6 - The basic OpenSSL library E<lt>-E<gt> provider functions
10 #include <openssl/core_dispatch.h>
13 * None of these are actual functions, but are displayed like this for
14 * the function signatures for functions that are offered as function
15 * pointers in OSSL_DISPATCH arrays.
18 /* Functions offered by libcrypto to the providers */
19 const OSSL_ITEM *core_gettable_params(const OSSL_CORE_HANDLE *handle);
20 int core_get_params(const OSSL_CORE_HANDLE *handle, OSSL_PARAM params[]);
22 typedef void (*OSSL_thread_stop_handler_fn)(void *arg);
23 int core_thread_start(const OSSL_CORE_HANDLE *handle,
24 OSSL_thread_stop_handler_fn handfn,
27 OPENSSL_CORE_CTX *core_get_libctx(const OSSL_CORE_HANDLE *handle);
28 void core_new_error(const OSSL_CORE_HANDLE *handle);
29 void core_set_error_debug(const OSSL_CORE_HANDLE *handle,
30 const char *file, int line, const char *func);
31 void core_vset_error(const OSSL_CORE_HANDLE *handle,
32 uint32_t reason, const char *fmt, va_list args);
34 int core_obj_add_sigid(const OSSL_CORE_HANDLE *prov, const char *sign_name,
35 const char *digest_name, const char *pkey_name);
36 int core_obj_create(const OSSL_CORE_HANDLE *handle, const char *oid,
37 const char *sn, const char *ln);
40 * Some OpenSSL functionality is directly offered to providers via
43 void *CRYPTO_malloc(size_t num, const char *file, int line);
44 void *CRYPTO_zalloc(size_t num, const char *file, int line);
45 void *CRYPTO_memdup(const void *str, size_t siz,
46 const char *file, int line);
47 char *CRYPTO_strdup(const char *str, const char *file, int line);
48 char *CRYPTO_strndup(const char *str, size_t s,
49 const char *file, int line);
50 void CRYPTO_free(void *ptr, const char *file, int line);
51 void CRYPTO_clear_free(void *ptr, size_t num,
52 const char *file, int line);
53 void *CRYPTO_realloc(void *addr, size_t num,
54 const char *file, int line);
55 void *CRYPTO_clear_realloc(void *addr, size_t old_num, size_t num,
56 const char *file, int line);
57 void *CRYPTO_secure_malloc(size_t num, const char *file, int line);
58 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);
59 void CRYPTO_secure_free(void *ptr, const char *file, int line);
60 void CRYPTO_secure_clear_free(void *ptr, size_t num,
61 const char *file, int line);
62 int CRYPTO_secure_allocated(const void *ptr);
63 void OPENSSL_cleanse(void *ptr, size_t len);
65 unsigned char *OPENSSL_hexstr2buf(const char *str, long *buflen);
67 OSSL_CORE_BIO *BIO_new_file(const char *filename, const char *mode);
68 OSSL_CORE_BIO *BIO_new_membuf(const void *buf, int len);
69 int BIO_read_ex(OSSL_CORE_BIO *bio, void *data, size_t data_len,
71 int BIO_write_ex(OSSL_CORE_BIO *bio, const void *data, size_t data_len,
73 int BIO_up_ref(OSSL_CORE_BIO *bio);
74 int BIO_free(OSSL_CORE_BIO *bio);
75 int BIO_vprintf(OSSL_CORE_BIO *bio, const char *format, va_list args);
76 int BIO_vsnprintf(char *buf, size_t n, const char *fmt, va_list args);
78 void OSSL_SELF_TEST_set_callback(OSSL_LIB_CTX *libctx, OSSL_CALLBACK *cb,
81 size_t get_entropy(const OSSL_CORE_HANDLE *handle,
82 unsigned char **pout, int entropy,
83 size_t min_len, size_t max_len);
84 void cleanup_entropy(const OSSL_CORE_HANDLE *handle,
85 unsigned char *buf, size_t len);
86 size_t get_nonce(const OSSL_CORE_HANDLE *handle,
87 unsigned char **pout, size_t min_len, size_t max_len,
88 const void *salt, size_t salt_len);
