provider-base - The basic OpenSSL library <-> provider functions
#include <openssl/core_dispatch.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_CORE_HANDLE *handle);
int core_get_params(const OSSL_CORE_HANDLE *handle, OSSL_PARAM params[]);
typedef void (*OSSL_thread_stop_handler_fn)(void *arg);
int core_thread_start(const OSSL_CORE_HANDLE *handle,
OSSL_thread_stop_handler_fn handfn,
void *arg);
OPENSSL_CORE_CTX *core_get_libctx(const OSSL_CORE_HANDLE *handle);
void core_new_error(const OSSL_CORE_HANDLE *handle);
void core_set_error_debug(const OSSL_CORE_HANDLE *handle,
const char *file, int line, const char *func);
void core_vset_error(const OSSL_CORE_HANDLE *handle,
uint32_t reason, const char *fmt, va_list args);
int core_obj_add_sigid(const OSSL_CORE_HANDLE *prov, const char *sign_name,
const char *digest_name, const char *pkey_name);
int core_obj_create(const OSSL_CORE_HANDLE *handle, const char *oid,
const char *sn, const char *ln);
/*
* 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_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 *buflen);
OSSL_CORE_BIO *BIO_new_file(const char *filename, const char *mode);
OSSL_CORE_BIO *BIO_new_membuf(const void *buf, int len);
int BIO_read_ex(OSSL_CORE_BIO *bio, void *data, size_t data_len,
size_t *bytes_read);
int BIO_write_ex(OSSL_CORE_BIO *bio, const void *data, size_t data_len,
size_t *written);
int BIO_up_ref(OSSL_CORE_BIO *bio);
int BIO_free(OSSL_CORE_BIO *bio);
int BIO_vprintf(OSSL_CORE_BIO *bio, const char *format, va_list args);
int BIO_vsnprintf(char *buf, size_t n, const char *fmt, va_list args);
void OSSL_SELF_TEST_set_callback(OSSL_LIB_CTX *libctx, OSSL_CALLBACK *cb,
void *cbarg);
size_t get_entropy(const OSSL_CORE_HANDLE *handle,
unsigned char **pout, int entropy,
size_t min_len, size_t max_len);
void cleanup_entropy(const OSSL_CORE_HANDLE *handle,
unsigned char *buf, size_t len);
size_t get_nonce(const OSSL_CORE_HANDLE *handle,
unsigned char **pout, size_t min_len, size_t max_len,
const void *salt, size_t salt_len);
void cleanup_nonce(const OSSL_CORE_HANDLE *handle,
unsigned char *buf, size_t len);
/* Functions for querying the providers in the application library context */
int provider_register_child_cb(const OSSL_CORE_HANDLE *handle,
int (*create_cb)(const OSSL_CORE_HANDLE *provider,
void *cbdata),
int (*remove_cb)(const OSSL_CORE_HANDLE *provider,
void *cbdata),
int (*global_props_cb)(const char *props, void *cbdata),
void *cbdata);
void provider_deregister_child_cb(const OSSL_CORE_HANDLE *handle);
const char *provider_name(const OSSL_CORE_HANDLE *prov);
void *provider_get0_provider_ctx(const OSSL_CORE_HANDLE *prov);
const OSSL_DISPATCH *provider_get0_dispatch(const OSSL_CORE_HANDLE *prov);
int provider_up_ref(const OSSL_CORE_HANDLE *prov, int activate);
int provider_free(const OSSL_CORE_HANDLE *prov, int deactivate);
/* 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);
void provider_unquery_operation(void *provctx, int operation_id,
const OSSL_ALGORITHM *algs);
const OSSL_ITEM *provider_get_reason_strings(void *provctx);
int provider_get_capabilities(void *provctx, const char *capability,
OSSL_CALLBACK *cb, void *arg);
int provider_self_test(void *provctx);
All "functions" mentioned here are passed as function pointers between
libcrypto and the provider in
OSSL_DISPATCH(3) arrays, in the
call of the provider initialization function. See "Provider" in
provider(7) for a description of the initialization function. They are
known as "upcalls".
