provider-keymgmt.pod 16 KB

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  1. =pod
  2. =head1 NAME
  3. provider-keymgmt - The KEYMGMT library E<lt>-E<gt> provider functions
  4. =head1 SYNOPSIS
  5. #include <openssl/core_dispatch.h>
  6. /*
  7. * None of these are actual functions, but are displayed like this for
  8. * the function signatures for functions that are offered as function
  9. * pointers in OSSL_DISPATCH arrays.
  10. */
  11. /* Key object (keydata) creation and destruction */
  12. void *OSSL_FUNC_keymgmt_new(void *provctx);
  13. void OSSL_FUNC_keymgmt_free(void *keydata);
  14. void *OSSL_FUNC_keymgmt_gen_init(void *provctx, int selection);
  15. int OSSL_FUNC_keymgmt_gen_set_template(void *genctx, void *template);
  16. int OSSL_FUNC_keymgmt_gen_set_params(void *genctx, const OSSL_PARAM params[]);
  17. const OSSL_PARAM *OSSL_FUNC_keymgmt_gen_settable_params(void *provctx);
  18. void *OSSL_FUNC_keymgmt_gen(void *genctx, OSSL_CALLBACK *cb, void *cbarg);
  19. void OSSL_FUNC_keymgmt_gen_cleanup(void *genctx);
  20. /* Key object information */
  21. int OSSL_FUNC_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
  22. const OSSL_PARAM *OSSL_FUNC_keymgmt_gettable_params(void);
  23. int OSSL_FUNC_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
  24. const OSSL_PARAM *OSSL_FUNC_keymgmt_settable_params(void);
  25. /* Key object content checks */
  26. int OSSL_FUNC_keymgmt_has(void *keydata, int selection);
  27. int OSSL_FUNC_keymgmt_match(const void *keydata1, const void *keydata2,
  28. int selection);
  29. /* Discovery of supported operations */
  30. const char *OSSL_FUNC_keymgmt_query_operation_name(int operation_id);
  31. /* Key object import and export functions */
  32. int OSSL_FUNC_keymgmt_import(int selection, void *keydata, const OSSL_PARAM params[]);
  33. const OSSL_PARAM *OSSL_FUNC_keymgmt_import_types(int selection);
  34. int OSSL_FUNC_keymgmt_export(int selection, void *keydata,
  35. OSSL_CALLBACK *param_cb, void *cbarg);
  36. const OSSL_PARAM *OSSL_FUNC_keymgmt_export_types(int selection);
  37. /* Key object copy */
  38. int OSSL_FUNC_keymgmt_copy(void *keydata_to, const void *keydata_from, int selection);
  39. /* Key object validation */
  40. int OSSL_FUNC_keymgmt_validate(void *keydata, int selection);
  41. =head1 DESCRIPTION
  42. The KEYMGMT operation doesn't have much public visibility in OpenSSL
  43. libraries, it's rather an internal operation that's designed to work
  44. in tandem with operations that use private/public key pairs.
  45. Because the KEYMGMT operation shares knowledge with the operations it
  46. works with in tandem, they must belong to the same provider.
  47. The OpenSSL libraries will ensure that they do.
  48. The primary responsibility of the KEYMGMT operation is to hold the
  49. provider side key data for the OpenSSL library EVP_PKEY structure.
  50. All "functions" mentioned here are passed as function pointers between
  51. F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
  52. B<OSSL_ALGORITHM> arrays that are returned by the provider's
  53. provider_query_operation() function
  54. (see L<provider-base(7)/Provider Functions>).