89 void cleanup_nonce(const OSSL_CORE_HANDLE *handle,
90 unsigned char *buf, size_t len);
92 /* Functions for querying the providers in the application library context */
93 int provider_register_child_cb(const OSSL_CORE_HANDLE *handle,
94 int (*create_cb)(const OSSL_CORE_HANDLE *provider,
96 int (*remove_cb)(const OSSL_CORE_HANDLE *provider,
98 int (*global_props_cb)(const char *props, void *cbdata),
100 void provider_deregister_child_cb(const OSSL_CORE_HANDLE *handle);
101 const char *provider_name(const OSSL_CORE_HANDLE *prov);
102 void *provider_get0_provider_ctx(const OSSL_CORE_HANDLE *prov);
103 const OSSL_DISPATCH *provider_get0_dispatch(const OSSL_CORE_HANDLE *prov);
104 int provider_up_ref(const OSSL_CORE_HANDLE *prov, int activate);
105 int provider_free(const OSSL_CORE_HANDLE *prov, int deactivate);
107 /* Functions offered by the provider to libcrypto */
108 void provider_teardown(void *provctx);
109 const OSSL_ITEM *provider_gettable_params(void *provctx);
110 int provider_get_params(void *provctx, OSSL_PARAM params[]);
111 const OSSL_ALGORITHM *provider_query_operation(void *provctx,
113 const int *no_store);
114 void provider_unquery_operation(void *provctx, int operation_id,
115 const OSSL_ALGORITHM *algs);
116 const OSSL_ITEM *provider_get_reason_strings(void *provctx);
117 int provider_get_capabilities(void *provctx, const char *capability,
118 OSSL_CALLBACK *cb, void *arg);
119 int provider_self_test(void *provctx);
123 All "functions" mentioned here are passed as function pointers between
124 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays, in the call
125 of the provider initialization function. See L<provider(7)/Provider>
126 for a description of the initialization function. They are known as "upcalls".
128 All these "functions" have a corresponding function type definition
129 named B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the
130 function pointer from a B<OSSL_DISPATCH> element named
132 For example, the "function" core_gettable_params() has these:
135 (OSSL_FUNC_core_gettable_params_fn)(const OSSL_CORE_HANDLE *handle);
136 static ossl_inline OSSL_NAME_core_gettable_params_fn
137 OSSL_FUNC_core_gettable_params(const OSSL_DISPATCH *opf);
139 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
140 macros in L<openssl-core_dispatch.h(7)>, as follows:
142 For I<in> (the B<OSSL_DISPATCH> array passed from F<libcrypto> to the
145 core_gettable_params OSSL_FUNC_CORE_GETTABLE_PARAMS
146 core_get_params OSSL_FUNC_CORE_GET_PARAMS
147 core_thread_start OSSL_FUNC_CORE_THREAD_START
148 core_get_libctx OSSL_FUNC_CORE_GET_LIBCTX
149 core_new_error OSSL_FUNC_CORE_NEW_ERROR
150 core_set_error_debug OSSL_FUNC_CORE_SET_ERROR_DEBUG
151 core_vset_error OSSL_FUNC_CORE_VSET_ERROR
152 core_obj_add_sigid OSSL_FUNC_CORE_OBJ_ADD_SIGID
153 core_obj_create OSSL_FUNC_CORE_OBJ_CREATE
154 CRYPTO_malloc OSSL_FUNC_CRYPTO_MALLOC
155 CRYPTO_zalloc OSSL_FUNC_CRYPTO_ZALLOC
156 CRYPTO_memdup OSSL_FUNC_CRYPTO_MEMDUP
157 CRYPTO_strdup OSSL_FUNC_CRYPTO_STRDUP
158 CRYPTO_strndup OSSL_FUNC_CRYPTO_STRNDUP
159 CRYPTO_free OSSL_FUNC_CRYPTO_FREE
160 CRYPTO_clear_free OSSL_FUNC_CRYPTO_CLEAR_FREE
161 CRYPTO_realloc OSSL_FUNC_CRYPTO_REALLOC
162 CRYPTO_clear_realloc OSSL_FUNC_CRYPTO_CLEAR_REALLOC
163 CRYPTO_secure_malloc OSSL_FUNC_CRYPTO_SECURE_MALLOC
164 CRYPTO_secure_zalloc OSSL_FUNC_CRYPTO_SECURE_ZALLOC
