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[]);
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_FUNC_core_gettable_params_fn)(const OSSL_CORE_HANDLE *handle);
95 static ossl_inline OSSL_NAME_core_gettable_params_fn
96 OSSL_FUNC_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_dispatch.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
142 provider_self_test OSSL_FUNC_PROVIDER_SELF_TEST
144 =head2 Core functions
146 core_gettable_params() returns a constant array of descriptor
147 B<OSSL_PARAM>, for parameters that core_get_params() can handle.
149 core_get_params() retrieves parameters from the core for the given I<handle>.
150 See L</Core parameters> below for a description of currently known
153 =for comment core_thread_start() TBA
155 core_get_library_context() retrieves the library context in which the library
156 object for the current provider is stored, accessible through the I<handle>.
157 This may sometimes be useful if the provider wishes to store a
158 reference to its context in the same library context.
160 core_new_error(), core_set_error_debug() and core_set_error() are
161 building blocks for reporting an error back to the core, with
162 reference to the I<handle>.
166 =item core_new_error()
168 allocates a new thread specific error record.
170 This corresponds to the OpenSSL function L<ERR_new(3)>.
172 =item core_set_error_debug()
174 sets debugging information in the current thread specific error
176 The debugging information includes the name of the file I<file>, the
177 line I<line> and the function name I<func> where the error occurred.
179 This corresponds to the OpenSSL function L<ERR_set_debug(3)>.
181 =item core_set_error()
183 sets the I<reason> for the error, along with any addition data.
184 The I<reason> is a number defined by the provider and used to index
185 the reason strings table that's returned by
186 provider_get_reason_strings().
187 The additional data is given as a format string I<fmt> and a set of
188 arguments I<args>, which are treated in the same manner as with
190 I<file> and I<line> may also be passed to indicate exactly where the
191 error occurred or was reported.
193 This corresponds to the OpenSSL function L<ERR_vset_error(3)>.
197 CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_memdup(), CRYPTO_strdup(),
198 CRYPTO_strndup(), CRYPTO_free(), CRYPTO_clear_free(),
199 CRYPTO_realloc(), CRYPTO_clear_realloc(), CRYPTO_secure_malloc(),
200 CRYPTO_secure_zalloc(), CRYPTO_secure_free(),
201 CRYPTO_secure_clear_free(), CRYPTO_secure_allocated(),
202 BIO_new_file(), BIO_new_mem_buf(), BIO_read_ex(), BIO_free(),
203 BIO_vprintf(), OPENSSL_cleanse(), and OPENSSL_hexstr2buf()
204 correspond exactly to the public functions with the same name.
205 As a matter of fact, the pointers in the B<OSSL_DISPATCH> array are
206 direct pointers to those public functions. Note that the BIO functions take an
207 B<OSSL_CORE_BIO> type rather than the standard B<BIO> type. This is to ensure
208 that a provider does not mix BIOs from the core with BIOs used on the provider
209 side (the two are not compatible).
210 OSSL_SELF_TEST_set_callback() is used to set an optional callback that can be
211 passed into a provider. This may be ignored by a provider.
213 =head2 Provider functions
215 provider_teardown() is called when a provider is shut down and removed
216 from the core's provider store.
217 It must free the passed I<provctx>.
219 provider_gettable_params() should return a constant array of
220 descriptor B<OSSL_PARAM>, for parameters that provider_get_params()
223 provider_get_params() should process the B<OSSL_PARAM> array
224 I<params>, setting the values of the parameters it understands.
226 provider_query_operation() should return a constant B<OSSL_ALGORITHM>
227 that corresponds to the given I<operation_id>.
228 It should indicate if the core may store a reference to this array by
229 setting I<*no_store> to 0 (core may store a reference) or 1 (core may
230 not store a reference).
232 provider_get_reason_strings() should return a constant B<OSSL_ITEM>
233 array that provides reason strings for reason codes the provider may
234 use when reporting errors using core_put_error().
