2 * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
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
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"
24 /* The number of elements in the query cache before we initiate a flush */
25 #define IMPL_CACHE_FLUSH_THRESHOLD 500
28 OSSL_PROPERTY_LIST *properties;
30 void (*method_destruct)(void *);
33 DEFINE_STACK_OF(IMPLEMENTATION)
41 DEFINE_LHASH_OF(QUERY);
45 STACK_OF(IMPLEMENTATION) *impls;
46 LHASH_OF(QUERY) *cache;
49 struct ossl_method_store_st {
52 SPARSE_ARRAY_OF(ALGORITHM) *algs;
53 OSSL_PROPERTY_LIST *global_properties;
56 unsigned char rand_bits[(IMPL_CACHE_FLUSH_THRESHOLD + 7) / 8];
61 LHASH_OF(QUERY) *cache;
66 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);
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);
71 int ossl_property_read_lock(OSSL_METHOD_STORE *p)
73 return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
76 int ossl_property_write_lock(OSSL_METHOD_STORE *p)
78 return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
81 int ossl_property_unlock(OSSL_METHOD_STORE *p)
83 return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
86 static openssl_ctx_run_once_fn do_method_store_init;
87 int do_method_store_init(OPENSSL_CTX *ctx)
89 return ossl_property_parse_init(ctx);
92 static unsigned long query_hash(const QUERY *a)
94 return OPENSSL_LH_strhash(a->query);
97 static int query_cmp(const QUERY *a, const QUERY *b)
99 return strcmp(a->query, b->query);
102 static void impl_free(IMPLEMENTATION *impl)
105 if (impl->method_destruct)
106 impl->method_destruct(impl->method);
111 static void impl_cache_free(QUERY *elem)
116 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
119 sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
120 lh_QUERY_doall(a->cache, &impl_cache_free);
121 lh_QUERY_free(a->cache);
127 * The OPENSSL_CTX param here allows access to underlying property data needed
130 OSSL_METHOD_STORE *ossl_method_store_new(OPENSSL_CTX *ctx)
132 OSSL_METHOD_STORE *res;
134 if (!openssl_ctx_run_once(ctx,
135 OPENSSL_CTX_METHOD_STORE_RUN_ONCE_INDEX,
136 do_method_store_init))
139 res = OPENSSL_zalloc(sizeof(*res));
142 if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
146 if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
147 OPENSSL_free(res->algs);
155 void ossl_method_store_free(OSSL_METHOD_STORE *store)
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);
166 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
168 return ossl_sa_ALGORITHM_get(store->algs, nid);
171 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
173 return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
176 int ossl_method_store_add(OSSL_METHOD_STORE *store,
177 int nid, const char *properties,
178 void *method, void (*method_destruct)(void *))
180 ALGORITHM *alg = NULL;
181 IMPLEMENTATION *impl;
184 if (nid <= 0 || method == NULL || store == NULL)
186 if (properties == NULL)
189 /* Create new entry */
190 impl = OPENSSL_malloc(sizeof(*impl));
193 impl->method = method;
194 impl->method_destruct = method_destruct;
197 * Insert into the hash table if required.
199 * A write lock is used unconditionally because we wend our way down to the
200 * property string code which isn't locking friendly.
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)
208 ossl_prop_defn_set(store->ctx, properties, impl->properties);
211 alg = ossl_method_store_retrieve(store, nid);
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)
218 if (!ossl_method_store_insert(store, alg))
222 /* Push onto stack */
223 if (sk_IMPLEMENTATION_push(alg->impls, impl))
225 ossl_property_unlock(store);
231 ossl_property_unlock(store);
237 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
240 ALGORITHM *alg = NULL;
243 if (nid <= 0 || method == NULL || store == NULL)
246 ossl_property_write_lock(store);
247 ossl_method_cache_flush(store, nid);
248 alg = ossl_method_store_retrieve(store, nid);
250 ossl_property_unlock(store);
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).
259 for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
260 IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
262 if (impl->method == method) {
263 sk_IMPLEMENTATION_delete(alg->impls, i);
264 ossl_property_unlock(store);
269 ossl_property_unlock(store);
273 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
274 const char *prop_query, void **method)
277 IMPLEMENTATION *impl;
278 OSSL_PROPERTY_LIST *pq = NULL, *p2;
280 int j, best = -1, score, optional;
282 if (nid <= 0 || method == NULL || store == NULL)
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.
289 ossl_property_read_lock(store);
290 alg = ossl_method_store_retrieve(store, nid);
292 ossl_property_unlock(store);
296 if (prop_query == NULL) {
297 if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
298 *method = impl->method;
303 pq = ossl_parse_query(store->ctx, prop_query);
306 if (store->global_properties != NULL) {
307 p2 = ossl_property_merge(pq, store->global_properties);
310 ossl_property_free(pq);
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);
318 *method = impl->method;
326 ossl_property_unlock(store);
327 ossl_property_free(pq);
331 int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
332 const char *prop_query) {
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);
346 store->global_properties = ossl_parse_query(store->ctx, prop_query);
347 ret = store->global_properties != NULL;
348 ossl_property_unlock(store);
352 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
354 lh_QUERY_doall(alg->cache, &impl_cache_free);
355 lh_QUERY_flush(alg->cache);
358 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
360 ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
363 store->nelem -= lh_QUERY_num_items(alg->cache);
364 impl_cache_flush_alg(0, alg);
368 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
370 ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
374 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
377 * Flush an element from the query cache (perhaps).
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.
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
392 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
397 * Implement the 32 bit xorshift as suggested by George Marsaglia in:
398 * https://doi.org/10.18637/jss.v008.i14
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.
410 OPENSSL_free(lh_QUERY_delete(state->cache, c));
415 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
418 IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
420 state->cache = alg->cache;
421 lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
425 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
427 IMPL_CACHE_FLUSH state;
430 if ((state.seed = OPENSSL_rdtsc()) == 0)
432 ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
433 store->need_flush = 0;
434 store->nelem = state.nelem;
437 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
438 const char *prop_query, void **method)
443 if (nid <= 0 || store == NULL)
446 ossl_property_read_lock(store);
447 alg = ossl_method_store_retrieve(store, nid);
449 ossl_property_unlock(store);
453 elem.query = prop_query != NULL ? prop_query : "";
454 r = lh_QUERY_retrieve(alg->cache, &elem);
456 ossl_property_unlock(store);
460 ossl_property_unlock(store);
464 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
465 const char *prop_query, void *method)
467 QUERY elem, *old, *p = NULL;
471 if (nid <= 0 || store == NULL)
473 if (prop_query == NULL)
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);
481 ossl_property_unlock(store);
485 if (method == NULL) {
486 elem.query = prop_query;
487 if (lh_QUERY_delete(alg->cache, &elem) != NULL)
489 ossl_property_unlock(store);
492 p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
496 memcpy((char *)p->query, prop_query, len + 1);
497 if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
499 ossl_property_unlock(store);
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);
509 ossl_property_unlock(store);