165 CRYPTO_secure_free OSSL_FUNC_CRYPTO_SECURE_FREE
166 CRYPTO_secure_clear_free OSSL_FUNC_CRYPTO_SECURE_CLEAR_FREE
167 CRYPTO_secure_allocated OSSL_FUNC_CRYPTO_SECURE_ALLOCATED
168 BIO_new_file OSSL_FUNC_BIO_NEW_FILE
169 BIO_new_mem_buf OSSL_FUNC_BIO_NEW_MEMBUF
170 BIO_read_ex OSSL_FUNC_BIO_READ_EX
171 BIO_write_ex OSSL_FUNC_BIO_WRITE_EX
172 BIO_up_ref OSSL_FUNC_BIO_UP_REF
173 BIO_free OSSL_FUNC_BIO_FREE
174 BIO_vprintf OSSL_FUNC_BIO_VPRINTF
175 BIO_vsnprintf OSSL_FUNC_BIO_VSNPRINTF
176 BIO_puts OSSL_FUNC_BIO_PUTS
177 BIO_gets OSSL_FUNC_BIO_GETS
178 BIO_ctrl OSSL_FUNC_BIO_CTRL
179 OPENSSL_cleanse OSSL_FUNC_OPENSSL_CLEANSE
180 OSSL_SELF_TEST_set_callback OSSL_FUNC_SELF_TEST_CB
181 ossl_rand_get_entropy OSSL_FUNC_GET_ENTROPY
182 ossl_rand_cleanup_entropy OSSL_FUNC_CLEANUP_ENTROPY
183 ossl_rand_get_nonce OSSL_FUNC_GET_NONCE
184 ossl_rand_cleanup_nonce OSSL_FUNC_CLEANUP_NONCE
185 provider_register_child_cb OSSL_FUNC_PROVIDER_REGISTER_CHILD_CB
186 provider_deregister_child_cb OSSL_FUNC_PROVIDER_DEREGISTER_CHILD_CB
187 provider_name OSSL_FUNC_PROVIDER_NAME
188 provider_get0_provider_ctx OSSL_FUNC_PROVIDER_GET0_PROVIDER_CTX
189 provider_get0_dispatch OSSL_FUNC_PROVIDER_GET0_DISPATCH
190 provider_up_ref OSSL_FUNC_PROVIDER_UP_REF
191 provider_free OSSL_FUNC_PROVIDER_FREE
193 For I<*out> (the B<OSSL_DISPATCH> array passed from the provider to
196 provider_teardown OSSL_FUNC_PROVIDER_TEARDOWN
197 provider_gettable_params OSSL_FUNC_PROVIDER_GETTABLE_PARAMS
198 provider_get_params OSSL_FUNC_PROVIDER_GET_PARAMS
199 provider_query_operation OSSL_FUNC_PROVIDER_QUERY_OPERATION
200 provider_unquery_operation OSSL_FUNC_PROVIDER_UNQUERY_OPERATION
201 provider_get_reason_strings OSSL_FUNC_PROVIDER_GET_REASON_STRINGS
202 provider_get_capabilities OSSL_FUNC_PROVIDER_GET_CAPABILITIES
203 provider_self_test OSSL_FUNC_PROVIDER_SELF_TEST
205 =head2 Core functions
207 core_gettable_params() returns a constant array of descriptor
208 B<OSSL_PARAM>, for parameters that core_get_params() can handle.
210 core_get_params() retrieves parameters from the core for the given I<handle>.
211 See L</Core parameters> below for a description of currently known
214 The core_thread_start() function informs the core that the provider has stated
215 an interest in the current thread. The core will inform the provider when the
216 thread eventually stops. It must be passed the I<handle> for this provider, as
217 well as a callback I<handfn> which will be called when the thread stops. The
218 callback will subsequently be called, with the supplied argument I<arg>, from
219 the thread that is stopping and gets passed the provider context as an
220 argument. This may be useful to perform thread specific clean up such as
221 freeing thread local variables.
223 core_get_libctx() retrieves the core context in which the library
224 object for the current provider is stored, accessible through the I<handle>.
225 This function is useful only for built-in providers such as the default
226 provider. Never cast this to OSSL_LIB_CTX in a provider that is not
227 built-in as the OSSL_LIB_CTX of the library loading the provider might be
228 a completely different structure than the OSSL_LIB_CTX of the library the
229 provider is linked to. Use L<OSSL_LIB_CTX_new_child(3)> instead to obtain
230 a proper library context that is linked to the application library context.
