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