crypto/property/property.c

   1 /*
   2  * Copyright 2019-2020 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/property.h"
  16 #include "crypto/ctype.h"
  17 #include <openssl/lhash.h>
  18 #include <openssl/rand.h>
  19 #include "internal/thread_once.h"
  20 #include "crypto/lhash.h"
  21 #include "crypto/sparse_array.h"
  22 #include "property_local.h"
  23
  24 /*
  25  * The number of elements in the query cache before we initiate a flush.
  26  * If reducing this, also ensure the stochastic test in test/property_test.c
  27  * isn't likely to fail.
  28  */
  29 #define IMPL_CACHE_FLUSH_THRESHOLD  500
  30
  31 typedef struct {
  32     void *method;
  33     int (*up_ref)(void *);
  34     void (*free)(void *);
  35 } METHOD;
  36
  37 typedef struct {
  38     const OSSL_PROVIDER *provider;
  39     OSSL_PROPERTY_LIST *properties;
  40     METHOD method;
  41 } IMPLEMENTATION;
  42
  43 DEFINE_STACK_OF(IMPLEMENTATION)
  44
  45 typedef struct {
  46     const char *query;
  47     METHOD method;
  48     char body[1];
  49 } QUERY;
  50
  51 DEFINE_LHASH_OF(QUERY);
  52
  53 typedef struct {
  54     int nid;
  55     STACK_OF(IMPLEMENTATION) *impls;
  56     LHASH_OF(QUERY) *cache;
  57 } ALGORITHM;
  58
  59 struct ossl_method_store_st {
  60     OSSL_LIB_CTX *ctx;
  61     size_t nelem;
  62     SPARSE_ARRAY_OF(ALGORITHM) *algs;
  63     int need_flush;
  64     CRYPTO_RWLOCK *lock;
  65 };
  66
  67 typedef struct {
  68     LHASH_OF(QUERY) *cache;
  69     size_t nelem;
  70     uint32_t seed;
  71 } IMPL_CACHE_FLUSH;
  72
  73 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);
  74
  75 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);
  76
  77 /* Global properties are stored per library context */
  78 static void ossl_ctx_global_properties_free(void *vstore)
  79 {
  80     OSSL_PROPERTY_LIST **plp = vstore;
  81
  82     if (plp != NULL) {
  83         ossl_property_free(*plp);
  84         OPENSSL_free(plp);
  85     }
  86 }
  87
  88 static void *ossl_ctx_global_properties_new(OSSL_LIB_CTX *ctx)
  89 {
  90     return OPENSSL_zalloc(sizeof(OSSL_PROPERTY_LIST **));
  91 }
  92
  93
  94 static const OSSL_LIB_CTX_METHOD ossl_ctx_global_properties_method = {
  95     ossl_ctx_global_properties_new,
  96     ossl_ctx_global_properties_free,
  97 };
  98
  99 OSSL_PROPERTY_LIST **ossl_ctx_global_properties(OSSL_LIB_CTX *libctx,
 100                                                 int loadconfig)
 101 {
 102 #ifndef FIPS_MODULE
 103     if (loadconfig && !OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
 104         return NULL;
 105 #endif
 106     return ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES,
 107                                  &ossl_ctx_global_properties_method);
 108 }
 109
 110 static int ossl_method_up_ref(METHOD *method)
 111 {
 112     return (*method->up_ref)(method->method);
 113 }
 114
 115 static void ossl_method_free(METHOD *method)
 116 {
 117     (*method->free)(method->method);
 118 }
 119
 120 int ossl_property_read_lock(OSSL_METHOD_STORE *p)
 121 {
 122     return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
 123 }
 124
 125 int ossl_property_write_lock(OSSL_METHOD_STORE *p)
 126 {
 127     return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
 128 }
 129
 130 int ossl_property_unlock(OSSL_METHOD_STORE *p)
 131 {
 132     return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
 133 }
 134
 135 static unsigned long query_hash(const QUERY *a)
 136 {
 137     return OPENSSL_LH_strhash(a->query);
 138 }
 139
 140 static int query_cmp(const QUERY *a, const QUERY *b)
 141 {
 142     return strcmp(a->query, b->query);
 143 }
 144
 145 static void impl_free(IMPLEMENTATION *impl)
 146 {
 147     if (impl != NULL) {
 148         ossl_method_free(&impl->method);
 149         OPENSSL_free(impl);
 150     }
 151 }
 152
 153 static void impl_cache_free(QUERY *elem)
 154 {
 155     if (elem != NULL) {
 156         ossl_method_free(&elem->method);
 157         OPENSSL_free(elem);
 158     }
 159 }
 160
 161 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
 162 {
 163     if (a != NULL) {
 164         sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
 165         lh_QUERY_doall(a->cache, &impl_cache_free);
 166         lh_QUERY_free(a->cache);
 167         OPENSSL_free(a);
 168     }
 169 }
 170
 171 /*
 172  * The OSSL_LIB_CTX param here allows access to underlying property data needed
 173  * for computation
 174  */
 175 OSSL_METHOD_STORE *ossl_method_store_new(OSSL_LIB_CTX *ctx)
 176 {
 177     OSSL_METHOD_STORE *res;
 178
 179     res = OPENSSL_zalloc(sizeof(*res));