232 core_new_error(), core_set_error_debug() and core_vset_error() are
233 building blocks for reporting an error back to the core, with
234 reference to the I<handle>.
238 =item core_new_error()
240 allocates a new thread specific error record.
242 This corresponds to the OpenSSL function L<ERR_new(3)>.
244 =item core_set_error_debug()
246 sets debugging information in the current thread specific error
248 The debugging information includes the name of the file I<file>, the
249 line I<line> and the function name I<func> where the error occurred.
251 This corresponds to the OpenSSL function L<ERR_set_debug(3)>.
253 =item core_vset_error()
255 sets the I<reason> for the error, along with any addition data.
256 The I<reason> is a number defined by the provider and used to index
257 the reason strings table that's returned by
258 provider_get_reason_strings().
259 The additional data is given as a format string I<fmt> and a set of
260 arguments I<args>, which are treated in the same manner as with
262 I<file> and I<line> may also be passed to indicate exactly where the
263 error occurred or was reported.
265 This corresponds to the OpenSSL function L<ERR_vset_error(3)>.
269 The core_obj_create() function registers a new OID and associated short name
270 I<sn> and long name I<ln> for the given I<handle>. It is similar to the OpenSSL
271 function L<OBJ_create(3)> except that it returns 1 on success or 0 on failure.
272 It will treat as success the case where the OID already exists (even if the
273 short name I<sn> or long name I<ln> provided as arguments differ from those
274 associated with the existing OID, in which case the new names are not
277 The core_obj_add_sigid() function registers a new composite signature algorithm
278 (I<sign_name>) consisting of an underlying signature algorithm (I<pkey_name>)
279 and digest algorithm (I<digest_name>) for the given I<handle>. It assumes that
280 the OIDs for the composite signature algorithm as well as for the underlying
281 signature and digest algorithms are either already known to OpenSSL or have been
282 registered via a call to core_obj_create(). It corresponds to the OpenSSL
283 function L<OBJ_add_sigid(3)>, except that the objects are identified by name
284 rather than a numeric NID. Any name (OID, short name or long name) can be used
285 to identify the object. It will treat as success the case where the composite
286 signature algorithm already exists (even if registered against a different
287 underlying signature or digest algorithm). It returns 1 on success or 0 on
290 CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_memdup(), CRYPTO_strdup(),
291 CRYPTO_strndup(), CRYPTO_free(), CRYPTO_clear_free(),
292 CRYPTO_realloc(), CRYPTO_clear_realloc(), CRYPTO_secure_malloc(),
293 CRYPTO_secure_zalloc(), CRYPTO_secure_free(),
294 CRYPTO_secure_clear_free(), CRYPTO_secure_allocated(),
295 BIO_new_file(), BIO_new_mem_buf(), BIO_read_ex(), BIO_write_ex(), BIO_up_ref(),
296 BIO_free(), BIO_vprintf(), BIO_vsnprintf(), BIO_gets(), BIO_puts(),
297 BIO_ctrl(), OPENSSL_cleanse() and
298 OPENSSL_hexstr2buf() correspond exactly to the public functions with
299 the same name. As a matter of fact, the pointers in the B<OSSL_DISPATCH>
300 array are typically direct pointers to those public functions. Note that the BIO
301 functions take an B<OSSL_CORE_BIO> type rather than the standard B<BIO>
302 type. This is to ensure that a provider does not mix BIOs from the core
303 with BIOs used on the provider side (the two are not compatible).
304 OSSL_SELF_TEST_set_callback() is used to set an optional callback that can be
305 passed into a provider. This may be ignored by a provider.
307 get_entropy() retrieves seeding material from the operating system.
308 The seeding material will have at least I<entropy> bytes of randomness and the
309 output will have at least I<min_len> and at most I<max_len> bytes.
310 The buffer address is stored in I<*pout> and the buffer length is
311 returned to the caller. On error, zero is returned.
313 cleanup_entropy() is used to clean up and free the buffer returned by
314 get_entropy(). The entropy pointer returned by get_entropy() is passed in
315 B<buf> and its length in B<len>.
317 get_nonce() retrieves a nonce using the passed I<salt> parameter
318 of length I<salt_len> and operating system specific information.
