[thirdparty/openssl.git] / crypto / property / property.c

/*
 * Copyright 2019 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/property.h"
#include "internal/ctype.h"
#include <openssl/lhash.h>
#include <openssl/rand.h>
#include "internal/thread_once.h"
#include "internal/lhash.h"
#include "internal/sparse_array.h"
#include "property_lcl.h"

/* The number of elements in the query cache before we initiate a flush */
#define IMPL_CACHE_FLUSH_THRESHOLD  500

typedef struct {
    OSSL_PROPERTY_LIST *properties;
    void *method;
    void (*method_destruct)(void *);
} IMPLEMENTATION;

DEFINE_STACK_OF(IMPLEMENTATION)

typedef struct {
    const char *query;
    void *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 {
    OPENSSL_CTX *ctx;
    size_t nelem;
    SPARSE_ARRAY_OF(ALGORITHM) *algs;
    OSSL_PROPERTY_LIST *global_properties;
    int need_flush;
    unsigned int nbits;
    unsigned char rand_bits[(IMPL_CACHE_FLUSH_THRESHOLD + 7) / 8];
    CRYPTO_RWLOCK *lock;
};

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

DEFINE_SPARSE_ARRAY_OF(ALGORITHM);

static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);
static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *c);

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

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

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

static openssl_ctx_run_once_fn do_method_store_init;
int do_method_store_init(OPENSSL_CTX *ctx)
{
    return ossl_property_parse_init(ctx);
}

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

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

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

static void impl_cache_free(QUERY *elem)
{
    OPENSSL_free(elem);
}

static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
{
    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);
    }
}

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

    if (!openssl_ctx_run_once(ctx,
                              OPENSSL_CTX_METHOD_STORE_RUN_ONCE_INDEX,
                              do_method_store_init))
        return NULL;

    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) {
            OPENSSL_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(store->algs, &alg_cleanup);
        ossl_sa_ALGORITHM_free(store->algs);
        ossl_property_free(store->global_properties);
        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,
                          int nid, const char *properties, void *method,
                          int (*method_up_ref)(void *),
                          void (*method_destruct)(void *))
{
    ALGORITHM *alg = NULL;
    IMPLEMENTATION *impl;
    int ret = 0;

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

    /* Create new entry */
    impl = OPENSSL_malloc(sizeof(*impl));
    if (impl == NULL)
        return 0;
    if (method_up_ref != NULL && !method_up_ref(method))
        return 0;
    impl->method = method;
    impl->method_destruct = method_destruct;

    /*
     * Insert into the hash table if required.
     *
     * A write lock is used unconditionally because we wend our way down to the
     * property string code which isn't locking friendly.
     */
    ossl_property_write_lock(store);
    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 (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);
    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;

    ossl_property_write_lock(store);
    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) {
            sk_IMPLEMENTATION_delete(alg->impls, i);
            ossl_property_unlock(store);
            impl_free(impl);
            return 1;
        }
    }
    ossl_property_unlock(store);
    return 0;
}

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

#ifndef FIPS_MODE
    OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL);
#endif

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

    /*
     * This only needs to be a read lock, because queries never create property
     * names or value and thus don't modify any of the property string layer.
     */
    ossl_property_read_lock(store);
    alg = ossl_method_store_retrieve(store, nid);
    if (alg == NULL) {
        ossl_property_unlock(store);
        return 0;
    }

    if (prop_query == NULL) {
        if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
            *method = impl->method;
            ret = 1;
        }
        goto fin;
    }
    pq = ossl_parse_query(store->ctx, prop_query);
    if (pq == NULL)
        goto fin;
    if (store->global_properties != NULL) {
        p2 = ossl_property_merge(pq, store->global_properties);
        if (p2 == NULL)
            goto fin;
        ossl_property_free(pq);
        pq = p2;
    }
    optional = ossl_property_has_optional(pq);
    for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
        impl = sk_IMPLEMENTATION_value(alg->impls, j);
        score = ossl_property_match_count(pq, impl->properties);
        if (score > best) {
            *method = impl->method;
            ret = 1;
            if (!optional)
                goto fin;
            best = score;
        }
    }
fin:
    ossl_property_unlock(store);
    ossl_property_free(pq);
    return ret;
}

int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
                                            const char *prop_query) {
    int ret = 0;

    if (store == NULL)
        return 1;

    ossl_property_write_lock(store);
    ossl_method_cache_flush_all(store);
    if (prop_query == NULL) {
        ossl_property_free(store->global_properties);
        store->global_properties = NULL;
        ossl_property_unlock(store);
        return 1;
    }
    store->global_properties = ossl_parse_query(store->ctx, prop_query);
    ret = store->global_properties != NULL;
    ossl_property_unlock(store);
    return ret;
}

