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567db2c1 RL |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
7cfa1717 | 5 | EVP_MAC, EVP_MAC_fetch, EVP_MAC_up_ref, EVP_MAC_free, |
c9452d74 | 6 | EVP_MAC_is_a, EVP_MAC_number, EVP_MAC_name, EVP_MAC_names_do_all, |
7dd0f299 | 7 | EVP_MAC_provider, EVP_MAC_get_params, EVP_MAC_gettable_params, |
865adf97 MC |
8 | EVP_MAC_CTX, EVP_MAC_CTX_new, EVP_MAC_CTX_free, EVP_MAC_CTX_dup, |
9 | EVP_MAC_CTX_mac, EVP_MAC_CTX_get_params, EVP_MAC_CTX_set_params, | |
90a2576b | 10 | EVP_MAC_CTX_get_mac_size, EVP_MAC_init, EVP_MAC_update, EVP_MAC_final, |
41f7ecf3 | 11 | EVP_MAC_gettable_ctx_params, EVP_MAC_settable_ctx_params, |
251e610c | 12 | EVP_MAC_do_all_provided - EVP MAC routines |
567db2c1 RL |
13 | |
14 | =head1 SYNOPSIS | |
15 | ||
16 | #include <openssl/evp.h> | |
17 | ||
18 | typedef struct evp_mac_st EVP_MAC; | |
19 | typedef struct evp_mac_ctx_st EVP_MAC_CTX; | |
20 | ||
b4250010 | 21 | EVP_MAC *EVP_MAC_fetch(OSSL_LIB_CTX *libctx, const char *algorithm, |
e74bd290 RL |
22 | const char *properties); |
23 | int EVP_MAC_up_ref(EVP_MAC *mac); | |
24 | void EVP_MAC_free(EVP_MAC *mac); | |
7cfa1717 | 25 | int EVP_MAC_is_a(const EVP_MAC *mac, const char *name); |
506cb0f6 | 26 | int EVP_MAC_number(const EVP_MAC *mac); |
c9452d74 | 27 | const char *EVP_MAC_name(const EVP_MAC *mac); |
f651c727 RL |
28 | void EVP_MAC_names_do_all(const EVP_MAC *mac, |
29 | void (*fn)(const char *name, void *data), | |
30 | void *data); | |
7dd0f299 | 31 | const OSSL_PROVIDER *EVP_MAC_provider(const EVP_MAC *mac); |
e74bd290 RL |
32 | int EVP_MAC_get_params(EVP_MAC *mac, OSSL_PARAM params[]); |
33 | ||
865adf97 MC |
34 | EVP_MAC_CTX *EVP_MAC_CTX_new(EVP_MAC *mac); |
35 | void EVP_MAC_CTX_free(EVP_MAC_CTX *ctx); | |
36 | EVP_MAC_CTX *EVP_MAC_CTX_dup(const EVP_MAC_CTX *src); | |
37 | EVP_MAC *EVP_MAC_CTX_mac(EVP_MAC_CTX *ctx); | |
38 | int EVP_MAC_CTX_get_params(EVP_MAC_CTX *ctx, OSSL_PARAM params[]); | |
39 | int EVP_MAC_CTX_set_params(EVP_MAC_CTX *ctx, const OSSL_PARAM params[]); | |
e74bd290 | 40 | |
90a2576b | 41 | size_t EVP_MAC_CTX_get_mac_size(EVP_MAC_CTX *ctx); |
567db2c1 RL |
42 | int EVP_MAC_init(EVP_MAC_CTX *ctx); |
43 | int EVP_MAC_update(EVP_MAC_CTX *ctx, const unsigned char *data, size_t datalen); | |
e74bd290 RL |
44 | int EVP_MAC_final(EVP_MAC_CTX *ctx, |
45 | unsigned char *out, size_t *outl, size_t outsize); | |
46 | ||
47 | const OSSL_PARAM *EVP_MAC_gettable_params(const EVP_MAC *mac); | |
41f7ecf3 P |
48 | const OSSL_PARAM *EVP_MAC_gettable_ctx_params(const EVP_MAC *mac); |
49 | const OSSL_PARAM *EVP_MAC_settable_ctx_params(const EVP_MAC *mac); | |
567db2c1 | 50 | |
b4250010 | 51 | void EVP_MAC_do_all_provided(OSSL_LIB_CTX *libctx, |
251e610c RL |
52 | void (*fn)(EVP_MAC *mac, void *arg), |
53 | void *arg); | |
d1cafb08 | 54 | |
567db2c1 RL |
55 | =head1 DESCRIPTION |
56 | ||
57 | These types and functions help the application to calculate MACs of | |
58 | different types and with different underlying algorithms if there are | |
59 | any. | |
60 | ||
61 | MACs are a bit complex insofar that some of them use other algorithms | |
62 | for actual computation. HMAC uses a digest, and CMAC uses a cipher. | |
63 | Therefore, there are sometimes two contexts to keep track of, one for | |
