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 
14 typedef struct {
15     unsigned char nothing;
16 } NULLMD_CTX;
17 
null_init(NULLMD_CTX * ctx)18 static int null_init(NULLMD_CTX *ctx)
19 {
20     return 1;
21 }
22 
null_update(NULLMD_CTX * ctx,const void * data,size_t datalen)23 static int null_update(NULLMD_CTX *ctx, const void *data, size_t datalen)
24 {
25     return 1;
26 }
27 
null_final(unsigned char * md,NULLMD_CTX * ctx)28 static 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)                            \
39 static OSSL_FUNC_digest_final_fn name##_internal_final;                        \
40 static 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 
50 IMPLEMENT_digest_functions(nullmd, NULLMD_CTX,
51                            0, 0, 0,
52                            null_init, null_update, null_final)
53