crypto/property/property.c - third_party/openssl - Git at Google

 /*
  * Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  */

 #include <string.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <openssl/crypto.h>
 #include "internal/core.h"
 #include "internal/property.h"
 #include "internal/provider.h"
 #include "crypto/ctype.h"
 #include <openssl/lhash.h>
 #include <openssl/rand.h>
 #include "internal/thread_once.h"
 #include "crypto/lhash.h"
 #include "crypto/sparse_array.h"
 #include "property_local.h"
 #include "crypto/context.h"

 /*
  * The number of elements in the query cache before we initiate a flush.
  * If reducing this, also ensure the stochastic test in test/property_test.c
  * isn't likely to fail.
  */
 #define IMPL_CACHE_FLUSH_THRESHOLD  500

 typedef struct {
     void *method;
     int (*up_ref)(void *);
     void (*free)(void *);
 } METHOD;

 typedef struct {
     const OSSL_PROVIDER *provider;
     OSSL_PROPERTY_LIST *properties;
     METHOD method;
 } IMPLEMENTATION;

 DEFINE_STACK_OF(IMPLEMENTATION)

 typedef struct {
     const OSSL_PROVIDER *provider;
     const char *query;
     METHOD method;
     char body[1];
 } QUERY;

 DEFINE_LHASH_OF(QUERY);

 typedef struct {
     int nid;
     STACK_OF(IMPLEMENTATION) *impls;
     LHASH_OF(QUERY) *cache;
 } ALGORITHM;

 struct ossl_method_store_st {
     OSSL_LIB_CTX *ctx;
     SPARSE_ARRAY_OF(ALGORITHM) *algs;
     CRYPTO_RWLOCK *lock;

     /* query cache specific values */

     /* Count of the query cache entries for all algs */
     size_t cache_nelem;

     /* Flag: 1 if query cache entries for all algs need flushing */
     int cache_need_flush;
 };

 typedef struct {
     LHASH_OF(QUERY) *cache;
     size_t nelem;
     uint32_t seed;
 } IMPL_CACHE_FLUSH;

 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);

 typedef struct ossl_global_properties_st {
     OSSL_PROPERTY_LIST *list;
 #ifndef FIPS_MODULE
     unsigned int no_mirrored : 1;
 #endif
 } OSSL_GLOBAL_PROPERTIES;

 static void ossl_method_cache_flush_alg(OSSL_METHOD_STORE *store,
                                         ALGORITHM *alg);
 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);

 /* Global properties are stored per library context */
 void ossl_ctx_global_properties_free(void *vglobp)
 {
     OSSL_GLOBAL_PROPERTIES *globp = vglobp;

     if (globp != NULL) {
         ossl_property_free(globp->list);
         OPENSSL_free(globp);
     }
 }

 void *ossl_ctx_global_properties_new(OSSL_LIB_CTX *ctx)
 {
     return OPENSSL_zalloc(sizeof(OSSL_GLOBAL_PROPERTIES));
 }

 OSSL_PROPERTY_LIST **ossl_ctx_global_properties(OSSL_LIB_CTX *libctx,
                                                 int loadconfig)
 {
     OSSL_GLOBAL_PROPERTIES *globp;

 #ifndef FIPS_MODULE
     if (loadconfig && !OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
         return NULL;
 #endif
     globp = ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

     return globp != NULL ? &globp->list : NULL;
 }

 #ifndef FIPS_MODULE
 int ossl_global_properties_no_mirrored(OSSL_LIB_CTX *libctx)
 {
     OSSL_GLOBAL_PROPERTIES *globp
         = ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

     return globp != NULL && globp->no_mirrored ? 1 : 0;
 }

 void ossl_global_properties_stop_mirroring(OSSL_LIB_CTX *libctx)
 {
     OSSL_GLOBAL_PROPERTIES *globp
         = ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

     if (globp != NULL)
         globp->no_mirrored = 1;
 }
 #endif

 static int ossl_method_up_ref(METHOD *method)
 {
     return (*method->up_ref)(method->method);
 }

 static void ossl_method_free(METHOD *method)
 {
     (*method->free)(method->method);
 }

 static __owur int ossl_property_read_lock(OSSL_METHOD_STORE *p)
 {
     return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
 }

 static __owur int ossl_property_write_lock(OSSL_METHOD_STORE *p)
 {
     return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
 }

 static int ossl_property_unlock(OSSL_METHOD_STORE *p)
 {
     return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
 }

 static unsigned long query_hash(const QUERY *a)
 {
     return OPENSSL_LH_strhash(a->query);
 }

 static int query_cmp(const QUERY *a, const QUERY *b)
 {
     int res = strcmp(a->query, b->query);

     if (res == 0 && a->provider != NULL && b->provider != NULL)
         res = b->provider > a->provider ? 1
             : b->provider < a->provider ? -1
             : 0;
     return res;
 }

 static void impl_free(IMPLEMENTATION *impl)
 {
     if (impl != NULL) {
         ossl_method_free(&impl->method);
         OPENSSL_free(impl);
     }
 }

 static void impl_cache_free(QUERY *elem)
 {
     if (elem != NULL) {
         ossl_method_free(&elem->method);
         OPENSSL_free(elem);
     }
 }