64 | the MAC algorithm itself and one for the underlying computation | |
65 | algorithm if there is one. | |
66 | ||
67 | To make things less ambiguous, this manual talks about a "context" or | |
68 | "MAC context", which is to denote the MAC level context, and about a | |
69 | "underlying context", or "computation context", which is to denote the | |
70 | context for the underlying computation algorithm if there is one. | |
71 | ||
72 | =head2 Types | |
73 | ||
74 | B<EVP_MAC> is a type that holds the implementation of a MAC. | |
75 | ||
76 | B<EVP_MAC_CTX> is a context type that holds internal MAC information | |
77 | as well as a reference to a computation context, for those MACs that | |
78 | rely on an underlying computation algorithm. | |
79 | ||
e74bd290 RL |
80 | =head2 Algorithm implementation fetching |
81 | ||
82 | EVP_MAC_fetch() fetches an implementation of a MAC I<algorithm>, given | |
83 | a library context I<libctx> and a set of I<properties>. | |
84 | See L<provider(7)/Fetching algorithms> for further information. | |
85 | ||
b8086652 SL |
86 | See L<OSSL_PROVIDER-default(7)/Message Authentication Code (MAC)> for the list |
87 | of algorithms supported by the default provider. | |
88 | ||
e74bd290 RL |
89 | The returned value must eventually be freed with |
90 | L<EVP_MAC_free(3)>. | |
91 | ||
92 | EVP_MAC_up_ref() increments the reference count of an already fetched | |
93 | MAC. | |
94 | ||
95 | EVP_MAC_free() frees a fetched algorithm. | |
96 | NULL is a valid parameter, for which this function is a no-op. | |
97 | ||
567db2c1 RL |
98 | =head2 Context manipulation functions |
99 | ||
865adf97 | 100 | EVP_MAC_CTX_new() creates a new context for the MAC type I<mac>. |
567db2c1 RL |
101 | The created context can then be used with most other functions |
102 | described here. | |
103 | ||
865adf97 | 104 | EVP_MAC_CTX_free() frees the contents of the context, including an |
567db2c1 | 105 | underlying context if there is one, as well as the context itself. |
e74bd290 | 106 | NULL is a valid parameter, for which this function is a no-op. |
567db2c1 | 107 | |
865adf97 | 108 | EVP_MAC_CTX_dup() duplicates the I<src> context and returns a newly allocated |
be5fc053 | 109 | context. |
567db2c1 | 110 | |
865adf97 | 111 | EVP_MAC_CTX_mac() returns the B<EVP_MAC> associated with the context |
e74bd290 | 112 | I<ctx>. |
567db2c1 RL |
113 | |
114 | =head2 Computing functions | |
115 | ||
116 | EVP_MAC_init() sets up the underlying context with information given | |
117 | through diverse controls. | |
118 | This should be called before calling EVP_MAC_update() and | |
119 | EVP_MAC_final(). | |
120 | ||
e74bd290 | 121 | EVP_MAC_update() adds I<datalen> bytes from I<data> to the MAC input. |
567db2c1 RL |
122 | |
123 | EVP_MAC_final() does the final computation and stores the result in | |
e74bd290 RL |
124 | the memory pointed at by I<out> of size I<outsize>, and sets the number |
125 | of bytes written in I<*outl> at. | |
ee2161e8 | 126 | If I<out> is NULL or I<outsize> is too small, then no computation |
e74bd290 | 127 | is made. |
567db2c1 | 128 | To figure out what the output length will be and allocate space for it |
ee2161e8 | 129 | dynamically, simply call with I<out> being NULL and I<outl> |
567db2c1 | 130 | pointing at a valid location, then allocate space and make a second |
