[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 {
    OSSL_METHOD_STORE *store;
    LHASH_OF(QUERY) *cache;
    size_t nelem;
} 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, 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;
    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;

    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;
    }
    for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
        impl = sk_IMPLEMENTATION_value(alg->impls, j);

        if (ossl_property_match(pq, impl->properties)) {
            *method = impl->method;
            ret = 1;
            goto fin;
        }
    }
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 to keep accurate LRU information or
 * using atomic operations to approximate similar, the procedure used here
 * is to stochastically flush approximately half the cache.  Since generating
 * random numbers is relatively expensive, we produce them in blocks and
 * consume them as we go, saving generated bits between generations of flushes.
 *
 * This procedure isn't ideal, LRU would be better.  However, in normal
 * operation, reaching a full cache would be quite unexpected.  It means
 * that no steady state of algorithm queries has been reached.  I.e. 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)
{
    OSSL_METHOD_STORE *store = state->store;
    unsigned int n;

    if (store->nbits == 0) {
        if (!RAND_bytes(store->rand_bits, sizeof(store->rand_bits)))
            return;
        store->nbits = sizeof(store->rand_bits) * 8;
    }
    n = --store->nbits;
    if ((store->rand_bits[n >> 3] & (1 << (n & 7))) != 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;
    state.store = store;
    ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
    store->need_flush = 0;
    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;
        lh_QUERY_delete(alg->cache, &elem);
        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);
        if (old != NULL || !lh_QUERY_error(alg->cache)) {
            store->nelem++;
            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 {
	61	OSSL_METHOD_STORE *store;
	62	LHASH_OF(QUERY) *cache;
	63	size_t nelem;
	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,
	177	int nid, const char *properties,
0a79572a	178	void method, void (method_destruct)(void *))
1bdbdaff P	179	{
	180	ALGORITHM *alg = NULL;
	181	IMPLEMENTATION *impl;
	182	int ret = 0;
	183
0a79572a	184	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	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;
0a79572a RL	193	impl->method = method;
0a79572a RL	194	impl->method_destruct = method_destruct;
1bdbdaff P	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);
1aedc35f MC	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)
1bdbdaff	207	goto err;
1aedc35f	208	ossl_prop_defn_set(store->ctx, properties, impl->properties);
1bdbdaff P	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,
0a79572a	238	const void *method)
1bdbdaff P	239	{
	240	ALGORITHM *alg = NULL;
	241	int i;
	242
0a79572a	243	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	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
0a79572a	262	if (impl->method == method) {
1bdbdaff P	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,
0a79572a	274	const char prop_query, void *method)
1bdbdaff P	275	{
	276	ALGORITHM *alg;
	277	IMPLEMENTATION *impl;
	278	OSSL_PROPERTY_LIST pq = NULL, p2;
	279	int ret = 0;
	280	int j;
	281
0a79572a	282	if (nid <= 0 \|\| method == NULL \|\| store == NULL)
1bdbdaff P	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) {
0a79572a	298	*method = impl->method;
1bdbdaff P	299	ret = 1;
	300	}
	301	goto fin;
	302	}
1aedc35f	303	pq = ossl_parse_query(store->ctx, prop_query);
1bdbdaff P	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	for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
	314	impl = sk_IMPLEMENTATION_value(alg->impls, j);
	315
	316	if (ossl_property_match(pq, impl->properties)) {
0a79572a	317	*method = impl->method;
1bdbdaff P	318	ret = 1;
	319	goto fin;
	320	}
	321	}
	322	fin:
	323	ossl_property_unlock(store);
	324	ossl_property_free(pq);
	325	return ret;
	326	}
	327
	328	int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
	329	const char *prop_query) {
	330	int ret = 0;
	331
	332	if (store == NULL)
	333	return 1;
	334
	335	ossl_property_write_lock(store);
	336	ossl_method_cache_flush_all(store);
	337	if (prop_query == NULL) {
	338	ossl_property_free(store->global_properties);
	339	store->global_properties = NULL;
	340	ossl_property_unlock(store);
	341	return 1;
	342	}
1aedc35f	343	store->global_properties = ossl_parse_query(store->ctx, prop_query);
1bdbdaff P	344	ret = store->global_properties != NULL;
	345	ossl_property_unlock(store);