All these "functions" have a corresponding function type definition
named
OSSL_FUNC_{name}_fn, and a helper function to retrieve the
function pointer from a
OSSL_DISPATCH(3) element named
OSSL_FUNC_{name}. For example, the "function"
core_gettable_params() has these:
typedef OSSL_PARAM *
(OSSL_FUNC_core_gettable_params_fn)(const OSSL_CORE_HANDLE *handle);
static ossl_inline OSSL_NAME_core_gettable_params_fn
OSSL_FUNC_core_gettable_params(const OSSL_DISPATCH *opf);
OSSL_DISPATCH(3) arrays are indexed by numbers that are provided as
macros in
openssl-core_dispatch.h(7), as follows:
For
in (the
OSSL_DISPATCH(3) 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_libctx OSSL_FUNC_CORE_GET_LIBCTX
core_new_error OSSL_FUNC_CORE_NEW_ERROR
core_set_error_debug OSSL_FUNC_CORE_SET_ERROR_DEBUG
core_vset_error OSSL_FUNC_CORE_VSET_ERROR
core_obj_add_sigid OSSL_FUNC_CORE_OBJ_ADD_SIGID
core_obj_create OSSL_FUNC_CORE_OBJ_CREATE
CRYPTO_malloc OSSL_FUNC_CRYPTO_MALLOC
CRYPTO_zalloc OSSL_FUNC_CRYPTO_ZALLOC
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_write_ex OSSL_FUNC_BIO_WRITE_EX
BIO_up_ref OSSL_FUNC_BIO_UP_REF
BIO_free OSSL_FUNC_BIO_FREE
BIO_vprintf OSSL_FUNC_BIO_VPRINTF
BIO_vsnprintf OSSL_FUNC_BIO_VSNPRINTF
BIO_puts OSSL_FUNC_BIO_PUTS
BIO_gets OSSL_FUNC_BIO_GETS
BIO_ctrl OSSL_FUNC_BIO_CTRL
OPENSSL_cleanse OSSL_FUNC_OPENSSL_CLEANSE
OSSL_SELF_TEST_set_callback OSSL_FUNC_SELF_TEST_CB
ossl_rand_get_entropy OSSL_FUNC_GET_ENTROPY
ossl_rand_cleanup_entropy OSSL_FUNC_CLEANUP_ENTROPY
ossl_rand_get_nonce OSSL_FUNC_GET_NONCE
ossl_rand_cleanup_nonce OSSL_FUNC_CLEANUP_NONCE
provider_register_child_cb OSSL_FUNC_PROVIDER_REGISTER_CHILD_CB
provider_deregister_child_cb OSSL_FUNC_PROVIDER_DEREGISTER_CHILD_CB
provider_name OSSL_FUNC_PROVIDER_NAME
provider_get0_provider_ctx OSSL_FUNC_PROVIDER_GET0_PROVIDER_CTX
provider_get0_dispatch OSSL_FUNC_PROVIDER_GET0_DISPATCH
provider_up_ref OSSL_FUNC_PROVIDER_UP_REF
provider_free OSSL_FUNC_PROVIDER_FREE
For
*out (the
OSSL_DISPATCH(3) 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_unquery_operation OSSL_FUNC_PROVIDER_UNQUERY_OPERATION
provider_get_reason_strings OSSL_FUNC_PROVIDER_GET_REASON_STRINGS
provider_get_capabilities OSSL_FUNC_PROVIDER_GET_CAPABILITIES
provider_self_test OSSL_FUNC_PROVIDER_SELF_TEST
core_gettable_params() returns a constant array of descriptor
OSSL_PARAM(3), for parameters that
core_get_params() can handle.
core_get_params() retrieves parameters from the core for the given
handle. See "Core parameters" below for a description of
currently known parameters.
