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,
 178                           void *method, void (*method_destruct)(void *))
 179 {
 180     ALGORITHM *alg = NULL;
 181     IMPLEMENTATION *impl;
 182     int ret = 0;
 183
 184     if (nid <= 0 || method == NULL || store == NULL)
 185         return 0;
 186     if (properties == NULL)
 187         properties = "";
 188
 189     /* Create new entry */
 190     impl = OPENSSL_malloc(sizeof(*impl));
 191     if (impl == NULL)
 192         return 0;
 193     impl->method = method;
 194     impl->method_destruct = method_destruct;
 195
 196     /*
 197      * Insert into the hash table if required.
 198      *
 199      * A write lock is used unconditionally because we wend our way down to the
 200      * property string code which isn't locking friendly.
 201      */
 202     ossl_property_write_lock(store);
 203     ossl_method_cache_flush(store, nid);
 204     if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
 205         impl->properties = ossl_parse_property(store->ctx, properties);
 206         if (impl->properties == NULL)
 207             goto err;
 208         ossl_prop_defn_set(store->ctx, properties, impl->properties);
 209     }
 210
 211     alg = ossl_method_store_retrieve(store, nid);
 212     if (alg == NULL) {
 213         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 214                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 215                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 216             goto err;
 217         alg->nid = nid;
 218         if (!ossl_method_store_insert(store, alg))
 219             goto err;
 220     }
 221
 222     /* Push onto stack */
 223     if (sk_IMPLEMENTATION_push(alg->impls, impl))
 224         ret = 1;
 225     ossl_property_unlock(store);
 226     if (ret == 0)
 227         impl_free(impl);
 228     return ret;
 229
 230 err:
 231     ossl_property_unlock(store);
 232     alg_cleanup(0, alg);
 233     impl_free(impl);
 234     return 0;
 235 }
 236
 237 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 238                              const void *method)
 239 {
 240     ALGORITHM *alg = NULL;
 241     int i;
 242
 243     if (nid <= 0 || method == NULL || store == NULL)
 244         return 0;
 245
 246     ossl_property_write_lock(store);
 247     ossl_method_cache_flush(store, nid);
 248     alg = ossl_method_store_retrieve(store, nid);
 249     if (alg == NULL) {
 250         ossl_property_unlock(store);
 251         return 0;
 252     }
 253
 254     /*
 255      * A sorting find then a delete could be faster but these stacks should be
 256      * relatively small, so we avoid the overhead.  Sorting could also surprise
 257      * users when result orderings change (even though they are not guaranteed).
 258      */
 259     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 260         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 261
 262         if (impl->method == method) {
 263             sk_IMPLEMENTATION_delete(alg->impls, i);
 264             ossl_property_unlock(store);
 265             impl_free(impl);
 266             return 1;
 267         }
 268     }
 269     ossl_property_unlock(store);
 270     return 0;
 271 }
 272
 273 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 274                             const char *prop_query, void **method)
 275 {
 276     ALGORITHM *alg;
 277     IMPLEMENTATION *impl;
 278     OSSL_PROPERTY_LIST *pq = NULL, *p2;
 279     int ret = 0;
 280     int j, best = -1, score, optional;
 281
 282     if (nid <= 0 || method == NULL || store == NULL)
 283         return 0;
 284
 285     /*
 286      * This only needs to be a read lock, because queries never create property
 287      * names or value and thus don't modify any of the property string layer.