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

    if (alg != NULL) {
        store->nelem -= lh_QUERY_num_items(alg->cache);
        impl_cache_flush_alg(0, alg);
    }
}

static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
{
    ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
    store->nelem = 0;
}

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)
        OPENSSL_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->need_flush = 0;
    ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
    store->nelem = state.nelem;
}

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

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

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

    elem.query = prop_query != NULL ? prop_query : "";
    r = lh_QUERY_retrieve(alg->cache, &elem);
    if (r == NULL) {
        ossl_property_unlock(store);
        return 0;
    }
    *method = r->method;
    ossl_property_unlock(store);
    return 1;
}

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

    if (nid <= 0 || store == NULL)
        return 0;
    if (prop_query == NULL)
        return 1;

    ossl_property_write_lock(store);
    if (store->need_flush)
        ossl_method_cache_flush_some(store);
    alg = ossl_method_store_retrieve(store, nid);
    if (alg == NULL) {
        ossl_property_unlock(store);
        return 0;
    }

    if (method == NULL) {
        elem.query = prop_query;
        if (lh_QUERY_delete(alg->cache, &elem) != NULL)
            store->nelem--;
        ossl_property_unlock(store);
        return 1;
    }
    p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
    if (p != NULL) {
        p->query = p->body;
        p->method = method;
        memcpy((char *)p->query, prop_query, len + 1);
        if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
            OPENSSL_free(old);
            ossl_property_unlock(store);
            return 1;
        }
        if (!lh_QUERY_error(alg->cache)) {
            if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
                store->need_flush = 1;
            ossl_property_unlock(store);
            return 1;
        }
    }
    ossl_property_unlock(store);
    OPENSSL_free(p);
    return 0;
}
Commit	Line	Data
1bdbdaff P	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;
0a79572a RL	29	void *method;
0a79572a RL	30	void (method_destruct)(void );
1bdbdaff P	31	} IMPLEMENTATION;
	32
	33	DEFINE_STACK_OF(IMPLEMENTATION)
	34
	35	typedef struct {
	36	const char *query;
0a79572a	37	void *method;
1bdbdaff P	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 {
1aedc35f	50	OPENSSL_CTX *ctx;
1bdbdaff P	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 {
1bdbdaff P	61	LHASH_OF(QUERY) *cache;
1bdbdaff P	62	size_t nelem;
f06cf3c4	63	uint32_t seed;
1bdbdaff P	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
1aedc35f MC	86	static openssl_ctx_run_once_fn do_method_store_init;
1aedc35f MC	87	int do_method_store_init(OPENSSL_CTX *ctx)
1bdbdaff	88	{
1aedc35f	89	return ossl_property_parse_init(ctx);
1bdbdaff P	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) {
0a79572a RL	105	if (impl->method_destruct)
0a79572a RL	106	impl->method_destruct(impl->method);
1bdbdaff P	107	OPENSSL_free(impl);
	108	}
	109	}
	110
	111	static void impl_cache_free(QUERY *elem)
	112	{
	113	OPENSSL_free(elem);
	114	}
	115
8ab53b19	116	static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
1bdbdaff P	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
1aedc35f MC	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)
1bdbdaff	131	{
909f2e59	132	OSSL_METHOD_STORE *res;
1bdbdaff	133
1aedc35f MC	134	if (!openssl_ctx_run_once(ctx,
	135	OPENSSL_CTX_METHOD_STORE_RUN_ONCE_INDEX,
	136	do_method_store_init))
	137	return NULL;
1bdbdaff	138
909f2e59	139	res = OPENSSL_zalloc(sizeof(*res));
1bdbdaff	140	if (res != NULL) {
1aedc35f	141	res->ctx = ctx;
1bdbdaff P	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,
b1d40ddf RL	177	int nid, const char properties, void method,
	178	int (method_up_ref)(void ),
	179	void (method_destruct)(void ))
1bdbdaff P	180	{
	181	ALGORITHM *alg = NULL;
	182	IMPLEMENTATION *impl;
	183	int ret = 0;
	184
0a79572a	185	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	186	return 0;
	187	if (properties == NULL)
	188	properties = "";
	189
	190	/* Create new entry */
	191	impl = OPENSSL_malloc(sizeof(*impl));
	192	if (impl == NULL)
	193	return 0;