236 The provider_get_capabilities() function should call the callback I<cb> passing
237 it a set of B<OSSL_PARAM>s and the caller supplied argument I<arg>. The
238 B<OSSL_PARAM>s should provide details about the capability with the name given
239 in the I<capability> argument relevant for the provider context I<provctx>. If a
240 provider supports multiple capabilities with the given name then it may call the
241 callback multiple times (one for each capability). Capabilities can be useful for
242 describing the services that a provider can offer. For further details see the
243 L</CAPABILITIES> section below. It should return 1 on success or 0 on error.
245 The provider_self_test() function should perform known answer tests on a subset
246 of the algorithms that it uses, and may also verify the integrity of the
247 provider module. It should return 1 on success or 0 on error. It will return 1
248 if this function is not used.
250 None of these functions are mandatory, but a provider is fairly
251 useless without at least provider_query_operation(), and
252 provider_gettable_params() is fairly useless if not accompanied by
253 provider_get_params().
255 =head2 Provider parameters
257 provider_get_params() can return the following provider parameters to the core:
261 =item "name" (B<OSSL_PROV_PARAM_NAME>) <UTF8_ptr>
263 This points to a string that should give a unique name for the provider.
265 =item "version" (B<OSSL_PROV_PARAM_VERSION>) <UTF8_ptr>
267 This points to a string that is a version number associated with this provider.
268 OpenSSL in-built providers use OPENSSL_VERSION_STR, but this may be different
269 for any third party provider. This string is for informational purposes only.
271 =item "buildinfo" (B<OSSL_PROV_PARAM_BUILDINFO>) <UTF8_ptr>
273 This points to a string that is a build information associated with this provider.
274 OpenSSL in-built providers use OPENSSL_FULL_VERSION_STR, but this may be
275 different for any third party provider.
277 =item "status" (B<OSSL_PROV_PARAM_STATUS>) <unsigned integer>
279 This returns 0 if the provider has entered an error state, otherwise it returns
284 provider_gettable_params() should return the above parameters.
287 =head2 Core parameters
289 core_get_params() can retrieve the following core parameters for each provider:
293 =item "openssl-version" (B<OSSL_PROV_PARAM_CORE_VERSION>) <UTF8_ptr>
295 This points to the OpenSSL libraries' full version string, i.e. the string
296 expanded from the macro B<OPENSSL_VERSION_STR>.
298 =item "provider-name" (B<OSSL_PROV_PARAM_CORE_PROV_NAME>) <UTF8_ptr>
300 This points to the OpenSSL libraries' idea of what the calling provider is named.
302 =item "module-filename" (B<OSSL_PROV_PARAM_CORE_MODULE_FILENAME>) <UTF8_ptr>
304 This points to a string containing the full filename of the providers
309 Additionally, provider specific configuration parameters from the
310 config file are available, in dotted name form.
311 The dotted name form is a concatenation of section names and final
312 config command name separated by periods.
314 For example, let's say we have the following config example:
316 openssl_conf = openssl_init
319 providers = providers_sect
333 The provider will have these additional parameters available:
339 pointing at the string "1"
343 pointing at the string "2"
347 pointing at the string "str"
351 pointing at the string "foo,bar"
355 For more information on handling parameters, see L<OSSL_PARAM(3)> as
356 L<OSSL_PARAM_int(3)>.
360 Capabilities describe some of the services that a provider can offer.
361 Applications can query the capabilities to discover those services.
363 =head3 "TLS-GROUP" Capability
365 The "TLS-GROUP" capability can be queried by libssl to discover the list of
366 TLS groups that a provider can support. Each group supported can be used for
367 key exchange during a TLS handshake. TLS clients can advertise the list of
368 TLS groups they support in the supported_groups extension, and TLS servers can
369 select a group from the offered list that they also support. In this way a
370 provider can add to the list of groups that libssl already supports with
373 Each TLS group that a provider supports should be described via the callback
374 passed in through the provider_get_capabilities function. Each group should have
375 the following details supplied (all are mandatory):
379 =item "tls-group-name" (B<OSSL_CAPABILITY_TLS_GROUP_NAME>) <utf8 string>
381 The name of the group as given in the IANA TLS Supported Groups registry
382 L<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8>.
384 =item "tls-group-name-internal" (B<OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL>) <utf8 string>
386 The name of the group as known by the provider. This could be the same as the
387 "tls-group-name", but does not have to be.