 180     if (res != NULL) {
 181         res->ctx = ctx;
 182         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
 183             OPENSSL_free(res);
 184             return NULL;
 185         }
 186         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
 187             ossl_sa_ALGORITHM_free(res->algs);
 188             OPENSSL_free(res);
 189             return NULL;
 190         }
 191     }
 192     return res;
 193 }
 194
 195 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 196 {
 197     if (store != NULL) {
 198         ossl_sa_ALGORITHM_doall(store->algs, &alg_cleanup);
 199         ossl_sa_ALGORITHM_free(store->algs);
 200         CRYPTO_THREAD_lock_free(store->lock);
 201         OPENSSL_free(store);
 202     }
 203 }
 204
 205 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 206 {
 207     return ossl_sa_ALGORITHM_get(store->algs, nid);
 208 }
 209
 210 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 211 {
 212         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 213 }
 214
 215 int ossl_method_store_add(OSSL_METHOD_STORE *store, const OSSL_PROVIDER *prov,
 216                           int nid, const char *properties, void *method,
 217                           int (*method_up_ref)(void *),
 218                           void (*method_destruct)(void *))
 219 {
 220     ALGORITHM *alg = NULL;
 221     IMPLEMENTATION *impl;
 222     int ret = 0;
 223     int i;
 224
 225     if (nid <= 0 || method == NULL || store == NULL)
 226         return 0;
 227     if (properties == NULL)
 228         properties = "";
 229
 230     /* Create new entry */
 231     impl = OPENSSL_malloc(sizeof(*impl));
 232     if (impl == NULL)
 233         return 0;
 234     impl->method.method = method;
 235     impl->method.up_ref = method_up_ref;
 236     impl->method.free = method_destruct;
 237     if (!ossl_method_up_ref(&impl->method)) {
 238         OPENSSL_free(impl);
 239         return 0;
 240     }
 241     impl->provider = prov;
 242
 243     /*
 244      * Insert into the hash table if required.
 245      *
 246      * A write lock is used unconditionally because we wend our way down to the
 247      * property string code which isn't locking friendly.
 248      */
 249     ossl_property_write_lock(store);
 250     ossl_method_cache_flush(store, nid);
 251     if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
 252         impl->properties = ossl_parse_property(store->ctx, properties);
 253         if (impl->properties == NULL)
 254             goto err;
 255         ossl_prop_defn_set(store->ctx, properties, impl->properties);
 256     }
 257
 258     alg = ossl_method_store_retrieve(store, nid);
 259     if (alg == NULL) {
 260         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 261                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 262                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 263             goto err;
 264         alg->nid = nid;
 265         if (!ossl_method_store_insert(store, alg))
 266             goto err;
 267     }
 268
 269     /* Push onto stack if there isn't one there already */
 270     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 271         const IMPLEMENTATION *tmpimpl = sk_IMPLEMENTATION_value(alg->impls, i);
 272
 273         if (tmpimpl->provider == impl->provider
 274             && tmpimpl->properties == impl->properties)
 275             break;
 276     }
 277     if (i == sk_IMPLEMENTATION_num(alg->impls)
 278         && sk_IMPLEMENTATION_push(alg->impls, impl))
 279         ret = 1;
 280     ossl_property_unlock(store);
 281     if (ret == 0)
 282         impl_free(impl);
 283     return ret;
 284
 285 err:
 286     ossl_property_unlock(store);
 287     alg_cleanup(0, alg);
 288     impl_free(impl);
 289     return 0;
 290 }
 291
 292 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 293                              const void *method)
 294 {
 295     ALGORITHM *alg = NULL;
 296     int i;
 297
 298     if (nid <= 0 || method == NULL || store == NULL)
 299         return 0;
 300
 301     ossl_property_write_lock(store);
 302     ossl_method_cache_flush(store, nid);
 303     alg = ossl_method_store_retrieve(store, nid);
 304     if (alg == NULL) {
 305         ossl_property_unlock(store);
 306         return 0;
 307     }
 308
 309     /*
 310      * A sorting find then a delete could be faster but these stacks should be
 311      * relatively small, so we avoid the overhead.  Sorting could also surprise
 312      * users when result orderings change (even though they are not guaranteed).
