Provided by: openssl_3.0.2-0ubuntu1.18_amd64 
NAME
provider-keymgmt - The KEYMGMT library <-> provider functions
SYNOPSIS
#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.
*/
/* Key object (keydata) creation and destruction */
void *OSSL_FUNC_keymgmt_new(void *provctx);
void OSSL_FUNC_keymgmt_free(void *keydata);
/* Generation, a more complex constructor */
void *OSSL_FUNC_keymgmt_gen_init(void *provctx, int selection,
const OSSL_PARAM params[]);
int OSSL_FUNC_keymgmt_gen_set_template(void *genctx, void *template);
int OSSL_FUNC_keymgmt_gen_set_params(void *genctx, const OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_keymgmt_gen_settable_params(void *genctx,
void *provctx);
void *OSSL_FUNC_keymgmt_gen(void *genctx, OSSL_CALLBACK *cb, void *cbarg);
void OSSL_FUNC_keymgmt_gen_cleanup(void *genctx);
/* Key loading by object reference, also a constructor */
void *OSSL_FUNC_keymgmt_load(const void *reference, size_t *reference_sz);
/* Key object information */
int OSSL_FUNC_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_keymgmt_gettable_params(void *provctx);
int OSSL_FUNC_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_keymgmt_settable_params(void *provctx);
/* Key object content checks */
int OSSL_FUNC_keymgmt_has(const void *keydata, int selection);
int OSSL_FUNC_keymgmt_match(const void *keydata1, const void *keydata2,
int selection);
/* Discovery of supported operations */
const char *OSSL_FUNC_keymgmt_query_operation_name(int operation_id);
/* Key object import and export functions */
int OSSL_FUNC_keymgmt_import(int selection, void *keydata, const OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_keymgmt_import_types(int selection);
int OSSL_FUNC_keymgmt_export(int selection, void *keydata,
OSSL_CALLBACK *param_cb, void *cbarg);
const OSSL_PARAM *OSSL_FUNC_keymgmt_export_types(int selection);
/* Key object duplication, a constructor */
void *OSSL_FUNC_keymgmt_dup(const void *keydata_from, int selection);
/* Key object validation */
int OSSL_FUNC_keymgmt_validate(const void *keydata, int selection, int checktype);
DESCRIPTION
The KEYMGMT operation doesn't have much public visibility in OpenSSL libraries, it's
rather an internal operation that's designed to work in tandem with operations that use
private/public key pairs.
Because the KEYMGMT operation shares knowledge with the operations it works with in
tandem, they must belong to the same provider. The OpenSSL libraries will ensure that
they do.
The primary responsibility of the KEYMGMT operation is to hold the provider side key data
for the OpenSSL library EVP_PKEY structure.
All "functions" mentioned here are passed as function pointers between libcrypto and the
provider in OSSL_DISPATCH arrays via OSSL_ALGORITHM arrays that are returned by the
provider's provider_query_operation() function (see "Provider Functions" in
provider-base(7)).
