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.
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 library context in which the library
224 object for the current provider is stored, accessible through the I<handle>.
225 This may sometimes be useful if the provider wishes to store a
226 reference to its context in the same library context.
228 core_new_error(), core_set_error_debug() and core_vset_error() are
229 building blocks for reporting an error back to the core, with
230 reference to the I<handle>.
234 =item core_new_error()
236 allocates a new thread specific error record.
238 This corresponds to the OpenSSL function L<ERR_new(3)>.
240 =item core_set_error_debug()
242 sets debugging information in the current thread specific error
244 The debugging information includes the name of the file I<file>, the
245 line I<line> and the function name I<func> where the error occurred.
247 This corresponds to the OpenSSL function L<ERR_set_debug(3)>.
249 =item core_vset_error()
251 sets the I<reason> for the error, along with any addition data.
252 The I<reason> is a number defined by the provider and used to index
253 the reason strings table that's returned by
254 provider_get_reason_strings().
255 The additional data is given as a format string I<fmt> and a set of
256 arguments I<args>, which are treated in the same manner as with
258 I<file> and I<line> may also be passed to indicate exactly where the
259 error occurred or was reported.
261 This corresponds to the OpenSSL function L<ERR_vset_error(3)>.
265 The core_obj_create() function registers a new OID and associated short name
266 I<sn> and long name I<ln> for the given I<handle>. It is similar to the OpenSSL
267 function L<OBJ_create(3)> except that it returns 1 on success or 0 on failure.
268 It will treat as success the case where the OID already exists (even if the
269 short name I<sn> or long name I<ln> provided as arguments differ from those
270 associated with the existing OID, in which case the new names are not
272 This function is not thread safe.
274 The core_obj_add_sigid() function registers a new composite signature algorithm
275 (I<sign_name>) consisting of an underlying signature algorithm (I<pkey_name>)
276 and digest algorithm (I<digest_name>) for the given I<handle>. It assumes that
277 the OIDs for the composite signature algorithm as well as for the underlying
278 signature and digest algorithms are either already known to OpenSSL or have been
279 registered via a call to core_obj_create(). It corresponds to the OpenSSL
280 function L<OBJ_add_sigid(3)>, except that the objects are identified by name
281 rather than a numeric NID. Any name (OID, short name or long name) can be used
282 to identify the object. It will treat as success the case where the composite
283 signature algorithm already exists (even if registered against a different
284 underlying signature or digest algorithm). It returns 1 on success or 0 on
286 This function is not thread safe.
288 CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_memdup(), CRYPTO_strdup(),
289 CRYPTO_strndup(), CRYPTO_free(), CRYPTO_clear_free(),
290 CRYPTO_realloc(), CRYPTO_clear_realloc(), CRYPTO_secure_malloc(),
291 CRYPTO_secure_zalloc(), CRYPTO_secure_free(),
292 CRYPTO_secure_clear_free(), CRYPTO_secure_allocated(),
293 BIO_new_file(), BIO_new_mem_buf(), BIO_read_ex(), BIO_write_ex(), BIO_up_ref(),
294 BIO_free(), BIO_vprintf(), BIO_vsnprintf(), BIO_gets(), BIO_puts(),
295 BIO_ctrl(), OPENSSL_cleanse() and
296 OPENSSL_hexstr2buf() correspond exactly to the public functions with
297 the same name. As a matter of fact, the pointers in the B<OSSL_DISPATCH>
298 array are typically direct pointers to those public functions. Note that the BIO
299 functions take an B<OSSL_CORE_BIO> type rather than the standard B<BIO>
300 type. This is to ensure that a provider does not mix BIOs from the core
301 with BIOs used on the provider side (the two are not compatible).
302 OSSL_SELF_TEST_set_callback() is used to set an optional callback that can be
303 passed into a provider. This may be ignored by a provider.
305 get_entropy() retrieves seeding material from the operating system.
306 The seeding material will have at least I<entropy> bytes of randomness and the
307 output will have at least I<min_len> and at most I<max_len> bytes.
308 The buffer address is stored in I<*pout> and the buffer length is
309 returned to the caller. On error, zero is returned.
