crypto/property/property.c

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