provider-base - The basic OpenSSL library <-> provider functions
#include <openssl/core_numbers.h>
/* * None of these are actual functions, but are displayed like this for * the function signatures for functions that are offered as function * pointers in OSSL_DISPATCH arrays. */
/* Functions offered by libcrypto to the providers */
const OSSL_ITEM *core_gettable_params(const OSSL_PROVIDER *prov);
int core_get_params(const OSSL_PROVIDER *prov, OSSL_PARAM params[]);
int core_thread_start(const OSSL_PROVIDER *prov,
OSSL_thread_stop_handler_fn handfn);
OPENSSL_CTX *core_get_library_context(const OSSL_PROVIDER *prov);
void core_new_error(const OSSL_PROVIDER *prov);
void core_set_error_debug(const OSSL_PROVIDER *prov,
const char *file, int line, const char *func);
void core_vset_error(const OSSL_PROVIDER *prov,
uint32_t reason, const char *fmt, va_list args);
/*
* Some OpenSSL functionality is directly offered to providers via
* dispatch
*/
void *CRYPTO_malloc(size_t num, const char *file, int line);
void *CRYPTO_zalloc(size_t num, const char *file, int line);
void *CRYPTO_memdup(const void *str, size_t siz,
const char *file, int line);
char *CRYPTO_strdup(const char *str, const char *file, int line);
char *CRYPTO_strndup(const char *str, size_t s,
const char *file, int line);
void CRYPTO_free(void *ptr, const char *file, int line);
void CRYPTO_clear_free(void *ptr, size_t num,
const char *file, int line);
void *CRYPTO_realloc(void *addr, size_t num,
const char *file, int line);
void *CRYPTO_clear_realloc(void *addr, size_t old_num, size_t num,
const char *file, int line);
void *CRYPTO_secure_malloc(size_t num, const char *file, int line);
void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);
void CRYPTO_secure_free(void *ptr, const char *file, int line);
void CRYPTO_secure_clear_free(void *ptr, size_t num,
const char *file, int line);
int CRYPTO_secure_allocated(const void *ptr);
void OPENSSL_cleanse(void *ptr, size_t len);
unsigned char *OPENSSL_hexstr2buf(const char *str, long *len);
/* Functions offered by the provider to libcrypto */
void provider_teardown(void *provctx);
const OSSL_ITEM *provider_gettable_params(void *provctx);
int provider_get_params(void *provctx, OSSL_PARAM params[]);
const OSSL_ALGORITHM *provider_query_operation(void *provctx,
int operation_id,
const int *no_store);
const OSSL_ITEM *provider_get_reason_strings(void *provctx);
All "functions" mentioned here are passed as function pointers between libcrypto and the provider in OSSL_DISPATCH arrays, in the call of the provider initialization function. See provider(7)/Provider for a description of the initialization function.
All these "functions" have a corresponding function type definition
named OSSL_{name}_fn, and a helper function to retrieve the
function pointer from a OSSL_DISPATCH element named
OSSL_get_{name}.
