1=pod 2 3=head1 NAME 4 5provider-object - A specification for a provider-native object abstraction 6 7=head1 SYNOPSIS 8 9=for openssl multiple includes 10 11 #include <openssl/core_object.h> 12 #include <openssl/core_names.h> 13 14=head1 DESCRIPTION 15 16The provider-native object abstraction is a set of L<OSSL_PARAM(3)> keys and 17values that can be used to pass provider-native objects to OpenSSL library 18code or between different provider operation implementations with the help 19of OpenSSL library code. 20 21The intention is that certain provider-native operations can pass any sort 22of object that belong with other operations, or with OpenSSL library code. 23 24An object may be passed in the following manners: 25 26=over 4 27 28=item 1. 29 30I<By value> 31 32This means that the I<object data> is passed as an octet string or an UTF8 33string, which can be handled in diverse ways by other provided implementations. 34The encoding of the object depends on the context it's used in; for example, 35L<OSSL_DECODER(3)> allows multiple encodings, depending on existing decoders. 36If central OpenSSL library functionality is to handle the data directly, it 37B<must> be encoded in DER for all object types except for B<OSSL_OBJECT_NAME> 38(see L</Parameter reference> below), where it's assumed to a plain UTF8 string. 39 40=for comment A future extension might be to be able to specify encoding as a 41separate parameter. 42 43=item 2. 44 45I<By reference> 46 47This means that the I<object data> isn't passed directly, an I<object 48reference> is passed instead. It's an octet string that only the correct 49provider understands correctly. 50 51=back 52 53Objects I<by value> can be used by anything that handles DER encoded 54objects. 55 56Objects I<by reference> need a higher level of cooperation from the 57implementation where the object originated (let's call it X) and its target 58implementation (let's call it Y): 59 60=over 4 61 62=item 1. 63 64I<An object loading function in the target implementation> 65 66The target implementation (Y) may have a function that can take an I<object 67reference>. This can only be used if the target implementation is from the 68same provider as the one originating the object abstraction in question (X). 69 70The exact target implementation to use is determined from the I<object type> 71and possibly the I<object data type>. 72For example, when the OpenSSL library receives an object abstraction with the 73I<object type> B<OSSL_OBJECT_PKEY>, it will fetch a L<provider-keymgmt(7)> 74using the I<object data type> as its key type (the second argument in 75L<EVP_KEYMGMT_fetch(3)>). 76 77=item 2. 78 79I<An object exporter in the originating implementation> 80 81The originating implementation (X) may have an exporter function. This 82exporter function can be used to export the object in L<OSSL_PARAM(3)> form, 83that can then be imported by the target implementation's imported function. 84 85This can be used when it's not possible to fetch the target implementation 86(Y) from the same provider. 87 88=back 89 90=head2 Parameter reference 91 92A provider-native object abstraction is an L<OSSL_PARAM(3)> with a selection 93of the following parameters: 94 95=over 4 96 97=item "data" (B<OSSL_OBJECT_PARAM_DATA>) <octet string> or <UTF8 string> 98 99The object data I<passed by value>. 100 101=item "reference" (B<OSSL_OBJECT_PARAM_REFERENCE>) <octet string> 102 103The object data I<passed by reference>. 104 105=item "type" (B<OSSL_OBJECT_PARAM_TYPE>) <integer> 106 107The I<object type>, a number that may have any of the following values (all 108defined in F<< <openssl/core_object.h> >>): 109 110=over 4 111 112=item B<OSSL_OBJECT_NAME> 113 114The object data may only be I<passed by value>, and should be a UTF8 115string. 116 117This is useful for L<provider-storemgmt(7)> when a URI load results in new 118URIs. 119 120=item B<OSSL_OBJECT_PKEY> 121 122The object data is suitable as provider-native B<EVP_PKEY> key data. The 123object data may be I<passed by value> or I<passed by reference>. 124 125=item B<OSSL_OBJECT_CERT> 126 127The object data is suitable as B<X509> data. The object data for this 128object type can only be I<passed by value>, and should be an octet string. 129 130Since there's no provider-native X.509 object, OpenSSL libraries that 131receive this object abstraction are expected to convert the data to a 132B<X509> object with d2i_X509(). 133 134=item B<OSSL_OBJECT_CRL> 135 136The object data is suitable as B<X509_CRL> data. The object data can 137only be I<passed by value>, and should be an octet string. 138 139Since there's no provider-native X.509 CRL object, OpenSSL libraries that 140receive this object abstraction are expected to convert the data to a 141B<X509_CRL> object with d2i_X509_CRL(). 142 143=back 144 145=item "data-type" (B<OSSL_OBJECT_PARAM_DATA_TYPE>) <UTF8 string> 146 147The specific type of the object content. Legitimate values depend on the 148object type; if it is B<OSSL_OBJECT_PKEY>, the data type is expected to be a 149key type suitable for fetching a L<provider-keymgmt(7)> that can handle the 150data. 151 152=for comment For objects with an unknown object type (OSSL_OBJECT_PARAM_TYPE 153is either missing or has the value OSSL_OBJECT_UNKNOWN), libcrypto 154interprets the object data type as the input type for a decoder. 155 156=item "data-structure" (B<OSSL_OBJECT_PARAM_DATA_STRUCTURE>) <UTF8 string> 157 158The outermost structure of the object content. Legitimate values depend on 159the object type. 160 161=item "desc" (B<OSSL_OBJECT_PARAM_DESC>) <UTF8 string> 162 163A human readable text that describes extra details on the object. 164 165=back 166 167When a provider-native object abtraction is used, it I<must> contain object 168data in at least one form (object data I<passed by value>, i.e. the "data" 169item, or object data I<passed by reference>, i.e. the "reference" item). 170Both may be present at once, in which case the OpenSSL library code that 171receives this will use the most optimal variant. 172 173For objects with the object type B<OSSL_OBJECT_NAME>, that object type 174I<must> be given. 175 176=head1 SEE ALSO 177 178L<provider(7)>, L<OSSL_DECODER(3)> 179 180=head1 HISTORY 181 182The concept of providers and everything surrounding them was 183introduced in OpenSSL 3.0. 184 185=head1 COPYRIGHT 186 187Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved. 188 189Licensed under the Apache License 2.0 (the "License"). You may not use 190this file except in compliance with the License. You can obtain a copy 191in the file LICENSE in the source distribution or at 192L<https://www.openssl.org/source/license.html>. 193 194=cut 195