The
core_thread_start() function informs the core that the provider has
stated an interest in the current thread. The core will inform the provider
when the thread eventually stops. It must be passed the
handle for this
provider, as well as a callback
handfn which will be called when the
thread stops. The callback will subsequently be called, with the supplied
argument
arg, from the thread that is stopping and gets passed the
provider context as an argument. This may be useful to perform thread specific
clean up such as freeing thread local variables.
core_get_libctx() retrieves the core context in which the library object
for the current provider is stored, accessible through the
handle. This
function is useful only for built-in providers such as the default provider.
Never cast this to OSSL_LIB_CTX in a provider that is not built-in as the
OSSL_LIB_CTX of the library loading the provider might be a completely
different structure than the OSSL_LIB_CTX of the library the provider is
linked to. Use
OSSL_LIB_CTX_new_child(3) instead to obtain a proper
library context that is linked to the application library context.
core_new_error(),
core_set_error_debug() and
core_vset_error() are building blocks for reporting an error back to
the core, with reference to the
handle.
- 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_vset_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).
The
core_obj_create() function registers a new OID and associated short
name
sn and long name
ln for the given
handle. It is
similar to the OpenSSL function
OBJ_create(3) except that it returns 1
on success or 0 on failure. It will treat as success the case where the OID
already exists (even if the short name
sn or long name
ln
provided as arguments differ from those associated with the existing OID, in
which case the new names are not associated). This function is not thread
safe.
The
core_obj_add_sigid() function registers a new composite signature
algorithm (
sign_name) consisting of an underlying signature algorithm
(
pkey_name) and digest algorithm (
digest_name) for the given
handle. It assumes that the OIDs for the composite signature algorithm
as well as for the underlying signature and digest algorithms are either
already known to OpenSSL or have been registered via a call to
core_obj_create(). It corresponds to the OpenSSL function
OBJ_add_sigid(3), except that the objects are identified by name rather
than a numeric NID. Any name (OID, short name or long name) can be used to
identify the object. It will treat as success the case where the composite
signature algorithm already exists (even if registered against a different
underlying signature or digest algorithm). For
digest_name, NULL or an
empty string is permissible for signature algorithms that do not need a digest
to operate correctly. The function returns 1 on success or 0 on failure. This
function is not thread safe.
CRYPTO_malloc(),
CRYPTO_zalloc(),
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_write_ex(),
BIO_up_ref(),
BIO_free(),
BIO_vprintf(),
BIO_vsnprintf(),
BIO_gets(),
BIO_puts(),
BIO_ctrl(),
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(3) array are typically direct pointers to those public
functions. Note that the BIO functions take an
OSSL_CORE_BIO type
rather than the standard
BIO type. This is to ensure that a provider
does not mix BIOs from the core with BIOs used on the provider side (the two
are not compatible).
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.
get_entropy() retrieves seeding material from the operating system. The
seeding material will have at least
entropy bytes of randomness and the
output will have at least
min_len and at most
max_len bytes. The
buffer address is stored in
*pout and the buffer length is returned to
the caller. On error, zero is returned.
cleanup_entropy() is used to clean up and free the buffer returned by
get_entropy(). The entropy pointer returned by
get_entropy() is
passed in
buf and its length in
len.
get_nonce() retrieves a nonce using the passed
salt parameter of
length
salt_len and operating system specific information. The
salt should contain uniquely identifying information and this is
included, in an unspecified manner, as part of the output. The output is
stored in a buffer which contains at least
min_len and at most
max_len bytes. The buffer address is stored in
*pout and the
buffer length returned to the caller. On error, zero is returned.
cleanup_nonce() is used to clean up and free the buffer returned by
get_nonce(). The nonce pointer returned by
get_nonce() is passed
in
buf and its length in
len.
provider_register_child_cb() registers callbacks for being informed about
the loading and unloading of providers in the application's library context.
