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