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     size_t nelem;
  51     SPARSE_ARRAY_OF(ALGORITHM) *algs;
  52     OSSL_PROPERTY_LIST *global_properties;
  53     int need_flush;
  54     unsigned int nbits;
  55     unsigned char rand_bits[(IMPL_CACHE_FLUSH_THRESHOLD + 7) / 8];
  56     CRYPTO_RWLOCK *lock;
  57 };
  58
  59 typedef struct {
  60     OSSL_METHOD_STORE *store;
  61     LHASH_OF(QUERY) *cache;
  62     size_t nelem;
  63 } IMPL_CACHE_FLUSH;
  64
  65 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);
  66
  67 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);
  68 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *c);
  69
  70 int ossl_property_read_lock(OSSL_METHOD_STORE *p)
  71 {
  72     return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
  73 }
  74
  75 int ossl_property_write_lock(OSSL_METHOD_STORE *p)
  76 {
  77     return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
  78 }
  79
  80 int ossl_property_unlock(OSSL_METHOD_STORE *p)
  81 {
  82     return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
  83 }
  84
  85 int ossl_method_store_init(void)
  86 {
  87     if (ossl_property_string_init()
  88             && ossl_prop_defn_init()
  89             && ossl_property_parse_init())
  90         return 1;
  91
  92     ossl_method_store_cleanup();
  93     return 0;
  94 }
  95
  96 void ossl_method_store_cleanup(void)
  97 {
  98     ossl_property_string_cleanup();
  99     ossl_prop_defn_cleanup();
 100 }
 101
 102 static CRYPTO_ONCE method_store_init_flag = CRYPTO_ONCE_STATIC_INIT;
 103 DEFINE_RUN_ONCE_STATIC(do_method_store_init)
 104 {
 105     return OPENSSL_init_crypto(0, NULL)
 106         && ossl_method_store_init()
 107         && OPENSSL_atexit(&ossl_method_store_cleanup);
 108 }
 109
 110 static unsigned long query_hash(const QUERY *a)
 111 {
 112     return OPENSSL_LH_strhash(a->query);
 113 }
 114
 115 static int query_cmp(const QUERY *a, const QUERY *b)
 116 {
 117     return strcmp(a->query, b->query);
 118 }
 119
 120 static void impl_free(IMPLEMENTATION *impl)
 121 {
 122     if (impl != NULL) {
 123         if (impl->method_destruct)
 124             impl->method_destruct(impl->method);
 125         OPENSSL_free(impl);
 126     }
 127 }
 128
 129 static void impl_cache_free(QUERY *elem)
 130 {
 131     OPENSSL_free(elem);
 132 }
 133
 134 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
 135 {
 136     if (a != NULL) {
 137         sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
 138         lh_QUERY_doall(a->cache, &impl_cache_free);
 139         lh_QUERY_free(a->cache);
 140         OPENSSL_free(a);
 141     }
 142 }
 143
 144 OSSL_METHOD_STORE *ossl_method_store_new(void)
 145 {
 146     OSSL_METHOD_STORE *res;
 147
 148     if (!RUN_ONCE(&method_store_init_flag, do_method_store_init))
 149         return 0;
 150
 151     res = OPENSSL_zalloc(sizeof(*res));
 152     if (res != NULL) {
 153         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
 154             OPENSSL_free(res);
 155             return NULL;
 156         }
 157         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
 158             OPENSSL_free(res->algs);
 159             OPENSSL_free(res);
 160             return NULL;
 161         }
 162     }
 163     return res;
 164 }
 165
 166 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 167 {
 168     if (store != NULL) {
 169         ossl_sa_ALGORITHM_doall(store->algs, &alg_cleanup);
 170         ossl_sa_ALGORITHM_free(store->algs);
 171         ossl_property_free(store->global_properties);
 172         CRYPTO_THREAD_lock_free(store->lock);
 173         OPENSSL_free(store);
 174     }
 175 }
 176
 177 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 178 {
 179     return ossl_sa_ALGORITHM_get(store->algs, nid);
 180 }
 181
 182 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 183 {
 184         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 185 }
 186
 187 int ossl_method_store_add(OSSL_METHOD_STORE *store,
 188                           int nid, const char *properties,
 189                           void *method, void (*method_destruct)(void *))
 190 {
 191     ALGORITHM *alg = NULL;
 192     IMPLEMENTATION *impl;
 193     int ret = 0;
 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;
 205     impl->method_destruct = method_destruct;
 206
 207     /*
 208      * Insert into the hash table if required.
