1=pod 2 3=head1 NAME 4 5provider-mac - The mac library E<lt>-E<gt> provider functions 6 7=head1 SYNOPSIS 8 9=for openssl multiple includes 10 11 #include <openssl/core_dispatch.h> 12 #include <openssl/core_names.h> 13 14 /* 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. 18 */ 19 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); 24 25 /* Encryption/decryption */ 26 int OSSL_FUNC_mac_init(void *mctx, unsigned char *key, size_t keylen, 27 const OSSL_PARAM params[]); 28 int OSSL_FUNC_mac_update(void *mctx, const unsigned char *in, size_t inl); 29 int OSSL_FUNC_mac_final(void *mctx, unsigned char *out, size_t *outl, size_t outsize); 30 31 /* MAC parameter descriptors */ 32 const OSSL_PARAM *OSSL_FUNC_mac_gettable_params(void *provctx); 33 const OSSL_PARAM *OSSL_FUNC_mac_gettable_ctx_params(void *mctx, void *provctx); 34 const OSSL_PARAM *OSSL_FUNC_mac_settable_ctx_params(void *mctx, void *provctx); 35 36 /* MAC parameters */ 37 int OSSL_FUNC_mac_get_params(OSSL_PARAM params[]); 38 int OSSL_FUNC_mac_get_ctx_params(void *mctx, OSSL_PARAM params[]); 39 int OSSL_FUNC_mac_set_ctx_params(void *mctx, const OSSL_PARAM params[]); 40 41=head1 DESCRIPTION 42 43This documentation is primarily aimed at provider authors. See L<provider(7)> 44for further information. 45 46The MAC operation enables providers to implement mac algorithms and make 47them available to applications via the API functions L<EVP_MAC_init(3)>, 48L<EVP_MAC_update(3)> and L<EVP_MAC_final(3)>. 49 50All "functions" mentioned here are passed as function pointers between 51F<libcrypto> and the provider in L<OSSL_DISPATCH(3)> arrays via 52L<OSSL_ALGORITHM(3)> arrays that are returned by the provider's 53provider_query_operation() function 54(see L<provider-base(7)/Provider Functions>). 55 56All these "functions" have a corresponding function type definition 57named B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the 58function pointer from an L<OSSL_DISPATCH(3)> element named 59B<OSSL_FUNC_{name}>. 60For example, the "function" OSSL_FUNC_mac_newctx() has these: 61 62 typedef void *(OSSL_FUNC_mac_newctx_fn)(void *provctx); 63 static ossl_inline OSSL_FUNC_mac_newctx_fn 64 OSSL_FUNC_mac_newctx(const OSSL_DISPATCH *opf); 65 66L<OSSL_DISPATCH(3)> arrays are indexed by numbers that are provided as 67macros in L<openssl-core_dispatch.h(7)>, as follows: 68 69 OSSL_FUNC_mac_newctx OSSL_FUNC_MAC_NEWCTX 70 OSSL_FUNC_mac_freectx OSSL_FUNC_MAC_FREECTX 71 OSSL_FUNC_mac_dupctx OSSL_FUNC_MAC_DUPCTX 72 73 OSSL_FUNC_mac_init OSSL_FUNC_MAC_INIT 74 OSSL_FUNC_mac_update OSSL_FUNC_MAC_UPDATE 75 OSSL_FUNC_mac_final OSSL_FUNC_MAC_FINAL 76 77 OSSL_FUNC_mac_get_params OSSL_FUNC_MAC_GET_PARAMS 78 OSSL_FUNC_mac_get_ctx_params OSSL_FUNC_MAC_GET_CTX_PARAMS 79 OSSL_FUNC_mac_set_ctx_params OSSL_FUNC_MAC_SET_CTX_PARAMS 80 81 OSSL_FUNC_mac_gettable_params OSSL_FUNC_MAC_GETTABLE_PARAMS 82 OSSL_FUNC_mac_gettable_ctx_params OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS 83 OSSL_FUNC_mac_settable_ctx_params OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS 84 85A mac algorithm implementation may not implement all of these functions. 86In order to be a consistent set of functions, at least the following functions 87must be implemented: OSSL_FUNC_mac_newctx(), OSSL_FUNC_mac_freectx(), OSSL_FUNC_mac_init(), 88OSSL_FUNC_mac_update(), OSSL_FUNC_mac_final(). 89All other functions are optional. 90 91=head2 Context Management Functions 92 93OSSL_FUNC_mac_newctx() should create and return a pointer to a provider side 94structure for holding context information during a mac operation. 95A pointer to this context will be passed back in a number of the other mac 96operation function calls. 97The parameter I<provctx> is the provider context generated during provider 98initialisation (see L<provider(7)>). 99 100OSSL_FUNC_mac_freectx() is passed a pointer to the provider side mac context in 101the I<mctx> parameter. 102If it receives NULL as I<mctx> value, it should not do anything other than 103return. 104This function should free any resources associated with that context. 105 106OSSL_FUNC_mac_dupctx() should duplicate the provider side mac context in the 107I<mctx> parameter and return the duplicate copy. 108 109=head2 Encryption/Decryption Functions 110 111OSSL_FUNC_mac_init() initialises a mac operation given a newly created provider 112side mac context in the I<mctx> parameter. The I<params> are set before setting 113the MAC I<key> of I<keylen> bytes. 114 115OSSL_FUNC_mac_update() is called to supply data for MAC computation of a previously 116initialised mac operation. 