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 element named OSSL_FUNC_{name}. For example, the "function"
OSSL_FUNC_keymgmt_new() has these:
typedef void *(OSSL_FUNC_keymgmt_new_fn)(void *provctx);
static ossl_inline OSSL_FUNC_keymgmt_new_fn
OSSL_FUNC_keymgmt_new(const OSSL_DISPATCH *opf);
OSSL_DISPATCH arrays are indexed by numbers that are provided as macros in
openssl-core_dispatch.h(7), as follows:
OSSL_FUNC_keymgmt_new OSSL_FUNC_KEYMGMT_NEW
OSSL_FUNC_keymgmt_free OSSL_FUNC_KEYMGMT_FREE
OSSL_FUNC_keymgmt_gen_init OSSL_FUNC_KEYMGMT_GEN_INIT
OSSL_FUNC_keymgmt_gen_set_template OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE
OSSL_FUNC_keymgmt_gen_set_params OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS
OSSL_FUNC_keymgmt_gen_settable_params OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS
OSSL_FUNC_keymgmt_gen OSSL_FUNC_KEYMGMT_GEN
OSSL_FUNC_keymgmt_gen_cleanup OSSL_FUNC_KEYMGMT_GEN_CLEANUP
OSSL_FUNC_keymgmt_load OSSL_FUNC_KEYMGMT_LOAD
OSSL_FUNC_keymgmt_get_params OSSL_FUNC_KEYMGMT_GET_PARAMS
OSSL_FUNC_keymgmt_gettable_params OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
OSSL_FUNC_keymgmt_set_params OSSL_FUNC_KEYMGMT_SET_PARAMS
OSSL_FUNC_keymgmt_settable_params OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS
OSSL_FUNC_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME
OSSL_FUNC_keymgmt_has OSSL_FUNC_KEYMGMT_HAS
OSSL_FUNC_keymgmt_validate OSSL_FUNC_KEYMGMT_VALIDATE
OSSL_FUNC_keymgmt_match OSSL_FUNC_KEYMGMT_MATCH
OSSL_FUNC_keymgmt_import OSSL_FUNC_KEYMGMT_IMPORT
OSSL_FUNC_keymgmt_import_types OSSL_FUNC_KEYMGMT_IMPORT_TYPES
OSSL_FUNC_keymgmt_export OSSL_FUNC_KEYMGMT_EXPORT
OSSL_FUNC_keymgmt_export_types OSSL_FUNC_KEYMGMT_EXPORT_TYPES
OSSL_FUNC_keymgmt_dup OSSL_FUNC_KEYMGMT_DUP
Key Objects
A key object is a collection of data for an asymmetric key, and is represented as keydata
in this manual.
The exact contents of a key object are defined by the provider, and it is assumed that
different operations in one and the same provider use the exact same structure to
represent this collection of data, so that for example, a key object that has been created
using the KEYMGMT interface that we document here can be passed as is to other provider
operations, such as OP_signature_sign_init() (see provider-signature(7)).
With some of the KEYMGMT functions, it's possible to select a specific subset of data to
handle, governed by the bits in a selection indicator. The bits are:
OSSL_KEYMGMT_SELECT_PRIVATE_KEY
Indicating that the private key data in a key object should be considered.
OSSL_KEYMGMT_SELECT_PUBLIC_KEY
Indicating that the public key data in a key object should be considered.
OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS
Indicating that the domain parameters in a key object should be considered.
OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS
Indicating that other parameters in a key object should be considered.
Other parameters are key parameters that don't fit any other classification. In other
words, this particular selector bit works as a last resort bit bucket selector.
Some selector bits have also been combined for easier use:
OSSL_KEYMGMT_SELECT_ALL_PARAMETERS
Indicating that all key object parameters should be considered, regardless of their
more granular classification.
This is a combination of OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS and
OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS.
OSSL_KEYMGMT_SELECT_KEYPAIR
Indicating that both the whole key pair in a key object should be considered, i.e. the
combination of public and private key.
This is a combination of OSSL_KEYMGMT_SELECT_PRIVATE_KEY and
OSSL_KEYMGMT_SELECT_PUBLIC_KEY.
OSSL_KEYMGMT_SELECT_ALL
Indicating that everything in a key object should be considered.
The exact interpretation of those bits or how they combine is left to each function where
you can specify a selector.
It's left to the provider implementation to decide what is reasonable to do with regards
to received selector bits and how to do it. Among others, an implementation of
OSSL_FUNC_keymgmt_match() might opt to not compare the private half if it has compared the
public half, since a match of one half implies a match of the other half.
Constructing and Destructing Functions
OSSL_FUNC_keymgmt_new() should create a provider side key object. The provider context
provctx is passed and may be incorporated in the key object, but that is not mandatory.
OSSL_FUNC_keymgmt_free() should free the passed keydata.
OSSL_FUNC_keymgmt_gen_init(), OSSL_FUNC_keymgmt_gen_set_template(),
OSSL_FUNC_keymgmt_gen_set_params(), OSSL_FUNC_keymgmt_gen_settable_params(),
OSSL_FUNC_keymgmt_gen() and OSSL_FUNC_keymgmt_gen_cleanup() work together as a more
elaborate context based key object constructor.