 209      *
 210      * A write lock is used unconditionally because we wend our way down to the
 211      * property string code which isn't locking friendly.
 212      */
 213     ossl_property_write_lock(store);
 214     ossl_method_cache_flush(store, nid);
 215     if ((impl->properties = ossl_prop_defn_get(properties)) == NULL) {
 216         if ((impl->properties = ossl_parse_property(properties)) == NULL)
 217             goto err;
 218         ossl_prop_defn_set(properties, impl->properties);
 219     }
 220
 221     alg = ossl_method_store_retrieve(store, nid);
 222     if (alg == NULL) {
 223         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 224                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 225                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 226             goto err;
 227         alg->nid = nid;
 228         if (!ossl_method_store_insert(store, alg))
 229             goto err;
 230     }
 231
 232     /* Push onto stack */
 233     if (sk_IMPLEMENTATION_push(alg->impls, impl))
 234         ret = 1;
 235     ossl_property_unlock(store);
 236     if (ret == 0)
 237         impl_free(impl);
 238     return ret;
 239
 240 err:
 241     ossl_property_unlock(store);
 242     alg_cleanup(0, alg);
 243     impl_free(impl);
 244     return 0;
 245 }
 246
 247 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 248                              const void *method)
 249 {
 250     ALGORITHM *alg = NULL;
 251     int i;
 252
 253     if (nid <= 0 || method == NULL || store == NULL)
 254         return 0;
 255
 256     ossl_property_write_lock(store);
 257     ossl_method_cache_flush(store, nid);
 258     alg = ossl_method_store_retrieve(store, nid);
 259     if (alg == NULL) {
 260         ossl_property_unlock(store);
 261         return 0;
 262     }
 263
 264     /*
 265      * A sorting find then a delete could be faster but these stacks should be
 266      * relatively small, so we avoid the overhead.  Sorting could also surprise
 267      * users when result orderings change (even though they are not guaranteed).
 268      */
 269     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 270         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 271
 272         if (impl->method == method) {
 273             sk_IMPLEMENTATION_delete(alg->impls, i);
 274             ossl_property_unlock(store);
 275             impl_free(impl);
 276             return 1;
 277         }
 278     }
 279     ossl_property_unlock(store);
 280     return 0;
 281 }
 282
 283 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 284                             const char *prop_query, void **method)
 285 {
 286     ALGORITHM *alg;
 287     IMPLEMENTATION *impl;
 288     OSSL_PROPERTY_LIST *pq = NULL, *p2;
 289     int ret = 0;
 290     int j;
 291
 292     if (nid <= 0 || method == NULL || store == NULL)
 293         return 0;
 294
 295     /*
 296      * This only needs to be a read lock, because queries never create property
 297      * names or value and thus don't modify any of the property string layer.
 298      */
 299     ossl_property_read_lock(store);
 300     alg = ossl_method_store_retrieve(store, nid);
 301     if (alg == NULL) {
 302         ossl_property_unlock(store);
 303         return 0;
 304     }
 305
 306     if (prop_query == NULL) {
 307         if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
 308             *method = impl->method;
 309             ret = 1;
 310         }
 311         goto fin;
 312     }
 313     pq = ossl_parse_query(prop_query);
 314     if (pq == NULL)
 315         goto fin;
 316     if (store->global_properties != NULL) {
 317         p2 = ossl_property_merge(pq, store->global_properties);
 318         if (p2 == NULL)
 319             goto fin;
 320         ossl_property_free(pq);
 321         pq = p2;
 322     }
 323     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 324         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 325
 326         if (ossl_property_match(pq, impl->properties)) {
 327             *method = impl->method;
 328             ret = 1;
 329             goto fin;
 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(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 to keep accurate LRU information or
 387  * using atomic operations to approximate similar, the procedure used here
 388  * is to stochastically flush approximately half the cache.  Since generating
 389  * random numbers is relatively expensive, we produce them in blocks and
 390  * consume them as we go, saving generated bits between generations of flushes.
