1=pod 2 3=head1 NAME 4 5EVP_PKEY_get_attr, 6EVP_PKEY_get_attr_count, 7EVP_PKEY_get_attr_by_NID, EVP_PKEY_get_attr_by_OBJ, 8EVP_PKEY_delete_attr, 9EVP_PKEY_add1_attr, 10EVP_PKEY_add1_attr_by_OBJ, EVP_PKEY_add1_attr_by_NID, EVP_PKEY_add1_attr_by_txt 11- EVP_PKEY B<X509_ATTRIBUTE> functions 12 13=head1 SYNOPSIS 14 15 #include <openssl/x509.h> 16 17 int EVP_PKEY_get_attr_count(const EVP_PKEY *key); 18 int EVP_PKEY_get_attr_by_NID(const EVP_PKEY *key, int nid, int lastpos); 19 int EVP_PKEY_get_attr_by_OBJ(const EVP_PKEY *key, const ASN1_OBJECT *obj, 20 int lastpos); 21 X509_ATTRIBUTE *EVP_PKEY_get_attr(const EVP_PKEY *key, int loc); 22 X509_ATTRIBUTE *EVP_PKEY_delete_attr(EVP_PKEY *key, int loc); 23 int EVP_PKEY_add1_attr(EVP_PKEY *key, X509_ATTRIBUTE *attr); 24 int EVP_PKEY_add1_attr_by_OBJ(EVP_PKEY *key, 25 const ASN1_OBJECT *obj, int type, 26 const unsigned char *bytes, int len); 27 int EVP_PKEY_add1_attr_by_NID(EVP_PKEY *key, 28 int nid, int type, 29 const unsigned char *bytes, int len); 30 int EVP_PKEY_add1_attr_by_txt(EVP_PKEY *key, 31 const char *attrname, int type, 32 const unsigned char *bytes, int len); 33 34=head1 DESCRIPTION 35 36These functions are used by B<PKCS12>. 37 38EVP_PKEY_get_attr_by_OBJ() finds the location of the first matching object I<obj> 39in the I<key> attribute list. The search starts at the position after I<lastpos>. 40If the returned value is positive then it can be used on the next call to 41EVP_PKEY_get_attr_by_OBJ() as the value of I<lastpos> in order to iterate through 42the remaining attributes. I<lastpos> can be set to any negative value on the 43first call, in order to start searching from the start of the attribute list. 44 45EVP_PKEY_get_attr_by_NID() is similar to EVP_PKEY_get_attr_by_OBJ() except that 46it passes the numerical identifier (NID) I<nid> associated with the object. 47See <openssl/obj_mac.h> for a list of NID_*. 48 49EVP_PKEY_get_attr() returns the B<X509_ATTRIBUTE> object at index I<loc> in the 50I<key> attribute list. I<loc> should be in the range from 0 to 51EVP_PKEY_get_attr_count() - 1. 52 53EVP_PKEY_delete_attr() removes the B<X509_ATTRIBUTE> object at index I<loc> in 54the I<key> attribute list. 55 56EVP_PKEY_add1_attr() pushes a copy of the passed in B<X509_ATTRIBUTE> object 57to the I<key> attribute list. A new I<key> attribute list is created if required. 58An error occurs if either I<attr> is NULL, or the attribute already exists. 59 60EVP_PKEY_add1_attr_by_OBJ() creates a new B<X509_ATTRIBUTE> using 61X509_ATTRIBUTE_set1_object() and X509_ATTRIBUTE_set1_data() to assign a new 62I<obj> with type I<type> and data I<bytes> of length I<len> and then pushes it 63to the I<key> object's attribute list. If I<obj> already exists in the attribute 64list then an error occurs. 65 66EVP_PKEY_add1_attr_by_NID() is similar to EVP_PKEY_add1_attr_by_OBJ() except 67that it passes the numerical identifier (NID) I<nid> associated with the object. 68See <openssl/obj_mac.h> for a list of NID_*. 69 70EVP_PKEY_add1_attr_by_txt() is similar to EVP_PKEY_add1_attr_by_OBJ() except 71that it passes a name I<attrname> associated with the object. 72See <openssl/obj_mac.h> for a list of SN_* names. 73 74=head1 RETURN VALUES 75 76EVP_PKEY_get_attr_count() returns the number of attributes in the I<key> object 77attribute list or -1 if the attribute list is NULL. 78 79EVP_PKEY_get_attr_by_OBJ() returns -1 if either the list is empty OR the object 80is not found, otherwise it returns the location of the object in the list. 81 82EVP_PKEY_get_attr_by_NID() is similar to EVP_PKEY_get_attr_by_OBJ(), except that 83it returns -2 if the I<nid> is not known by OpenSSL. 84 85EVP_PKEY_get_attr() returns either a B<X509_ATTRIBUTE> or NULL if there is a 86error. 87 88EVP_PKEY_delete_attr() returns either the removed B<X509_ATTRIBUTE> or NULL if 89there is a error. 90 91EVP_PKEY_add1_attr(), EVP_PKEY_add1_attr_by_OBJ(), EVP_PKEY_add1_attr_by_NID() 92and EVP_PKEY_add1_attr_by_txt() return 1 on success or 0 otherwise. 93 94=head1 NOTES 95 96A B<EVP_PKEY> object's attribute list is initially NULL. All the above functions 97listed will return an error unless EVP_PKEY_add1_attr() is called. 98All functions listed assume that the I<key> is not NULL. 99 100=head1 SEE ALSO 101 102L<X509_ATTRIBUTE(3)> 103 104=head1 COPYRIGHT 105 106Copyright 2023-2024 The OpenSSL Project Authors. All Rights Reserved. 107 108Licensed under the Apache License 2.0 (the "License"). You may not use 109this file except in compliance with the License. You can obtain a copy 110in the file LICENSE in the source distribution or at 111L<https://www.openssl.org/source/license.html>. 112 113=cut 114