e74bd290 RL |
131 | call with I<out> pointing at the allocated space. |
132 | ||
133 | EVP_MAC_get_params() retrieves details about the implementation | |
134 | I<mac>. | |
135 | The set of parameters given with I<params> determine exactly what | |
136 | parameters should be retrieved. | |
137 | Note that a parameter that is unknown in the underlying context is | |
138 | simply ignored. | |
139 | ||
865adf97 | 140 | EVP_MAC_CTX_get_params() retrieves chosen parameters, given the |
e74bd290 RL |
141 | context I<ctx> and its underlying context. |
142 | The set of parameters given with I<params> determine exactly what | |
143 | parameters should be retrieved. | |
144 | Note that a parameter that is unknown in the underlying context is | |
145 | simply ignored. | |
146 | ||
865adf97 | 147 | EVP_MAC_CTX_set_params() passes chosen parameters to the underlying |
e74bd290 RL |
148 | context, given a context I<ctx>. |
149 | The set of parameters given with I<params> determine exactly what | |
150 | parameters are passed down. | |
151 | Note that a parameter that is unknown in the underlying context is | |
152 | simply ignored. | |
153 | Also, what happens when a needed parameter isn't passed down is | |
154 | defined by the implementation. | |
155 | ||
41f7ecf3 P |
156 | EVP_MAC_gettable_params(), EVP_MAC_gettable_ctx_params() and |
157 | EVP_MAC_settable_ctx_params() get a constant B<OSSL_PARAM> array that | |
79c44b4e | 158 | describes the retrievable and settable parameters, i.e. parameters that |
865adf97 MC |
159 | can be used with EVP_MAC_get_params(), EVP_MAC_CTX_get_params() |
160 | and EVP_MAC_CTX_set_params(), respectively. | |
e74bd290 | 161 | See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor. |
567db2c1 RL |
162 | |
163 | =head2 Information functions | |
164 | ||
90a2576b | 165 | EVP_MAC_CTX_get_mac_size() returns the MAC output size for the given context. |
567db2c1 | 166 | |
7cfa1717 RL |
167 | EVP_MAC_is_a() checks if the given I<mac> is an implementation of an |
168 | algorithm that's identifiable with I<name>. | |
169 | ||
7dd0f299 RL |
170 | EVP_MAC_provider() returns the provider that holds the implementation |
171 | of the given I<mac>. | |
172 | ||
251e610c | 173 | EVP_MAC_do_all_provided() traverses all MAC implemented by all activated |
d1cafb08 RL |
174 | providers in the given library context I<libctx>, and for each of the |
175 | implementations, calls the given function I<fn> with the implementation method | |
176 | and the given I<arg> as argument. | |
177 | ||
506cb0f6 RL |
178 | EVP_MAC_number() returns the internal dynamic number assigned to |
179 | I<mac>. | |
180 | ||
c9452d74 P |
181 | EVP_MAC_name() return the name of the given MAC. For fetched MACs |
182 | with multiple names, only one of them is returned; it's | |
183 | recommended to use EVP_MAC_names_do_all() instead. | |
184 | ||
f651c727 RL |
185 | EVP_MAC_names_do_all() traverses all names for I<mac>, and calls |
186 | I<fn> with each name and I<data>. | |
187 | ||
b1cabee8 | 188 | =head1 PARAMETERS |
567db2c1 | 189 | |
e592dbde RL |
190 | Parameters are identified by name as strings, and have an expected |
191 | data type and maximum size. | |
192 | OpenSSL has a set of macros for parameter names it expects to see in | |
193 | its own MAC implementations. | |