	346	return ret;
	347	}
	348
8ab53b19	349	static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
1bdbdaff P	350	{
	351	lh_QUERY_doall(alg->cache, &impl_cache_free);
	352	lh_QUERY_flush(alg->cache);
	353	}
	354
	355	static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
	356	{
	357	ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
	358
	359	if (alg != NULL) {
	360	store->nelem -= lh_QUERY_num_items(alg->cache);
	361	impl_cache_flush_alg(0, alg);
	362	}
	363	}
	364
	365	static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
	366	{
	367	ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
	368	store->nelem = 0;
	369	}
	370
	371	IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
	372
	373	/*
	374	* Flush an element from the query cache (perhaps).
	375	*
	376	* In order to avoid taking a write lock to keep accurate LRU information or
	377	* using atomic operations to approximate similar, the procedure used here
	378	* is to stochastically flush approximately half the cache. Since generating
	379	* random numbers is relatively expensive, we produce them in blocks and
	380	* consume them as we go, saving generated bits between generations of flushes.
	381	*
	382	* This procedure isn't ideal, LRU would be better. However, in normal
	383	* operation, reaching a full cache would be quite unexpected. It means
	384	* that no steady state of algorithm queries has been reached. I.e. it is most
	385	* likely an attack of some form. A suboptimal clearance strategy that doesn't
	386	* degrade performance of the normal case is preferable to a more refined
	387	* approach that imposes a performance impact.
	388	*/
	389	static void impl_cache_flush_cache(QUERY c, IMPL_CACHE_FLUSH state)
	390	{
	391	OSSL_METHOD_STORE *store = state->store;
	392	unsigned int n;
	393
	394	if (store->nbits == 0) {
	395	if (!RAND_bytes(store->rand_bits, sizeof(store->rand_bits)))
	396	return;
	397	store->nbits = sizeof(store->rand_bits) * 8;
	398	}
	399	n = --store->nbits;
	400	if ((store->rand_bits[n >> 3] & (1 << (n & 7))) != 0)
	401	OPENSSL_free(lh_QUERY_delete(state->cache, c));
	402	else
	403	state->nelem++;
	404	}
	405
8ab53b19 P	406	static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
8ab53b19 P	407	void *v)
1bdbdaff P	408	{
	409	IMPL_CACHE_FLUSH state = (IMPL_CACHE_FLUSH )v;
	410
	411	state->cache = alg->cache;
	412	lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
	413	state);
	414	}
	415
	416	static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
	417	{
	418	IMPL_CACHE_FLUSH state;
	419
	420	state.nelem = 0;
	421	state.store = store;
	422	ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
	423	store->need_flush = 0;
	424	store->nelem = state.nelem;
	425	}
	426
	427	int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
0a79572a	428	const char prop_query, void *method)
1bdbdaff P	429	{
	430	ALGORITHM *alg;
	431	QUERY elem, *r;
	432
	433	if (nid <= 0 \|\| store == NULL)
	434	return 0;
	435
	436	ossl_property_read_lock(store);
	437	alg = ossl_method_store_retrieve(store, nid);
	438	if (alg == NULL) {
	439	ossl_property_unlock(store);
	440	return 0;
	441	}
	442
1393722a	443	elem.query = prop_query != NULL ? prop_query : "";
1bdbdaff P	444	r = lh_QUERY_retrieve(alg->cache, &elem);
	445	if (r == NULL) {
	446	ossl_property_unlock(store);
	447	return 0;
	448	}
0a79572a	449	*method = r->method;
1bdbdaff P	450	ossl_property_unlock(store);
	451	return 1;
	452	}
	453
	454	int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
0a79572a	455	const char prop_query, void method)
1bdbdaff P	456	{
	457	QUERY elem, old, p = NULL;
	458	ALGORITHM *alg;
	459	size_t len;
	460
	461	if (nid <= 0 \|\| store == NULL)
	462	return 0;
	463	if (prop_query == NULL)
	464	return 1;
	465
	466	ossl_property_write_lock(store);
	467	if (store->need_flush)
	468	ossl_method_cache_flush_some(store);
	469	alg = ossl_method_store_retrieve(store, nid);
	470	if (alg == NULL) {
	471	ossl_property_unlock(store);
	472	return 0;
	473	}
	474
0a79572a	475	if (method == NULL) {
1bdbdaff P	476	elem.query = prop_query;
	477	lh_QUERY_delete(alg->cache, &elem);
	478	ossl_property_unlock(store);
	479	return 1;
	480	}
	481	p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
	482	if (p != NULL) {
	483	p->query = p->body;
0a79572a	484	p->method = method;
1bdbdaff P	485	memcpy((char *)p->query, prop_query, len + 1);
	486	if ((old = lh_QUERY_insert(alg->cache, p)) != NULL)
	487	OPENSSL_free(old);
	488	if (old != NULL \|\| !lh_QUERY_error(alg->cache)) {
	489	store->nelem++;
	490	if (store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
	491	store->need_flush = 1;
	492	ossl_property_unlock(store);
	493	return 1;
	494	}
	495	}
	496	ossl_property_unlock(store);
	497	OPENSSL_free(p);
	498	return 0;
	499	}