NAME

provider-keymgmt - The KEYMGMT library <-> provider functions

SYNOPSIS

 #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.
  */

 /* Key object (keydata) creation and destruction */
 void *OP_keymgmt_new(void *provctx);
 void OP_keymgmt_free(void *keydata);

 void *OP_keymgmt_gen_init(void *provctx, int selection);
 int OP_keymgmt_gen_set_template(void *genctx, void *template);
 int OP_keymgmt_gen_set_params(void *genctx, const OSSL_PARAM params[]);
 const OSSL_PARAM *OP_keymgmt_gen_settable_params(void *provctx);
 int OP_keymgmt_gen_get_params(void *genctx, const OSSL_PARAM params[]);
 const OSSL_PARAM *OP_keymgmt_gen_gettable_params(void *provctx);
 void *OP_keymgmt_gen(void *genctx, OSSL_CALLBACK *cb, void *cbarg);
 void OP_keymgmt_gen_cleanup(void *genctx);

 /* Key object information */
 int OP_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
 const OSSL_PARAM *OP_keymgmt_gettable_params(void);
 int OP_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
 const OSSL_PARAM *OP_keymgmt_settable_params(void);

 /* Key object content checks */
 int OP_keymgmt_has(void *keydata, int selection);
 int OP_keymgmt_match(const void *keydata1, const void *keydata2,
                      int selection);

 /* Discovery of supported operations */
 const char *OP_keymgmt_query_operation_name(int operation_id);

 /* Key object import and export functions */
 int OP_keymgmt_import(int selection, void *keydata, const OSSL_PARAM params[]);
 const OSSL_PARAM *OP_keymgmt_import_types(int selection);
 int OP_keymgmt_export(int selection, void *keydata,
                       OSSL_CALLBACK *param_cb, void *cbarg);
 const OSSL_PARAM *OP_keymgmt_export_types(int selection);

 /* Key object copy */
 int OP_keymgmt_copy(void *keydata_to, const void *keydata_from, int selection);

 /* Key object validation */
 int OP_keymgmt_validate(void *keydata, int selection);

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 openssl-core_numbers.h(7), as follows:

 OP_keymgmt_new                  OSSL_FUNC_KEYMGMT_NEW
 OP_keymgmt_free                 OSSL_FUNC_KEYMGMT_FREE

 OP_keymgmt_gen_init             OSSL_FUNC_KEYMGMT_GEN_INIT
 OP_keymgmt_gen_set_template     OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE
 OP_keymgmt_gen_set_params       OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS
 OP_keymgmt_gen_settable_params  OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS
 OP_keymgmt_gen_get_params       OSSL_FUNC_KEYMGMT_GEN_GET_PARAMS
 OP_keymgmt_gen_gettable_params  OSSL_FUNC_KEYMGMT_GEN_GETTABLE_PARAMS
 OP_keymgmt_gen                  OSSL_FUNC_KEYMGMT_GEN
 OP_keymgmt_gen_cleanup          OSSL_FUNC_KEYMGMT_GEN_CLEANUP

 OP_keymgmt_get_params           OSSL_FUNC_KEYMGMT_GET_PARAMS
 OP_keymgmt_gettable_params      OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
 OP_keymgmt_set_params           OSSL_FUNC_KEYMGMT_SET_PARAMS
 OP_keymgmt_settable_params      OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS

 OP_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME

 OP_keymgmt_has                  OSSL_FUNC_KEYMGMT_HAS
 OP_keymgmt_validate             OSSL_FUNC_KEYMGMT_VALIDATE
 OP_keymgmt_match                OSSL_FUNC_KEYMGMT_MATCH

 OP_keymgmt_import               OSSL_FUNC_KEYMGMT_IMPORT
 OP_keymgmt_import_types         OSSL_FUNC_KEYMGMT_IMPORT_TYPES
 OP_keymgmt_export               OSSL_FUNC_KEYMGMT_EXPORT
 OP_keymgmt_export_types         OSSL_FUNC_KEYMGMT_EXPORT_TYPES

 OP_keymgmt_copy                 OSSL_FUNC_KEYMGMT_COPY

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 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.