319 The I<salt> should contain uniquely identifying information and this is
320 included, in an unspecified manner, as part of the output.
321 The output is stored in a buffer which contrains at least I<min_len> and at
322 most I<max_len> bytes. The buffer address is stored in I<*pout> and the
323 buffer length returned to the caller. On error, zero is returned.
325 cleanup_nonce() is used to clean up and free the buffer returned by
326 get_nonce(). The nonce pointer returned by get_nonce() is passed in
327 B<buf> and its length in B<len>.
329 provider_register_child_cb() registers callbacks for being informed about the
330 loading and unloading of providers in the application's library context.
331 I<handle> is this provider's handle and I<cbdata> is this provider's data
332 that will be passed back to the callbacks. It returns 1 on success or 0
333 otherwise. These callbacks may be called while holding locks in libcrypto. In
334 order to avoid deadlocks the callback implementation must not be long running
335 and must not call other OpenSSL API functions or upcalls.
337 I<create_cb> is a callback that will be called when a new provider is loaded
338 into the application's library context. It is also called for any providers that
339 are already loaded at the point that this callback is registered. The callback
340 is passed the handle being used for the new provider being loadded and this
341 provider's data in I<cbdata>. It should return 1 on success or 0 on failure.
343 I<remove_cb> is a callback that will be called when a new provider is unloaded
344 from the application's library context. It is passed the handle being used for
345 the provider being unloaded and this provider's data in I<cbdata>. It should
346 return 1 on success or 0 on failure.
348 I<global_props_cb> is a callback that will be called when the global properties
349 from the parent library context are changed. It should return 1 on success
352 provider_deregister_child_cb() unregisters callbacks previously registered via
353 provider_register_child_cb(). If provider_register_child_cb() has been called
354 then provider_deregister_child_cb() should be called at or before the point that
355 this provider's teardown function is called.
357 provider_name() returns a string giving the name of the provider identified by
360 provider_get0_provider_ctx() returns the provider context that is associated
361 with the provider identified by I<prov>.
363 provider_get0_dispatch() gets the dispatch table registered by the provider
364 identified by I<prov> when it initialised.
366 provider_up_ref() increments the reference count on the provider I<prov>. If
367 I<activate> is nonzero then the provider is also loaded if it is not already
368 loaded. It returns 1 on success or 0 on failure.
370 provider_free() decrements the reference count on the provider I<prov>. If
371 I<deactivate> is nonzero then the provider is also unloaded if it is not
372 already loaded. It returns 1 on success or 0 on failure.
374 =head2 Provider functions
376 provider_teardown() is called when a provider is shut down and removed
377 from the core's provider store.
378 It must free the passed I<provctx>.
380 provider_gettable_params() should return a constant array of
381 descriptor B<OSSL_PARAM>, for parameters that provider_get_params()
384 provider_get_params() should process the B<OSSL_PARAM> array
385 I<params>, setting the values of the parameters it understands.
387 provider_query_operation() should return a constant B<OSSL_ALGORITHM>
388 that corresponds to the given I<operation_id>.
389 It should indicate if the core may store a reference to this array by
390 setting I<*no_store> to 0 (core may store a reference) or 1 (core may
391 not store a reference).
393 provider_unquery_operation() informs the provider that the result of a
394 provider_query_operation() is no longer directly required and that the function
395 pointers have been copied. The I<operation_id> should match that passed to
396 provider_query_operation() and I<algs> should be its return value.
398 provider_get_reason_strings() should return a constant B<OSSL_ITEM>
399 array that provides reason strings for reason codes the provider may
400 use when reporting errors using core_put_error().
402 The provider_get_capabilities() function should call the callback I<cb> passing
403 it a set of B<OSSL_PARAM>s and the caller supplied argument I<arg>. The
404 B<OSSL_PARAM>s should provide details about the capability with the name given
405 in the I<capability> argument relevant for the provider context I<provctx>. If a
406 provider supports multiple capabilities with the given name then it may call the
407 callback multiple times (one for each capability). Capabilities can be useful for
408 describing the services that a provider can offer. For further details see the
409 L</CAPABILITIES> section below. It should return 1 on success or 0 on error.
411 The provider_self_test() function should perform known answer tests on a subset
412 of the algorithms that it uses, and may also verify the integrity of the
413 provider module. It should return 1 on success or 0 on error. It will return 1
414 if this function is not used.