389 =item "tls-group-id" (B<OSSL_CAPABILITY_TLS_GROUP_ID>) <unsigned integer>
391 The TLS group id value as given in the IANA TLS Supported Groups registry.
393 =item "tls-group-alg" (B<OSSL_CAPABILITY_TLS_GROUP_ALG>) <utf8 string>
395 The name of a Key Management algorithm that the provider offers and that should
396 be used with this group. Keys created should be able to support key exchange.
397 The algorithm must support key and parameter generation as well as the
398 key/parameter generation parameter, B<OSSL_PKEY_PARAM_GROUP_NAME>. The group
399 name given via "tls-group-name-internal" above will be passed via
400 B<OSSL_PKEY_PARAM_GROUP_NAME> when libssl wishes to generate keys/parameters.
402 =item "tls-group-sec-bits" (B<OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS>) <unsigned integer>
404 The number of bits of security offered by keys in this group. The number of bits
405 should be comparable with the ones given in table 2 and 3 of the NIST SP800-57
408 =item "tls-min-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_TLS>) <integer>
410 =item "tls-max-tls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_TLS>) <integer>
412 =item "tls-min-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS>) <integer>
414 =item "tls-max-dtls" (B<OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS>) <integer>
416 These parameters can be used to describe the minimum and maximum TLS and DTLS
417 versions supported by the group. The values equate to the on-the-wire encoding
418 of the various TLS versions. For example TLSv1.3 is 0x0304 (772 decimal), and
419 TLSv1.2 is 0x0303 (771 decimal). A 0 indicates that there is no defined minimum
420 or maximum. A -1 indicates that the group should not be used in that protocol.
426 This is an example of a simple provider made available as a
427 dynamically loadable module.
428 It implements the fictitious algorithm C<FOO> for the fictitious
432 #include <openssl/core.h>
433 #include <openssl/core_dispatch.h>
435 /* Errors used in this provider */
438 static const OSSL_ITEM reasons[] = {
439 { E_MALLOC, "memory allocation failure" }.
440 { 0, NULL } /* Termination */
444 * To ensure we get the function signature right, forward declare
445 * them using function types provided by openssl/core_dispatch.h
447 OSSL_FUNC_bar_newctx_fn foo_newctx;
448 OSSL_FUNC_bar_freectx_fn foo_freectx;
449 OSSL_FUNC_bar_init_fn foo_init;
450 OSSL_FUNC_bar_update_fn foo_update;
451 OSSL_FUNC_bar_final_fn foo_final;
453 OSSL_FUNC_provider_query_operation_fn p_query;
454 OSSL_FUNC_provider_get_reason_strings_fn p_reasons;
455 OSSL_FUNC_provider_teardown_fn p_teardown;
457 OSSL_provider_init_fn OSSL_provider_init;
459 OSSL_FUNC_core_put_error *c_put_error = NULL;
461 /* Provider context */
463 OSSL_CORE_HANDLE *handle;
466 /* operation context for the algorithm FOO */
468 struct prov_ctx_st *provctx;
472 static void *foo_newctx(void *provctx)
474 struct foo_ctx_st *fooctx = malloc(sizeof(*fooctx));
477 fooctx->provctx = provctx;
479 c_put_error(provctx->handle, E_MALLOC, __FILE__, __LINE__);
483 static void foo_freectx(void *fooctx)
488 static int foo_init(void *vfooctx)
490 struct foo_ctx_st *fooctx = vfooctx;
495 static int foo_update(void *vfooctx, unsigned char *in, size_t inl)