For example, the "function" core_gettable_params() has these:
typedef OSSL_ITEM *
(OSSL_core_gettable_params_fn)(const OSSL_PROVIDER *prov);
static ossl_inline OSSL_NAME_core_gettable_params_fn
OSSL_get_core_gettable_params(const OSSL_DISPATCH *opf);
OSSL_DISPATCH arrays are indexed by numbers that are provided as macros in openssl-core_numbers.h(7), as follows:
For in (the OSSL_DISPATCH array passed from libcrypto to the provider):
core_gettable_params OSSL_FUNC_CORE_GETTABLE_PARAMS core_get_params OSSL_FUNC_CORE_GET_PARAMS core_thread_start OSSL_FUNC_CORE_THREAD_START core_get_library_context OSSL_FUNC_CORE_GET_LIBRARY_CONTEXT core_new_error OSSL_FUNC_CORE_NEW_ERROR core_set_error_debug OSSL_FUNC_CORE_SET_ERROR_DEBUG core_set_error OSSL_FUNC_CORE_SET_ERROR CRYPTO_malloc OSSL_FUNC_CRYPTO_MALLOC CRYPTO_zalloc OSSL_FUNC_CRYPTO_ZALLOC CRYPTO_memdup OSSL_FUNC_CRYPTO_MEMDUP CRYPTO_strdup OSSL_FUNC_CRYPTO_STRDUP CRYPTO_strndup OSSL_FUNC_CRYPTO_STRNDUP CRYPTO_free OSSL_FUNC_CRYPTO_FREE CRYPTO_clear_free OSSL_FUNC_CRYPTO_CLEAR_FREE CRYPTO_realloc OSSL_FUNC_CRYPTO_REALLOC CRYPTO_clear_realloc OSSL_FUNC_CRYPTO_CLEAR_REALLOC CRYPTO_secure_malloc OSSL_FUNC_CRYPTO_SECURE_MALLOC CRYPTO_secure_zalloc OSSL_FUNC_CRYPTO_SECURE_ZALLOC CRYPTO_secure_free OSSL_FUNC_CRYPTO_SECURE_FREE CRYPTO_secure_clear_free OSSL_FUNC_CRYPTO_SECURE_CLEAR_FREE CRYPTO_secure_allocated OSSL_FUNC_CRYPTO_SECURE_ALLOCATED BIO_new_file OSSL_FUNC_BIO_NEW_FILE BIO_new_mem_buf OSSL_FUNC_BIO_NEW_MEMBUF BIO_read_ex OSSL_FUNC_BIO_READ_EX BIO_free OSSL_FUNC_BIO_FREE BIO_vprintf OSSL_FUNC_BIO_VPRINTF OPENSSL_cleanse OSSL_FUNC_OPENSSL_CLEANSE OPENSSL_hexstr2buf OSSL_FUNC_OPENSSL_HEXSTR2BUF OSSL_SELF_TEST_set_callback OSSL_FUNC_SELF_TEST_CB
For *out (the OSSL_DISPATCH array passed from the provider to libcrypto):
provider_teardown OSSL_FUNC_PROVIDER_TEARDOWN provider_gettable_params OSSL_FUNC_PROVIDER_GETTABLE_PARAMS provider_get_params OSSL_FUNC_PROVIDER_GET_PARAMS provider_query_operation OSSL_FUNC_PROVIDER_QUERY_OPERATION provider_get_reason_strings OSSL_FUNC_PROVIDER_GET_REASON_STRINGS
core_gettable_params() returns a constant array of descriptor
OSSL_PARAM, for parameters that core_get_params() can handle.
core_get_params() retrieves prov parameters from the core.
See Core parameters below for a description of currently known
parameters.
core_get_library_context() retrieves the library context in which the
OSSL_PROVIDER object prov is stored.
This may sometimes be useful if the provider wishes to store a
reference to its context in the same library context.
core_new_error(), core_set_error_debug() and core_set_error() are
building blocks for reporting an error back to the core, with
reference to the provider object prov.
core_new_error()allocates a new thread specific error record.
This corresponds to the OpenSSL function ERR_new(3).
core_set_error_debug()sets debugging information in the current thread specific error record. The debugging information includes the name of the file file, the line line and the function name func where the error occurred.
This corresponds to the OpenSSL function ERR_set_debug(3).
core_set_error()sets the reason for the error, along with any addition data.
The reason is a number defined by the provider and used to index
the reason strings table that's returned by
provider_get_reason_strings().
The additional data is given as a format string fmt and a set of
arguments args, which are treated in the same manner as with
BIO_vsnprintf().
file and line may also be passed to indicate exactly where the
error occurred or was reported.
This corresponds to the OpenSSL function ERR_vset_error(3).
CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_memdup(), CRYPTO_strdup(),
CRYPTO_strndup(), CRYPTO_free(), CRYPTO_clear_free(),
CRYPTO_realloc(), CRYPTO_clear_realloc(), CRYPTO_secure_malloc(),
CRYPTO_secure_zalloc(), CRYPTO_secure_free(),
CRYPTO_secure_clear_free(), CRYPTO_secure_allocated(),
BIO_new_file(), BIO_new_mem_buf(), BIO_read_ex(), BIO_free(),
BIO_vprintf(), OPENSSL_cleanse(), and OPENSSL_hexstr2buf()
correspond exactly to the public functions with the same name.
