1/*
2 * Copyright 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 <openssl/crypto.h>
11#include "prov/digestcommon.h"
12#include "prov/implementations.h"
13
14typedef struct {
15    unsigned char nothing;
16} NULLMD_CTX;
17
18static int null_init(NULLMD_CTX *ctx)
19{
20    return 1;
21}
22
23static int null_update(NULLMD_CTX *ctx, const void *data, size_t datalen)
24{
25    return 1;
26}
27
28static int null_final(unsigned char *md, NULLMD_CTX *ctx)
29{
30    return 1;
31}
32
33/*
34 * We must override the PROV_FUNC_DIGEST_FINAL as dgstsize == 0
35 * and that would cause compilation warnings with the default implementation.
36 */
37#undef PROV_FUNC_DIGEST_FINAL
38#define PROV_FUNC_DIGEST_FINAL(name, dgstsize, fin)                            \
39static OSSL_FUNC_digest_final_fn name##_internal_final;                        \
40static int name##_internal_final(void *ctx, unsigned char *out, size_t *outl,  \
41                                 size_t outsz)                                 \
42{                                                                              \
43    if (ossl_prov_is_running() && fin(out, ctx)) {                             \
44        *outl = dgstsize;                                                      \
45        return 1;                                                              \
46    }                                                                          \
47    return 0;                                                                  \
48}
49
50IMPLEMENT_digest_functions(nullmd, NULLMD_CTX,
51                           0, 0, 0,
52                           null_init, null_update, null_final)
53