6 - The basic OpenSSL library E<lt>-E<gt> provider functions
10 #include <openssl/core_numbers.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[]);
21 int core_thread_start(const OSSL_CORE_HANDLE *handle,
22 OSSL_thread_stop_handler_fn handfn);
23 OPENSSL_CORE_CTX *core_get_library_context(const OSSL_CORE_HANDLE *handle);
24 void core_new_error(const OSSL_CORE_HANDLE *handle);
25 void core_set_error_debug(const OSSL_CORE_HANDLE *handle,
26 const char *file, int line, const char *func);
27 void core_vset_error(const OSSL_CORE_HANDLE *handle,
28 uint32_t reason, const char *fmt, va_list args);
31 * Some OpenSSL functionality is directly offered to providers via
34 void *CRYPTO_malloc(size_t num, const char *file, int line);
35 void *CRYPTO_zalloc(size_t num, const char *file, int line);
36 void *CRYPTO_memdup(const void *str, size_t siz,
37 const char *file, int line);
38 char *CRYPTO_strdup(const char *str, const char *file, int line);
39 char *CRYPTO_strndup(const char *str, size_t s,
40 const char *file, int line);
41 void CRYPTO_free(void *ptr, const char *file, int line);
42 void CRYPTO_clear_free(void *ptr, size_t num,
43 const char *file, int line);
44 void *CRYPTO_realloc(void *addr, size_t num,
45 const char *file, int line);
46 void *CRYPTO_clear_realloc(void *addr, size_t old_num, size_t num,
47 const char *file, int line);
48 void *CRYPTO_secure_malloc(size_t num, const char *file, int line);
49 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);
50 void CRYPTO_secure_free(void *ptr, const char *file, int line);
51 void CRYPTO_secure_clear_free(void *ptr, size_t num,
52 const char *file, int line);
53 int CRYPTO_secure_allocated(const void *ptr);
54 void OPENSSL_cleanse(void *ptr, size_t len);
56 OSSL_CORE_BIO * BIO_new_file(const char *filename, const char *mode)
57 OSSL_CORE_BIO * BIO_new_membuf(const void *buf, int len)
58 int BIO_read_ex(OSSL_CORE_BIO *bio, void *data, size_t data_len,
60 int BIO_write_ex(OSSL_CORE_BIO *bio, const void *data, size_t data_len,
62 int BIO_free(OSSL_CORE_BIO *bio))
63 int BIO_vprintf(OSSL_CORE_BIO *bio, const char *format, va_list args)
64 int BIO_vsnprintf(char *buf, size_t n, const char *fmt, va_list args)
66 void self_test_cb(OPENSSL_CORE_CTX *ctx, OSSL_CALLBACK **cb, void **cbarg)
69 /* Functions offered by the provider to libcrypto */
70 void provider_teardown(void *provctx);
71 const OSSL_ITEM *provider_gettable_params(void *provctx);
72 int provider_get_params(void *provctx, OSSL_PARAM params[]);
73 const OSSL_ALGORITHM *provider_query_operation(void *provctx,
76 const OSSL_ITEM *provider_get_reason_strings(void *provctx);
77 int provider_get_capabilities(void *provctx, const char *capability,
78 OSSL_CALLBACK *cb, void *arg);
82 All "functions" mentioned here are passed as function pointers between
83 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays, in the call
84 of the provider initialization function. See L<provider(7)/Provider>
85 for a description of the initialization function.