 313      */
 314     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 315         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 316
 317         if (impl->method.method == method) {
 318             impl_free(impl);
 319             (void)sk_IMPLEMENTATION_delete(alg->impls, i);
 320             ossl_property_unlock(store);
 321             return 1;
 322         }
 323     }
 324     ossl_property_unlock(store);
 325     return 0;
 326 }
 327
 328 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 329                             const char *prop_query,
 330                             void **method)
 331 {
 332     OSSL_PROPERTY_LIST **plp;
 333     ALGORITHM *alg;
 334     IMPLEMENTATION *impl;
 335     OSSL_PROPERTY_LIST *pq = NULL, *p2 = NULL;
 336     METHOD *best_method = NULL;
 337     int ret = 0;
 338     int j, best = -1, score, optional;
 339
 340 #ifndef FIPS_MODULE
 341     if (!OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
 342         return 0;
 343 #endif
 344
 345     if (nid <= 0 || method == NULL || store == NULL)
 346         return 0;
 347
 348     /*
 349      * This only needs to be a read lock, because queries never create property
 350      * names or value and thus don't modify any of the property string layer.
 351      */
 352     ossl_property_read_lock(store);
 353     alg = ossl_method_store_retrieve(store, nid);
 354     if (alg == NULL) {
 355         ossl_property_unlock(store);
 356         return 0;
 357     }
 358
 359     if (prop_query != NULL)
 360         p2 = pq = ossl_parse_query(store->ctx, prop_query);
 361     plp = ossl_ctx_global_properties(store->ctx, 0);
 362     if (plp != NULL && *plp != NULL) {
 363         if (pq == NULL) {
 364             pq = *plp;
 365         } else {
 366             p2 = ossl_property_merge(pq, *plp);
 367             ossl_property_free(pq);
 368             if (p2 == NULL)
 369                 goto fin;
 370             pq = p2;
 371         }
 372     }
 373
 374     if (pq == NULL) {
 375         if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
 376             best_method = &impl->method;
 377             ret = 1;
 378         }
 379         goto fin;
 380     }
 381     optional = ossl_property_has_optional(pq);
 382     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 383         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 384         score = ossl_property_match_count(pq, impl->properties);
 385         if (score > best) {
 386             best_method = &impl->method;
 387             best = score;
 388             ret = 1;
 389             if (!optional)
 390                 goto fin;
 391         }
 392     }
 393 fin:
 394     if (ret && ossl_method_up_ref(best_method))
 395         *method = best_method->method;
 396     else
 397         ret = 0;
 398     ossl_property_unlock(store);
 399     ossl_property_free(p2);
 400     return ret;
 401 }
 402
 403 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg, void *arg)
 404 {
 405     SPARSE_ARRAY_OF(ALGORITHM) *algs = arg;
 406
 407     lh_QUERY_doall(alg->cache, &impl_cache_free);
 408     if (algs != NULL) {
 409         sk_IMPLEMENTATION_pop_free(alg->impls, &impl_free);
 410         lh_QUERY_free(alg->cache);
 411         OPENSSL_free(alg);
 412         ossl_sa_ALGORITHM_set(algs, idx, NULL);
 413     } else {
 414         lh_QUERY_flush(alg->cache);
 415     }
 416 }
 417
 418 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 419 {
 420     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
 421
 422     if (alg != NULL) {
 423         store->nelem -= lh_QUERY_num_items(alg->cache);
 424         impl_cache_flush_alg(0, alg, NULL);
 425     }
 426 }
 427
 428 void ossl_method_store_flush_cache(OSSL_METHOD_STORE *store, int all)
 429 {
 430     void *arg = (all != 0 ? store->algs : NULL);
 431
 432     ossl_property_write_lock(store);
 433     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_alg, arg);
 434     store->nelem = 0;
 435     ossl_property_unlock(store);
 436 }
 437
 438 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
 439
 440 /*
 441  * Flush an element from the query cache (perhaps).
