doc/man7/provider-storemgmt.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 provider-storemgmt - The OSSL_STORE library E<lt>-E<gt> provider functions
   6
   7 =head1 SYNOPSIS
   8
   9  #include <openssl/core_dispatch.h>
  10
  11  /*
  12   * None of these are actual functions, but are displayed like this for
  13   * the function signatures for functions that are offered as function
  14   * pointers in OSSL_DISPATCH arrays.
  15   */
  16
  17  void *OSSL_FUNC_store_open(void *provctx, const char *uri);
  18  void *OSSL_FUNC_store_attach(void *provctx, OSSL_CORE_BIO *bio);
  19  const OSSL_PARAM *store_settable_ctx_params(void *provctx);
  20  int OSSL_FUNC_store_set_ctx_params(void *loaderctx, const OSSL_PARAM[]);
  21  int OSSL_FUNC_store_load(void *loaderctx,
  22                           OSSL_CALLBACK *object_cb, void *object_cbarg,
  23                           OSSL_PASSPHRASE_CALLBACK *pw_cb, void *pw_cbarg);
  24  int OSSL_FUNC_store_eof(void *loaderctx);
  25  int OSSL_FUNC_store_close(void *loaderctx);
  26
  27  int OSSL_FUNC_store_export_object
  28      (void *loaderctx, const void *objref, size_t objref_sz,
  29       OSSL_CALLBACK *export_cb, void *export_cbarg);
  30
  31 =head1 DESCRIPTION
  32
  33 The STORE operation is the provider side of the L<ossl_store(7)> API.
  34
  35 The primary responsibility of the STORE operation is to load all sorts
  36 of objects from a container indicated by URI.  These objects are given
  37 to the OpenSSL library in provider-native object abstraction form (see
  38 L<provider-object(7)>).  The OpenSSL library is then responsible for
  39 passing on that abstraction to suitable provided functions.
  40
  41 Examples of functions that the OpenSSL library can pass the abstraction to
  42 include OSSL_FUNC_keymgmt_load() (L<provider-keymgmt(7)>),
  43 OSSL_FUNC_store_export_object() (which exports the object in parameterized
  44 form).
  45
  46 All "functions" mentioned here are passed as function pointers between
  47 F<libcrypto> and the provider in L<OSSL_DISPATCH(3)> arrays via
  48 L<OSSL_ALGORITHM(3)> arrays that are returned by the provider's
  49 provider_query_operation() function
  50 (see L<provider-base(7)/Provider Functions>).
  51
  52 All these "functions" have a corresponding function type definition named
  53 B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the function pointer
  54 from a L<OSSL_DISPATCH(3)> element named B<OSSL_get_{name}>.
  55 For example, the "function" OSSL_FUNC_store_attach() has these:
  56
  57  typedef void *(OSSL_FUNC_store_attach_fn)(void *provctx,
  58                                            OSSL_CORE_BIO * bio);
  59  static ossl_inline OSSL_FUNC_store_attach_fn
  60      OSSL_FUNC_store_attach(const OSSL_DISPATCH *opf);
  61
  62 L<OSSL_DISPATCH(3)> arrays are indexed by numbers that are provided as macros
  63 in L<openssl-core_dispatch.h(7)>, as follows:
  64
  65  OSSL_FUNC_store_open                 OSSL_FUNC_STORE_OPEN
  66  OSSL_FUNC_store_attach               OSSL_FUNC_STORE_ATTACH
  67  OSSL_FUNC_store_settable_ctx_params  OSSL_FUNC_STORE_SETTABLE_CTX_PARAMS
  68  OSSL_FUNC_store_set_ctx_params       OSSL_FUNC_STORE_SET_CTX_PARAMS
  69  OSSL_FUNC_store_load                 OSSL_FUNC_STORE_LOAD
  70  OSSL_FUNC_store_eof                  OSSL_FUNC_STORE_EOF
  71  OSSL_FUNC_store_close                OSSL_FUNC_STORE_CLOSE
  72  OSSL_FUNC_store_export_object        OSSL_FUNC_STORE_EXPORT_OBJECT
  73
  74 =head2 Functions
  75
  76 OSSL_FUNC_store_open() should create a provider side context with data based
  77 on the input I<uri>.  The implementation is entirely responsible for the
  78 interpretation of the URI.
  79
  80 OSSL_FUNC_store_attach() should create a provider side context with the core
  81 B<BIO> I<bio> attached.  This is an alternative to using a URI to find storage,
  82 supporting L<OSSL_STORE_attach(3)>.
  83
  84 OSSL_FUNC_store_settable_ctx_params() should return a constant array of
  85 descriptor L<OSSL_PARAM(3)>, for parameters that OSSL_FUNC_store_set_ctx_params()
  86 can handle.