87 All these "functions" have a corresponding function type definition
88 named B<OSSL_{name}_fn>, and a helper function to retrieve the
89 function pointer from a B<OSSL_DISPATCH> element named
91 For example, the "function" core_gettable_params() has these:
94 (OSSL_core_gettable_params_fn)(const OSSL_CORE_HANDLE *handle);
95 static ossl_inline OSSL_NAME_core_gettable_params_fn
96 OSSL_get_core_gettable_params(const OSSL_DISPATCH *opf);
98 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
99 macros in L<openssl-core_numbers.h(7)>, as follows:
101 For I<in> (the B<OSSL_DISPATCH> array passed from F<libcrypto> to the
104 core_gettable_params OSSL_FUNC_CORE_GETTABLE_PARAMS
105 core_get_params OSSL_FUNC_CORE_GET_PARAMS
106 core_thread_start OSSL_FUNC_CORE_THREAD_START
107 core_get_library_context OSSL_FUNC_CORE_GET_LIBRARY_CONTEXT
108 core_new_error OSSL_FUNC_CORE_NEW_ERROR
109 core_set_error_debug OSSL_FUNC_CORE_SET_ERROR_DEBUG
110 core_set_error OSSL_FUNC_CORE_SET_ERROR
111 CRYPTO_malloc OSSL_FUNC_CRYPTO_MALLOC
112 CRYPTO_zalloc OSSL_FUNC_CRYPTO_ZALLOC
113 CRYPTO_memdup OSSL_FUNC_CRYPTO_MEMDUP
114 CRYPTO_strdup OSSL_FUNC_CRYPTO_STRDUP
115 CRYPTO_strndup OSSL_FUNC_CRYPTO_STRNDUP
116 CRYPTO_free OSSL_FUNC_CRYPTO_FREE
117 CRYPTO_clear_free OSSL_FUNC_CRYPTO_CLEAR_FREE
118 CRYPTO_realloc OSSL_FUNC_CRYPTO_REALLOC
119 CRYPTO_clear_realloc OSSL_FUNC_CRYPTO_CLEAR_REALLOC
120 CRYPTO_secure_malloc OSSL_FUNC_CRYPTO_SECURE_MALLOC
121 CRYPTO_secure_zalloc OSSL_FUNC_CRYPTO_SECURE_ZALLOC
122 CRYPTO_secure_free OSSL_FUNC_CRYPTO_SECURE_FREE
123 CRYPTO_secure_clear_free OSSL_FUNC_CRYPTO_SECURE_CLEAR_FREE
124 CRYPTO_secure_allocated OSSL_FUNC_CRYPTO_SECURE_ALLOCATED
125 BIO_new_file OSSL_FUNC_BIO_NEW_FILE
126 BIO_new_mem_buf OSSL_FUNC_BIO_NEW_MEMBUF
127 BIO_read_ex OSSL_FUNC_BIO_READ_EX
128 BIO_free OSSL_FUNC_BIO_FREE
129 BIO_vprintf OSSL_FUNC_BIO_VPRINTF
130 OPENSSL_cleanse OSSL_FUNC_OPENSSL_CLEANSE
131 OSSL_SELF_TEST_set_callback OSSL_FUNC_SELF_TEST_CB
133 For I<*out> (the B<OSSL_DISPATCH> array passed from the provider to
136 provider_teardown OSSL_FUNC_PROVIDER_TEARDOWN
137 provider_gettable_params OSSL_FUNC_PROVIDER_GETTABLE_PARAMS
138 provider_get_params OSSL_FUNC_PROVIDER_GET_PARAMS
139 provider_query_operation OSSL_FUNC_PROVIDER_QUERY_OPERATION
140 provider_get_reason_strings OSSL_FUNC_PROVIDER_GET_REASON_STRINGS
141 provider_get_capabilities OSSL_FUNC_PROVIDER_GET_CAPABILITIES
143 =head2 Core functions
145 core_gettable_params() returns a constant array of descriptor
146 B<OSSL_PARAM>, for parameters that core_get_params() can handle.
148 core_get_params() retrieves parameters from the core for the given I<handle>.
149 See L</Core parameters> below for a description of currently known
152 =for comment core_thread_start() TBA
154 core_get_library_context() retrieves the library context in which the library
155 object for the current provider is stored, accessible through the I<handle>.
156 This may sometimes be useful if the provider wishes to store a
157 reference to its context in the same library context.
159 core_new_error(), core_set_error_debug() and core_set_error() are
160 building blocks for reporting an error back to the core, with
161 reference to the I<handle>.
165 =item core_new_error()
167 allocates a new thread specific error record.
169 This corresponds to the OpenSSL function L<ERR_new(3)>.
171 =item core_set_error_debug()
173 sets debugging information in the current thread specific error
175 The debugging information includes the name of the file I<file>, the
176 line I<line> and the function name I<func> where the error occurred.
178 This corresponds to the OpenSSL function L<ERR_set_debug(3)>.
180 =item core_set_error()
182 sets the I<reason> for the error, along with any addition data.
183 The I<reason> is a number defined by the provider and used to index
184 the reason strings table that's returned by
185 provider_get_reason_strings().
186 The additional data is given as a format string I<fmt> and a set of
187 arguments I<args>, which are treated in the same manner as with
189 I<file> and I<line> may also be passed to indicate exactly where the
190 error occurred or was reported.