 288      */
 289     ossl_property_read_lock(store);
 290     alg = ossl_method_store_retrieve(store, nid);
 291     if (alg == NULL) {
 292         ossl_property_unlock(store);
 293         return 0;
 294     }
 295
 296     if (prop_query == NULL) {
 297         if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
 298             *method = impl->method;
 299             ret = 1;
 300         }
 301         goto fin;
 302     }
 303     pq = ossl_parse_query(store->ctx, prop_query);
 304     if (pq == NULL)
 305         goto fin;
 306     if (store->global_properties != NULL) {
 307         p2 = ossl_property_merge(pq, store->global_properties);
 308         if (p2 == NULL)
 309             goto fin;
 310         ossl_property_free(pq);
 311         pq = p2;
 312     }
 313     optional = ossl_property_has_optional(pq);
 314     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 315         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 316         score = ossl_property_match_count(pq, impl->properties);
 317         if (score > best) {
 318             *method = impl->method;
 319             ret = 1;
 320             if (!optional)
 321                 goto fin;
 322             best = score;
 323         }
 324     }
 325 fin:
 326     ossl_property_unlock(store);
 327     ossl_property_free(pq);
 328     return ret;
 329 }
 330
 331 int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
 332                                             const char *prop_query) {
 333     int ret = 0;
 334
 335     if (store == NULL)
 336         return 1;
 337
 338     ossl_property_write_lock(store);
 339     ossl_method_cache_flush_all(store);
 340     if (prop_query == NULL) {
 341         ossl_property_free(store->global_properties);
 342         store->global_properties = NULL;
 343         ossl_property_unlock(store);
 344         return 1;
 345     }
 346     store->global_properties = ossl_parse_query(store->ctx, prop_query);
 347     ret = store->global_properties != NULL;
 348     ossl_property_unlock(store);
 349     return ret;
 350 }
 351
 352 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
 353 {
 354     lh_QUERY_doall(alg->cache, &impl_cache_free);
 355     lh_QUERY_flush(alg->cache);
 356 }
 357
 358 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 359 {
 360     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
 361
 362     if (alg != NULL) {
 363         store->nelem -= lh_QUERY_num_items(alg->cache);
 364         impl_cache_flush_alg(0, alg);
 365     }
 366 }
 367
 368 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
 369 {
 370     ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
 371     store->nelem = 0;
 372 }
 373
 374 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
 375
 376 /*
 377  * Flush an element from the query cache (perhaps).
 378  *
 379  * In order to avoid taking a write lock or using atomic operations
 380  * to keep accurate least recently used (LRU) or least frequently used
 381  * (LFU) information, the procedure used here is to stochastically
 382  * flush approximately half the cache.
 383  *
 384  * This procedure isn't ideal, LRU or LFU would be better.  However,
 385  * in normal operation, reaching a full cache would be unexpected.
 386  * It means that no steady state of algorithm queries has been reached.
 387  * That is, it is most likely an attack of some form.  A suboptimal clearance
 388  * strategy that doesn't degrade performance of the normal case is
 389  * preferable to a more refined approach that imposes a performance
 390  * impact.
 391  */
 392 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 393 {
 394     uint32_t n;
 395
 396     /*
 397      * Implement the 32 bit xorshift as suggested by George Marsaglia in:
 398      *      https://doi.org/10.18637/jss.v008.i14
 399      *
 400      * This is a very fast PRNG so there is no need to extract bits one at a
 401      * time and use the entire value each time.
 402      */
 403     n = state->seed;
 404     n ^= n << 13;
 405     n ^= n >> 17;
 406     n ^= n << 5;
 407     state->seed = n;
 408
 409     if ((n & 1) != 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(ossl_uintmax_t idx, ALGORITHM *alg,
 416                                      void *v)
 417 {
 418     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 419
 420     state->cache = alg->cache;
 421     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 422                                     state);
 423 }
 424
 425 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 426 {
 427     IMPL_CACHE_FLUSH state;
 428
 429     state.nelem = 0;
 430     if ((state.seed = OPENSSL_rdtsc()) == 0)
 431         state.seed = 1;
 432     store->need_flush = 0;
 433     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 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 != NULL ? 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         if (lh_QUERY_delete(alg->cache, &elem) != NULL)
 488             store->nelem--;
 489         ossl_property_unlock(store);
 490         return 1;
 491     }
 492     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 493     if (p != NULL) {
 494         p->query = p->body;
 495         p->method = method;
 496         memcpy((char *)p->query, prop_query, len + 1);
 497         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
 498             OPENSSL_free(old);
 499             ossl_property_unlock(store);
 500             return 1;
 501         }
 502         if (!lh_QUERY_error(alg->cache)) {
 503             if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 504                 store->need_flush = 1;
 505             ossl_property_unlock(store);
 506             return 1;
 507         }
 508     }
 509     ossl_property_unlock(store);
 510     OPENSSL_free(p);
 511     return 0;
 512 }