property.c
/*
* Copyright 2019-2020 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 "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"
/*
* 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 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;
size_t nelem;
SPARSE_ARRAY_OF(ALGORITHM) *algs;
int need_flush;
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);
/* Global properties are stored per library context */
static void ossl_ctx_global_properties_free(void *vstore)
{
OSSL_PROPERTY_LIST **plp = vstore;
if (plp != NULL) {
ossl_property_free(*plp);
OPENSSL_free(plp);
}
}
static void *ossl_ctx_global_properties_new(OSSL_LIB_CTX *ctx)
{
return OPENSSL_zalloc(sizeof(OSSL_PROPERTY_LIST **));
}
static const OSSL_LIB_CTX_METHOD ossl_ctx_global_properties_method = {
ossl_ctx_global_properties_new,
ossl_ctx_global_properties_free,
};
OSSL_PROPERTY_LIST **ossl_ctx_global_properties(OSSL_LIB_CTX *libctx,
int loadconfig)
{
#ifndef FIPS_MODULE
if (loadconfig && !OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL))
return NULL;
#endif
return ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_GLOBAL_PROPERTIES,
&ossl_ctx_global_properties_method);
}
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);
}
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 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) {
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 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 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(store->algs, &alg_cleanup);
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 = "";
/* 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.
*
* 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 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);
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 == method) {
impl_free(impl);
(void)sk_IMPLEMENTATION_delete(alg->impls, i);
ossl_property_unlock(store);
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)
{
OSSL_PROPERTY_LIST **plp;
ALGORITHM *alg;
IMPLEMENTATION *impl;
OSSL_PROPERTY_LIST *pq = NULL, *p2 = NULL;
METHOD *best_method = NULL;
int ret = 0;
int j, best = -1, score, optional;
#ifndef FIPS_MODULE
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)
p2 = pq = ossl_parse_query(store->ctx, prop_query);
plp = ossl_ctx_global_properties(store->ctx, 1);
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) {
if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
best_method = &impl->method;
ret = 1;
}
goto fin;
}
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) {
best_method = &impl->method;
best = score;
ret = 1;
if (!optional)
goto fin;
}
}
fin:
if (ret && ossl_method_up_ref(best_method))
*method = best_method->method;
else
ret = 0;
ossl_property_unlock(store);
ossl_property_free(p2);
return ret;
}
static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg, void *arg)
{
SPARSE_ARRAY_OF(ALGORITHM) *algs = arg;
lh_QUERY_doall(alg->cache, &impl_cache_free);
if (algs != NULL) {
sk_IMPLEMENTATION_pop_free(alg->impls, &impl_free);
lh_QUERY_free(alg->cache);
OPENSSL_free(alg);
ossl_sa_ALGORITHM_set(algs, idx, NULL);
} else {
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, NULL);
}
}
void ossl_method_store_flush_cache(OSSL_METHOD_STORE *store, int all)
{
void *arg = (all != 0 ? store->algs : NULL);
ossl_property_write_lock(store);
ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_alg, arg);
store->nelem = 0;
ossl_property_unlock(store);
}
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->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;
int res = 0;
if (nid <= 0 || store == NULL)
return 0;
ossl_property_read_lock(store);
alg = ossl_method_store_retrieve(store, nid);
if (alg == NULL)
goto err;
elem.query = prop_query != NULL ? prop_query : "";
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, 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)
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)
goto err;
if (method == NULL) {
elem.query = prop_query;
if ((old = lh_QUERY_delete(alg->cache, &elem)) != NULL) {
impl_cache_free(old);
store->nelem--;
}
goto end;
}
p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
if (p != NULL) {
p->query = p->body;
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->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
store->need_flush = 1;
goto end;
}
ossl_method_free(&p->method);
}
err:
res = 0;
OPENSSL_free(p);
end:
ossl_property_unlock(store);
return res;
}