416 None of these functions are mandatory, but a provider is fairly
417 useless without at least provider_query_operation(), and
418 provider_gettable_params() is fairly useless if not accompanied by
419 provider_get_params().
421 =head2 Provider parameters
423 provider_get_params() can return the following provider parameters to the core:
427 =item "name" (B<OSSL_PROV_PARAM_NAME>) <UTF8 string ptr>
429 This points to a string that should give a unique name for the provider.
431 =item "version" (B<OSSL_PROV_PARAM_VERSION>) <UTF8 string ptr>
433 This points to a string that is a version number associated with this provider.
434 OpenSSL in-built providers use OPENSSL_VERSION_STR, but this may be different
435 for any third party provider. This string is for informational purposes only.
437 =item "buildinfo" (B<OSSL_PROV_PARAM_BUILDINFO>) <UTF8 string ptr>
439 This points to a string that is a build information associated with this provider.
440 OpenSSL in-built providers use OPENSSL_FULL_VERSION_STR, but this may be
441 different for any third party provider.
443 =item "status" (B<OSSL_PROV_PARAM_STATUS>) <unsigned integer>
445 This returns 0 if the provider has entered an error state, otherwise it returns
450 provider_gettable_params() should return the above parameters.
453 =head2 Core parameters
455 core_get_params() can retrieve the following core parameters for each provider:
459 =item "openssl-version" (B<OSSL_PROV_PARAM_CORE_VERSION>) <UTF8 string ptr>
461 This points to the OpenSSL libraries' full version string, i.e. the string
462 expanded from the macro B<OPENSSL_VERSION_STR>.
464 =item "provider-name" (B<OSSL_PROV_PARAM_CORE_PROV_NAME>) <UTF8 string ptr>
466 This points to the OpenSSL libraries' idea of what the calling provider is named.
468 =item "module-filename" (B<OSSL_PROV_PARAM_CORE_MODULE_FILENAME>) <UTF8 string ptr>
470 This points to a string containing the full filename of the providers
475 Additionally, provider specific configuration parameters from the
476 config file are available, in dotted name form.
477 The dotted name form is a concatenation of section names and final
478 config command name separated by periods.
480 For example, let's say we have the following config example:
482 config_diagnostics = 1
483 openssl_conf = openssl_init
486 providers = providers_sect
500 The provider will have these additional parameters available:
506 pointing at the string "1"
510 pointing at the string "2"
514 pointing at the string "str"
518 pointing at the string "foo,bar"
522 For more information on handling parameters, see L<OSSL_PARAM(3)> as
523 L<OSSL_PARAM_int(3)>.
527 Capabilities describe some of the services that a provider can offer.
528 Applications can query the capabilities to discover those services.
530 =head3 "TLS-GROUP" Capability
532 The "TLS-GROUP" capability can be queried by libssl to discover the list of
533 TLS groups that a provider can support. Each group supported can be used for
534 I<key exchange> (KEX) or I<key encapsulation method> (KEM) during a TLS
536 TLS clients can advertise the list of TLS groups they support in the
537 supported_groups extension, and TLS servers can select a group from the offered
538 list that they also support. In this way a provider can add to the list of
539 groups that libssl already supports with additional ones.
541 Each TLS group that a provider supports should be described via the callback
542 passed in through the provider_get_capabilities function. Each group should have
543 the following details supplied (all are mandatory, except
544 B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM>):
548 =item "tls-group-name" (B<OSSL_CAPABILITY_TLS_GROUP_NAME>) <UTF8 string>
550 The name of the group as given in the IANA TLS Supported Groups registry
551 L<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8>.
553 =item "tls-group-name-internal" (B<OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL>) <UTF8 string>
555 The name of the group as known by the provider. This could be the same as the
556 "tls-group-name", but does not have to be.