 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
 {
     lh_QUERY_doall(alg->cache, &impl_cache_free);
     lh_QUERY_flush(alg->cache);
 }

 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a, void *arg)
 {
     OSSL_METHOD_STORE *store = arg;

     if (a != NULL) {
         sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
         lh_QUERY_doall(a->cache, &impl_cache_free);
         lh_QUERY_free(a->cache);
         OPENSSL_free(a);
     }
     if (store != NULL)
         ossl_sa_ALGORITHM_set(store->algs, idx, NULL);
 }

 /*
  * The OSSL_LIB_CTX param here allows access to underlying property data needed
  * for computation
  */
 OSSL_METHOD_STORE *ossl_method_store_new(OSSL_LIB_CTX *ctx)
 {
     OSSL_METHOD_STORE *res;

     res = OPENSSL_zalloc(sizeof(*res));
     if (res != NULL) {
         res->ctx = ctx;
         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
             OPENSSL_free(res);
             return NULL;
         }
         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
             ossl_sa_ALGORITHM_free(res->algs);
             OPENSSL_free(res);
             return NULL;
         }
     }
     return res;
 }

 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 {
     if (store != NULL) {
         ossl_sa_ALGORITHM_doall_arg(store->algs, &alg_cleanup, store);
         ossl_sa_ALGORITHM_free(store->algs);
         CRYPTO_THREAD_lock_free(store->lock);
         OPENSSL_free(store);
     }
 }

 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 {
     return ossl_sa_ALGORITHM_get(store->algs, nid);
 }

 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 {
         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 }

 int ossl_method_store_add(OSSL_METHOD_STORE *store, const OSSL_PROVIDER *prov,
                           int nid, const char *properties, void *method,
                           int (*method_up_ref)(void *),
                           void (*method_destruct)(void *))
 {
     ALGORITHM *alg = NULL;
     IMPLEMENTATION *impl;
     int ret = 0;
     int i;

     if (nid <= 0 || method == NULL || store == NULL)
         return 0;
     if (properties == NULL)
         properties = "";

     if (!ossl_assert(prov != NULL))
         return 0;

     /* Create new entry */
     impl = OPENSSL_malloc(sizeof(*impl));
     if (impl == NULL)
         return 0;
     impl->method.method = method;
     impl->method.up_ref = method_up_ref;
     impl->method.free = method_destruct;
     if (!ossl_method_up_ref(&impl->method)) {
         OPENSSL_free(impl);
         return 0;
     }
     impl->provider = prov;

     /* Insert into the hash table if required */
     if (!ossl_property_write_lock(store)) {
         OPENSSL_free(impl);
         return 0;
     }
     ossl_method_cache_flush(store, nid);
     if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
         impl->properties = ossl_parse_property(store->ctx, properties);
         if (impl->properties == NULL)
             goto err;
         ossl_prop_defn_set(store->ctx, properties, impl->properties);
     }

     alg = ossl_method_store_retrieve(store, nid);
     if (alg == NULL) {
         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
             goto err;
         alg->nid = nid;
         if (!ossl_method_store_insert(store, alg))
             goto err;
     }

     /* Push onto stack if there isn't one there already */
     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
         const IMPLEMENTATION *tmpimpl = sk_IMPLEMENTATION_value(alg->impls, i);

         if (tmpimpl->provider == impl->provider
             && tmpimpl->properties == impl->properties)
             break;
     }
     if (i == sk_IMPLEMENTATION_num(alg->impls)
         && sk_IMPLEMENTATION_push(alg->impls, impl))
         ret = 1;
     ossl_property_unlock(store);
     if (ret == 0)
         impl_free(impl);
     return ret;

 err:
     ossl_property_unlock(store);
     alg_cleanup(0, alg, NULL);
     impl_free(impl);
     return 0;
 }

 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
                              const void *method)
 {
     ALGORITHM *alg = NULL;
     int i;

     if (nid <= 0 || method == NULL || store == NULL)
         return 0;

     if (!ossl_property_write_lock(store))
         return 0;
     ossl_method_cache_flush(store, nid);
     alg = ossl_method_store_retrieve(store, nid);
     if (alg == NULL) {
         ossl_property_unlock(store);
         return 0;
     }

     /*
      * A sorting find then a delete could be faster but these stacks should be
      * relatively small, so we avoid the overhead.  Sorting could also surprise
      * users when result orderings change (even though they are not guaranteed).
      */
     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

         if (impl->method.method == method) {
             impl_free(impl);
             (void)sk_IMPLEMENTATION_delete(alg->impls, i);
             ossl_property_unlock(store);
             return 1;
         }
     }
     ossl_property_unlock(store);
     return 0;
 }

 struct alg_cleanup_by_provider_data_st {
     OSSL_METHOD_STORE *store;
     const OSSL_PROVIDER *prov;
 };

 static void
 alg_cleanup_by_provider(ossl_uintmax_t idx, ALGORITHM *alg, void *arg)
 {
     struct alg_cleanup_by_provider_data_st *data = arg;
     int i, count;