311 cleanup_entropy() is used to clean up and free the buffer returned by
312 get_entropy(). The entropy pointer returned by get_entropy() is passed in
313 B<buf> and its length in B<len>.
315 get_nonce() retrieves a nonce using the passed I<salt> parameter
316 of length I<salt_len> and operating system specific information.
317 The I<salt> should contain uniquely identifying information and this is
318 included, in an unspecified manner, as part of the output.
319 The output is stored in a buffer which contrains at least I<min_len> and at
320 most I<max_len> bytes. The buffer address is stored in I<*pout> and the
321 buffer length returned to the caller. On error, zero is returned.
323 cleanup_nonce() is used to clean up and free the buffer returned by
324 get_nonce(). The nonce pointer returned by get_nonce() is passed in
325 B<buf> and its length in B<len>.
327 provider_register_child_cb() registers callbacks for being informed about the
328 loading and unloading of providers in the application's library context.
329 I<handle> is this provider's handle and I<cbdata> is this provider's data
330 that will be passed back to the callbacks. It returns 1 on success or 0
333 I<create_cb> is a callback that will be called when a new provider is loaded
334 into the application's library context. It is also called for any providers that
335 are already loaded at the point that this callback is registered. The callback
336 is passed the handle being used for the new provider being loadded and this
337 provider's data in I<cbdata>. It should return 1 on success or 0 on failure.
339 I<remove_cb> is a callback that will be called when a new provider is unloaded
340 from the application's library context. It is passed the handle being used for
341 the provider being unloaded and this provider's data in I<cbdata>. It should
342 return 1 on success or 0 on failure.
344 I<global_props_cb> is a callback that will be called when the global properties
345 from the parent library context are changed. It should return 1 on success
348 provider_deregister_child_cb() unregisters callbacks previously registered via
349 provider_register_child_cb(). If provider_register_child_cb() has been called
350 then provider_deregister_child_cb() should be called at or before the point that
351 this provider's teardown function is called.
353 provider_name() returns a string giving the name of the provider identified by
356 provider_get0_provider_ctx() returns the provider context that is associated
357 with the provider identified by I<prov>.
359 provider_get0_dispatch() gets the dispatch table registered by the provider
360 identified by I<prov> when it initialised.
362 provider_up_ref() increments the reference count on the provider I<prov>. If
363 I<activate> is nonzero then the provider is also loaded if it is not already
364 loaded. It returns 1 on success or 0 on failure.
366 provider_free() decrements the reference count on the provider I<prov>. If
367 I<deactivate> is nonzero then the provider is also unloaded if it is not
368 already loaded. It returns 1 on success or 0 on failure.
370 =head2 Provider functions
372 provider_teardown() is called when a provider is shut down and removed
373 from the core's provider store.
374 It must free the passed I<provctx>.
376 provider_gettable_params() should return a constant array of
377 descriptor B<OSSL_PARAM>, for parameters that provider_get_params()
380 provider_get_params() should process the B<OSSL_PARAM> array
381 I<params>, setting the values of the parameters it understands.
383 provider_query_operation() should return a constant B<OSSL_ALGORITHM>
384 that corresponds to the given I<operation_id>.
385 It should indicate if the core may store a reference to this array by
386 setting I<*no_store> to 0 (core may store a reference) or 1 (core may
387 not store a reference).
389 provider_unquery_operation() informs the provider that the result of a
390 provider_query_operation() is no longer directly required and that the function
391 pointers have been copied. The I<operation_id> should match that passed to
392 provider_query_operation() and I<algs> should be its return value.
394 provider_get_reason_strings() should return a constant B<OSSL_ITEM>
395 array that provides reason strings for reason codes the provider may
396 use when reporting errors using core_put_error().
398 The provider_get_capabilities() function should call the callback I<cb> passing
399 it a set of B<OSSL_PARAM>s and the caller supplied argument I<arg>. The
400 B<OSSL_PARAM>s should provide details about the capability with the name given
401 in the I<capability> argument relevant for the provider context I<provctx>. If a
402 provider supports multiple capabilities with the given name then it may call the
403 callback multiple times (one for each capability). Capabilities can be useful for
404 describing the services that a provider can offer. For further details see the
405 L</CAPABILITIES> section below. It should return 1 on success or 0 on error.
407 The provider_self_test() function should perform known answer tests on a subset
408 of the algorithms that it uses, and may also verify the integrity of the
409 provider module. It should return 1 on success or 0 on error. It will return 1
410 if this function is not used.