 391  *
 392  * This procedure isn't ideal, LRU would be better.  However, in normal
 393  * operation, reaching a full cache would be quite unexpected.  It means
 394  * that no steady state of algorithm queries has been reached.  I.e. it is most
 395  * likely an attack of some form.  A suboptimal clearance strategy that doesn't
 396  * degrade performance of the normal case is preferable to a more refined
 397  * approach that imposes a performance impact.
 398  */
 399 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 400 {
 401     OSSL_METHOD_STORE *store = state->store;
 402     unsigned int n;
 403
 404     if (store->nbits == 0) {
 405         if (!RAND_bytes(store->rand_bits, sizeof(store->rand_bits)))
 406             return;
 407         store->nbits = sizeof(store->rand_bits) * 8;
 408     }
 409     n = --store->nbits;
 410     if ((store->rand_bits[n >> 3] & (1 << (n & 7))) != 0)
 411         OPENSSL_free(lh_QUERY_delete(state->cache, c));
 412     else
 413         state->nelem++;
 414 }
 415
 416 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
 417                                      void *v)
 418 {
 419     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 420
 421     state->cache = alg->cache;
 422     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 423                                     state);
 424 }
 425
 426 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 427 {
 428     IMPL_CACHE_FLUSH state;
 429
 430     state.nelem = 0;
 431     state.store = store;
 432     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 433     store->need_flush = 0;
 434     store->nelem = state.nelem;
 435 }
 436
 437 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
 438                                 const char *prop_query, void **method)
 439 {
 440     ALGORITHM *alg;
 441     QUERY elem, *r;
 442
 443     if (nid <= 0 || store == NULL)
 444         return 0;
 445
 446     ossl_property_read_lock(store);
 447     alg = ossl_method_store_retrieve(store, nid);
 448     if (alg == NULL) {
 449         ossl_property_unlock(store);
 450         return 0;
 451     }
 452
 453     elem.query = prop_query;
 454     r = lh_QUERY_retrieve(alg->cache, &elem);
 455     if (r == NULL) {
 456         ossl_property_unlock(store);
 457         return 0;
 458     }
 459     *method = r->method;
 460     ossl_property_unlock(store);
 461     return 1;
 462 }
 463
 464 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
 465                                 const char *prop_query, void *method)
 466 {
 467     QUERY elem, *old, *p = NULL;
 468     ALGORITHM *alg;
 469     size_t len;
 470
 471     if (nid <= 0 || store == NULL)
 472         return 0;
 473     if (prop_query == NULL)
 474         return 1;
 475
 476     ossl_property_write_lock(store);
 477     if (store->need_flush)
 478         ossl_method_cache_flush_some(store);
 479     alg = ossl_method_store_retrieve(store, nid);
 480     if (alg == NULL) {
 481         ossl_property_unlock(store);
 482         return 0;
 483     }
 484
 485     if (method == NULL) {
 486         elem.query = prop_query;
 487         lh_QUERY_delete(alg->cache, &elem);
 488         ossl_property_unlock(store);
 489         return 1;
 490     }
 491     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 492     if (p != NULL) {
 493         p->query = p->body;
 494         p->method = method;
 495         memcpy((char *)p->query, prop_query, len + 1);
 496         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL)
 497             OPENSSL_free(old);
 498         if (old != NULL || !lh_QUERY_error(alg->cache)) {
 499             store->nelem++;
 500             if (store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 501                 store->need_flush = 1;
 502             ossl_property_unlock(store);
 503             return 1;
 504         }
 505     }
 506     ossl_property_unlock(store);
 507     OPENSSL_free(p);
 508     return 0;
 509 }