     /*
      * We walk the stack backwards, to avoid having to deal with stack shifts
      * caused by deletion
      */
     for (count = 0, i = sk_IMPLEMENTATION_num(alg->impls); i-- > 0;) {
         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

         if (impl->provider == data->prov) {
             impl_free(impl);
             (void)sk_IMPLEMENTATION_delete(alg->impls, i);
             count++;
         }
     }

     /*
      * If we removed any implementation, we also clear the whole associated
      * cache, 'cause that's the sensible thing to do.
      * There's no point flushing the cache entries where we didn't remove
      * any implementation, though.
      */
     if (count > 0)
         ossl_method_cache_flush_alg(data->store, alg);
 }

 int ossl_method_store_remove_all_provided(OSSL_METHOD_STORE *store,
                                           const OSSL_PROVIDER *prov)
 {
     struct alg_cleanup_by_provider_data_st data;

     if (!ossl_property_write_lock(store))
         return 0;
     data.prov = prov;
     data.store = store;
     ossl_sa_ALGORITHM_doall_arg(store->algs, &alg_cleanup_by_provider, &data);
     ossl_property_unlock(store);
     return 1;
 }

 static void alg_do_one(ALGORITHM *alg, IMPLEMENTATION *impl,
                        void (*fn)(int id, void *method, void *fnarg),
                        void *fnarg)
 {
     fn(alg->nid, impl->method.method, fnarg);
 }

 struct alg_do_each_data_st {
     void (*fn)(int id, void *method, void *fnarg);
     void *fnarg;
 };

 static void alg_do_each(ossl_uintmax_t idx, ALGORITHM *alg, void *arg)
 {
     struct alg_do_each_data_st *data = arg;
     int i, end = sk_IMPLEMENTATION_num(alg->impls);

     for (i = 0; i < end; i++) {
         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

         alg_do_one(alg, impl, data->fn, data->fnarg);
     }
 }

 void ossl_method_store_do_all(OSSL_METHOD_STORE *store,
                               void (*fn)(int id, void *method, void *fnarg),
                               void *fnarg)
 {
     struct alg_do_each_data_st data;

     data.fn = fn;
     data.fnarg = fnarg;
     if (store != NULL)
         ossl_sa_ALGORITHM_doall_arg(store->algs, alg_do_each, &data);
 }

 int ossl_method_store_fetch(OSSL_METHOD_STORE *store,
                             int nid, const char *prop_query,
                             const OSSL_PROVIDER **prov_rw, void **method)
 {
     OSSL_PROPERTY_LIST **plp;
     ALGORITHM *alg;
     IMPLEMENTATION *impl, *best_impl = NULL;
     OSSL_PROPERTY_LIST *pq = NULL, *p2 = NULL;
     const OSSL_PROVIDER *prov = prov_rw != NULL ? *prov_rw : NULL;
     int ret = 0;
     int j, best = -1, score, optional;

 #ifndef FIPS_MODULE
     if (!OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
         return 0;
 #endif

     if (nid <= 0 || method == NULL || store == NULL)
         return 0;

     /* This only needs to be a read lock, because the query won't create anything */
     if (!ossl_property_read_lock(store))
         return 0;
     alg = ossl_method_store_retrieve(store, nid);
     if (alg == NULL) {
         ossl_property_unlock(store);
         return 0;
     }

     if (prop_query != NULL)
         p2 = pq = ossl_parse_query(store->ctx, prop_query, 0);
     plp = ossl_ctx_global_properties(store->ctx, 0);
     if (plp != NULL && *plp != NULL) {
         if (pq == NULL) {
             pq = *plp;
         } else {
             p2 = ossl_property_merge(pq, *plp);
             ossl_property_free(pq);
             if (p2 == NULL)
                 goto fin;
             pq = p2;
         }
     }

     if (pq == NULL) {
         for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
             if ((impl = sk_IMPLEMENTATION_value(alg->impls, j)) != NULL
                 && (prov == NULL || impl->provider == prov)) {
                 best_impl = impl;
                 ret = 1;
                 break;
             }
         }
         goto fin;
     }
     optional = ossl_property_has_optional(pq);
     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
         if ((impl = sk_IMPLEMENTATION_value(alg->impls, j)) != NULL
             && (prov == NULL || impl->provider == prov)) {
             score = ossl_property_match_count(pq, impl->properties);
             if (score > best) {
                 best_impl = impl;
                 best = score;
                 ret = 1;
                 if (!optional)
                     goto fin;
             }
         }
     }
 fin:
     if (ret && ossl_method_up_ref(&best_impl->method)) {
         *method = best_impl->method.method;
         if (prov_rw != NULL)
             *prov_rw = best_impl->provider;
     } else {
         ret = 0;
     }
     ossl_property_unlock(store);
     ossl_property_free(p2);
     return ret;
 }

 static void ossl_method_cache_flush_alg(OSSL_METHOD_STORE *store,
                                         ALGORITHM *alg)
 {
     store->cache_nelem -= lh_QUERY_num_items(alg->cache);
     impl_cache_flush_alg(0, alg);
 }

