5 provider-mac - The mac library E<lt>-E<gt> provider functions
9 =for openssl multiple includes
11 #include <openssl/core_dispatch.h>
12 #include <openssl/core_names.h>
15 * None of these are actual functions, but are displayed like this for
16 * the function signatures for functions that are offered as function
17 * pointers in OSSL_DISPATCH arrays.
20 /* Context management */
21 void *OSSL_FUNC_mac_newctx(void *provctx);
22 void OSSL_FUNC_mac_freectx(void *mctx);
23 void *OSSL_FUNC_mac_dupctx(void *src);
25 /* Encryption/decryption */
26 int OSSL_FUNC_mac_init(void *mctx);
27 int OSSL_FUNC_mac_update(void *mctx, const unsigned char *in, size_t inl);
28 int OSSL_FUNC_mac_final(void *mctx, unsigned char *out, size_t *outl, size_t outsize);
30 /* MAC parameter descriptors */
31 const OSSL_PARAM *OSSL_FUNC_mac_gettable_params(void *provctx);
32 const OSSL_PARAM *OSSL_FUNC_mac_gettable_ctx_params(void *mctx, void *provctx);
33 const OSSL_PARAM *OSSL_FUNC_mac_settable_ctx_params(void *mctx, void *provctx);
36 int OSSL_FUNC_mac_get_params(OSSL_PARAM params[]);
37 int OSSL_FUNC_mac_get_ctx_params(void *mctx, OSSL_PARAM params[]);
38 int OSSL_FUNC_mac_set_ctx_params(void *mctx, const OSSL_PARAM params[]);
42 This documentation is primarily aimed at provider authors. See L<provider(7)>
43 for further information.
45 The MAC operation enables providers to implement mac algorithms and make
46 them available to applications via the API functions L<EVP_MAC_init(3)>,
47 L<EVP_MAC_update(3)> and L<EVP_MAC_final(3)>.
49 All "functions" mentioned here are passed as function pointers between
50 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
51 B<OSSL_ALGORITHM> arrays that are returned by the provider's
52 provider_query_operation() function
53 (see L<provider-base(7)/Provider Functions>).
55 All these "functions" have a corresponding function type definition
56 named B<OSSL_{name}_fn>, and a helper function to retrieve the
57 function pointer from an B<OSSL_DISPATCH> element named
59 For example, the "function" OSSL_FUNC_mac_newctx() has these:
61 typedef void *(OSSL_OSSL_FUNC_mac_newctx_fn)(void *provctx);
62 static ossl_inline OSSL_OSSL_FUNC_mac_newctx_fn
63 OSSL_FUNC_mac_newctx(const OSSL_DISPATCH *opf);
65 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
66 macros in L<openssl-core_dispatch.h(7)>, as follows:
68 OSSL_FUNC_mac_newctx OSSL_FUNC_MAC_NEWCTX
69 OSSL_FUNC_mac_freectx OSSL_FUNC_MAC_FREECTX
70 OSSL_FUNC_mac_dupctx OSSL_FUNC_MAC_DUPCTX
72 OSSL_FUNC_mac_init OSSL_FUNC_MAC_INIT
73 OSSL_FUNC_mac_update OSSL_FUNC_MAC_UPDATE
74 OSSL_FUNC_mac_final OSSL_FUNC_MAC_FINAL
76 OSSL_FUNC_mac_get_params OSSL_FUNC_MAC_GET_PARAMS
77 OSSL_FUNC_mac_get_ctx_params OSSL_FUNC_MAC_GET_CTX_PARAMS
78 OSSL_FUNC_mac_set_ctx_params OSSL_FUNC_MAC_SET_CTX_PARAMS
80 OSSL_FUNC_mac_gettable_params OSSL_FUNC_MAC_GETTABLE_PARAMS
81 OSSL_FUNC_mac_gettable_ctx_params OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS
82 OSSL_FUNC_mac_settable_ctx_params OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS
84 A mac algorithm implementation may not implement all of these functions.
85 In order to be a consistent set of functions, at least the following functions
86 must be implemented: OSSL_FUNC_mac_newctx(), OSSL_FUNC_mac_freectx(), OSSL_FUNC_mac_init(),
87 OSSL_FUNC_mac_update(), OSSL_FUNC_mac_final().
88 All other functions are optional.
90 =head2 Context Management Functions
92 OSSL_FUNC_mac_newctx() should create and return a pointer to a provider side
93 structure for holding context information during a mac operation.
94 A pointer to this context will be passed back in a number of the other mac
95 operation function calls.
96 The parameter I<provctx> is the provider context generated during provider
97 initialisation (see L<provider(7)>).
99 OSSL_FUNC_mac_freectx() is passed a pointer to the provider side mac context in
100 the I<mctx> parameter.
101 If it receives NULL as I<mctx> value, it should not do anything other than
103 This function should free any resources associated with that context.
105 OSSL_FUNC_mac_dupctx() should duplicate the provider side mac context in the
106 I<mctx> parameter and return the duplicate copy.
108 =head2 Encryption/Decryption Functions
110 OSSL_FUNC_mac_init() initialises a mac operation given a newly created provider
111 side mac context in the I<mctx> parameter.