412 None of these functions are mandatory, but a provider is fairly
413 useless without at least provider_query_operation(), and
414 provider_gettable_params() is fairly useless if not accompanied by
415 provider_get_params().
417 =head2 Provider parameters
419 provider_get_params() can return the following provider parameters to the core:
423 =item "name" (B<OSSL_PROV_PARAM_NAME>) <UTF8 string ptr>
425 This points to a string that should give a unique name for the provider.
427 =item "version" (B<OSSL_PROV_PARAM_VERSION>) <UTF8 string ptr>
429 This points to a string that is a version number associated with this provider.
430 OpenSSL in-built providers use OPENSSL_VERSION_STR, but this may be different
431 for any third party provider. This string is for informational purposes only.
433 =item "buildinfo" (B<OSSL_PROV_PARAM_BUILDINFO>) <UTF8 string ptr>
435 This points to a string that is a build information associated with this provider.
436 OpenSSL in-built providers use OPENSSL_FULL_VERSION_STR, but this may be
437 different for any third party provider.
439 =item "status" (B<OSSL_PROV_PARAM_STATUS>) <unsigned integer>
441 This returns 0 if the provider has entered an error state, otherwise it returns
446 provider_gettable_params() should return the above parameters.
449 =head2 Core parameters
451 core_get_params() can retrieve the following core parameters for each provider:
455 =item "openssl-version" (B<OSSL_PROV_PARAM_CORE_VERSION>) <UTF8 string ptr>
457 This points to the OpenSSL libraries' full version string, i.e. the string
458 expanded from the macro B<OPENSSL_VERSION_STR>.
460 =item "provider-name" (B<OSSL_PROV_PARAM_CORE_PROV_NAME>) <UTF8 string ptr>
462 This points to the OpenSSL libraries' idea of what the calling provider is named.
464 =item "module-filename" (B<OSSL_PROV_PARAM_CORE_MODULE_FILENAME>) <UTF8 string ptr>
466 This points to a string containing the full filename of the providers
471 Additionally, provider specific configuration parameters from the
472 config file are available, in dotted name form.
473 The dotted name form is a concatenation of section names and final
474 config command name separated by periods.
476 For example, let's say we have the following config example:
478 config_diagnostics = 1
479 openssl_conf = openssl_init
482 providers = providers_sect
496 The provider will have these additional parameters available:
502 pointing at the string "1"
506 pointing at the string "2"
510 pointing at the string "str"
514 pointing at the string "foo,bar"
518 For more information on handling parameters, see L<OSSL_PARAM(3)> as
519 L<OSSL_PARAM_int(3)>.
523 Capabilities describe some of the services that a provider can offer.
524 Applications can query the capabilities to discover those services.
526 =head3 "TLS-GROUP" Capability
528 The "TLS-GROUP" capability can be queried by libssl to discover the list of
529 TLS groups that a provider can support. Each group supported can be used for
530 I<key exchange> (KEX) or I<key encapsulation method> (KEM) during a TLS
532 TLS clients can advertise the list of TLS groups they support in the
533 supported_groups extension, and TLS servers can select a group from the offered
534 list that they also support. In this way a provider can add to the list of
535 groups that libssl already supports with additional ones.
537 Each TLS group that a provider supports should be described via the callback
538 passed in through the provider_get_capabilities function. Each group should have
539 the following details supplied (all are mandatory, except
540 B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM>):
544 =item "tls-group-name" (B<OSSL_CAPABILITY_TLS_GROUP_NAME>) <UTF8 string>
546 The name of the group as given in the IANA TLS Supported Groups registry
547 L<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8>.
549 =item "tls-group-name-internal" (B<OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL>) <UTF8 string>
551 The name of the group as known by the provider. This could be the same as the
552 "tls-group-name", but does not have to be.