 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 {
     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);

     if (alg != NULL)
         ossl_method_cache_flush_alg(store, alg);
 }

 int ossl_method_store_cache_flush_all(OSSL_METHOD_STORE *store)
 {
     if (!ossl_property_write_lock(store))
         return 0;
     ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
     store->cache_nelem = 0;
     ossl_property_unlock(store);
     return 1;
 }

 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);

 /*
  * Flush an element from the query cache (perhaps).
  *
  * In order to avoid taking a write lock or using atomic operations
  * to keep accurate least recently used (LRU) or least frequently used
  * (LFU) information, the procedure used here is to stochastically
  * flush approximately half the cache.
  *
  * This procedure isn't ideal, LRU or LFU would be better.  However,
  * in normal operation, reaching a full cache would be unexpected.
  * It means that no steady state of algorithm queries has been reached.
  * That is, it is most likely an attack of some form.  A suboptimal clearance
  * strategy that doesn't degrade performance of the normal case is
  * preferable to a more refined approach that imposes a performance
  * impact.
  */
 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 {
     uint32_t n;

     /*
      * Implement the 32 bit xorshift as suggested by George Marsaglia in:
      *      https://doi.org/10.18637/jss.v008.i14
      *
      * This is a very fast PRNG so there is no need to extract bits one at a
      * time and use the entire value each time.
      */
     n = state->seed;
     n ^= n << 13;
     n ^= n >> 17;
     n ^= n << 5;
     state->seed = n;

     if ((n & 1) != 0)
         impl_cache_free(lh_QUERY_delete(state->cache, c));
     else
         state->nelem++;
 }

 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
                                      void *v)
 {
     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;

     state->cache = alg->cache;
     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
                                     state);
 }

 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 {
     IMPL_CACHE_FLUSH state;

     state.nelem = 0;
     if ((state.seed = OPENSSL_rdtsc()) == 0)
         state.seed = 1;
     store->cache_need_flush = 0;
     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
     store->cache_nelem = state.nelem;
 }

 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, OSSL_PROVIDER *prov,
                                 int nid, const char *prop_query, void **method)
 {
     ALGORITHM *alg;
     QUERY elem, *r;
     int res = 0;

     if (nid <= 0 || store == NULL || prop_query == NULL)
         return 0;

     if (!ossl_property_read_lock(store))
         return 0;
     alg = ossl_method_store_retrieve(store, nid);
     if (alg == NULL)
         goto err;

     elem.query = prop_query;
     elem.provider = prov;
     r = lh_QUERY_retrieve(alg->cache, &elem);
     if (r == NULL)
         goto err;
     if (ossl_method_up_ref(&r->method)) {
         *method = r->method.method;
         res = 1;
     }
 err:
     ossl_property_unlock(store);
     return res;
 }

 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, OSSL_PROVIDER *prov,
                                 int nid, const char *prop_query, void *method,
                                 int (*method_up_ref)(void *),
                                 void (*method_destruct)(void *))
 {
     QUERY elem, *old, *p = NULL;
     ALGORITHM *alg;
     size_t len;
     int res = 1;

     if (nid <= 0 || store == NULL || prop_query == NULL)
         return 0;

     if (!ossl_assert(prov != NULL))
         return 0;

     if (!ossl_property_write_lock(store))
         return 0;
     if (store->cache_need_flush)
         ossl_method_cache_flush_some(store);
     alg = ossl_method_store_retrieve(store, nid);
     if (alg == NULL)
         goto err;

     if (method == NULL) {
         elem.query = prop_query;
         elem.provider = prov;
         if ((old = lh_QUERY_delete(alg->cache, &elem)) != NULL) {
             impl_cache_free(old);
             store->cache_nelem--;
         }
         goto end;
     }
     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
     if (p != NULL) {
         p->query = p->body;
         p->provider = prov;
         p->method.method = method;
         p->method.up_ref = method_up_ref;
         p->method.free = method_destruct;
         if (!ossl_method_up_ref(&p->method))
             goto err;
         memcpy((char *)p->query, prop_query, len + 1);
         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
             impl_cache_free(old);
             goto end;
         }
         if (!lh_QUERY_error(alg->cache)) {
             if (++store->cache_nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
                 store->cache_need_flush = 1;
             goto end;
         }
         ossl_method_free(&p->method);
     }
 err:
     res = 0;
     OPENSSL_free(p);
 end:
     ossl_property_unlock(store);
     return res;
 }
	/*
	* Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
	* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
	*
	* Licensed under the Apache License 2.0 (the "License"). You may not use
	* this file except in compliance with the License. You can obtain a copy
	* in the file LICENSE in the source distribution or at
	* https://www.openssl.org/source/license.html
	*/