  87
  88 OSSL_FUNC_store_set_ctx_params() should set additional parameters, such as what
  89 kind of data to expect, search criteria, and so on.  More on those below, in
  90 L</Load Parameters>.  Whether unrecognised parameters are an error or simply
  91 ignored is at the implementation's discretion.
  92 Passing NULL for I<params> should return true.
  93
  94 OSSL_FUNC_store_load() loads the next object from the URI opened by
  95 OSSL_FUNC_store_open(), creates an object abstraction for it (see
  96 L<provider-object(7)>), and calls I<object_cb> with it as well as
  97 I<object_cbarg>.  I<object_cb> will then interpret the object abstraction
  98 and do what it can to wrap it or decode it into an OpenSSL structure.  In
  99 case a passphrase needs to be prompted to unlock an object, I<pw_cb> should
 100 be called.
 101
 102 OSSL_FUNC_store_eof() indicates if the end of the set of objects from the
 103 URI has been reached.  When that happens, there's no point trying to do any
 104 further loading.
 105
 106 OSSL_FUNC_store_close() frees the provider side context I<ctx>.
 107
 108 When a provider-native object is created by a store manager it would be unsuitable
 109 for direct use with a foreign provider. The export function allows for
 110 exporting the object to that foreign provider if the foreign provider
 111 supports the type of the object and provides an import function.
 112
 113 OSSL_FUNC_store_export_object() should export the object of size I<objref_sz>
 114 referenced by I<objref> as an L<OSSL_PARAM(3)> array and pass that to the
 115 I<export_cb> as well as the given I<export_cbarg>.
 116
 117 =head2 Load Parameters
 118
 119 =over 4
 120
 121 =item "expect" (B<OSSL_STORE_PARAM_EXPECT>) <integer>
 122
 123 Is a hint of what type of data the OpenSSL library expects to get.
 124 This is only useful for optimization, as the library will check that the
 125 object types match the expectation too.
 126
 127 The number that can be given through this parameter is found in
 128 F<< <openssl/store.h> >>, with the macros having names starting with
 129 C<OSSL_STORE_INFO_>.  These are further described in
 130 L<OSSL_STORE_INFO(3)/SUPPORTED OBJECTS>.
 131
 132 =item "subject" (B<OSSL_STORE_PARAM_SUBJECT>) <octet string>
 133
 134 Indicates that the caller wants to search for an object with the given
 135 subject associated.  This can be used to select specific certificates
 136 by subject.
 137
 138 The contents of the octet string is expected to be in DER form.
 139
 140 =item "issuer" (B<OSSL_STORE_PARAM_ISSUER>) <octet string>
 141
 142 Indicates that the caller wants to search for an object with the given
 143 issuer associated.  This can be used to select specific certificates
 144 by issuer.
 145
 146 The contents of the octet string is expected to be in DER form.
 147
 148 =item "serial" (B<OSSL_STORE_PARAM_SERIAL>) <integer>
 149
 150 Indicates that the caller wants to search for an object with the given
 151 serial number associated.
 152
 153 =item "digest" (B<OSSL_STORE_PARAM_DIGEST>) <UTF8 string>
 154
 155 =item "fingerprint" (B<OSSL_STORE_PARAM_FINGERPRINT>) <octet string>
 156
 157 Indicates that the caller wants to search for an object with the given
 158 fingerprint, computed with the given digest.
 159
 160 =item "alias" (B<OSSL_STORE_PARAM_ALIAS>) <UTF8 string>
 161
 162 Indicates that the caller wants to search for an object with the given
 163 alias (some call it a "friendly name").
 164
 165 =item "properties" (B<OSSL_STORE_PARAM_PROPERTIES) <utf8 string>
 166
 167 Property string to use when querying for algorithms such as the B<OSSL_DECODER>
 168 decoder implementations.
 169
 170 =item "input-type" (B<OSSL_STORE_PARAM_INPUT_TYPE) <utf8 string>
 171
 172 Type of the input format as a hint to use when decoding the objects in the
 173 store.
 174
 175 =back
 176
 177 Several of these search criteria may be combined.  For example, to
 178 search for a certificate by issuer+serial, both the "issuer" and the
 179 "serial" parameters will be given.
 180
 181 =head1 SEE ALSO
 182
 183 L<provider(7)>
 184
 185 =head1 HISTORY
 186
 187 The STORE interface was introduced in OpenSSL 3.0.
 188
 189 =head1 COPYRIGHT
 190
 191 Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
 192
 193 Licensed under the Apache License 2.0 (the "License").  You may not use
 194 this file except in compliance with the License.  You can obtain a copy
 195 in the file LICENSE in the source distribution or at
 196 L<https://www.openssl.org/source/license.html>.
 197
 198 =cut