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(size_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 = OPENSSL_zalloc(sizeof(*res));
 147
 148     if (!RUN_ONCE(&method_store_init_flag, do_method_store_init))
 149         return 0;
 150
 151     if (res != NULL) {
 152         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
 153             OPENSSL_free(res);
 154             return NULL;
 155         }
 156         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
 157             OPENSSL_free(res->algs);
 158             OPENSSL_free(res);
 159             return NULL;
 160         }
 161     }
 162     return res;
 163 }
 164
 165 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 166 {
 167     if (store != NULL) {
 168         ossl_sa_ALGORITHM_doall(store->algs, &alg_cleanup);
 169         ossl_sa_ALGORITHM_free(store->algs);
 170         ossl_property_free(store->global_properties);
 171         CRYPTO_THREAD_lock_free(store->lock);
 172         OPENSSL_free(store);
 173     }
 174 }
 175
 176 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 177 {
 178     return ossl_sa_ALGORITHM_get(store->algs, nid);
 179 }
 180
 181 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 182 {
 183         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 184 }
 185
 186 int ossl_method_store_add(OSSL_METHOD_STORE *store,
 187                           int nid, const char *properties,
 188                           void *method, void (*method_destruct)(void *))
 189 {
 190     ALGORITHM *alg = NULL;
 191     IMPLEMENTATION *impl;
 192     int ret = 0;
 193
 194     if (nid <= 0 || method == NULL || store == NULL)
 195         return 0;
 196     if (properties == NULL)
 197         properties = "";
 198
 199     /* Create new entry */
 200     impl = OPENSSL_malloc(sizeof(*impl));
 201     if (impl == NULL)
 202         return 0;
 203     impl->method = method;
 204     impl->method_destruct = method_destruct;
 205
 206     /*
 207      * Insert into the hash table if required.
 208      *
 209      * A write lock is used unconditionally because we wend our way down to the
 210      * property string code which isn't locking friendly.
 211      */
 212     ossl_property_write_lock(store);
 213     ossl_method_cache_flush(store, nid);
 214     if ((impl->properties = ossl_prop_defn_get(properties)) == NULL) {
 215         if ((impl->properties = ossl_parse_property(properties)) == NULL)
 216             goto err;
 217         ossl_prop_defn_set(properties, impl->properties);
 218     }
 219
 220     alg = ossl_method_store_retrieve(store, nid);
 221     if (alg == NULL) {
 222         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 223                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 224                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 225             goto err;
 226         alg->nid = nid;
 227         if (!ossl_method_store_insert(store, alg))
 228             goto err;
 229     }
 230
 231     /* Push onto stack */
 232     if (sk_IMPLEMENTATION_push(alg->impls, impl))
 233         ret = 1;
 234     ossl_property_unlock(store);
 235     if (ret == 0)
 236         impl_free(impl);
 237     return ret;
 238
 239 err:
 240     ossl_property_unlock(store);
 241     alg_cleanup(0, alg);
 242     impl_free(impl);
 243     return 0;
 244 }
 245
 246 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 247                              const void *method)
 248 {
 249     ALGORITHM *alg = NULL;
 250     int i;
 251
 252     if (nid <= 0 || method == NULL || store == NULL)
 253         return 0;
 254
 255     ossl_property_write_lock(store);
 256     ossl_method_cache_flush(store, nid);
 257     alg = ossl_method_store_retrieve(store, nid);
 258     if (alg == NULL) {
 259         ossl_property_unlock(store);
 260         return 0;
 261     }
 262
 263     /*
 264      * A sorting find then a delete could be faster but these stacks should be
 265      * relatively small, so we avoid the overhead.  Sorting could also surprise
 266      * users when result orderings change (even though they are not guaranteed).
 267      */
 268     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 269         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 270
 271         if (impl->method == method) {
 272             sk_IMPLEMENTATION_delete(alg->impls, i);
 273             ossl_property_unlock(store);
 274             impl_free(impl);
 275             return 1;
 276         }
 277     }
 278     ossl_property_unlock(store);
 279     return 0;
 280 }
 281
 282 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 283                             const char *prop_query, void **method)
 284 {
 285     ALGORITHM *alg;
 286     IMPLEMENTATION *impl;
 287     OSSL_PROPERTY_LIST *pq = NULL, *p2;
 288     int ret = 0;
 289     int j;
 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(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     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 323         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 324
 325         if (ossl_property_match(pq, impl->properties)) {
 326             *method = impl->method;
 327             ret = 1;
 328             goto fin;
 329         }
 330     }
 331 fin:
 332     ossl_property_unlock(store);
 333     ossl_property_free(pq);
 334     return ret;
 335 }
 336
 337 int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
 338                                             const char *prop_query) {
 339     int ret = 0;
 340
 341     if (store == NULL)
 342         return 1;
 343
 344     ossl_property_write_lock(store);
 345     ossl_method_cache_flush_all(store);
 346     if (prop_query == NULL) {
 347         ossl_property_free(store->global_properties);
 348         store->global_properties = NULL;
 349         ossl_property_unlock(store);
 350         return 1;
 351     }
 352     store->global_properties = ossl_parse_query(prop_query);
 353     ret = store->global_properties != NULL;
 354     ossl_property_unlock(store);
 355     return ret;
 356 }
 357
 358 static void impl_cache_flush_alg(size_t idx, ALGORITHM *alg)
 359 {
 360     lh_QUERY_doall(alg->cache, &impl_cache_free);
 361     lh_QUERY_flush(alg->cache);
 362 }
 363
 364 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 365 {
 366     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
 367
 368     if (alg != NULL) {
 369         store->nelem -= lh_QUERY_num_items(alg->cache);
 370         impl_cache_flush_alg(0, alg);
 371     }
 372 }
 373
 374 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
 375 {
 376     ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
 377     store->nelem = 0;
 378 }
 379
 380 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
 381
 382 /*
 383  * Flush an element from the query cache (perhaps).