113 OSSL_FUNC_mac_update() is called to supply data for MAC computation of a previously
114 initialised mac operation.
115 The I<mctx> parameter contains a pointer to a previously initialised provider
117 OSSL_FUNC_mac_update() may be called multiple times for a single mac operation.
119 OSSL_FUNC_mac_final() completes the MAC computation started through previous
120 OSSL_FUNC_mac_init() and OSSL_FUNC_mac_update() calls.
121 The I<mctx> parameter contains a pointer to the provider side context.
122 The resulting MAC should be written to I<out> and the amount of data written
123 to I<*outl>, which should not exceed I<outsize> bytes.
124 The same expectations apply to I<outsize> as documented for
127 =head2 Mac Parameters
129 See L<OSSL_PARAM(3)> for further details on the parameters structure used by
132 OSSL_FUNC_mac_get_params() gets details of parameter values associated with the
133 provider algorithm and stores them in I<params>.
135 OSSL_FUNC_mac_set_ctx_params() sets mac parameters associated with the given
136 provider side mac context I<mctx> to I<params>.
137 Any parameter settings are additional to any that were previously set.
139 OSSL_FUNC_mac_get_ctx_params() gets details of currently set parameter values
140 associated with the given provider side mac context I<mctx> and stores them
143 OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params(),
144 and OSSL_FUNC_mac_settable_ctx_params() all return constant B<OSSL_PARAM>
145 arrays as descriptors of the parameters that OSSL_FUNC_mac_get_params(),
146 OSSL_FUNC_mac_get_ctx_params(), and OSSL_FUNC_mac_set_ctx_params()
147 can handle, respectively. OSSL_FUNC_mac_gettable_ctx_params() and
148 OSSL_FUNC_mac_settable_ctx_params() will return the parameters associated
149 with the provider side context I<mctx> in its current state if it is
150 not NULL. Otherwise, they return the parameters associated with the
151 provider side algorithm I<provctx>.
154 Parameters currently recognised by built-in macs are as follows. Not all
155 parameters are relevant to, or are understood by all macs:
159 =item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string>
161 Sets the key in the associated MAC ctx.
163 =item "iv" (B<OSSL_MAC_PARAM_IV>) <octet string>
165 Sets the IV of the underlying cipher, when applicable.
167 =item "custom" (B<OSSL_MAC_PARAM_CUSTOM>) <UTF8 string>
169 Sets the custom string in the associated MAC ctx.
171 =item "salt" (B<OSSL_MAC_PARAM_SALT>) <octet string>
173 Sets the salt of the underlying cipher, when applicable.
175 =item "xof" (B<OSSL_MAC_PARAM_BLOCK_XOF>) <integer>
177 Sets XOF mode in the associated MAC ctx.
178 0 means no XOF mode, 1 means XOF mode.
180 =item "digest-noinit" (B<OSSL_MAC_PARAM_DIGEST_NOINIT>) <integer>
182 A simple flag to set the MAC digest to not initialise the
183 implementation specific data. The value 0 or 1 is expected.
185 =item "digest-oneshot" (B<OSSL_MAC_PARAM_DIGEST_ONESHOT>) <integer>
187 A simple flag to set the MAC digest to be a oneshot operation.
188 The value 0 or 1 is expected.
191 =for comment We need to investigate if this is the right approach
193 =item "cipher" (B<OSSL_MAC_PARAM_CIPHER>) <UTF8 string>
195 =item "digest" (B<OSSL_MAC_PARAM_DIGEST>) <UTF8 string>
197 Sets the name of the underlying cipher or digest to be used.
198 It must name a suitable algorithm for the MAC that's being used.
200 =item "properties" (B<OSSL_MAC_PARAM_PROPERTIES>) <UTF8 string>
202 Sets the properties to be queried when trying to fetch the underlying algorithm.
203 This must be given together with the algorithm naming parameter to be
206 =item "size" (B<OSSL_MAC_PARAM_SIZE>) <integer>
208 Can be used to get the resulting MAC size.
210 With some MAC algorithms, it can also be used to set the size that the
211 resulting MAC should have.
212 Allowable sizes are decided within each implementation.
218 OSSL_FUNC_mac_newctx() and OSSL_FUNC_mac_dupctx() should return the newly created
219 provider side mac context, or NULL on failure.
221 OSSL_FUNC_mac_init(), OSSL_FUNC_mac_update(), OSSL_FUNC_mac_final(), OSSL_FUNC_mac_get_params(),
222 OSSL_FUNC_mac_get_ctx_params() and OSSL_FUNC_mac_set_ctx_params() should return 1 for
223 success or 0 on error.
225 OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params() and
226 OSSL_FUNC_mac_settable_ctx_params() should return a constant B<OSSL_PARAM>
227 array, or NULL if none is offered.
235 The provider MAC interface was introduced in OpenSSL 3.0.
239 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
241 Licensed under the Apache License 2.0 (the "License"). You may not use
242 this file except in compliance with the License. You can obtain a copy
243 in the file LICENSE in the source distribution or at
244 L<https://www.openssl.org/source/license.html>.