  55. All these "functions" have a corresponding function type definition
  56. named B<OSSL_{name}_fn>, and a helper function to retrieve the
  57. function pointer from a B<OSSL_DISPATCH> element named
  58. B<OSSL_FUNC_{name}>.
  59. For example, the "function" OSSL_FUNC_keymgmt_new() has these:
  60. typedef void *(OSSL_FUNC_keymgmt_new_fn)(void *provctx);
  61. static ossl_inline OSSL_FUNC_keymgmt_new_fn
  62. OSSL_FUNC_keymgmt_new(const OSSL_DISPATCH *opf);
  63. B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
  64. macros in L<openssl-core_dispatch.h(7)>, as follows:
  65. OSSL_FUNC_keymgmt_new OSSL_FUNC_KEYMGMT_NEW
  66. OSSL_FUNC_keymgmt_free OSSL_FUNC_KEYMGMT_FREE
  67. OSSL_FUNC_keymgmt_gen_init OSSL_FUNC_KEYMGMT_GEN_INIT
  68. OSSL_FUNC_keymgmt_gen_set_template OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE
  69. OSSL_FUNC_keymgmt_gen_set_params OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS
  70. OSSL_FUNC_keymgmt_gen_settable_params OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS
  71. OSSL_FUNC_keymgmt_gen OSSL_FUNC_KEYMGMT_GEN
  72. OSSL_FUNC_keymgmt_gen_cleanup OSSL_FUNC_KEYMGMT_GEN_CLEANUP
  73. OSSL_FUNC_keymgmt_get_params OSSL_FUNC_KEYMGMT_GET_PARAMS
  74. OSSL_FUNC_keymgmt_gettable_params OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
  75. OSSL_FUNC_keymgmt_set_params OSSL_FUNC_KEYMGMT_SET_PARAMS
  76. OSSL_FUNC_keymgmt_settable_params OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS
  77. OSSL_FUNC_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME
  78. OSSL_FUNC_keymgmt_has OSSL_FUNC_KEYMGMT_HAS
  79. OSSL_FUNC_keymgmt_validate OSSL_FUNC_KEYMGMT_VALIDATE
  80. OSSL_FUNC_keymgmt_match OSSL_FUNC_KEYMGMT_MATCH
  81. OSSL_FUNC_keymgmt_import OSSL_FUNC_KEYMGMT_IMPORT
  82. OSSL_FUNC_keymgmt_import_types OSSL_FUNC_KEYMGMT_IMPORT_TYPES
  83. OSSL_FUNC_keymgmt_export OSSL_FUNC_KEYMGMT_EXPORT
  84. OSSL_FUNC_keymgmt_export_types OSSL_FUNC_KEYMGMT_EXPORT_TYPES
  85. OSSL_FUNC_keymgmt_copy OSSL_FUNC_KEYMGMT_COPY
  86. =head2 Key Objects
  87. A key object is a collection of data for an asymmetric key, and is
  88. represented as I<keydata> in this manual.
  89. The exact contents of a key object are defined by the provider, and it
  90. is assumed that different operations in one and the same provider use
  91. the exact same structure to represent this collection of data, so that
  92. for example, a key object that has been created using the KEYMGMT
  93. interface that we document here can be passed as is to other provider
  94. operations, such as OP_signature_sign_init() (see
  95. L<provider-signature(7)>).
  96. With some of the KEYMGMT functions, it's possible to select a specific
  97. subset of data to handle, governed by the bits in a I<selection>
  98. indicator. The bits are:
  99. =over 4
  100. =item B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY>
  101. Indicating that the private key data in a key object should be
  102. considered.
  103. =item B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>
  104. Indicating that the public key data in a key object should be
  105. considered.
  106. =item B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS>
  107. Indicating that the domain parameters in a key object should be
  108. considered.
  109. =item B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>
  110. Indicating that other parameters in a key object should be
  111. considered.
  112. Other parameters are key parameters that don't fit any other
  113. classification. In other words, this particular selector bit works as
  114. a last resort bit bucket selector.
  115. =back
  116. Some selector bits have also been combined for easier use:
  117. =over 4
  118. =item B<OSSL_KEYMGMT_SELECT_ALL_PARAMETERS>
  119. Indicating that all key object parameters should be considered,
  120. regardless of their more granular classification.
  121. =for comment This should used by EVP functions such as
  122. EVP_PKEY_copy_parameters() and EVP_PKEY_cmp_parameters()
  123. This is a combination of B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS> and
  124. B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>.
  125. =for comment If more parameter categories are added, they should be
  126. mentioned here too.
  127. =item B<OSSL_KEYMGMT_SELECT_KEYPAIR>
  128. Indicating that both the whole key pair in a key object should be
  129. considered, i.e. the combination of public and private key.
  130. This is a combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
  131. B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>.
  132. =item B<OSSL_KEYMGMT_SELECT_ALL>
  133. Indicating that everything in a key object should be considered.
  134. =back
  135. The exact interpretation of those bits or how they combine is left to
  136. each function where you can specify a selector.
  137. =for comment One might think that a combination of bits means that all
  138. the selected data subsets must be considered, but then you have to
  139. consider that when comparing key objects (future function), an
  140. implementation might opt to not compare the private key if it has
  141. compared the public key, since a match of one half implies a match of
  142. the other half.
  143. =head2 Constructing and Destructing Functions
  144. OSSL_FUNC_keymgmt_new() should create a provider side key object. The
  145. provider context I<provctx> is passed and may be incorporated in the
  146. key object, but that is not mandatory.