194 | Here, we show all three, the OpenSSL macro for the parameter name, the | |
195 | name in string form, and a type description. | |
196 | ||
e74bd290 | 197 | The standard parameter names are: |
567db2c1 RL |
198 | |
199 | =over 4 | |
200 | ||
0c452a51 | 201 | =item "key" (B<OSSL_MAC_PARAM_KEY>) <octet string> |
567db2c1 | 202 | |
e74bd290 | 203 | Its value is the MAC key as an array of bytes. |
567db2c1 RL |
204 | |
205 | For MACs that use an underlying computation algorithm, the algorithm | |
e74bd290 | 206 | must be set first, see parameter names "algorithm" below. |
afc580b9 | 207 | |
0c452a51 | 208 | =item "iv" (B<OSSL_MAC_PARAM_IV>) <octet string> |
afc580b9 | 209 | |
e74bd290 | 210 | Some MAC implementations require an IV, this parameter sets the IV. |
6e624a64 | 211 | |
0c452a51 | 212 | =item "custom" (B<OSSL_MAC_PARAM_CUSTOM>) <octet string> |
6e624a64 | 213 | |
13b3cd7b | 214 | Some MAC implementations (KMAC, BLAKE2) accept a Customization String, |
e74bd290 RL |
215 | this parameter sets the Customization String. The default value is the |
216 | empty string. | |
6e624a64 | 217 | |
0c452a51 | 218 | =item "salt" (B<OSSL_MAC_PARAM_SALT>) <octet string> |
13b3cd7b AS |
219 | |
220 | This option is used by BLAKE2 MAC. | |
221 | ||
0c452a51 | 222 | =item "xof" (B<OSSL_MAC_PARAM_XOF>) <integer> |
6e624a64 | 223 | |
e74bd290 | 224 | It's a simple flag, the value 0 or 1 are expected. |
6e624a64 SL |
225 | |
226 | This option is used by KMAC. | |
227 | ||
36978c19 | 228 | =item "digest-noinit" (B<OSSL_MAC_PARAM_DIGEST_NOINIT>) <integer> |
567db2c1 | 229 | |
36978c19 SL |
230 | A simple flag to set the MAC digest to not initialise the |
231 | implementation specific data. The value 0 or 1 is expected. | |
232 | ||
233 | This option is used by HMAC. | |
234 | ||
235 | =item "digest-oneshot" (B<OSSL_MAC_PARAM_DIGEST_ONESHOT>) <integer> | |
236 | ||
237 | A simple flag to set the MAC digest to be a oneshot operation. | |
238 | The value 0 or 1 is expected. | |
239 | ||
240 | This option is used by HMAC. | |
567db2c1 | 241 | |
0c452a51 | 242 | =item "properties" (B<OSSL_MAC_PARAM_PROPERTIES>) <UTF8 string> |
567db2c1 | 243 | |
0c452a51 | 244 | =item "digest" (B<OSSL_MAC_PARAM_DIGEST>) <UTF8 string> |
567db2c1 | 245 | |
0c452a51 | 246 | =item "cipher" (B<OSSL_MAC_PARAM_CIPHER>) <UTF8 string> |
e74bd290 | 247 | |
f3b8d77f | 248 | For MAC implementations that use an underlying computation cipher or |
9bd9c440 | 249 | digest, these parameters set what the algorithm should be. |
567db2c1 | 250 | |
9bd9c440 | 251 | The value is always the name of the intended algorithm, |
f3b8d77f | 252 | or the properties. |
567db2c1 | 253 | |
e74bd290 RL |
254 | Note that not all algorithms may support all digests. |
255 | HMAC does not support variable output length digests such as SHAKE128 | |
256 | or SHAKE256. | |
567db2c1 | 257 | |
0c452a51 | 258 | =item "size" (B<OSSL_MAC_PARAM_SIZE>) <unsigned integer> |
567db2c1 RL |
259 | |
260 | For MAC implementations that support it, set the output size that | |
261 | EVP_MAC_final() should produce. | |
1aa01009 P |
262 | The allowed sizes vary between MAC implementations, but must never exceed |
263 | what can be given with a B<size_t>. | |
567db2c1 | 264 | |
820d87bc MC |
265 | =item "tls-data-size" (B<OSSL_MAC_PARAM_TLS_DATA_SIZE>) <unsigned integer> |