OSSL_FUNC_keymgmt_gen_init() should create the key object generation context and
initialize it with selections, which will determine what kind of contents the key object
to be generated should get. The params, if not NULL, should be set on the context in a
manner similar to using OSSL_FUNC_keymgmt_set_params().
OSSL_FUNC_keymgmt_gen_set_template() should add template to the context genctx. The
template is assumed to be a key object constructed with the same KEYMGMT, and from which
content that the implementation chooses can be used as a template for the key object to be
generated. Typically, the generation of a DSA or DH key would get the domain parameters
from this template.
OSSL_FUNC_keymgmt_gen_set_params() should set additional parameters from params in the key
object generation context genctx.
OSSL_FUNC_keymgmt_gen_settable_params() should return a constant array of descriptor
OSSL_PARAM, for parameters that OSSL_FUNC_keymgmt_gen_set_params() can handle.
OSSL_FUNC_keymgmt_gen() should perform the key object generation itself, and return the
result. The callback cb should be called at regular intervals with indications on how the
key object generation progresses.
OSSL_FUNC_keymgmt_gen_cleanup() should clean up and free the key object generation context
genctx
OSSL_FUNC_keymgmt_load() creates a provider side key object based on a reference object
with a size of reference_sz bytes, that only the provider knows how to interpret, but that
may come from other operations. Outside the provider, this reference is simply an array
of bytes.
At least one of OSSL_FUNC_keymgmt_new(), OSSL_FUNC_keymgmt_gen() and
OSSL_FUNC_keymgmt_load() are mandatory, as well as OSSL_FUNC_keymgmt_free() and
OSSL_FUNC_keymgmt_has(). Additionally, if OSSL_FUNC_keymgmt_gen() is present,
OSSL_FUNC_keymgmt_gen_init() and OSSL_FUNC_keymgmt_gen_cleanup() must be present as well.
Key Object Information Functions
OSSL_FUNC_keymgmt_get_params() should extract information data associated with the given
keydata, see "Common Information Parameters".
OSSL_FUNC_keymgmt_gettable_params() should return a constant array of descriptor
OSSL_PARAM, for parameters that OSSL_FUNC_keymgmt_get_params() can handle.
If OSSL_FUNC_keymgmt_gettable_params() is present, OSSL_FUNC_keymgmt_get_params() must
also be present, and vice versa.
OSSL_FUNC_keymgmt_set_params() should update information data associated with the given
keydata, see "Common Information Parameters".
OSSL_FUNC_keymgmt_settable_params() should return a constant array of descriptor
OSSL_PARAM, for parameters that OSSL_FUNC_keymgmt_set_params() can handle.
If OSSL_FUNC_keymgmt_settable_params() is present, OSSL_FUNC_keymgmt_set_params() must
also be present, and vice versa.
Key Object Checking Functions
OSSL_FUNC_keymgmt_query_operation_name() should return the name of the supported algorithm
for the operation operation_id. This is similar to provider_query_operation() (see
provider-base(7)), but only works as an advisory. If this function is not present, or
returns NULL, the caller is free to assume that there's an algorithm from the same
provider, of the same name as the one used to fetch the keymgmt and try to use that.
OSSL_FUNC_keymgmt_has() should check whether the given keydata contains the subsets of
data indicated by the selector. A combination of several selector bits must consider all
those subsets, not just one. An implementation is, however, free to consider an empty
subset of data to still be a valid subset. For algorithms where some selection is not
meaningful such as OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS for RSA keys the function should
just return 1 as the selected subset is not really missing in the key.
OSSL_FUNC_keymgmt_validate() should check if the keydata contains valid data subsets
indicated by selection. Some combined selections of data subsets may cause validation of
the combined data. For example, the combination of OSSL_KEYMGMT_SELECT_PRIVATE_KEY and
OSSL_KEYMGMT_SELECT_PUBLIC_KEY (or OSSL_KEYMGMT_SELECT_KEYPAIR for short) is expected to
check that the pairwise consistency of keydata is valid. The checktype parameter controls
what type of check is performed on the subset of data. Two types of check are defined:
OSSL_KEYMGMT_VALIDATE_FULL_CHECK and OSSL_KEYMGMT_VALIDATE_QUICK_CHECK. The
interpretation of how much checking is performed in a full check versus a quick check is
key type specific. Some providers may have no distinction between a full check and a quick
check. For algorithms where some selection is not meaningful such as
OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS for RSA keys the function should just return 1 as
there is nothing to validate for that selection.