  147. OSSL_FUNC_keymgmt_free() should free the passed I<keydata>.
  148. OSSL_FUNC_keymgmt_gen_init(), OSSL_FUNC_keymgmt_gen_set_template(),
  149. OSSL_FUNC_keymgmt_gen_set_params(), OSSL_FUNC_keymgmt_gen_settable_params(),
  150. OSSL_FUNC_keymgmt_gen() and OSSL_FUNC_keymgmt_gen_cleanup() work together as a more
  151. elaborate context based key object constructor.
  152. OSSL_FUNC_keymgmt_gen_init() should create the key object generation context
  153. and initialize it with I<selections>, which will determine what kind
  154. of contents the key object to be generated should get.
  155. OSSL_FUNC_keymgmt_gen_set_template() should add I<template> to the context
  156. I<genctx>. The I<template> is assumed to be a key object constructed
  157. with the same KEYMGMT, and from which content that the implementation
  158. chooses can be used as a template for the key object to be generated.
  159. Typically, the generation of a DSA or DH key would get the domain
  160. parameters from this I<template>.
  161. OSSL_FUNC_keymgmt_gen_set_params() should set additional parameters from
  162. I<params> in the key object generation context I<genctx>.
  163. OSSL_FUNC_keymgmt_gen_settable_params() should return a constant array of
  164. descriptor B<OSSL_PARAM>, for parameters that OSSL_FUNC_keymgmt_gen_set_params()
  165. can handle.
  166. OSSL_FUNC_keymgmt_gen() should perform the key object generation itself, and
  167. return the result. The callback I<cb> should be called at regular
  168. intervals with indications on how the key object generation
  169. progresses.
  170. OSSL_FUNC_keymgmt_gen_cleanup() should clean up and free the key object
  171. generation context I<genctx>
  172. At least one of OSSL_FUNC_keymgmt_new() and OSSL_FUNC_keymgmt_gen() are mandatory,
  173. as well as OSSL_FUNC_keymgmt_free(). Additionally, if OSSL_FUNC_keymgmt_gen() is
  174. present, OSSL_FUNC_keymgmt_gen_init() and OSSL_FUNC_keymgmt_gen_cleanup() must be
  175. present as well.
  176. =head2 Key Object Information Functions
  177. OSSL_FUNC_keymgmt_get_params() should extract information data associated
  178. with the given I<keydata>, see L</Common Information Parameters>.
  179. OSSL_FUNC_keymgmt_gettable_params() should return a constant array of
  180. descriptor B<OSSL_PARAM>, for parameters that OSSL_FUNC_keymgmt_get_params()
  181. can handle.
  182. If OSSL_FUNC_keymgmt_gettable_params() is present, OSSL_FUNC_keymgmt_get_params()
  183. must also be present, and vice versa.
  184. OSSL_FUNC_keymgmt_set_params() should update information data associated
  185. with the given I<keydata>, see L</Common Information Parameters>.
  186. OSSL_FUNC_keymgmt_settable_params() should return a constant array of
  187. descriptor B<OSSL_PARAM>, for parameters that OSSL_FUNC_keymgmt_set_params()
  188. can handle.
  189. If OSSL_FUNC_keymgmt_settable_params() is present, OSSL_FUNC_keymgmt_set_params()
  190. must also be present, and vice versa.
  191. =head2 Key Object Checking Functions
  192. OSSL_FUNC_keymgmt_query_operation_name() should return the name of the
  193. supported algorithm for the operation I<operation_id>. This is
  194. similar to provider_query_operation() (see L<provider-base(7)>),
  195. but only works as an advisory. If this function is not present, or
  196. returns NULL, the caller is free to assume that there's an algorithm
  197. from the same provider, of the same name as the one used to fetch the
  198. keymgmt and try to use that.
  199. OSSL_FUNC_keymgmt_has() should check whether the given I<keydata> contains the subsets
  200. of data indicated by the I<selector>. A combination of several
  201. selector bits must consider all those subsets, not just one. An
  202. implementation is, however, free to consider an empty subset of data
  203. to still be a valid subset.
  204. OSSL_FUNC_keymgmt_validate() should check if the I<keydata> contains valid
  205. data subsets indicated by I<selection>. Some combined selections of
  206. data subsets may cause validation of the combined data.
  207. For example, the combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
  208. B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY> (or B<OSSL_KEYMGMT_SELECT_KEYPAIR>
  209. for short) is expected to check that the pairwise consistency of
  210. I<keydata> is valid.
  211. OSSL_FUNC_keymgmt_match() should check if the data subset indicated by
  212. I<selection> in I<keydata1> and I<keydata2> match. It is assumed that
  213. the caller has ensured that I<keydata1> and I<keydata2> are both owned
  214. by the implementation of this function.
