p = NULL;
 548     ALGORITHM *alg;
 549     size_t len;
 550     int res = 1;
 551
 552     if (nid <= 0 || store == NULL)
 553         return 0;
 554     if (prop_query == NULL)
 555         return 1;
 556
 557     if (!ossl_property_write_lock(store))
 558         return 0;
 559     if (store->need_flush)
 560         ossl_method_cache_flush_some(store);
 561     alg = ossl_method_store_retrieve(store, nid);
 562     if (alg == NULL)
 563         goto err;
 564
 565     if (method == NULL) {
 566         elem.query = prop_query;
 567         if ((old = lh_QUERY_delete(alg->cache, &elem)) != NULL) {
 568             impl_cache_free(old);
 569             store->nelem--;
 570         }
 571         goto end;
 572     }
 573     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 574     if (p != NULL) {
 575         p->query = p->body;
 576         p->method.method = method;
 577         p->method.up_ref = method_up_ref;
 578         p->method.free = method_destruct;
 579         if (!ossl_method_up_ref(&p->method))
 580             goto err;
 581         memcpy((char *)p->query, prop_query, len + 1);
 582         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
 583             impl_cache_free(old);
 584             goto end;
 585         }
 586         if (!lh_QUERY_error(alg->cache)) {
 587             if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 588                 store->need_flush = 1;
 589             goto end;
 590         }
 591         ossl_method_free(&p->method);
 592     }
 593 err:
 594     res = 0;
 595     OPENSSL_free(p);
 596 end:
 597     ossl_property_unlock(store);
 598     return res;
 599 }