497 struct foo_ctx_st *fooctx = vfooctx;
499 /* did you expect something serious? */
502 for (; inl-- > 0; in++)
507 static int foo_final(void *vfooctx)
509 struct foo_ctx_st *fooctx = vfooctx;
514 static const OSSL_DISPATCH foo_fns[] = {
515 { OSSL_FUNC_BAR_NEWCTX, (void (*)(void))foo_newctx },
516 { OSSL_FUNC_BAR_FREECTX, (void (*)(void))foo_freectx },
517 { OSSL_FUNC_BAR_INIT, (void (*)(void))foo_init },
518 { OSSL_FUNC_BAR_UPDATE, (void (*)(void))foo_update },
519 { OSSL_FUNC_BAR_FINAL, (void (*)(void))foo_final },
523 static const OSSL_ALGORITHM bars[] = {
524 { "FOO", "provider=chumbawamba", foo_fns },
528 static const OSSL_ALGORITHM *p_query(void *provctx, int operation_id,
531 switch (operation_id) {
538 static const OSSL_ITEM *p_reasons(void *provctx)
543 static void p_teardown(void *provctx)
548 static const OSSL_DISPATCH prov_fns[] = {
549 { OSSL_FUNC_PROVIDER_TEARDOWN, (void (*)(void))p_teardown },
550 { OSSL_FUNC_PROVIDER_QUERY_OPERATION, (void (*)(void))p_query },
551 { OSSL_FUNC_PROVIDER_GET_REASON_STRINGS, (void (*)(void))p_reasons },
555 int OSSL_provider_init(const OSSL_CORE_HANDLE *handle,
556 const OSSL_DISPATCH *in,
557 const OSSL_DISPATCH **out,
560 struct prov_ctx_st *pctx = NULL;
562 for (; in->function_id != 0; in++)
563 switch (in->function_id) {
564 case OSSL_FUNC_CORE_PUT_ERROR:
565 c_put_error = OSSL_FUNC_core_put_error(in);
571 if ((pctx = malloc(sizeof(*pctx))) == NULL) {
573 * ALEA IACTA EST, if the core retrieves the reason table
574 * regardless, that string will be displayed, otherwise not.
576 c_put_error(handle, E_MALLOC, __FILE__, __LINE__);
579 pctx->handle = handle;
583 This relies on a few things existing in F<openssl/core_dispatch.h>:
585 #define OSSL_OP_BAR 4711
587 #define OSSL_FUNC_BAR_NEWCTX 1
588 typedef void *(OSSL_FUNC_bar_newctx_fn)(void *provctx);
589 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
590 { return (OSSL_FUNC_bar_newctx_fn *)opf->function; }
592 #define OSSL_FUNC_BAR_FREECTX 2
593 typedef void (OSSL_FUNC_bar_freectx_fn)(void *ctx);
594 static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
595 { return (OSSL_FUNC_bar_freectx_fn *)opf->function; }
597 #define OSSL_FUNC_BAR_INIT 3
598 typedef void *(OSSL_FUNC_bar_init_fn)(void *ctx);
599 static ossl_inline OSSL_FUNC_bar_init(const OSSL_DISPATCH *opf)
600 { return (OSSL_FUNC_bar_init_fn *)opf->function; }
602 #define OSSL_FUNC_BAR_UPDATE 4
603 typedef void *(OSSL_FUNC_bar_update_fn)(void *ctx,
604 unsigned char *in, size_t inl);
605 static ossl_inline OSSL_FUNC_bar_update(const OSSL_DISPATCH *opf)
606 { return (OSSL_FUNC_bar_update_fn *)opf->function; }
608 #define OSSL_FUNC_BAR_FINAL 5
609 typedef void *(OSSL_FUNC_bar_final_fn)(void *ctx);
610 static ossl_inline OSSL_FUNC_bar_final(const OSSL_DISPATCH *opf)
611 { return (OSSL_FUNC_bar_final_fn *)opf->function; }
619 The concept of providers and everything surrounding them was
620 introduced in OpenSSL 3.0.
624 Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
626 Licensed under the Apache License 2.0 (the "License"). You may not use
627 this file except in compliance with the License. You can obtain a copy
628 in the file LICENSE in the source distribution or at
629 L<https://www.openssl.org/source/license.html>.