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b11ba50fd9
When a fetch is attempted simultaneously from multiple threads then both threads can attempt to construct the method. However only one of those will get added to the global evp method store. The one that "lost" the race to add the method to the global evp method store ended up with the fetch call returning NULL, instead of returning the method that was already available. Fixes #13682 Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org> (Merged from https://github.com/openssl/openssl/pull/13660)
147 lines
4.8 KiB
C
147 lines
4.8 KiB
C
/*
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* Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <stddef.h>
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#include <openssl/core.h>
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#include "internal/cryptlib.h"
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#include "internal/core.h"
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#include "internal/property.h"
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#include "internal/provider.h"
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struct construct_data_st {
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OSSL_LIB_CTX *libctx;
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OSSL_METHOD_STORE *store;
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int operation_id;
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int force_store;
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OSSL_METHOD_CONSTRUCT_METHOD *mcm;
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void *mcm_data;
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};
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static int ossl_method_construct_precondition(OSSL_PROVIDER *provider,
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int operation_id, void *cbdata,
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int *result)
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{
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if (!ossl_assert(result != NULL)) {
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ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
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return 0;
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}
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if (!ossl_provider_test_operation_bit(provider, operation_id, result))
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return 0;
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/*
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* The result we get tells if methods have already been constructed.
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* However, we want to tell whether construction should happen (true)
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* or not (false), which is the opposite of what we got.
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*/
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*result = !*result;
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return 1;
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}
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static int ossl_method_construct_postcondition(OSSL_PROVIDER *provider,
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int operation_id, int no_store,
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void *cbdata, int *result)
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{
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if (!ossl_assert(result != NULL)) {
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ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
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return 0;
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}
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*result = 1;
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return no_store != 0
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|| ossl_provider_set_operation_bit(provider, operation_id);
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}
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static void ossl_method_construct_this(OSSL_PROVIDER *provider,
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const OSSL_ALGORITHM *algo,
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int no_store, void *cbdata)
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{
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struct construct_data_st *data = cbdata;
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void *method = NULL;
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if ((method = data->mcm->construct(algo, provider, data->mcm_data))
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== NULL)
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return;
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/*
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* Note regarding putting the method in stores:
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*
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* we don't need to care if it actually got in or not here.
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* If it didn't get in, it will simply not be available when
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* ossl_method_construct() tries to get it from the store.
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*
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* It is *expected* that the put function increments the refcnt
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* of the passed method.
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*/
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if (data->force_store || !no_store) {
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/*
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* If we haven't been told not to store,
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* add to the global store
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*/
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data->mcm->put(data->libctx, NULL, method, provider,
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data->operation_id, algo->algorithm_names,
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algo->property_definition, data->mcm_data);
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}
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data->mcm->put(data->libctx, data->store, method, provider,
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data->operation_id, algo->algorithm_names,
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algo->property_definition, data->mcm_data);
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/* refcnt-- because we're dropping the reference */
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data->mcm->destruct(method, data->mcm_data);
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}
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void *ossl_method_construct(OSSL_LIB_CTX *libctx, int operation_id,
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int force_store,
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OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data)
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{
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void *method = NULL;
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if ((method = mcm->get(libctx, NULL, mcm_data)) == NULL) {
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struct construct_data_st cbdata;
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/*
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* We have a temporary store to be able to easily search among new
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* items, or items that should find themselves in the global store.
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*/
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if ((cbdata.store = mcm->alloc_tmp_store(libctx)) == NULL)
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goto fin;
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cbdata.libctx = libctx;
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cbdata.operation_id = operation_id;
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cbdata.force_store = force_store;
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cbdata.mcm = mcm;
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cbdata.mcm_data = mcm_data;
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ossl_algorithm_do_all(libctx, operation_id, NULL,
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ossl_method_construct_precondition,
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ossl_method_construct_this,
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ossl_method_construct_postcondition,
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&cbdata);
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method = mcm->get(libctx, cbdata.store, mcm_data);
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if (method == NULL) {
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/*
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* If we get here then we did not construct the method that we
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* attempted to construct. It's possible that another thread got
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* there first and so we skipped construction (pre-condition
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* failed). We check the global store again to see if it has
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* appeared by now.
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*/
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method = mcm->get(libctx, NULL, mcm_data);
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}
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mcm->dealloc_tmp_store(cbdata.store);
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}
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fin:
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return method;
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}
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