 442  *
 443  * In order to avoid taking a write lock or using atomic operations
 444  * to keep accurate least recently used (LRU) or least frequently used
 445  * (LFU) information, the procedure used here is to stochastically
 446  * flush approximately half the cache.
 447  *
 448  * This procedure isn't ideal, LRU or LFU would be better.  However,
 449  * in normal operation, reaching a full cache would be unexpected.
 450  * It means that no steady state of algorithm queries has been reached.
 451  * That is, it is most likely an attack of some form.  A suboptimal clearance
 452  * strategy that doesn't degrade performance of the normal case is
 453  * preferable to a more refined approach that imposes a performance
 454  * impact.
 455  */
 456 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 457 {
 458     uint32_t n;
 459
 460     /*
 461      * Implement the 32 bit xorshift as suggested by George Marsaglia in:
 462      *      https://doi.org/10.18637/jss.v008.i14
 463      *
 464      * This is a very fast PRNG so there is no need to extract bits one at a
 465      * time and use the entire value each time.
 466      */
 467     n = state->seed;
 468     n ^= n << 13;
 469     n ^= n >> 17;
 470     n ^= n << 5;
 471     state->seed = n;
 472
 473     if ((n & 1) != 0)
 474         impl_cache_free(lh_QUERY_delete(state->cache, c));
 475     else
 476         state->nelem++;
 477 }
 478
 479 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
 480                                      void *v)
 481 {
 482     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 483
 484     state->cache = alg->cache;
 485     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 486                                     state);
 487 }
 488
 489 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 490 {
 491     IMPL_CACHE_FLUSH state;
 492
 493     state.nelem = 0;
 494     if ((state.seed = OPENSSL_rdtsc()) == 0)
 495         state.seed = 1;
 496     store->need_flush = 0;
 497     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 498     store->nelem = state.nelem;
 499 }
 500
 501 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
 502                                 const char *prop_query, void **method)
 503 {
 504     ALGORITHM *alg;
 505     QUERY elem, *r;
 506     int res = 0;
 507
 508     if (nid <= 0 || store == NULL)
 509         return 0;
 510
 511     ossl_property_read_lock(store);
 512     alg = ossl_method_store_retrieve(store, nid);
 513     if (alg == NULL)
 514         goto err;
 515
 516     elem.query = prop_query != NULL ? prop_query : "";
 517     r = lh_QUERY_retrieve(alg->cache, &elem);
 518     if (r == NULL)
 519         goto err;
 520     if (ossl_method_up_ref(&r->method)) {
 521         *method = r->method.method;
 522         res = 1;
 523     }
 524 err:
 525     ossl_property_unlock(store);
 526     return res;
 527 }
 528
 529 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
 530                                 const char *prop_query, void *method,
 531                                 int (*method_up_ref)(void *),
 532                                 void (*method_destruct)(void *))
 533 {
 534     QUERY elem, *old, *p = NULL;
 535     ALGORITHM *alg;
 536     size_t len;
 537     int res = 1;
 538
 539     if (nid <= 0 || store == NULL)
 540         return 0;
 541     if (prop_query == NULL)
 542         return 1;
 543
 544     ossl_property_write_lock(store);
 545     if (store->need_flush)
 546         ossl_method_cache_flush_some(store);
 547     alg = ossl_method_store_retrieve(store, nid);
 548     if (alg == NULL)
 549         goto err;
 550
 551     if (method == NULL) {
 552         elem.query = prop_query;
 553         if ((old = lh_QUERY_delete(alg->cache, &elem)) != NULL) {
 554             impl_cache_free(old);
 555             store->nelem--;
 556         }
 557         goto end;
 558     }
 559     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 560     if (p != NULL) {
 561         p->query = p->body;
 562         p->method.method = method;
 563         p->method.up_ref = method_up_ref;
 564         p->method.free = method_destruct;
 565         if (!ossl_method_up_ref(&p->method))
 566             goto err;
 567         memcpy((char *)p->query, prop_query, len + 1);
 568         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
 569             impl_cache_free(old);
 570             goto end;
 571         }
 572         if (!lh_QUERY_error(alg->cache)) {
 573             if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 574                 store->need_flush = 1;
 575             goto end;
 576         }
 577         ossl_method_free(&p->method);
 578     }
 579 err:
 580     res = 0;
 581     OPENSSL_free(p);
 582 end:
 583     ossl_property_unlock(store);
 584     return res;
 585 }