As a matter of fact, the pointers in the OSSL_DISPATCH array are
direct pointers to those public functions.
OSSL_SELF_TEST_set_callback() is used to set an optional callback that can be
passed into a provider. This may be ignored by a provider.
provider_teardown() is called when a provider is shut down and removed
from the core's provider store.
It must free the passed provctx.
provider_gettable_params() should return a constant array of
descriptor OSSL_PARAM, for parameters that provider_get_params()
can handle.
provider_get_params() should process the OSSL_PARAM array
params, setting the values of the parameters it understands.
provider_query_operation() should return a constant OSSL_ALGORITHM
that corresponds to the given operation_id.
It should indicate if the core may store a reference to this array by
setting *no_store to 0 (core may store a reference) or 1 (core may
not store a reference).
provider_get_reason_strings() should return a constant OSSL_ITEM
array that provides reason strings for reason codes the provider may
use when reporting errors using core_put_error().
None of these functions are mandatory, but a provider is fairly
useless without at least provider_query_operation(), and
provider_gettable_params() is fairly useless if not accompanied by
provider_get_params().
core_get_params() understands the following known parameters:
This is a OSSL_PARAM_UTF8_PTR type of parameter, pointing at the OpenSSL libraries' full version string, i.e. the string expanded from the macro OPENSSL_VERSION_STR.
This is a OSSL_PARAM_UTF8_PTR type of parameter, pointing at the OpenSSL libraries' idea of what the calling provider is called.
Additionally, provider specific configuration parameters from the config file are available, in dotted name form. The dotted name form is a concatenation of section names and final config command name separated by periods.
For example, let's say we have the following config example:
openssl_conf = openssl_init
[openssl_init] providers = providers_sect
[providers_sect] foo = foo_sect
[foo_sect] activate = 1 data1 = 2 data2 = str more = foo_more
[foo_more] data3 = foo,bar
The provider will have these additional parameters available:
pointing at the string "1"
pointing at the string "2"
pointing at the string "str"
pointing at the string "foo,bar"
For more information on handling parameters, see OSSL_PARAM(3) as OSSL_PARAM_int(3).
This is an example of a simple provider made available as a
dynamically loadable module.
It implements the fictitious algorithm FOO for the fictitious
operation BAR.
#include <malloc.h> #include <openssl/core.h> #include <openssl/core_numbers.h>
/* Errors used in this provider */ #define E_MALLOC 1
static const OSSL_ITEM reasons[] = {
{ E_MALLOC, "memory allocation failure" }.
{ 0, NULL } /* Termination */
};
/* * To ensure we get the function signature right, forward declare * them using function types provided by openssl/core_numbers.h */ OSSL_OP_bar_newctx_fn foo_newctx; OSSL_OP_bar_freectx_fn foo_freectx; OSSL_OP_bar_init_fn foo_init; OSSL_OP_bar_update_fn foo_update; OSSL_OP_bar_final_fn foo_final;
OSSL_provider_query_operation_fn p_query; OSSL_provider_get_reason_strings_fn p_reasons; OSSL_provider_teardown_fn p_teardown;
OSSL_provider_init_fn OSSL_provider_init;
OSSL_core_put_error *c_put_error = NULL;
/* Provider context */
struct prov_ctx_st {
OSSL_PROVIDER *prov;
}
/* operation context for the algorithm FOO */
struct foo_ctx_st {
struct prov_ctx_st *provctx;
