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