266 | ||
267 | This parameter is only supported by HMAC. If set then special handling is | |
268 | activated for calculating the MAC of a received mac-then-encrypt TLS record | |
269 | where variable length record padding has been used (as in the case of CBC mode | |
270 | ciphersuites). The value represents the total length of the record that is | |
271 | having the MAC calculated including the received MAC and the record padding. | |
272 | ||
273 | When used EVP_MAC_update must be called precisely twice. The first time with | |
274 | the 13 bytes of TLS "header" data, and the second time with the entire record | |
275 | including the MAC itself and any padding. The entire record length must equal | |
276 | the value passed in the "tls-data-size" parameter. The length passed in the | |
277 | B<datalen> parameter to EVP_MAC_update() should be equal to the length of the | |
278 | record after the MAC and any padding has been removed. | |
279 | ||
567db2c1 RL |
280 | =back |
281 | ||
e74bd290 | 282 | All these parameters should be used before the calls to any of |
567db2c1 RL |
283 | EVP_MAC_init(), EVP_MAC_update() and EVP_MAC_final() for a full |
284 | computation. | |
285 | Anything else may give undefined results. | |
286 | ||
e74bd290 | 287 | =head1 RETURN VALUES |
567db2c1 | 288 | |
e74bd290 RL |
289 | EVP_MAC_fetch() returns a pointer to a newly fetched EVP_MAC, or |
290 | NULL if allocation failed. | |
567db2c1 | 291 | |
e74bd290 RL |
292 | EVP_MAC_up_ref() returns 1 on success, 0 on error. |
293 | ||
294 | EVP_MAC_free() returns nothing at all. | |
295 | ||
7cfa1717 RL |
296 | EVP_MAC_is_a() returns 1 if the given method can be identified with |
297 | the given name, otherwise 0. | |
298 | ||
c9452d74 P |
299 | EVP_MAC_name() returns a name of the MAC, or NULL on error. |
300 | ||
7dd0f299 RL |
301 | EVP_MAC_provider() returns a pointer to the provider for the MAC, or |
302 | NULL on error. | |
303 | ||
865adf97 | 304 | EVP_MAC_CTX_new() and EVP_MAC_CTX_dup() return a pointer to a newly |
e74bd290 | 305 | created EVP_MAC_CTX, or NULL if allocation failed. |
567db2c1 | 306 | |
865adf97 | 307 | EVP_MAC_CTX_free() returns nothing at all. |
567db2c1 | 308 | |
865adf97 | 309 | EVP_MAC_CTX_get_params() and EVP_MAC_CTX_set_params() return 1 on |
e74bd290 | 310 | success, 0 on error. |
567db2c1 | 311 | |
e74bd290 RL |
312 | EVP_MAC_init(), EVP_MAC_update(), and EVP_MAC_final() return 1 on success, 0 |
313 | on error. | |
567db2c1 | 314 | |
90a2576b | 315 | EVP_MAC_CTX_get_mac_size() returns the expected output size, or 0 if it isn't set. |
567db2c1 RL |
316 | If it isn't set, a call to EVP_MAC_init() should get it set. |
317 | ||
251e610c | 318 | EVP_MAC_do_all_provided() returns nothing at all. |
567db2c1 | 319 | |
cda77422 | 320 | =head1 EXAMPLES |
567db2c1 RL |
321 | |
322 | #include <stdlib.h> | |
323 | #include <stdio.h> | |
324 | #include <string.h> | |
325 | #include <stdarg.h> | |
326 | #include <unistd.h> | |
327 | ||
328 | #include <openssl/evp.h> | |
329 | #include <openssl/err.h> | |
e74bd290 | 330 | #include <openssl/params.h> |
567db2c1 RL |
331 | |
332 | int main() { | |
e74bd290 RL |
333 | EVP_MAC *mac = EVP_MAC_fetch(NULL, getenv("MY_MAC"), NULL); |
334 | const char *cipher = getenv("MY_MAC_CIPHER"); | |