	#include <string.h>
	#include <stdio.h>
	#include <stdarg.h>
	#include <openssl/crypto.h>
	#include "internal/core.h"
	#include "internal/property.h"
	#include "internal/provider.h"
	#include "crypto/ctype.h"
	#include <openssl/lhash.h>
	#include <openssl/rand.h>
	#include "internal/thread_once.h"
	#include "crypto/lhash.h"
	#include "crypto/sparse_array.h"
	#include "property_local.h"
	#include "crypto/context.h"

	/*
	* The number of elements in the query cache before we initiate a flush.
	* If reducing this, also ensure the stochastic test in test/property_test.c
	* isn't likely to fail.
	*/
	#define IMPL_CACHE_FLUSH_THRESHOLD 500

	typedef struct {
	void *method;
	int (up_ref)(void );
	void (free)(void );
	} METHOD;

	typedef struct {
	const OSSL_PROVIDER *provider;
	OSSL_PROPERTY_LIST *properties;
	METHOD method;
	} IMPLEMENTATION;

	DEFINE_STACK_OF(IMPLEMENTATION)

	typedef struct {
	const OSSL_PROVIDER *provider;
	const char *query;
	METHOD method;
	char body[1];
	} QUERY;

	DEFINE_LHASH_OF(QUERY);

	typedef struct {
	int nid;
	STACK_OF(IMPLEMENTATION) *impls;
	LHASH_OF(QUERY) *cache;
	} ALGORITHM;

	struct ossl_method_store_st {
	OSSL_LIB_CTX *ctx;
	SPARSE_ARRAY_OF(ALGORITHM) *algs;
	CRYPTO_RWLOCK *lock;

	/* query cache specific values */

	/* Count of the query cache entries for all algs */
	size_t cache_nelem;

	/* Flag: 1 if query cache entries for all algs need flushing */
	int cache_need_flush;
	};

	typedef struct {
	LHASH_OF(QUERY) *cache;
	size_t nelem;
	uint32_t seed;
	} IMPL_CACHE_FLUSH;

	DEFINE_SPARSE_ARRAY_OF(ALGORITHM);

	typedef struct ossl_global_properties_st {
	OSSL_PROPERTY_LIST *list;
	#ifndef FIPS_MODULE
	unsigned int no_mirrored : 1;
	#endif
	} OSSL_GLOBAL_PROPERTIES;

	static void ossl_method_cache_flush_alg(OSSL_METHOD_STORE *store,
	ALGORITHM *alg);
	static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);

	/* Global properties are stored per library context */
	void ossl_ctx_global_properties_free(void *vglobp)
	{
	OSSL_GLOBAL_PROPERTIES *globp = vglobp;

	if (globp != NULL) {
	ossl_property_free(globp->list);
	OPENSSL_free(globp);
	}
	}

	void ossl_ctx_global_properties_new(OSSL_LIB_CTX ctx)
	{
	return OPENSSL_zalloc(sizeof(OSSL_GLOBAL_PROPERTIES));
	}

	OSSL_PROPERTY_LIST *ossl_ctx_global_properties(OSSL_LIB_CTX libctx,
	int loadconfig)
	{
	OSSL_GLOBAL_PROPERTIES *globp;

	#ifndef FIPS_MODULE
	if (loadconfig && !OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
	return NULL;
	#endif
	globp = ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

	return globp != NULL ? &globp->list : NULL;
	}

	#ifndef FIPS_MODULE
	int ossl_global_properties_no_mirrored(OSSL_LIB_CTX *libctx)
	{
	OSSL_GLOBAL_PROPERTIES *globp
	= ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

	return globp != NULL && globp->no_mirrored ? 1 : 0;
	}

	void ossl_global_properties_stop_mirroring(OSSL_LIB_CTX *libctx)
	{
	OSSL_GLOBAL_PROPERTIES *globp
	= ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES);

	if (globp != NULL)
	globp->no_mirrored = 1;
	}
	#endif

	static int ossl_method_up_ref(METHOD *method)
	{
	return (*method->up_ref)(method->method);
	}

	static void ossl_method_free(METHOD *method)
	{
	(*method->free)(method->method);
	}

	static __owur int ossl_property_read_lock(OSSL_METHOD_STORE *p)
	{
	return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
	}

	static __owur int ossl_property_write_lock(OSSL_METHOD_STORE *p)
	{
	return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
	}

	static int ossl_property_unlock(OSSL_METHOD_STORE *p)
	{
	return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
	}

	static unsigned long query_hash(const QUERY *a)
	{
	return OPENSSL_LH_strhash(a->query);
	}

	static int query_cmp(const QUERY a, const QUERY b)
	{
	int res = strcmp(a->query, b->query);

	if (res == 0 && a->provider != NULL && b->provider != NULL)
	res = b->provider > a->provider ? 1
	: b->provider < a->provider ? -1
	: 0;
	return res;
	}

	static void impl_free(IMPLEMENTATION *impl)
	{
	if (impl != NULL) {
	ossl_method_free(&impl->method);
	OPENSSL_free(impl);
	}
	}

	static void impl_cache_free(QUERY *elem)
	{
	if (elem != NULL) {
	ossl_method_free(&elem->method);
	OPENSSL_free(elem);
	}
	}

	static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
	{
	lh_QUERY_doall(alg->cache, &impl_cache_free);
	lh_QUERY_flush(alg->cache);
	}

	static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM a, void arg)
	{
	OSSL_METHOD_STORE *store = arg;

	if (a != NULL) {
	sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
	lh_QUERY_doall(a->cache, &impl_cache_free);
	lh_QUERY_free(a->cache);
	OPENSSL_free(a);
	}
	if (store != NULL)
	ossl_sa_ALGORITHM_set(store->algs, idx, NULL);
	}