192 This corresponds to the OpenSSL function L<ERR_vset_error(3)>.
196 CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_memdup(), CRYPTO_strdup(),
197 CRYPTO_strndup(), CRYPTO_free(), CRYPTO_clear_free(),
198 CRYPTO_realloc(), CRYPTO_clear_realloc(), CRYPTO_secure_malloc(),
199 CRYPTO_secure_zalloc(), CRYPTO_secure_free(),
200 CRYPTO_secure_clear_free(), CRYPTO_secure_allocated(),
201 BIO_new_file(), BIO_new_mem_buf(), BIO_read_ex(), BIO_free(),
202 BIO_vprintf(), OPENSSL_cleanse(), and OPENSSL_hexstr2buf()
203 correspond exactly to the public functions with the same name.
204 As a matter of fact, the pointers in the B<OSSL_DISPATCH> array are
205 direct pointers to those public functions. Note that the BIO functions take an
206 B<OSSL_CORE_BIO> type rather than the standard B<BIO> type. This is to ensure
207 that a provider does not mix BIOs from the core with BIOs used on the provider
208 side (the two are not compatible).
209 OSSL_SELF_TEST_set_callback() is used to set an optional callback that can be
210 passed into a provider. This may be ignored by a provider.
212 =head2 Provider functions
214 provider_teardown() is called when a provider is shut down and removed
215 from the core's provider store.
216 It must free the passed I<provctx>.
218 provider_gettable_params() should return a constant array of
219 descriptor B<OSSL_PARAM>, for parameters that provider_get_params()
222 provider_get_params() should process the B<OSSL_PARAM> array
223 I<params>, setting the values of the parameters it understands.
225 provider_query_operation() should return a constant B<OSSL_ALGORITHM>
226 that corresponds to the given I<operation_id>.
227 It should indicate if the core may store a reference to this array by
228 setting I<*no_store> to 0 (core may store a reference) or 1 (core may
229 not store a reference).
231 provider_get_reason_strings() should return a constant B<OSSL_ITEM>
232 array that provides reason strings for reason codes the provider may
233 use when reporting errors using core_put_error().
235 The provider_get_capabilities() function should call the callback I<cb> passing
236 it a set of B<OSSL_PARAM>s and the caller supplied argument I<arg>. The
237 B<OSSL_PARAM>s should provide details about the capability with the name given
238 in the I<capability> argument relevant for the provider context I<provctx>. If a
239 provider supports multiple capabilities with the given name then it may call the
240 callback multipe times (one for each capability). Capabilities can be useful for
241 describing the services that a provider can offer. For further details see the
242 L</CAPABILITIES> section below. It should return 1 on success or 0 on error.
244 None of these functions are mandatory, but a provider is fairly
245 useless without at least provider_query_operation(), and
246 provider_gettable_params() is fairly useless if not accompanied by
247 provider_get_params().
249 =head2 Provider parameters
251 provider_get_params() can return the following provider parameters to the core:
255 =item "name" (B<OSSL_PROV_PARAM_NAME>) <UTF8_ptr>
257 This points to a string that should give a unique name for the provider.
259 =item "version" (B<OSSL_PROV_PARAM_VERSION>) <UTF8_ptr>
261 This points to a string that is a version number associated with this provider.
262 OpenSSL in-built providers use OPENSSL_VERSION_STR, but this may be different
263 for any third party provider. This string is for informational purposes only.
265 =item "buildinfo" (B<OSSL_PROV_PARAM_BUILDINFO>) <UTF8_ptr>
267 This points to a string that is a build information associated with this provider.
268 OpenSSL in-built providers use OPENSSL_FULL_VERSION_STR, but this may be
269 different for any third party provider.
273 provider_gettable_params() should return the above parameters.
276 =head2 Core parameters
278 core_get_params() can retrieve the following core parameters for each provider:
282 =item "openssl-version" (B<OSSL_PROV_PARAM_CORE_VERSION>) <UTF8_ptr>
284 This points to the OpenSSL libraries' full version string, i.e. the string
285 expanded from the macro B<OPENSSL_VERSION_STR>.
287 =item "provider-name" (B<OSSL_PROV_PARAM_CORE_PROV_NAME>) <UTF8_ptr>
289 This points to the OpenSSL libraries' idea of what the calling provider is named.
291 =item "module-filename" (B<OSSL_PROV_PARAM_CORE_MODULE_FILENAME>) <UTF8_ptr>
293 This points to a string containing the full filename of the providers
298 Additionally, provider specific configuration parameters from the
299 config file are available, in dotted name form.
300 The dotted name form is a concatenation of section names and final
301 config command name separated by periods.