b1d40ddf RL	194	if (method_up_ref != NULL && !method_up_ref(method))
b1d40ddf RL	195	return 0;
0a79572a RL	196	impl->method = method;
0a79572a RL	197	impl->method_destruct = method_destruct;
1bdbdaff P	198
	199	/*
	200	* Insert into the hash table if required.
	201	*
	202	* A write lock is used unconditionally because we wend our way down to the
	203	* property string code which isn't locking friendly.
	204	*/
	205	ossl_property_write_lock(store);
	206	ossl_method_cache_flush(store, nid);
1aedc35f MC	207	if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
	208	impl->properties = ossl_parse_property(store->ctx, properties);
	209	if (impl->properties == NULL)
1bdbdaff	210	goto err;
1aedc35f	211	ossl_prop_defn_set(store->ctx, properties, impl->properties);
1bdbdaff P	212	}
	213
	214	alg = ossl_method_store_retrieve(store, nid);
	215	if (alg == NULL) {
	216	if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
	217	\|\| (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
	218	\|\| (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
	219	goto err;
	220	alg->nid = nid;
	221	if (!ossl_method_store_insert(store, alg))
	222	goto err;
	223	}
	224
	225	/* Push onto stack */
	226	if (sk_IMPLEMENTATION_push(alg->impls, impl))
	227	ret = 1;
	228	ossl_property_unlock(store);
	229	if (ret == 0)
	230	impl_free(impl);
	231	return ret;
	232
	233	err:
	234	ossl_property_unlock(store);
	235	alg_cleanup(0, alg);
	236	impl_free(impl);
	237	return 0;
	238	}
	239
	240	int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
0a79572a	241	const void *method)
1bdbdaff P	242	{
	243	ALGORITHM *alg = NULL;
	244	int i;
	245
0a79572a	246	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	247	return 0;
	248
	249	ossl_property_write_lock(store);
	250	ossl_method_cache_flush(store, nid);
	251	alg = ossl_method_store_retrieve(store, nid);
	252	if (alg == NULL) {
	253	ossl_property_unlock(store);
	254	return 0;
	255	}
	256
	257	/*
	258	* A sorting find then a delete could be faster but these stacks should be
	259	* relatively small, so we avoid the overhead. Sorting could also surprise
	260	* users when result orderings change (even though they are not guaranteed).
	261	*/
	262	for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
	263	IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
	264
0a79572a	265	if (impl->method == method) {
1bdbdaff P	266	sk_IMPLEMENTATION_delete(alg->impls, i);
	267	ossl_property_unlock(store);
	268	impl_free(impl);
	269	return 1;
	270	}
	271	}
	272	ossl_property_unlock(store);
	273	return 0;
	274	}
	275
	276	int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
0a79572a	277	const char prop_query, void *method)
1bdbdaff P	278	{
	279	ALGORITHM *alg;
	280	IMPLEMENTATION *impl;
	281	OSSL_PROPERTY_LIST pq = NULL, p2;
	282	int ret = 0;
da89ac0b	283	int j, best = -1, score, optional;
1bdbdaff	284
29dc6e00 MC	285	#ifndef FIPS_MODE
	286	OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL);
	287	#endif
	288
0a79572a	289	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	290	return 0;
	291
	292	/*
	293	* This only needs to be a read lock, because queries never create property
	294	* names or value and thus don't modify any of the property string layer.
	295	*/
	296	ossl_property_read_lock(store);
	297	alg = ossl_method_store_retrieve(store, nid);
	298	if (alg == NULL) {
	299	ossl_property_unlock(store);
	300	return 0;
	301	}
	302
	303	if (prop_query == NULL) {
	304	if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
0a79572a	305	*method = impl->method;
1bdbdaff P	306	ret = 1;
	307	}
	308	goto fin;
	309	}
1aedc35f	310	pq = ossl_parse_query(store->ctx, prop_query);
1bdbdaff P	311	if (pq == NULL)
	312	goto fin;
	313	if (store->global_properties != NULL) {
	314	p2 = ossl_property_merge(pq, store->global_properties);
	315	if (p2 == NULL)
	316	goto fin;
	317	ossl_property_free(pq);
	318	pq = p2;
	319	}
da89ac0b	320	optional = ossl_property_has_optional(pq);
1bdbdaff P	321	for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
1bdbdaff P	322	impl = sk_IMPLEMENTATION_value(alg->impls, j);
da89ac0b P	323	score = ossl_property_match_count(pq, impl->properties);
da89ac0b P	324	if (score > best) {
0a79572a	325	*method = impl->method;
1bdbdaff	326	ret = 1;
da89ac0b P	327	if (!optional)
	328	goto fin;
	329	best = score;
1bdbdaff P	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	}
1aedc35f	353	store->global_properties = ossl_parse_query(store->ctx, prop_query);