335 | const char *digest = getenv("MY_MAC_DIGEST"); | |
567db2c1 RL |
336 | const char *key = getenv("MY_KEY"); |
337 | EVP_MAC_CTX *ctx = NULL; | |
338 | ||
339 | unsigned char buf[4096]; | |
d5b170a2 | 340 | size_t read_l; |
567db2c1 RL |
341 | size_t final_l; |
342 | ||
343 | size_t i; | |
344 | ||
e74bd290 RL |
345 | OSSL_PARAM params[4]; |
346 | size_t params_n = 0; | |
347 | ||
348 | if (cipher != NULL) | |
349 | params[params_n++] = | |
d5b170a2 | 350 | OSSL_PARAM_construct_utf8_string("cipher", (char*)cipher, 0); |
e74bd290 RL |
351 | if (digest != NULL) |
352 | params[params_n++] = | |
d5b170a2 | 353 | OSSL_PARAM_construct_utf8_string("digest", (char*)digest, 0); |
e74bd290 | 354 | params[params_n++] = |
d5b170a2 | 355 | OSSL_PARAM_construct_octet_string("key", (void*)key, strlen(key)); |
e74bd290 RL |
356 | params[params_n] = OSSL_PARAM_construct_end(); |
357 | ||
567db2c1 RL |
358 | if (mac == NULL |
359 | || key == NULL | |
865adf97 MC |
360 | || (ctx = EVP_MAC_CTX_new(mac)) == NULL |
361 | || EVP_MAC_CTX_set_params(ctx, params) <= 0) | |
567db2c1 RL |
362 | goto err; |
363 | ||
364 | if (!EVP_MAC_init(ctx)) | |
365 | goto err; | |
366 | ||
38e6c490 | 367 | while ( (read_l = read(STDIN_FILENO, buf, sizeof(buf))) > 0) { |
567db2c1 RL |
368 | if (!EVP_MAC_update(ctx, buf, read_l)) |
369 | goto err; | |
370 | } | |
371 | ||
d5b170a2 | 372 | if (!EVP_MAC_final(ctx, buf, &final_l, sizeof(buf))) |
567db2c1 RL |
373 | goto err; |
374 | ||
375 | printf("Result: "); | |
376 | for (i = 0; i < final_l; i++) | |
377 | printf("%02X", buf[i]); | |
378 | printf("\n"); | |
379 | ||
865adf97 | 380 | EVP_MAC_CTX_free(ctx); |
e74bd290 | 381 | EVP_MAC_free(mac); |
567db2c1 RL |
382 | exit(0); |
383 | ||
384 | err: | |
865adf97 | 385 | EVP_MAC_CTX_free(ctx); |
e74bd290 | 386 | EVP_MAC_free(mac); |
567db2c1 RL |
387 | fprintf(stderr, "Something went wrong\n"); |
388 | ERR_print_errors_fp(stderr); | |
389 | exit (1); | |
390 | } | |
391 | ||
392 | A run of this program, called with correct environment variables, can | |
393 | look like this: | |
394 | ||
395 | $ MY_MAC=cmac MY_KEY=secret0123456789 MY_MAC_CIPHER=aes-128-cbc \ | |
396 | LD_LIBRARY_PATH=. ./foo < foo.c | |
38e6c490 | 397 | Result: C5C06683CD9DDEF904D754505C560A4E |
567db2c1 RL |
398 | |
399 | (in this example, that program was stored in F<foo.c> and compiled to | |
400 | F<./foo>) | |
401 | ||
402 | =head1 SEE ALSO | |
403 | ||
e74bd290 RL |
404 | L<property(7)> |
405 | L<OSSL_PARAM(3)>, | |
d7cea0b8 RS |
406 | L<EVP_MAC-BLAKE2(7)>, |
407 | L<EVP_MAC-CMAC(7)>, | |
408 | L<EVP_MAC-GMAC(7)>, | |
409 | L<EVP_MAC-HMAC(7)>, | |
410 | L<EVP_MAC-KMAC(7)>, | |
411 | L<EVP_MAC-Siphash(7)>, | |
412 | L<EVP_MAC-Poly1305(7)> | |
567db2c1 | 413 | |
be5fc053 KR |
414 | =head1 HISTORY |
415 | ||
4674aaf4 | 416 | These functions were added in OpenSSL 3.0. |
be5fc053 | 417 | |
567db2c1 RL |
418 | =head1 COPYRIGHT |
419 | ||
a28d06f3 | 420 | Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved. |
567db2c1 | 421 | |
4746f25a | 422 | Licensed under the Apache License 2.0 (the "License"). You may not use |
567db2c1 RL |
423 | this file except in compliance with the License. You can obtain a copy |
424 | in the file LICENSE in the source distribution or at | |
425 | L<https://www.openssl.org/source/license.html>. | |
426 | ||
427 | =cut |