provider-keymgmt - The KEYMGMT 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.
*/
/* 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(void *keydata, int selection, const OSSL_PARAM params[]);
const OSSL_PARAM *OSSL_FUNC_keymgmt_import_types(int selection);
int OSSL_FUNC_keymgmt_export(void *keydata, int selection,
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);
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(3) arrays via
OSSL_ALGORITHM(3) 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(3) 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(3) 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
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.
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(3), 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.
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(3), 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(3), 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.
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.
OSSL_FUNC_keymgmt_import() should import data indicated by
selection into
keydata with values taken from the
OSSL_PARAM(3) array
params.
OSSL_FUNC_keymgmt_export() should extract values indicated by
selection from
keydata, create an
OSSL_PARAM(3) 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(3) 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(3) 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.
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 asymmetric 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.
- "mandatory-digest"
(OSSL_PKEY_PARAM_MANDATORY_DIGEST) <UTF8 string>
- If there is a mandatory digest for performing a signature
operation with keys from this keymgmt, this parameter should get its name
as value.
When EVP_PKEY_get_default_digest_name() queries this parameter and
it's filled in by the implementation, its return value will be 2.
If the keymgmt implementation fills in the value "" or
"UNDEF", EVP_PKEY_get_default_digest_name(3) will place
the string "UNDEF" into its argument mdname. This
signifies that no digest should be specified with the corresponding
signature operation.
- "default-digest"
(OSSL_PKEY_PARAM_DEFAULT_DIGEST) <UTF8 string>
- If there is a default digest for performing a signature
operation with keys from this keymgmt, this parameter should get its name
as value.
When EVP_PKEY_get_default_digest_name(3) queries this parameter and
it's filled in by the implementation, its return value will be 1. Note
that if OSSL_PKEY_PARAM_MANDATORY_DIGEST is responded to as well,
EVP_PKEY_get_default_digest_name(3) ignores the response to this
parameter.
If the keymgmt implementation fills in the value "" or
"UNDEF", EVP_PKEY_get_default_digest_name(3) will place
the string "UNDEF" into its argument mdname. This
signifies that no digest has to be specified with the corresponding
signature operation, but may be specified as an option.
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(3) array.
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)
The KEYMGMT interface was introduced in OpenSSL 3.0.
Copyright 2019-2024 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>.