int b;
};
static void *foo_newctx(void *provctx)
{
struct foo_ctx_st *fooctx = malloc(sizeof(*fooctx));
if (fooctx != NULL)
fooctx->provctx = provctx;
else
c_put_error(provctx->prov, E_MALLOC, __FILE__, __LINE__);
return fooctx;
}
static void foo_freectx(void *fooctx)
{
free(fooctx);
}
static int foo_init(void *vfooctx)
{
struct foo_ctx_st *fooctx = vfooctx;
fooctx->b = 0x33;
}
static int foo_update(void *vfooctx, unsigned char *in, size_t inl)
{
struct foo_ctx_st *fooctx = vfooctx;
/* did you expect something serious? */
if (inl == 0)
return 1;
for (; inl-- > 0; in++)
*in ^= fooctx->b;
return 1;
}
static int foo_final(void *vfooctx)
{
struct foo_ctx_st *fooctx = vfooctx;
fooctx->b = 0x66;
}
static const OSSL_DISPATCH foo_fns[] = {
{ OSSL_FUNC_BAR_NEWCTX, (void (*)(void))foo_newctx },
{ OSSL_FUNC_BAR_FREECTX, (void (*)(void))foo_freectx },
{ OSSL_FUNC_BAR_INIT, (void (*)(void))foo_init },
{ OSSL_FUNC_BAR_UPDATE, (void (*)(void))foo_update },
{ OSSL_FUNC_BAR_FINAL, (void (*)(void))foo_final },
{ 0, NULL }
};
static const OSSL_ALGORITHM bars[] = {
{ "FOO", "provider=chumbawamba", foo_fns },
{ NULL, NULL, NULL }
};
static const OSSL_ALGORITHM *p_query(void *provctx, int operation_id,
int *no_store)
{
switch (operation_id) {
case OSSL_OP_BAR:
return bars;
}
return NULL;
}
static const OSSL_ITEM *p_reasons(void *provctx)
{
return reasons;
}
static void p_teardown(void *provctx)
{
free(provctx);
}
static const OSSL_DISPATCH prov_fns[] = {
{ OSSL_FUNC_PROVIDER_TEARDOWN, (void (*)(void))p_teardown },
{ OSSL_FUNC_PROVIDER_QUERY_OPERATION, (void (*)(void))p_query },
{ OSSL_FUNC_PROVIDER_GET_REASON_STRINGS, (void (*)(void))p_reasons },
{ 0, NULL }
};
int OSSL_provider_init(const OSSL_PROVIDER *provider,
const OSSL_DISPATCH *in,
const OSSL_DISPATCH **out,
void **provctx)
{
struct prov_ctx_st *pctx = NULL;
for (; in->function_id != 0; in++)
switch (in->function_id) {
case OSSL_FUNC_CORE_PUT_ERROR:
c_put_error = OSSL_get_core_put_error(in);
break;
}
*out = prov_fns;
if ((pctx = malloc(sizeof(*pctx))) == NULL) {
/*
* ALEA IACTA EST, if the core retrieves the reason table
* regardless, that string will be displayed, otherwise not.
*/
c_put_error(provider, E_MALLOC, __FILE__, __LINE__);
return 0;
}
return 1;
}
This relies on a few things existing in openssl/core_numbers.h:
#define OSSL_OP_BAR 4711
#define OSSL_FUNC_BAR_NEWCTX 1
typedef void *(OSSL_OP_bar_newctx_fn)(void *provctx);
static ossl_inline OSSL_get_bar_newctx(const OSSL_DISPATCH *opf)
{ return (OSSL_OP_bar_newctx_fn *)opf->function; }
#define OSSL_FUNC_BAR_FREECTX 2
typedef void (OSSL_OP_bar_freectx_fn)(void *ctx);
static ossl_inline OSSL_get_bar_newctx(const OSSL_DISPATCH *opf)
{ return (OSSL_OP_bar_freectx_fn *)opf->function; }
#define OSSL_FUNC_BAR_INIT 3
typedef void *(OSSL_OP_bar_init_fn)(void *ctx);
static ossl_inline OSSL_get_bar_init(const OSSL_DISPATCH *opf)
{ return (OSSL_OP_bar_init_fn *)opf->function; }
#define OSSL_FUNC_BAR_UPDATE 4
typedef void *(OSSL_OP_bar_update_fn)(void *ctx,
unsigned char *in, size_t inl);
static ossl_inline OSSL_get_bar_update(const OSSL_DISPATCH *opf)
{ return (OSSL_OP_bar_update_fn *)opf->function; }
#define OSSL_FUNC_BAR_FINAL 5
typedef void *(OSSL_OP_bar_final_fn)(void *ctx);
static ossl_inline OSSL_get_bar_final(const OSSL_DISPATCH *opf)
{ return (OSSL_OP_bar_final_fn *)opf->function; }
provider(7)
The concept of providers and everything surrounding them was introduced in OpenSSL 3.0.
Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html.