 384  *
 385  * In order to avoid taking a write lock to keep accurate LRU information or
 386  * using atomic operations to approximate similar, the procedure used here
 387  * is to stochastically flush approximately half the cache.  Since generating
 388  * random numbers is relatively expensive, we produce them in blocks and
 389  * consume them as we go, saving generated bits between generations of flushes.
 390  *
 391  * This procedure isn't ideal, LRU would be better.  However, in normal
 392  * operation, reaching a full cache would be quite unexpected.  It means
 393  * that no steady state of algorithm queries has been reached.  I.e. it is most
 394  * likely an attack of some form.  A suboptimal clearance strategy that doesn't
 395  * degrade performance of the normal case is preferable to a more refined
 396  * approach that imposes a performance impact.
 397  */
 398 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 399 {
 400     OSSL_METHOD_STORE *store = state->store;
 401     unsigned int n;
 402
 403     if (store->nbits == 0) {
 404         if (!RAND_bytes(store->rand_bits, sizeof(store->rand_bits)))
 405             return;
 406         store->nbits = sizeof(store->rand_bits) * 8;
 407     }
 408     n = --store->nbits;
 409     if ((store->rand_bits[n >> 3] & (1 << (n & 7))) != 0)
 410         OPENSSL_free(lh_QUERY_delete(state->cache, c));
 411     else
 412         state->nelem++;
 413 }
 414
 415 static void impl_cache_flush_one_alg(size_t idx, ALGORITHM *alg, void *v)
 416 {
 417     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 418
 419     state->cache = alg->cache;
 420     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 421                                     state);
 422 }
 423
 424 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 425 {
 426     IMPL_CACHE_FLUSH state;
 427
 428     state.nelem = 0;
 429     state.store = store;
 430     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 431     store->need_flush = 0;
 432     store->nelem = state.nelem;
 433 }
 434
 435 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
 436                                 const char *prop_query, void **method)
 437 {
 438     ALGORITHM *alg;
 439     QUERY elem, *r;
 440
 441     if (nid <= 0 || store == NULL)
 442         return 0;
 443
 444     ossl_property_read_lock(store);
 445     alg = ossl_method_store_retrieve(store, nid);
 446     if (alg == NULL) {
 447         ossl_property_unlock(store);
 448         return 0;
 449     }
 450
 451     elem.query = prop_query;
 452     r = lh_QUERY_retrieve(alg->cache, &elem);
 453     if (r == NULL) {
 454         ossl_property_unlock(store);
 455         return 0;
 456     }
 457     *method = r->method;
 458     ossl_property_unlock(store);
 459     return 1;
 460 }
 461
 462 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
 463                                 const char *prop_query, void *method)
 464 {
 465     QUERY elem, *old, *p = NULL;
 466     ALGORITHM *alg;
 467     size_t len;
 468
 469     if (nid <= 0 || store == NULL)
 470         return 0;
 471     if (prop_query == NULL)
 472         return 1;
 473
 474     ossl_property_write_lock(store);
 475     if (store->need_flush)
 476         ossl_method_cache_flush_some(store);
 477     alg = ossl_method_store_retrieve(store, nid);
 478     if (alg == NULL) {
 479         ossl_property_unlock(store);
 480         return 0;
 481     }
 482
 483     if (method == NULL) {
 484         elem.query = prop_query;
 485         lh_QUERY_delete(alg->cache, &elem);
 486         ossl_property_unlock(store);
 487         return 1;
 488     }
 489     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 490     if (p != NULL) {
 491         p->query = p->body;
 492         p->method = method;
 493         memcpy((char *)p->query, prop_query, len + 1);
 494         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL)
 495             OPENSSL_free(old);
 496         if (old != NULL || !lh_QUERY_error(alg->cache)) {
 497             store->nelem++;
 498             if (store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 499                 store->need_flush = 1;
 500             ossl_property_unlock(store);
 501             return 1;
 502         }
 503     }
 504     ossl_property_unlock(store);
 505     OPENSSL_free(p);
 506     return 0;
 507 }