1bdbdaff P	354	ret = store->global_properties != NULL;
	355	ossl_property_unlock(store);
	356	return ret;
	357	}
	358
8ab53b19	359	static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
1bdbdaff P	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	*
f06cf3c4 P	386	* In order to avoid taking a write lock or using atomic operations
	387	* to keep accurate least recently used (LRU) or least frequently used
	388	* (LFU) information, the procedure used here is to stochastically
	389	* flush approximately half the cache.
1bdbdaff	390	*
f06cf3c4 P	391	* This procedure isn't ideal, LRU or LFU would be better. However,
	392	* in normal operation, reaching a full cache would be unexpected.
	393	* It means that no steady state of algorithm queries has been reached.
	394	* That is, it is most likely an attack of some form. A suboptimal clearance
	395	* strategy that doesn't degrade performance of the normal case is
	396	* preferable to a more refined approach that imposes a performance
	397	* impact.
1bdbdaff P	398	*/
	399	static void impl_cache_flush_cache(QUERY c, IMPL_CACHE_FLUSH state)
	400	{
f06cf3c4 P	401	uint32_t n;
	402
	403	/*
	404	* Implement the 32 bit xorshift as suggested by George Marsaglia in:
	405	* https://doi.org/10.18637/jss.v008.i14
	406	*
	407	* This is a very fast PRNG so there is no need to extract bits one at a
	408	* time and use the entire value each time.
	409	*/
	410	n = state->seed;
	411	n ^= n << 13;
	412	n ^= n >> 17;
	413	n ^= n << 5;
	414	state->seed = n;
	415
	416	if ((n & 1) != 0)
1bdbdaff P	417	OPENSSL_free(lh_QUERY_delete(state->cache, c));
	418	else
	419	state->nelem++;
	420	}
	421
8ab53b19 P	422	static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
8ab53b19 P	423	void *v)
1bdbdaff P	424	{
	425	IMPL_CACHE_FLUSH state = (IMPL_CACHE_FLUSH )v;
	426
	427	state->cache = alg->cache;
	428	lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
	429	state);
	430	}
	431
	432	static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
	433	{
	434	IMPL_CACHE_FLUSH state;
	435
	436	state.nelem = 0;
f06cf3c4 P	437	if ((state.seed = OPENSSL_rdtsc()) == 0)
f06cf3c4 P	438	state.seed = 1;
1bdbdaff	439	store->need_flush = 0;
e2e5abe4	440	ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
1bdbdaff P	441	store->nelem = state.nelem;
	442	}
	443
	444	int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
0a79572a	445	const char prop_query, void *method)
1bdbdaff P	446	{
	447	ALGORITHM *alg;
	448	QUERY elem, *r;
	449
	450	if (nid <= 0 \|\| store == NULL)
	451	return 0;
	452
	453	ossl_property_read_lock(store);
	454	alg = ossl_method_store_retrieve(store, nid);
	455	if (alg == NULL) {
	456	ossl_property_unlock(store);
	457	return 0;
	458	}
	459
1393722a	460	elem.query = prop_query != NULL ? prop_query : "";
1bdbdaff P	461	r = lh_QUERY_retrieve(alg->cache, &elem);
	462	if (r == NULL) {
	463	ossl_property_unlock(store);
	464	return 0;
	465	}
0a79572a	466	*method = r->method;
1bdbdaff P	467	ossl_property_unlock(store);
	468	return 1;
	469	}
	470
	471	int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
0a79572a	472	const char prop_query, void method)
1bdbdaff P	473	{
	474	QUERY elem, old, p = NULL;
	475	ALGORITHM *alg;
	476	size_t len;
	477
	478	if (nid <= 0 \|\| store == NULL)
	479	return 0;
	480	if (prop_query == NULL)
	481	return 1;
	482
	483	ossl_property_write_lock(store);
	484	if (store->need_flush)
	485	ossl_method_cache_flush_some(store);
	486	alg = ossl_method_store_retrieve(store, nid);
	487	if (alg == NULL) {
	488	ossl_property_unlock(store);
	489	return 0;
	490	}
	491
0a79572a	492	if (method == NULL) {
1bdbdaff	493	elem.query = prop_query;
f06cf3c4 P	494	if (lh_QUERY_delete(alg->cache, &elem) != NULL)
f06cf3c4 P	495	store->nelem--;
1bdbdaff P	496	ossl_property_unlock(store);
	497	return 1;
	498	}
	499	p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
	500	if (p != NULL) {
	501	p->query = p->body;
0a79572a	502	p->method = method;
1bdbdaff	503	memcpy((char *)p->query, prop_query, len + 1);
f06cf3c4	504	if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
1bdbdaff	505	OPENSSL_free(old);
f06cf3c4 P	506	ossl_property_unlock(store);
	507	return 1;
	508	}
	509	if (!lh_QUERY_error(alg->cache)) {
	510	if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
1bdbdaff P	511	store->need_flush = 1;
	512	ossl_property_unlock(store);
	513	return 1;
	514	}
	515	}
	516	ossl_property_unlock(store);
	517	OPENSSL_free(p);
	518	return 0;
	519	}