handle is this provider's handle and
cbdata is this provider's
data that will be passed back to the callbacks. It returns 1 on success or 0
otherwise. These callbacks may be called while holding locks in libcrypto. In
order to avoid deadlocks the callback implementation must not be long running
and must not call other OpenSSL API functions or upcalls.
create_cb is a callback that will be called when a new provider is loaded
into the application's library context. It is also called for any providers
that are already loaded at the point that this callback is registered. The
callback is passed the handle being used for the new provider being loadded
and this provider's data in
cbdata. It should return 1 on success or 0
on failure.
remove_cb is a callback that will be called when a new provider is
unloaded from the application's library context. It is passed the handle being
used for the provider being unloaded and this provider's data in
cbdata. It should return 1 on success or 0 on failure.
global_props_cb is a callback that will be called when the global
properties from the parent library context are changed. It should return 1 on
success or 0 on failure.
provider_deregister_child_cb() unregisters callbacks previously
registered via
provider_register_child_cb(). If
provider_register_child_cb() has been called then
provider_deregister_child_cb() should be called at or before the point
that this provider's teardown function is called.
provider_name() returns a string giving the name of the provider
identified by
handle.
provider_get0_provider_ctx() returns the provider context that is
associated with the provider identified by
prov.
provider_get0_dispatch() gets the dispatch table registered by the
provider identified by
prov when it initialised.
provider_up_ref() increments the reference count on the provider
prov. If
activate is nonzero then the provider is also loaded if
it is not already loaded. It returns 1 on success or 0 on failure.
provider_free() decrements the reference count on the provider
prov. If
deactivate is nonzero then the provider is also
unloaded if it is not already loaded. It returns 1 on success or 0 on failure.
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(3), for parameters that
provider_get_params() can
handle.
provider_get_params() should process the
OSSL_PARAM(3) array
params, setting the values of the parameters it understands.
provider_query_operation() should return a constant
OSSL_ALGORITHM(3) 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_unquery_operation() informs the provider that the result of a
provider_query_operation() is no longer directly required and that the
function pointers have been copied. The
operation_id should match that
passed to
provider_query_operation() and
algs should be its
return value.
provider_get_reason_strings() should return a constant
OSSL_ITEM(3) array that provides reason strings for reason codes the
provider may use when reporting errors using
core_put_error().
The
provider_get_capabilities() function should call the callback
cb passing it a set of
OSSL_PARAM(3)s and the caller supplied
argument
arg. The
OSSL_PARAM(3)s should provide details about
the capability with the name given in the
capability argument relevant
for the provider context
provctx. If a provider supports multiple
capabilities with the given name then it may call the callback multiple times
(one for each capability). Capabilities can be useful for describing the
services that a provider can offer. For further details see the
"CAPABILITIES" section below. It should return 1 on success or 0 on
error.
The
provider_self_test() function should perform known answer tests on a
subset of the algorithms that it uses, and may also verify the integrity of
the provider module. It should return 1 on success or 0 on error. It will
return 1 if this function is not used.
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().
provider_get_params() can return the following provider parameters to the
core:
- "name" (OSSL_PROV_PARAM_NAME) <UTF8
ptr>
- This points to a string that should give a unique name for
the provider.
- "version" (OSSL_PROV_PARAM_VERSION)
<UTF8 ptr>
- This points to a string that is a version number associated
with this provider. OpenSSL in-built providers use OPENSSL_VERSION_STR,
but this may be different for any third party provider. This string is for
informational purposes only.
- "buildinfo" (OSSL_PROV_PARAM_BUILDINFO)
<UTF8 ptr>
- This points to a string that is a build information
associated with this provider. OpenSSL in-built providers use
OPENSSL_FULL_VERSION_STR, but this may be different for any third party
provider.