	/*
	* The OSSL_LIB_CTX param here allows access to underlying property data needed
	* for computation
	*/
	OSSL_METHOD_STORE ossl_method_store_new(OSSL_LIB_CTX ctx)
	{
	OSSL_METHOD_STORE *res;

	res = OPENSSL_zalloc(sizeof(*res));
	if (res != NULL) {
	res->ctx = ctx;
	if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
	OPENSSL_free(res);
	return NULL;
	}
	if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
	ossl_sa_ALGORITHM_free(res->algs);
	OPENSSL_free(res);
	return NULL;
	}
	}
	return res;
	}

	void ossl_method_store_free(OSSL_METHOD_STORE *store)
	{
	if (store != NULL) {
	ossl_sa_ALGORITHM_doall_arg(store->algs, &alg_cleanup, store);
	ossl_sa_ALGORITHM_free(store->algs);
	CRYPTO_THREAD_lock_free(store->lock);
	OPENSSL_free(store);
	}
	}

	static ALGORITHM ossl_method_store_retrieve(OSSL_METHOD_STORE store, int nid)
	{
	return ossl_sa_ALGORITHM_get(store->algs, nid);
	}

	static int ossl_method_store_insert(OSSL_METHOD_STORE store, ALGORITHM alg)
	{
	return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
	}

	int ossl_method_store_add(OSSL_METHOD_STORE store, const OSSL_PROVIDER prov,
	int nid, const char properties, void method,
	int (method_up_ref)(void ),
	void (method_destruct)(void ))
	{
	ALGORITHM *alg = NULL;
	IMPLEMENTATION *impl;
	int ret = 0;
	int i;

	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
	return 0;
	if (properties == NULL)
	properties = "";

	if (!ossl_assert(prov != NULL))
	return 0;

	/* Create new entry */
	impl = OPENSSL_malloc(sizeof(*impl));
	if (impl == NULL)
	return 0;
	impl->method.method = method;
	impl->method.up_ref = method_up_ref;
	impl->method.free = method_destruct;
	if (!ossl_method_up_ref(&impl->method)) {
	OPENSSL_free(impl);
	return 0;
	}
	impl->provider = prov;

	/* Insert into the hash table if required */
	if (!ossl_property_write_lock(store)) {
	OPENSSL_free(impl);
	return 0;
	}
	ossl_method_cache_flush(store, nid);
	if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
	impl->properties = ossl_parse_property(store->ctx, properties);
	if (impl->properties == NULL)
	goto err;
	ossl_prop_defn_set(store->ctx, properties, impl->properties);
	}

	alg = ossl_method_store_retrieve(store, nid);
	if (alg == NULL) {
	if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
	\|\| (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
	\|\| (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
	goto err;
	alg->nid = nid;
	if (!ossl_method_store_insert(store, alg))
	goto err;
	}

	/* Push onto stack if there isn't one there already */
	for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
	const IMPLEMENTATION *tmpimpl = sk_IMPLEMENTATION_value(alg->impls, i);

	if (tmpimpl->provider == impl->provider
	&& tmpimpl->properties == impl->properties)
	break;
	}
	if (i == sk_IMPLEMENTATION_num(alg->impls)
	&& sk_IMPLEMENTATION_push(alg->impls, impl))
	ret = 1;
	ossl_property_unlock(store);
	if (ret == 0)
	impl_free(impl);
	return ret;

	err:
	ossl_property_unlock(store);
	alg_cleanup(0, alg, NULL);
	impl_free(impl);
	return 0;
	}

	int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
	const void *method)
	{
	ALGORITHM *alg = NULL;
	int i;

	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
	return 0;

	if (!ossl_property_write_lock(store))
	return 0;
	ossl_method_cache_flush(store, nid);
	alg = ossl_method_store_retrieve(store, nid);
	if (alg == NULL) {
	ossl_property_unlock(store);
	return 0;
	}

	/*
	* A sorting find then a delete could be faster but these stacks should be
	* relatively small, so we avoid the overhead. Sorting could also surprise
	* users when result orderings change (even though they are not guaranteed).
	*/
	for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
	IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

	if (impl->method.method == method) {
	impl_free(impl);
	(void)sk_IMPLEMENTATION_delete(alg->impls, i);
	ossl_property_unlock(store);
	return 1;
	}
	}
	ossl_property_unlock(store);
	return 0;
	}

	struct alg_cleanup_by_provider_data_st {
	OSSL_METHOD_STORE *store;
	const OSSL_PROVIDER *prov;
	};

	static void
	alg_cleanup_by_provider(ossl_uintmax_t idx, ALGORITHM alg, void arg)
	{
	struct alg_cleanup_by_provider_data_st *data = arg;
	int i, count;