558 =item "tls-group-id" (B<OSSL_CAPABILITY_TLS_GROUP_ID>) <unsigned integer>
560 The TLS group id value as given in the IANA TLS Supported Groups registry.
562 =item "tls-group-alg" (B<OSSL_CAPABILITY_TLS_GROUP_ALG>) <UTF8 string>
564 The name of a Key Management algorithm that the provider offers and that should
565 be used with this group. Keys created should be able to support I<key exchange>
566 or I<key encapsulation method> (KEM), as implied by the optional
567 B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM> flag.
568 The algorithm must support key and parameter generation as well as the
569 key/parameter generation parameter, B<OSSL_PKEY_PARAM_GROUP_NAME>. The group
570 name given via "tls-group-name-internal" above will be passed via
571 B<OSSL_PKEY_PARAM_GROUP_NAME> when libssl wishes to generate keys/parameters.
573 =item "tls-group-sec-bits" (B<OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS>) <unsigned integer>
575 The number of bits of security offered by keys in this group. The number of bits
576 should be comparable with the ones given in table 2 and 3 of the NIST SP800-57
579 =item "tls-group-is-kem" (B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM>) <unsigned integer>
581 Boolean flag to describe if the group should be used in I<key exchange> (KEX)
582 mode (0, default) or in I<key encapsulation method> (KEM) mode (1).
584 This parameter is optional: if not specified, KEX mode is assumed as the default
587 In KEX mode, in a typical Diffie-Hellman fashion, both sides execute I<keygen>
588 then I<derive> against the peer public key. To operate in KEX mode, the group
589 implementation must support the provider functions as described in
590 L<provider-keyexch(7)>.
592 In KEM mode, the client executes I<keygen> and sends its public key, the server
593 executes I<encapsulate> using the client's public key and sends back the
594 resulting I<ciphertext>, finally the client executes I<decapsulate> to retrieve
595 the same I<shared secret> generated by the server's I<encapsulate>. To operate
596 in KEM mode, the group implementation must support the provider functions as
597 described in L<provider-kem(7)>.
599 Both in KEX and KEM mode, the resulting I<shared secret> is then used according
600 to the protocol specification.
602 =item "tls-min-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_TLS>) <integer>
604 =item "tls-max-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_TLS>) <integer>
606 =item "tls-min-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS>) <integer>
608 =item "tls-max-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS>) <integer>
610 These parameters can be used to describe the minimum and maximum TLS and DTLS
611 versions supported by the group. The values equate to the on-the-wire encoding
612 of the various TLS versions. For example TLSv1.3 is 0x0304 (772 decimal), and
613 TLSv1.2 is 0x0303 (771 decimal). A 0 indicates that there is no defined minimum
614 or maximum. A -1 indicates that the group should not be used in that protocol.
620 The core_obj_create() and core_obj_add_sigid() functions were not thread safe
625 This is an example of a simple provider made available as a
626 dynamically loadable module.
627 It implements the fictitious algorithm C<FOO> for the fictitious
631 #include <openssl/core.h>
632 #include <openssl/core_dispatch.h>
634 /* Errors used in this provider */
637 static const OSSL_ITEM reasons[] = {
638 { E_MALLOC, "memory allocation failure" }.
639 { 0, NULL } /* Termination */
643 * To ensure we get the function signature right, forward declare
644 * them using function types provided by openssl/core_dispatch.h
646 OSSL_FUNC_bar_newctx_fn foo_newctx;
647 OSSL_FUNC_bar_freectx_fn foo_freectx;
648 OSSL_FUNC_bar_init_fn foo_init;
649 OSSL_FUNC_bar_update_fn foo_update;
650 OSSL_FUNC_bar_final_fn foo_final;
652 OSSL_FUNC_provider_query_operation_fn p_query;
