xref: /openssl/crypto/core_fetch.c (revision e1eafe8c)
1 /*
2  * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #include <stddef.h>
11 
12 #include <openssl/core.h>
13 #include "internal/cryptlib.h"
14 #include "internal/core.h"
15 #include "internal/property.h"
16 #include "internal/provider.h"
17 
18 struct construct_data_st {
19     OSSL_LIB_CTX *libctx;
20     OSSL_METHOD_STORE *store;
21     int operation_id;
22     int force_store;
23     OSSL_METHOD_CONSTRUCT_METHOD *mcm;
24     void *mcm_data;
25 };
26 
is_temporary_method_store(int no_store,void * cbdata)27 static int is_temporary_method_store(int no_store, void *cbdata)
28 {
29     struct construct_data_st *data = cbdata;
30 
31     return no_store && !data->force_store;
32 }
33 
ossl_method_construct_reserve_store(int no_store,void * cbdata)34 static int ossl_method_construct_reserve_store(int no_store, void *cbdata)
35 {
36     struct construct_data_st *data = cbdata;
37 
38     if (is_temporary_method_store(no_store, data) && data->store == NULL) {
39         /*
40          * If we have been told not to store the method "permanently", we
41          * ask for a temporary store, and store the method there.
42          * The owner of |data->mcm| is completely responsible for managing
43          * that temporary store.
44          */
45         if ((data->store = data->mcm->get_tmp_store(data->mcm_data)) == NULL)
46             return 0;
47     }
48 
49     return data->mcm->lock_store(data->store, data->mcm_data);
50 }
51 
ossl_method_construct_unreserve_store(void * cbdata)52 static int ossl_method_construct_unreserve_store(void *cbdata)
53 {
54     struct construct_data_st *data = cbdata;
55 
56     return data->mcm->unlock_store(data->store, data->mcm_data);
57 }
58 
ossl_method_construct_precondition(OSSL_PROVIDER * provider,int operation_id,int no_store,void * cbdata,int * result)59 static int ossl_method_construct_precondition(OSSL_PROVIDER *provider,
60                                               int operation_id, int no_store,
61                                               void *cbdata, int *result)
62 {
63     if (!ossl_assert(result != NULL)) {
64         ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
65         return 0;
66     }
67 
68     /* Assume that no bits are set */
69     *result = 0;
70 
71     /* No flag bits for temporary stores */
72     if (!is_temporary_method_store(no_store, cbdata)
73         && !ossl_provider_test_operation_bit(provider, operation_id, result))
74         return 0;
75 
76     /*
77      * The result we get tells if methods have already been constructed.
78      * However, we want to tell whether construction should happen (true)
79      * or not (false), which is the opposite of what we got.
80      */
81     *result = !*result;
82 
83     return 1;
84 }
85 
ossl_method_construct_postcondition(OSSL_PROVIDER * provider,int operation_id,int no_store,void * cbdata,int * result)86 static int ossl_method_construct_postcondition(OSSL_PROVIDER *provider,
87                                                int operation_id, int no_store,
88                                                void *cbdata, int *result)
89 {
90     if (!ossl_assert(result != NULL)) {
91         ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
92         return 0;
93     }
94 
95     *result = 1;
96 
97     /* No flag bits for temporary stores */
98     return is_temporary_method_store(no_store, cbdata)
99         || ossl_provider_set_operation_bit(provider, operation_id);
100 }
101 
ossl_method_construct_this(OSSL_PROVIDER * provider,const OSSL_ALGORITHM * algo,int no_store,void * cbdata)102 static void ossl_method_construct_this(OSSL_PROVIDER *provider,
103                                        const OSSL_ALGORITHM *algo,
104                                        int no_store, void *cbdata)
105 {
106     struct construct_data_st *data = cbdata;
107     void *method = NULL;
108 
109     if ((method = data->mcm->construct(algo, provider, data->mcm_data))
110         == NULL)
111         return;
112 
113     /*
114      * Note regarding putting the method in stores:
115      *
116      * we don't need to care if it actually got in or not here.
117      * If it didn't get in, it will simply not be available when
118      * ossl_method_construct() tries to get it from the store.
119      *
120      * It is *expected* that the put function increments the refcnt
121      * of the passed method.
122      */
123     data->mcm->put(data->store, method, provider, algo->algorithm_names,
124                    algo->property_definition, data->mcm_data);
125 
126     /* refcnt-- because we're dropping the reference */
127     data->mcm->destruct(method, data->mcm_data);
128 }
129 
ossl_method_construct(OSSL_LIB_CTX * libctx,int operation_id,OSSL_PROVIDER ** provider_rw,int force_store,OSSL_METHOD_CONSTRUCT_METHOD * mcm,void * mcm_data)130 void *ossl_method_construct(OSSL_LIB_CTX *libctx, int operation_id,
131                             OSSL_PROVIDER **provider_rw, int force_store,
132                             OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data)
133 {
134     void *method = NULL;
135     OSSL_PROVIDER *provider = provider_rw != NULL ? *provider_rw : NULL;
136     struct construct_data_st cbdata;
137 
138     /*
139      * We might be tempted to try to look into the method store without
140      * constructing to see if we can find our method there already.
141      * Unfortunately that does not work well if the query contains
142      * optional properties as newly loaded providers can match them better.
143      * We trust that ossl_method_construct_precondition() and
144      * ossl_method_construct_postcondition() make sure that the
145      * ossl_algorithm_do_all() does very little when methods from
146      * a provider have already been constructed.
147      */
148 
149     cbdata.store = NULL;
150     cbdata.force_store = force_store;
151     cbdata.mcm = mcm;
152     cbdata.mcm_data = mcm_data;
153     ossl_algorithm_do_all(libctx, operation_id, provider,
154                           ossl_method_construct_precondition,
155                           ossl_method_construct_reserve_store,
156                           ossl_method_construct_this,
157                           ossl_method_construct_unreserve_store,
158                           ossl_method_construct_postcondition,
159                           &cbdata);
160 
161     /* If there is a temporary store, try there first */
162     if (cbdata.store != NULL)
163         method = mcm->get(cbdata.store, (const OSSL_PROVIDER **)provider_rw,
164                           mcm_data);
165 
166     /* If no method was found yet, try the global store */
167     if (method == NULL)
168         method = mcm->get(NULL, (const OSSL_PROVIDER **)provider_rw, mcm_data);
169 
170     return method;
171 }
172