303 For example, let's say we have the following config example:
305 openssl_conf = openssl_init
308 providers = providers_sect
322 The provider will have these additional parameters available:
328 pointing at the string "1"
332 pointing at the string "2"
336 pointing at the string "str"
340 pointing at the string "foo,bar"
344 For more information on handling parameters, see L<OSSL_PARAM(3)> as
345 L<OSSL_PARAM_int(3)>.
349 Capabilties describe some of the services that a provider can offer.
350 Applications can query the capabilities to discover those services.
352 =head3 "TLS-GROUP" Capability
354 The "TLS-GROUP" capability can be queried by libssl to discover the list of
355 TLS groups that a provider can support. Each group supported can be used for
356 key exchange during a TLS handshake. TLS clients can advertise the list of
357 TLS groups they support in the supported_groups extension, and TLS servers can
358 select a group from the offered list that they also support. In this way a
359 provider can add to the list of groups that libssl already supports with
362 Each TLS group that a provider supports should be described via the callback
363 passed in through the provider_get_capabilities function. Each group should have
364 the following details supplied (all are mandatory):
368 =item "tls-group-name" (B<OSSL_CAPABILITY_TLS_GROUP_NAME>) <utf8 string>
370 The name of the group as given in the IANA TLS Supported Groups registry
371 L<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8>.
373 =item "tls-group-name-internal" (B<OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL>) <utf8 string>
375 The name of the group as known by the provider. This could be the same as the
376 "tls-group-name", but does not have to be.
378 =item "tls-group-id" (B<OSSL_CAPABILITY_TLS_GROUP_ID>) <unsigned integer>
380 The TLS group id value as given in the IANA TLS Supported Groups registry.
382 =item "tls-group-alg" (B<OSSL_CAPABILITY_TLS_GROUP_ALG>) <utf8 string>
384 The name of a Key Management algorithm that the provider offers and that should
385 be used with this group. Keys created should be able to support key exchange.
386 The algorithm must support key and parameter generation as well as the
387 key/parameter generation parameter, B<OSSL_PKEY_PARAM_GROUP_NAME>. The group
388 name given via "tls-group-name-internal" above will be passed via
389 B<OSSL_PKEY_PARAM_GROUP_NAME> when libssl wishes to generate keys/parameters.
391 =item "tls-group-sec-bits" (B<OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS>) <unsigned integer>
393 The number of bits of security offered by keys in this group. The number of bits
394 should be comparable with the ones given in table 2 and 3 of the NIST SP800-57
397 =item "tls-min-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_TLS>) <integer>
399 =item "tls-max-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_TLS>) <integer>
401 =item "tls-min-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS>) <integer>
403 =item "tls-max-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS>) <integer>
405 These parameters can be used to describe the minimum and maximum TLS and DTLS
406 versions supported by the group. The values equate to the on-the-wire encoding
407 of the various TLS versions. For example TLSv1.3 is 0x0304 (772 decimal), and
408 TLSv1.2 is 0x0303 (771 decimal). A 0 indicates that there is no defined minimum
409 or maximum. A -1 indicates that the group should not be used in that protocol.
415 This is an example of a simple provider made available as a
416 dynamically loadable module.
417 It implements the fictitious algorithm C<FOO> for the fictitious
421 #include <openssl/core.h>
422 #include <openssl/core_numbers.h>
424 /* Errors used in this provider */
427 static const OSSL_ITEM reasons[] = {
428 { E_MALLOC, "memory allocation failure" }.