OSSL_FUNC_keymgmt_match() should check if the data subset indicated by selection in
keydata1 and keydata2 match. It is assumed that the caller has ensured that keydata1 and
keydata2 are both owned by the implementation of this function.
Key Object Import, Export and Duplication Functions
OSSL_FUNC_keymgmt_import() should import data indicated by selection into keydata with
values taken from the OSSL_PARAM array params.
OSSL_FUNC_keymgmt_export() should extract values indicated by selection from keydata,
create an OSSL_PARAM array with them and call param_cb with that array as well as the
given cbarg.
OSSL_FUNC_keymgmt_import_types() should return a constant array of descriptor OSSL_PARAM
for data indicated by selection, for parameters that OSSL_FUNC_keymgmt_import() can
handle.
OSSL_FUNC_keymgmt_export_types() should return a constant array of descriptor OSSL_PARAM
for data indicated by selection, that the OSSL_FUNC_keymgmt_export() callback can expect
to receive.
OSSL_FUNC_keymgmt_dup() should duplicate data subsets indicated by selection or the whole
key data keydata_from and create a new provider side key object with the data.
Common Information Parameters
See OSSL_PARAM(3) for further details on the parameters structure.
Common information parameters currently recognised by all built-in keymgmt algorithms are
as follows:
"bits" (OSSL_PKEY_PARAM_BITS) <integer>
The value should be the cryptographic length of the cryptosystem to which the key
belongs, in bits. The definition of cryptographic length is specific to the key
cryptosystem.
"max-size" (OSSL_PKEY_PARAM_MAX_SIZE) <integer>
The value should be the maximum size that a caller should allocate to safely store a
signature (called sig in provider-signature(7)), the result of asymmmetric encryption
/ decryption (out in provider-asym_cipher(7), a derived secret (secret in
provider-keyexch(7), and similar data).
Because an EVP_KEYMGMT method is always tightly bound to another method (signature,
asymmetric cipher, key exchange, ...) and must be of the same provider, this number
only needs to be synchronised with the dimensions handled in the rest of the same
provider.
"security-bits" (OSSL_PKEY_PARAM_SECURITY_BITS) <integer>
The value should be the number of security bits of the given key. Bits of security is
defined in SP800-57.
RETURN VALUES
OSSL_FUNC_keymgmt_new() and OSSL_FUNC_keymgmt_dup() should return a valid reference to the
newly created provider side key object, or NULL on failure.
OSSL_FUNC_keymgmt_import(), OSSL_FUNC_keymgmt_export(), OSSL_FUNC_keymgmt_get_params() and
OSSL_FUNC_keymgmt_set_params() should return 1 for success or 0 on error.
OSSL_FUNC_keymgmt_validate() should return 1 on successful validation, or 0 on failure.
OSSL_FUNC_keymgmt_has() should return 1 if all the selected data subsets are contained in
the given keydata or 0 otherwise.
OSSL_FUNC_keymgmt_query_operation_name() should return a pointer to a string matching the
requested operation, or NULL if the same name used to fetch the keymgmt applies.
OSSL_FUNC_keymgmt_gettable_params() and OSSL_FUNC_keymgmt_settable_params()
OSSL_FUNC_keymgmt_import_types(), OSSL_FUNC_keymgmt_export_types() should always return a
constant OSSL_PARAM array.
SEE ALSO
provider(7), EVP_PKEY-X25519(7), EVP_PKEY-X448(7), EVP_PKEY-ED25519(7), EVP_PKEY-ED448(7),
EVP_PKEY-EC(7), EVP_PKEY-RSA(7), EVP_PKEY-DSA(7), EVP_PKEY-DH(7)
HISTORY
The KEYMGMT interface was introduced in OpenSSL 3.0.
COPYRIGHT
Copyright 2019-2021 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>.