- "status" (OSSL_PROV_PARAM_STATUS)
<unsigned integer>
- This returns 0 if the provider has entered an error state,
otherwise it returns 1.
provider_gettable_params() should return the above parameters.
core_get_params() can retrieve the following core parameters for each
provider:
- "openssl-version"
(OSSL_PROV_PARAM_CORE_VERSION) <UTF8 string ptr>
- This points to the OpenSSL libraries' full version string,
i.e. the string expanded from the macro OPENSSL_VERSION_STR.
- "provider-name"
(OSSL_PROV_PARAM_CORE_PROV_NAME) <UTF8 string ptr>
- This points to the OpenSSL libraries' idea of what the
calling provider is named.
- "module-filename"
(OSSL_PROV_PARAM_CORE_MODULE_FILENAME) <UTF8 string ptr>
- This points to a string containing the full filename of the
providers module file.
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:
config_diagnostics = 1
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:
- "activate"
- pointing at the string "1"
- "data1"
- pointing at the string "2"
- "data2"
- pointing at the string "str"
- "more.data3"
- pointing at the string "foo,bar"
For more information on handling parameters, see
OSSL_PARAM(3) as
OSSL_PARAM_int(3).
Capabilities describe some of the services that a provider can offer.
Applications can query the capabilities to discover those services.
"TLS-GROUP" Capability
The "TLS-GROUP" capability can be queried by libssl to discover the
list of TLS groups that a provider can support. Each group supported can be
used for
key exchange (KEX) or
key encapsulation method (KEM)
during a TLS handshake. TLS clients can advertise the list of TLS groups they
support in the supported_groups extension, and TLS servers can select a group
from the offered list that they also support. In this way a provider can add
to the list of groups that libssl already supports with additional ones.
Each TLS group that a provider supports should be described via the callback
passed in through the provider_get_capabilities function. Each group should
have the following details supplied (all are mandatory, except
OSSL_CAPABILITY_TLS_GROUP_IS_KEM):
- "tls-group-name"
(OSSL_CAPABILITY_TLS_GROUP_NAME) <UTF8 string>
- The name of the group as given in the IANA TLS Supported
Groups registry
<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8>.
- "tls-group-name-internal"
(OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL) <UTF8 string>
- The name of the group as known by the provider. This could
be the same as the "tls-group-name", but does not have to
be.
- "tls-group-id"
(OSSL_CAPABILITY_TLS_GROUP_ID) <unsigned integer>
- The TLS group id value as given in the IANA TLS Supported
Groups registry.
- "tls-group-alg"
(OSSL_CAPABILITY_TLS_GROUP_ALG) <UTF8 string>
- The name of a Key Management algorithm that the provider
offers and that should be used with this group. Keys created should be
able to support key exchange or key encapsulation method
(KEM), as implied by the optional OSSL_CAPABILITY_TLS_GROUP_IS_KEM
flag. The algorithm must support key and parameter generation as well as
the key/parameter generation parameter, OSSL_PKEY_PARAM_GROUP_NAME.
The group name given via "tls-group-name-internal" above will be
passed via OSSL_PKEY_PARAM_GROUP_NAME when libssl wishes to
generate keys/parameters.
- "tls-group-sec-bits"
(OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS) <unsigned
integer>
- The number of bits of security offered by keys in this
group. The number of bits should be comparable with the ones given in
table 2 and 3 of the NIST SP800-57 document.
- "tls-group-is-kem"
(OSSL_CAPABILITY_TLS_GROUP_IS_KEM) <unsigned integer>
- Boolean flag to describe if the group should be used in
key exchange (KEX) mode (0, default) or in key encapsulation
method (KEM) mode (1).
This parameter is optional: if not specified, KEX mode is assumed as the
default mode for the group.
In KEX mode, in a typical Diffie-Hellman fashion, both sides execute
keygen then derive against the peer public key. To operate
in KEX mode, the group implementation must support the provider functions
as described in provider-keyexch(7).