554 =item "tls-group-id" (B<OSSL_CAPABILITY_TLS_GROUP_ID>) <unsigned integer>
556 The TLS group id value as given in the IANA TLS Supported Groups registry.
558 =item "tls-group-alg" (B<OSSL_CAPABILITY_TLS_GROUP_ALG>) <UTF8 string>
560 The name of a Key Management algorithm that the provider offers and that should
561 be used with this group. Keys created should be able to support I<key exchange>
562 or I<key encapsulation method> (KEM), as implied by the optional
563 B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM> flag.
564 The algorithm must support key and parameter generation as well as the
565 key/parameter generation parameter, B<OSSL_PKEY_PARAM_GROUP_NAME>. The group
566 name given via "tls-group-name-internal" above will be passed via
567 B<OSSL_PKEY_PARAM_GROUP_NAME> when libssl wishes to generate keys/parameters.
569 =item "tls-group-sec-bits" (B<OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS>) <unsigned integer>
571 The number of bits of security offered by keys in this group. The number of bits
572 should be comparable with the ones given in table 2 and 3 of the NIST SP800-57
575 =item "tls-group-is-kem" (B<OSSL_CAPABILITY_TLS_GROUP_IS_KEM>) <unsigned integer>
577 Boolean flag to describe if the group should be used in I<key exchange> (KEX)
578 mode (0, default) or in I<key encapsulation method> (KEM) mode (1).
580 This parameter is optional: if not specified, KEX mode is assumed as the default
583 In KEX mode, in a typical Diffie-Hellman fashion, both sides execute I<keygen>
584 then I<derive> against the peer public key. To operate in KEX mode, the group
585 implementation must support the provider functions as described in
586 L<provider-keyexch(7)>.
588 In KEM mode, the client executes I<keygen> and sends its public key, the server
589 executes I<encapsulate> using the client's public key and sends back the
590 resulting I<ciphertext>, finally the client executes I<decapsulate> to retrieve
591 the same I<shared secret> generated by the server's I<encapsulate>. To operate
592 in KEM mode, the group implementation must support the provider functions as
593 described in L<provider-kem(7)>.
595 Both in KEX and KEM mode, the resulting I<shared secret> is then used according
596 to the protocol specification.
598 =item "tls-min-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_TLS>) <integer>
600 =item "tls-max-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_TLS>) <integer>
602 =item "tls-min-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS>) <integer>
604 =item "tls-max-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS>) <integer>
606 These parameters can be used to describe the minimum and maximum TLS and DTLS
607 versions supported by the group. The values equate to the on-the-wire encoding
608 of the various TLS versions. For example TLSv1.3 is 0x0304 (772 decimal), and
609 TLSv1.2 is 0x0303 (771 decimal). A 0 indicates that there is no defined minimum
610 or maximum. A -1 indicates that the group should not be used in that protocol.
616 This is an example of a simple provider made available as a
617 dynamically loadable module.
618 It implements the fictitious algorithm C<FOO> for the fictitious
622 #include <openssl/core.h>
623 #include <openssl/core_dispatch.h>
625 /* Errors used in this provider */
628 static const OSSL_ITEM reasons[] = {
629 { E_MALLOC, "memory allocation failure" }.
630 { 0, NULL } /* Termination */
634 * To ensure we get the function signature right, forward declare
635 * them using function types provided by openssl/core_dispatch.h
637 OSSL_FUNC_bar_newctx_fn foo_newctx;
638 OSSL_FUNC_bar_freectx_fn foo_freectx;
639 OSSL_FUNC_bar_init_fn foo_init;
640 OSSL_FUNC_bar_update_fn foo_update;
641 OSSL_FUNC_bar_final_fn foo_final;
643 OSSL_FUNC_provider_query_operation_fn p_query;
644 OSSL_FUNC_provider_get_reason_strings_fn p_reasons;