429 { 0, NULL } /* Termination */
433 * To ensure we get the function signature right, forward declare
434 * them using function types provided by openssl/core_numbers.h
436 OSSL_OP_bar_newctx_fn foo_newctx;
437 OSSL_OP_bar_freectx_fn foo_freectx;
438 OSSL_OP_bar_init_fn foo_init;
439 OSSL_OP_bar_update_fn foo_update;
440 OSSL_OP_bar_final_fn foo_final;
442 OSSL_provider_query_operation_fn p_query;
443 OSSL_provider_get_reason_strings_fn p_reasons;
444 OSSL_provider_teardown_fn p_teardown;
446 OSSL_provider_init_fn OSSL_provider_init;
448 OSSL_core_put_error *c_put_error = NULL;
450 /* Provider context */
452 OSSL_CORE_HANDLE *handle;
455 /* operation context for the algorithm FOO */
457 struct prov_ctx_st *provctx;
461 static void *foo_newctx(void *provctx)
463 struct foo_ctx_st *fooctx = malloc(sizeof(*fooctx));
466 fooctx->provctx = provctx;
468 c_put_error(provctx->handle, E_MALLOC, __FILE__, __LINE__);
472 static void foo_freectx(void *fooctx)
477 static int foo_init(void *vfooctx)
479 struct foo_ctx_st *fooctx = vfooctx;
484 static int foo_update(void *vfooctx, unsigned char *in, size_t inl)
486 struct foo_ctx_st *fooctx = vfooctx;
488 /* did you expect something serious? */
491 for (; inl-- > 0; in++)
496 static int foo_final(void *vfooctx)
498 struct foo_ctx_st *fooctx = vfooctx;
503 static const OSSL_DISPATCH foo_fns[] = {
504 { OSSL_FUNC_BAR_NEWCTX, (void (*)(void))foo_newctx },
505 { OSSL_FUNC_BAR_FREECTX, (void (*)(void))foo_freectx },
506 { OSSL_FUNC_BAR_INIT, (void (*)(void))foo_init },
507 { OSSL_FUNC_BAR_UPDATE, (void (*)(void))foo_update },
508 { OSSL_FUNC_BAR_FINAL, (void (*)(void))foo_final },
512 static const OSSL_ALGORITHM bars[] = {
513 { "FOO", "provider=chumbawamba", foo_fns },
517 static const OSSL_ALGORITHM *p_query(void *provctx, int operation_id,
520 switch (operation_id) {
527 static const OSSL_ITEM *p_reasons(void *provctx)
532 static void p_teardown(void *provctx)
537 static const OSSL_DISPATCH prov_fns[] = {
538 { OSSL_FUNC_PROVIDER_TEARDOWN, (void (*)(void))p_teardown },
539 { OSSL_FUNC_PROVIDER_QUERY_OPERATION, (void (*)(void))p_query },
540 { OSSL_FUNC_PROVIDER_GET_REASON_STRINGS, (void (*)(void))p_reasons },
544 int OSSL_provider_init(const OSSL_CORE_HANDLE *handle,
545 const OSSL_DISPATCH *in,
546 const OSSL_DISPATCH **out,
549 struct prov_ctx_st *pctx = NULL;
551 for (; in->function_id != 0; in++)
552 switch (in->function_id) {
553 case OSSL_FUNC_CORE_PUT_ERROR:
554 c_put_error = OSSL_get_core_put_error(in);
560 if ((pctx = malloc(sizeof(*pctx))) == NULL) {
562 * ALEA IACTA EST, if the core retrieves the reason table
563 * regardless, that string will be displayed, otherwise not.
565 c_put_error(handle, E_MALLOC, __FILE__, __LINE__);
568 pctx->handle = handle;
572 This relies on a few things existing in F<openssl/core_numbers.h>:
574 #define OSSL_OP_BAR 4711
576 #define OSSL_FUNC_BAR_NEWCTX 1
577 typedef void *(OSSL_OP_bar_newctx_fn)(void *provctx);
578 static ossl_inline OSSL_get_bar_newctx(const OSSL_DISPATCH *opf)
579 { return (OSSL_OP_bar_newctx_fn *)opf->function; }
581 #define OSSL_FUNC_BAR_FREECTX 2
582 typedef void (OSSL_OP_bar_freectx_fn)(void *ctx);
583 static ossl_inline OSSL_get_bar_newctx(const OSSL_DISPATCH *opf)
584 { return (OSSL_OP_bar_freectx_fn *)opf->function; }
586 #define OSSL_FUNC_BAR_INIT 3
587 typedef void *(OSSL_OP_bar_init_fn)(void *ctx);
588 static ossl_inline OSSL_get_bar_init(const OSSL_DISPATCH *opf)
589 { return (OSSL_OP_bar_init_fn *)opf->function; }
591 #define OSSL_FUNC_BAR_UPDATE 4
592 typedef void *(OSSL_OP_bar_update_fn)(void *ctx,
593 unsigned char *in, size_t inl);
594 static ossl_inline OSSL_get_bar_update(const OSSL_DISPATCH *opf)
595 { return (OSSL_OP_bar_update_fn *)opf->function; }
597 #define OSSL_FUNC_BAR_FINAL 5
598 typedef void *(OSSL_OP_bar_final_fn)(void *ctx);
599 static ossl_inline OSSL_get_bar_final(const OSSL_DISPATCH *opf)
600 { return (OSSL_OP_bar_final_fn *)opf->function; }
608 The concept of providers and everything surrounding them was
609 introduced in OpenSSL 3.0.
613 Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
615 Licensed under the Apache License 2.0 (the "License"). You may not use
616 this file except in compliance with the License. You can obtain a copy
617 in the file LICENSE in the source distribution or at
618 L<https://www.openssl.org/source/license.html>.