Constructing and Destructing Functions

OP_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.

OP_keymgmt_free() should free the passed keydata.

OP_keymgmt_gen_init(), OP_keymgmt_gen_set_template(), OP_keymgmt_gen_set_params(), OP_keymgmt_gen_settable_params(), OP_keymgmt_gen_get_params(), OP_keymgmt_gen_gettable_params(), OP_keymgmt_gen() and OP_keymgmt_gen_cleanup() work together as a more elaborate context based key object constructor.

OP_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.

OP_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.

OP_keymgmt_gen_set_params() should set additional parameters from params in the key object generation context genctx.

OP_keymgmt_gen_settable_params() should return a constant array of descriptor OSSL_PARAM, for parameters that OP_keymgmt_gen_set_params() can handle.

OP_keymgmt_gen_get_params() should extract information data associated with the key object generation context genctx.

OP_keymgmt_gen_gettable_params() should return a constant array of descriptor OSSL_PARAM, for parameters that OP_keymgmt_gen_get_params() can handle.

OP_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.

OP_keymgmt_gen_cleanup() should clean up and free the key object generation context genctx

At least one of OP_keymgmt_new() and OP_keymgmt_gen() are mandatory, as well as OP_keymgmt_free(). Additionally, if OP_keymgmt_gen() is present, OP_keymgmt_gen_init() and OP_keymgmt_gen_cleanup() must be present as well.

Key Object Information Functions

OP_keymgmt_get_params() should extract information data associated with the given keydata, see "Common Information Parameters".

OP_keymgmt_gettable_params() should return a constant array of descriptor OSSL_PARAM, for parameters that OP_keymgmt_get_params() can handle.

If OP_keymgmt_gettable_params() is present, OP_keymgmt_get_params() must also be present, and vice versa.

OP_keymgmt_set_params() should update information data associated with the given keydata, see "Common Information Parameters".

OP_keymgmt_settable_params() should return a constant array of descriptor OSSL_PARAM, for parameters that OP_keymgmt_set_params() can handle.

If OP_keymgmt_settable_params() is present, OP_keymgmt_set_params() must also be present, and vice versa.

Key Object Checking Functions

OP_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 Key Object Import, Export and Copy Functions

OP_keymgmt_import() should import data indicated by selection into keydata with values taken from the OSSL_PARAM array params.

OP_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.

OP_keymgmt_import_types() should return a constant array of descriptor OSSL_PARAM for data indicated by selection, for parameters that OP_keymgmt_import() can handle.

OP_keymgmt_export_types() should return a constant array of descriptor OSSL_PARAM for data indicated by selection, that the OP_keymgmt_export() callback can expect to receive.

OP_keymgmt_copy() should copy data subsets indicated by selection from keydata_from to keydata_to. It is assumed that the caller has ensured that keydata_to and keydata_from are both owned by the implementation of this function.

Common Information Parameters

See "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-asym_cipher(7), a derived secret (secret in "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

OP_keymgmt_new() should return a valid reference to the newly created provider side key object, or NULL on failure.

OP_keymgmt_import(), OP_keymgmt_export(), OP_keymgmt_get_params() and OP_keymgmt_set_params() should return 1 for success or 0 on error.

OP_keymgmt_validate() should return 1 on successful validation, or 0 on failure.

OP_keymgmt_has() should return 1 if all the selected data subsets are contained in the given keydata or 0 otherwise.

OP_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.

OP_keymgmt_gettable_params() and OP_keymgmt_settable_params() OP_keymgmt_import_types(), OP_keymgmt_export_types() should always return a constant OSSL_PARAM array.

SEE ALSO

EVP_PKEY-X25519(7), EVP_PKEY-ED25519(7), EVP_PKEY-EC(7), EVP_PKEY-DSA(7), HISTORY

The KEYMGMT interface was introduced in OpenSSL 3.0.

COPYRIGHT

Copyright 2019-2020 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.