645 OSSL_FUNC_provider_teardown_fn p_teardown;
647 OSSL_provider_init_fn OSSL_provider_init;
649 OSSL_FUNC_core_put_error *c_put_error = NULL;
651 /* Provider context */
653 OSSL_CORE_HANDLE *handle;
656 /* operation context for the algorithm FOO */
658 struct prov_ctx_st *provctx;
662 static void *foo_newctx(void *provctx)
664 struct foo_ctx_st *fooctx = malloc(sizeof(*fooctx));
667 fooctx->provctx = provctx;
669 c_put_error(provctx->handle, E_MALLOC, __FILE__, __LINE__);
673 static void foo_freectx(void *fooctx)
678 static int foo_init(void *vfooctx)
680 struct foo_ctx_st *fooctx = vfooctx;
685 static int foo_update(void *vfooctx, unsigned char *in, size_t inl)
687 struct foo_ctx_st *fooctx = vfooctx;
689 /* did you expect something serious? */
692 for (; inl-- > 0; in++)
697 static int foo_final(void *vfooctx)
699 struct foo_ctx_st *fooctx = vfooctx;
704 static const OSSL_DISPATCH foo_fns[] = {
705 { OSSL_FUNC_BAR_NEWCTX, (void (*)(void))foo_newctx },
706 { OSSL_FUNC_BAR_FREECTX, (void (*)(void))foo_freectx },
707 { OSSL_FUNC_BAR_INIT, (void (*)(void))foo_init },
708 { OSSL_FUNC_BAR_UPDATE, (void (*)(void))foo_update },
709 { OSSL_FUNC_BAR_FINAL, (void (*)(void))foo_final },
713 static const OSSL_ALGORITHM bars[] = {
714 { "FOO", "provider=chumbawamba", foo_fns },
718 static const OSSL_ALGORITHM *p_query(void *provctx, int operation_id,
721 switch (operation_id) {
728 static const OSSL_ITEM *p_reasons(void *provctx)
733 static void p_teardown(void *provctx)
738 static const OSSL_DISPATCH prov_fns[] = {
739 { OSSL_FUNC_PROVIDER_TEARDOWN, (void (*)(void))p_teardown },
740 { OSSL_FUNC_PROVIDER_QUERY_OPERATION, (void (*)(void))p_query },
741 { OSSL_FUNC_PROVIDER_GET_REASON_STRINGS, (void (*)(void))p_reasons },
745 int OSSL_provider_init(const OSSL_CORE_HANDLE *handle,
746 const OSSL_DISPATCH *in,
747 const OSSL_DISPATCH **out,
750 struct prov_ctx_st *pctx = NULL;
752 for (; in->function_id != 0; in++)
753 switch (in->function_id) {
754 case OSSL_FUNC_CORE_PUT_ERROR:
755 c_put_error = OSSL_FUNC_core_put_error(in);
761 if ((pctx = malloc(sizeof(*pctx))) == NULL) {
763 * ALEA IACTA EST, if the core retrieves the reason table
764 * regardless, that string will be displayed, otherwise not.
766 c_put_error(handle, E_MALLOC, __FILE__, __LINE__);
769 pctx->handle = handle;
773 This relies on a few things existing in F<openssl/core_dispatch.h>:
775 #define OSSL_OP_BAR 4711
777 #define OSSL_FUNC_BAR_NEWCTX 1
778 typedef void *(OSSL_FUNC_bar_newctx_fn)(void *provctx);
779 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
780 { return (OSSL_FUNC_bar_newctx_fn *)opf->function; }
782 #define OSSL_FUNC_BAR_FREECTX 2
783 typedef void (OSSL_FUNC_bar_freectx_fn)(void *ctx);
784 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
785 { return (OSSL_FUNC_bar_freectx_fn *)opf->function; }
787 #define OSSL_FUNC_BAR_INIT 3
788 typedef void *(OSSL_FUNC_bar_init_fn)(void *ctx);
789 static ossl_inline OSSL_FUNC_bar_init(const OSSL_DISPATCH *opf)
790 { return (OSSL_FUNC_bar_init_fn *)opf->function; }
792 #define OSSL_FUNC_BAR_UPDATE 4
793 typedef void *(OSSL_FUNC_bar_update_fn)(void *ctx,
794 unsigned char *in, size_t inl);
795 static ossl_inline OSSL_FUNC_bar_update(const OSSL_DISPATCH *opf)
796 { return (OSSL_FUNC_bar_update_fn *)opf->function; }
798 #define OSSL_FUNC_BAR_FINAL 5
799 typedef void *(OSSL_FUNC_bar_final_fn)(void *ctx);
800 static ossl_inline OSSL_FUNC_bar_final(const OSSL_DISPATCH *opf)
801 { return (OSSL_FUNC_bar_final_fn *)opf->function; }
809 The concept of providers and everything surrounding them was
810 introduced in OpenSSL 3.0.
814 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
816 Licensed under the Apache License 2.0 (the "License"). You may not use
817 this file except in compliance with the License. You can obtain a copy
818 in the file LICENSE in the source distribution or at
819 L<https://www.openssl.org/source/license.html>.