653 OSSL_FUNC_provider_get_reason_strings_fn p_reasons;
654 OSSL_FUNC_provider_teardown_fn p_teardown;
656 OSSL_provider_init_fn OSSL_provider_init;
658 OSSL_FUNC_core_put_error *c_put_error = NULL;
660 /* Provider context */
662 OSSL_CORE_HANDLE *handle;
665 /* operation context for the algorithm FOO */
667 struct prov_ctx_st *provctx;
671 static void *foo_newctx(void *provctx)
673 struct foo_ctx_st *fooctx = malloc(sizeof(*fooctx));
676 fooctx->provctx = provctx;
678 c_put_error(provctx->handle, E_MALLOC, __FILE__, __LINE__);
682 static void foo_freectx(void *fooctx)
687 static int foo_init(void *vfooctx)
689 struct foo_ctx_st *fooctx = vfooctx;
694 static int foo_update(void *vfooctx, unsigned char *in, size_t inl)
696 struct foo_ctx_st *fooctx = vfooctx;
698 /* did you expect something serious? */
701 for (; inl-- > 0; in++)
706 static int foo_final(void *vfooctx)
708 struct foo_ctx_st *fooctx = vfooctx;
713 static const OSSL_DISPATCH foo_fns[] = {
714 { OSSL_FUNC_BAR_NEWCTX, (void (*)(void))foo_newctx },
715 { OSSL_FUNC_BAR_FREECTX, (void (*)(void))foo_freectx },
716 { OSSL_FUNC_BAR_INIT, (void (*)(void))foo_init },
717 { OSSL_FUNC_BAR_UPDATE, (void (*)(void))foo_update },
718 { OSSL_FUNC_BAR_FINAL, (void (*)(void))foo_final },
722 static const OSSL_ALGORITHM bars[] = {
723 { "FOO", "provider=chumbawamba", foo_fns },
727 static const OSSL_ALGORITHM *p_query(void *provctx, int operation_id,
730 switch (operation_id) {
737 static const OSSL_ITEM *p_reasons(void *provctx)
742 static void p_teardown(void *provctx)
747 static const OSSL_DISPATCH prov_fns[] = {
748 { OSSL_FUNC_PROVIDER_TEARDOWN, (void (*)(void))p_teardown },
749 { OSSL_FUNC_PROVIDER_QUERY_OPERATION, (void (*)(void))p_query },
750 { OSSL_FUNC_PROVIDER_GET_REASON_STRINGS, (void (*)(void))p_reasons },
754 int OSSL_provider_init(const OSSL_CORE_HANDLE *handle,
755 const OSSL_DISPATCH *in,
756 const OSSL_DISPATCH **out,
759 struct prov_ctx_st *pctx = NULL;
761 for (; in->function_id != 0; in++)
762 switch (in->function_id) {
763 case OSSL_FUNC_CORE_PUT_ERROR:
764 c_put_error = OSSL_FUNC_core_put_error(in);
770 if ((pctx = malloc(sizeof(*pctx))) == NULL) {
772 * ALEA IACTA EST, if the core retrieves the reason table
773 * regardless, that string will be displayed, otherwise not.
775 c_put_error(handle, E_MALLOC, __FILE__, __LINE__);
778 pctx->handle = handle;
782 This relies on a few things existing in F<openssl/core_dispatch.h>:
784 #define OSSL_OP_BAR 4711
786 #define OSSL_FUNC_BAR_NEWCTX 1
787 typedef void *(OSSL_FUNC_bar_newctx_fn)(void *provctx);
788 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
789 { return (OSSL_FUNC_bar_newctx_fn *)opf->function; }
791 #define OSSL_FUNC_BAR_FREECTX 2
792 typedef void (OSSL_FUNC_bar_freectx_fn)(void *ctx);
793 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
794 { return (OSSL_FUNC_bar_freectx_fn *)opf->function; }
796 #define OSSL_FUNC_BAR_INIT 3
797 typedef void *(OSSL_FUNC_bar_init_fn)(void *ctx);
798 static ossl_inline OSSL_FUNC_bar_init(const OSSL_DISPATCH *opf)
799 { return (OSSL_FUNC_bar_init_fn *)opf->function; }
801 #define OSSL_FUNC_BAR_UPDATE 4
802 typedef void *(OSSL_FUNC_bar_update_fn)(void *ctx,
803 unsigned char *in, size_t inl);
804 static ossl_inline OSSL_FUNC_bar_update(const OSSL_DISPATCH *opf)
805 { return (OSSL_FUNC_bar_update_fn *)opf->function; }
807 #define OSSL_FUNC_BAR_FINAL 5
808 typedef void *(OSSL_FUNC_bar_final_fn)(void *ctx);
809 static ossl_inline OSSL_FUNC_bar_final(const OSSL_DISPATCH *opf)
810 { return (OSSL_FUNC_bar_final_fn *)opf->function; }
818 The concept of providers and everything surrounding them was
819 introduced in OpenSSL 3.0.
823 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
825 Licensed under the Apache License 2.0 (the "License"). You may not use
826 this file except in compliance with the License. You can obtain a copy
827 in the file LICENSE in the source distribution or at
828 L<https://www.openssl.org/source/license.html>.