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 /*
11  * This implemments a dummy key manager for legacy KDFs that still support the
12  * old way of performing a KDF via EVP_PKEY_derive(). New KDFs should not be
13  * implemented this way. In reality there is no key data for such KDFs, so this
14  * key manager does very little.
15  */
16 
17 #include <openssl/core_dispatch.h>
18 #include <openssl/core_names.h>
19 #include <openssl/err.h>
20 #include "prov/implementations.h"
21 #include "prov/providercommon.h"
22 #include "prov/provider_ctx.h"
23 #include "prov/kdfexchange.h"
24 
25 static OSSL_FUNC_keymgmt_new_fn kdf_newdata;
26 static OSSL_FUNC_keymgmt_free_fn kdf_freedata;
27 static OSSL_FUNC_keymgmt_has_fn kdf_has;
28 
29 KDF_DATA *ossl_kdf_data_new(void *provctx)
30 {
31     KDF_DATA *kdfdata;
32 
33     if (!ossl_prov_is_running())
34         return NULL;
35 
36     kdfdata = OPENSSL_zalloc(sizeof(*kdfdata));
37     if (kdfdata == NULL)
38         return NULL;
39 
40     kdfdata->lock = CRYPTO_THREAD_lock_new();
41     if (kdfdata->lock == NULL) {
42         OPENSSL_free(kdfdata);
43         return NULL;
44     }
45     kdfdata->libctx = PROV_LIBCTX_OF(provctx);
46     kdfdata->refcnt = 1;
47 
48     return kdfdata;
49 }
50 
51 void ossl_kdf_data_free(KDF_DATA *kdfdata)
52 {
53     int ref = 0;
54 
55     if (kdfdata == NULL)
56         return;
57 
58     CRYPTO_DOWN_REF(&kdfdata->refcnt, &ref, kdfdata->lock);
59     if (ref > 0)
60         return;
61 
62     CRYPTO_THREAD_lock_free(kdfdata->lock);
63     OPENSSL_free(kdfdata);
64 }
65 
66 int ossl_kdf_data_up_ref(KDF_DATA *kdfdata)
67 {
68     int ref = 0;
69 
70     /* This is effectively doing a new operation on the KDF_DATA and should be
71      * adequately guarded again modules' error states.  However, both current
72      * calls here are guarded propery in exchange/kdf_exch.c.  Thus, it
73      * could be removed here.  The concern is that something in the future
74      * might call this function without adequate guards.  It's a cheap call,
75      * it seems best to leave it even though it is currently redundant.
76      */
77     if (!ossl_prov_is_running())
78         return 0;
79 
80     CRYPTO_UP_REF(&kdfdata->refcnt, &ref, kdfdata->lock);
81     return 1;
82 }
83 
84 static void *kdf_newdata(void *provctx)
85 {
86     return ossl_kdf_data_new(provctx);
87 }
88 
89 static void kdf_freedata(void *kdfdata)
90 {
91     ossl_kdf_data_free(kdfdata);
92 }
93 
94 static int kdf_has(const void *keydata, int selection)
95 {
96     return 1; /* nothing is missing */
97 }
98 
99 const OSSL_DISPATCH ossl_kdf_keymgmt_functions[] = {
100     { OSSL_FUNC_KEYMGMT_NEW, (void (*)(void))kdf_newdata },
101     { OSSL_FUNC_KEYMGMT_FREE, (void (*)(void))kdf_freedata },
102     { OSSL_FUNC_KEYMGMT_HAS, (void (*)(void))kdf_has },
103     { 0, NULL }
104 };
105