In KEM mode, the client executes keygen and sends its public key, the
server executes encapsulate using the client's public key and sends
back the resulting ciphertext, finally the client executes
decapsulate to retrieve the same shared secret generated by
the server's encapsulate. To operate in KEM mode, the group
implementation must support the provider functions as described in
provider-kem(7).
Both in KEX and KEM mode, the resulting shared secret is then used
according to the protocol specification.
- "tls-min-tls"
(OSSL_CAPABILITY_TLS_GROUP_MIN_TLS) <integer>
- "tls-max-tls"
(OSSL_CAPABILITY_TLS_GROUP_MAX_TLS) <integer>
- "tls-min-dtls"
(OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS) <integer>
- "tls-max-dtls"
(OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS) <integer>
- These parameters can be used to describe the minimum and
maximum TLS and DTLS versions supported by the group. The values equate to
the on-the-wire encoding of the various TLS versions. For example TLSv1.3
is 0x0304 (772 decimal), and TLSv1.2 is 0x0303 (771 decimal). A 0
indicates that there is no defined minimum or maximum. A -1 indicates that
the group should not be used in that protocol.
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_dispatch.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_dispatch.h
*/
OSSL_FUNC_bar_newctx_fn foo_newctx;
OSSL_FUNC_bar_freectx_fn foo_freectx;
OSSL_FUNC_bar_init_fn foo_init;
OSSL_FUNC_bar_update_fn foo_update;
OSSL_FUNC_bar_final_fn foo_final;
OSSL_FUNC_provider_query_operation_fn p_query;
OSSL_FUNC_provider_get_reason_strings_fn p_reasons;
OSSL_FUNC_provider_teardown_fn p_teardown;
OSSL_provider_init_fn OSSL_provider_init;
OSSL_FUNC_core_put_error *c_put_error = NULL;
/* Provider context */
struct prov_ctx_st {
OSSL_CORE_HANDLE *handle;
}
/* 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->handle, 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_CORE_HANDLE *handle,
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_FUNC_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(handle, E_MALLOC, __FILE__, __LINE__);
return 0;
}
pctx->handle = handle;
return 1;
}
This relies on a few things existing in
openssl/core_dispatch.h:
#define OSSL_OP_BAR 4711
#define OSSL_FUNC_BAR_NEWCTX 1
typedef void *(OSSL_FUNC_bar_newctx_fn)(void *provctx);
static ossl_inline OSSL_FUNC_bar_newctx(const OSSL_DISPATCH *opf)
{ return (OSSL_FUNC_bar_newctx_fn *)opf->function; }
#define OSSL_FUNC_BAR_FREECTX 2
typedef void (OSSL_FUNC_bar_freectx_fn)(void *ctx);
static ossl_inline OSSL_FUNC_bar_freectx(const OSSL_DISPATCH *opf)
{ return (OSSL_FUNC_bar_freectx_fn *)opf->function; }
#define OSSL_FUNC_BAR_INIT 3
typedef void *(OSSL_FUNC_bar_init_fn)(void *ctx);
static ossl_inline OSSL_FUNC_bar_init(const OSSL_DISPATCH *opf)
{ return (OSSL_FUNC_bar_init_fn *)opf->function; }
#define OSSL_FUNC_BAR_UPDATE 4
typedef void *(OSSL_FUNC_bar_update_fn)(void *ctx,
unsigned char *in, size_t inl);
static ossl_inline OSSL_FUNC_bar_update(const OSSL_DISPATCH *opf)
{ return (OSSL_FUNC_bar_update_fn *)opf->function; }
#define OSSL_FUNC_BAR_FINAL 5
typedef void *(OSSL_FUNC_bar_final_fn)(void *ctx);
static ossl_inline OSSL_FUNC_bar_final(const OSSL_DISPATCH *opf)
{ return (OSSL_FUNC_bar_final_fn *)opf->function; }
provider(7)
The concept of providers and everything surrounding them was introduced in
OpenSSL 3.0.
Copyright 2019-2023 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>.