  215. =head2 Key Object Import, Export and Copy Functions
  216. OSSL_FUNC_keymgmt_import() should import data indicated by I<selection> into
  217. I<keydata> with values taken from the B<OSSL_PARAM> array I<params>.
  218. OSSL_FUNC_keymgmt_export() should extract values indicated by I<selection>
  219. from I<keydata>, create an B<OSSL_PARAM> array with them and call
  220. I<param_cb> with that array as well as the given I<cbarg>.
  221. OSSL_FUNC_keymgmt_import_types() should return a constant array of descriptor
  222. B<OSSL_PARAM> for data indicated by I<selection>, for parameters that
  223. OSSL_FUNC_keymgmt_import() can handle.
  224. OSSL_FUNC_keymgmt_export_types() should return a constant array of descriptor
  225. B<OSSL_PARAM> for data indicated by I<selection>, that the
  226. OSSL_FUNC_keymgmt_export() callback can expect to receive.
  227. OSSL_FUNC_keymgmt_copy() should copy data subsets indicated by I<selection>
  228. from I<keydata_from> to I<keydata_to>. It is assumed that the caller
  229. has ensured that I<keydata_to> and I<keydata_from> are both owned by
  230. the implementation of this function.
  231. =head2 Common Information Parameters
  232. See L<OSSL_PARAM(3)> for further details on the parameters structure.
  233. Common information parameters currently recognised by all built-in
  234. keymgmt algorithms are as follows:
  235. =over 4
  236. =item "bits" (B<OSSL_PKEY_PARAM_BITS>) <integer>
  237. The value should be the cryptographic length of the cryptosystem to
  238. which the key belongs, in bits. The definition of cryptographic
  239. length is specific to the key cryptosystem.
  240. =item "max-size" (B<OSSL_PKEY_PARAM_MAX_SIZE>) <integer>
  241. The value should be the maximum size that a caller should allocate to
  242. safely store a signature (called I<sig> in L<provider-signature(7)>),
  243. the result of asymmmetric encryption / decryption (I<out> in
  244. L<provider-asym_cipher(7)>, a derived secret (I<secret> in
  245. L<provider-keyexch(7)>, and similar data).
  246. Because an EVP_KEYMGMT method is always tightly bound to another method
  247. (signature, asymmetric cipher, key exchange, ...) and must be of the
  248. same provider, this number only needs to be synchronised with the
  249. dimensions handled in the rest of the same provider.
  250. =item "security-bits" (B<OSSL_PKEY_PARAM_SECURITY_BITS>) <integer>
  251. The value should be the number of security bits of the given key.
  252. Bits of security is defined in SP800-57.
  253. =back
  254. =head1 RETURN VALUES
  255. OSSL_FUNC_keymgmt_new() should return a valid reference to the newly created provider
  256. side key object, or NULL on failure.
  257. OSSL_FUNC_keymgmt_import(), OSSL_FUNC_keymgmt_export(), OSSL_FUNC_keymgmt_get_params() and
  258. OSSL_FUNC_keymgmt_set_params() should return 1 for success or 0 on error.
  259. OSSL_FUNC_keymgmt_validate() should return 1 on successful validation, or 0 on
  260. failure.
  261. OSSL_FUNC_keymgmt_has() should return 1 if all the selected data subsets are contained
  262. in the given I<keydata> or 0 otherwise.
  263. OSSL_FUNC_keymgmt_query_operation_name() should return a pointer to a string matching
  264. the requested operation, or NULL if the same name used to fetch the keymgmt
  265. applies.
  266. OSSL_FUNC_keymgmt_gettable_params() and OSSL_FUNC_keymgmt_settable_params()
  267. OSSL_FUNC_keymgmt_import_types(), OSSL_FUNC_keymgmt_export_types()
  268. should
  269. always return a constant B<OSSL_PARAM> array.
  270. =head1 SEE ALSO
  271. L<provider(7)>,
  272. L<EVP_PKEY-X25519(7)>, L<EVP_PKEY-X448(7)>, L<EVP_PKEY-ED25519(7)>,
  273. L<EVP_PKEY-ED448(7)>, L<EVP_PKEY-EC(7)>, L<EVP_PKEY-RSA(7)>,
  274. L<EVP_PKEY-DSA(7)>, L<EVP_PKEY-DH(7)>
  275. =head1 HISTORY
  276. The KEYMGMT interface was introduced in OpenSSL 3.0.
  277. =head1 COPYRIGHT
  278. Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
  279. Licensed under the Apache License 2.0 (the "License"). You may not use
  280. this file except in compliance with the License. You can obtain a copy
  281. in the file LICENSE in the source distribution or at
  282. L<https://www.openssl.org/source/license.html>.
  283. =cut