117The I<mctx> parameter contains a pointer to a previously initialised provider 118side context. 119OSSL_FUNC_mac_update() may be called multiple times for a single mac operation. 120 121OSSL_FUNC_mac_final() completes the MAC computation started through previous 122OSSL_FUNC_mac_init() and OSSL_FUNC_mac_update() calls. 123The I<mctx> parameter contains a pointer to the provider side context. 124The resulting MAC should be written to I<out> and the amount of data written 125to I<*outl>, which should not exceed I<outsize> bytes. 126The same expectations apply to I<outsize> as documented for 127L<EVP_MAC_final(3)>. 128 129=head2 Mac Parameters 130 131See L<OSSL_PARAM(3)> for further details on the parameters structure used by 132these functions. 133 134OSSL_FUNC_mac_get_params() gets details of parameter values associated with the 135provider algorithm and stores them in I<params>. 136 137OSSL_FUNC_mac_set_ctx_params() sets mac parameters associated with the given 138provider side mac context I<mctx> to I<params>. 139Any parameter settings are additional to any that were previously set. 140Passing NULL for I<params> should return true. 141 142OSSL_FUNC_mac_get_ctx_params() gets details of currently set parameter values 143associated with the given provider side mac context I<mctx> and stores them 144in I<params>. 145Passing NULL for I<params> should return true. 146 147OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params(), 148and OSSL_FUNC_mac_settable_ctx_params() all return constant L<OSSL_PARAM(3)> 149arrays as descriptors of the parameters that OSSL_FUNC_mac_get_params(), 150OSSL_FUNC_mac_get_ctx_params(), and OSSL_FUNC_mac_set_ctx_params() 151can handle, respectively. OSSL_FUNC_mac_gettable_ctx_params() and 152OSSL_FUNC_mac_settable_ctx_params() will return the parameters associated 153with the provider side context I<mctx> in its current state if it is 154not NULL. Otherwise, they return the parameters associated with the 155provider side algorithm I<provctx>. 156 157All MAC implementations are expected to handle the following parameters: 158 159=over 4 160 161=item with OSSL_FUNC_set_ctx_params(): 162 163=over 4 164 165=item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string> 166 167Sets the key in the associated MAC ctx. This is identical to passing a I<key> 168argument to the OSSL_FUNC_mac_init() function. 169 170=back 171 172=item with OSSL_FUNC_get_params(): 173 174=over 4 175 176=item "size" (B<OSSL_MAC_PARAM_SIZE>) <integer> 177 178Can be used to get the default MAC size (which might be the only allowable 179MAC size for the implementation). 180 181Note that some implementations allow setting the size that the resulting MAC 182should have as well, see the documentation of the implementation. 183 184=back 185 186=over 4 187 188=item "size" (B<OSSL_MAC_PARAM_BLOCK_SIZE>) <integer> 189 190Can be used to get the MAC block size (if supported by the algorithm). 191 192=back 193 194=back 195 196=head1 NOTES 197 198The MAC life-cycle is described in L<life_cycle-rand(7)>. Providers should 199ensure that the various transitions listed there are supported. At some point 200the EVP layer will begin enforcing the listed transitions. 201 202=head1 RETURN VALUES 203 204OSSL_FUNC_mac_newctx() and OSSL_FUNC_mac_dupctx() should return the newly created 205provider side mac context, or NULL on failure. 206 207OSSL_FUNC_mac_init(), OSSL_FUNC_mac_update(), OSSL_FUNC_mac_final(), OSSL_FUNC_mac_get_params(), 208OSSL_FUNC_mac_get_ctx_params() and OSSL_FUNC_mac_set_ctx_params() should return 1 for 209success or 0 on error. 210 211OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params() and 212OSSL_FUNC_mac_settable_ctx_params() should return a constant L<OSSL_PARAM(3)> 213array, or NULL if none is offered. 214 215=head1 SEE ALSO 216 217L<provider(7)>, 218L<EVP_MAC-BLAKE2(7)>, L<EVP_MAC-CMAC(7)>, L<EVP_MAC-GMAC(7)>, 219L<EVP_MAC-HMAC(7)>, L<EVP_MAC-KMAC(7)>, L<EVP_MAC-Poly1305(7)>, 220L<EVP_MAC-Siphash(7)>, 221L<life_cycle-mac(7)>, L<EVP_MAC(3)> 222 223=head1 HISTORY 224 225The provider MAC interface was introduced in OpenSSL 3.0. 226 227=head1 COPYRIGHT 228 229Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved. 230 231Licensed under the Apache License 2.0 (the "License"). You may not use 232this file except in compliance with the License. You can obtain a copy 233in the file LICENSE in the source distribution or at 234L<https://www.openssl.org/source/license.html>. 235 236=cut 237