	/*
	* We walk the stack backwards, to avoid having to deal with stack shifts
	* caused by deletion
	*/
	for (count = 0, i = sk_IMPLEMENTATION_num(alg->impls); i-- > 0;) {
	IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

	if (impl->provider == data->prov) {
	impl_free(impl);
	(void)sk_IMPLEMENTATION_delete(alg->impls, i);
	count++;
	}
	}

	/*
	* If we removed any implementation, we also clear the whole associated
	* cache, 'cause that's the sensible thing to do.
	* There's no point flushing the cache entries where we didn't remove
	* any implementation, though.
	*/
	if (count > 0)
	ossl_method_cache_flush_alg(data->store, alg);
	}

	int ossl_method_store_remove_all_provided(OSSL_METHOD_STORE *store,
	const OSSL_PROVIDER *prov)
	{
	struct alg_cleanup_by_provider_data_st data;

	if (!ossl_property_write_lock(store))
	return 0;
	data.prov = prov;
	data.store = store;
	ossl_sa_ALGORITHM_doall_arg(store->algs, &alg_cleanup_by_provider, &data);
	ossl_property_unlock(store);
	return 1;
	}

	static void alg_do_one(ALGORITHM alg, IMPLEMENTATION impl,
	void (fn)(int id, void method, void *fnarg),
	void *fnarg)
	{
	fn(alg->nid, impl->method.method, fnarg);
	}

	struct alg_do_each_data_st {
	void (fn)(int id, void method, void *fnarg);
	void *fnarg;
	};

	static void alg_do_each(ossl_uintmax_t idx, ALGORITHM alg, void arg)
	{
	struct alg_do_each_data_st *data = arg;
	int i, end = sk_IMPLEMENTATION_num(alg->impls);

	for (i = 0; i < end; i++) {
	IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);

	alg_do_one(alg, impl, data->fn, data->fnarg);
	}
	}

	void ossl_method_store_do_all(OSSL_METHOD_STORE *store,
	void (fn)(int id, void method, void *fnarg),
	void *fnarg)
	{
	struct alg_do_each_data_st data;

	data.fn = fn;
	data.fnarg = fnarg;
	if (store != NULL)
	ossl_sa_ALGORITHM_doall_arg(store->algs, alg_do_each, &data);
	}

	int ossl_method_store_fetch(OSSL_METHOD_STORE *store,
	int nid, const char *prop_query,
	const OSSL_PROVIDER prov_rw, void method)
	{
	OSSL_PROPERTY_LIST **plp;
	ALGORITHM *alg;
	IMPLEMENTATION impl, best_impl = NULL;
	OSSL_PROPERTY_LIST pq = NULL, p2 = NULL;
	const OSSL_PROVIDER prov = prov_rw != NULL ? prov_rw : NULL;
	int ret = 0;
	int j, best = -1, score, optional;

	#ifndef FIPS_MODULE
	if (!OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
	return 0;
	#endif

	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
	return 0;

	/* This only needs to be a read lock, because the query won't create anything */
	if (!ossl_property_read_lock(store))
	return 0;
	alg = ossl_method_store_retrieve(store, nid);
	if (alg == NULL) {
	ossl_property_unlock(store);
	return 0;
	}

	if (prop_query != NULL)
	p2 = pq = ossl_parse_query(store->ctx, prop_query, 0);
	plp = ossl_ctx_global_properties(store->ctx, 0);
	if (plp != NULL && *plp != NULL) {
	if (pq == NULL) {
	pq = *plp;
	} else {
	p2 = ossl_property_merge(pq, *plp);
	ossl_property_free(pq);
	if (p2 == NULL)
	goto fin;
	pq = p2;
	}
	}

	if (pq == NULL) {
	for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
	if ((impl = sk_IMPLEMENTATION_value(alg->impls, j)) != NULL
	&& (prov == NULL \|\| impl->provider == prov)) {
	best_impl = impl;
	ret = 1;
	break;
	}
	}
	goto fin;
	}
	optional = ossl_property_has_optional(pq);
	for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
	if ((impl = sk_IMPLEMENTATION_value(alg->impls, j)) != NULL
	&& (prov == NULL \|\| impl->provider == prov)) {
	score = ossl_property_match_count(pq, impl->properties);
	if (score > best) {
	best_impl = impl;
	best = score;
	ret = 1;
	if (!optional)
	goto fin;
	}
	}
	}
	fin:
	if (ret && ossl_method_up_ref(&best_impl->method)) {
	*method = best_impl->method.method;
	if (prov_rw != NULL)
	*prov_rw = best_impl->provider;
	} else {
	ret = 0;
	}
	ossl_property_unlock(store);
	ossl_property_free(p2);
	return ret;
	}

	static void ossl_method_cache_flush_alg(OSSL_METHOD_STORE *store,
	ALGORITHM *alg)
	{
	store->cache_nelem -= lh_QUERY_num_items(alg->cache);
	impl_cache_flush_alg(0, alg);
	}

	static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
	{
	ALGORITHM *alg = ossl_method_store_retrieve(store, nid);

	if (alg != NULL)
	ossl_method_cache_flush_alg(store, alg);
	}

	int ossl_method_store_cache_flush_all(OSSL_METHOD_STORE *store)
	{
	if (!ossl_property_write_lock(store))
	return 0;
	ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
	store->cache_nelem = 0;
	ossl_property_unlock(store);
	return 1;
	}

	IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);

	/*
	* Flush an element from the query cache (perhaps).
	*
	* In order to avoid taking a write lock or using atomic operations
	* to keep accurate least recently used (LRU) or least frequently used
	* (LFU) information, the procedure used here is to stochastically
	* flush approximately half the cache.
	*
	* This procedure isn't ideal, LRU or LFU would be better. However,
	* in normal operation, reaching a full cache would be unexpected.
	* It means that no steady state of algorithm queries has been reached.
	* That is, it is most likely an attack of some form. A suboptimal clearance
	* strategy that doesn't degrade performance of the normal case is
	* preferable to a more refined approach that imposes a performance
	* impact.
	*/
	static void impl_cache_flush_cache(QUERY c, IMPL_CACHE_FLUSH state)
	{
	uint32_t n;

	/*
	* Implement the 32 bit xorshift as suggested by George Marsaglia in:
	* https://doi.org/10.18637/jss.v008.i14
	*
	* This is a very fast PRNG so there is no need to extract bits one at a
	* time and use the entire value each time.
	*/
	n = state->seed;
	n ^= n << 13;
	n ^= n >> 17;
	n ^= n << 5;
	state->seed = n;

	if ((n & 1) != 0)
	impl_cache_free(lh_QUERY_delete(state->cache, c));
	else
	state->nelem++;
	}

	static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
	void *v)
	{
	IMPL_CACHE_FLUSH state = (IMPL_CACHE_FLUSH )v;

	state->cache = alg->cache;
	lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
	state);
	}

	static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
	{
	IMPL_CACHE_FLUSH state;

	state.nelem = 0;
	if ((state.seed = OPENSSL_rdtsc()) == 0)
	state.seed = 1;
	store->cache_need_flush = 0;
	ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
	store->cache_nelem = state.nelem;
	}

	int ossl_method_store_cache_get(OSSL_METHOD_STORE store, OSSL_PROVIDER prov,
	int nid, const char prop_query, void *method)
	{
	ALGORITHM *alg;
	QUERY elem, *r;
	int res = 0;

	if (nid <= 0 \|\| store == NULL \|\| prop_query == NULL)
	return 0;

	if (!ossl_property_read_lock(store))
	return 0;
	alg = ossl_method_store_retrieve(store, nid);
	if (alg == NULL)
	goto err;

	elem.query = prop_query;
	elem.provider = prov;
	r = lh_QUERY_retrieve(alg->cache, &elem);
	if (r == NULL)
	goto err;
	if (ossl_method_up_ref(&r->method)) {
	*method = r->method.method;
	res = 1;
	}
	err:
	ossl_property_unlock(store);
	return res;
	}

	int ossl_method_store_cache_set(OSSL_METHOD_STORE store, OSSL_PROVIDER prov,
	int nid, const char prop_query, void method,
	int (method_up_ref)(void ),
	void (method_destruct)(void ))
	{
	QUERY elem, old, p = NULL;
	ALGORITHM *alg;
	size_t len;
	int res = 1;

	if (nid <= 0 \|\| store == NULL \|\| prop_query == NULL)
	return 0;

	if (!ossl_assert(prov != NULL))
	return 0;

	if (!ossl_property_write_lock(store))
	return 0;
	if (store->cache_need_flush)
	ossl_method_cache_flush_some(store);
	alg = ossl_method_store_retrieve(store, nid);
	if (alg == NULL)
	goto err;

	if (method == NULL) {
	elem.query = prop_query;
	elem.provider = prov;
	if ((old = lh_QUERY_delete(alg->cache, &elem)) != NULL) {
	impl_cache_free(old);
	store->cache_nelem--;
	}
	goto end;
	}
	p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
	if (p != NULL) {
	p->query = p->body;
	p->provider = prov;
	p->method.method = method;
	p->method.up_ref = method_up_ref;
	p->method.free = method_destruct;
	if (!ossl_method_up_ref(&p->method))
	goto err;
	memcpy((char *)p->query, prop_query, len + 1);
	if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
	impl_cache_free(old);
	goto end;
	}
	if (!lh_QUERY_error(alg->cache)) {
	if (++store->cache_nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
	store->cache_need_flush = 1;
	goto end;
	}
	ossl_method_free(&p->method);
	}
	err:
	res = 0;
	OPENSSL_free(p);
	end:
	ossl_property_unlock(store);
	return res;
	}