1=pod
2
3=head1 NAME
4
5X509v3_get_ext_count, X509v3_get_ext, X509v3_get_ext_by_NID,
6X509v3_get_ext_by_OBJ, X509v3_get_ext_by_critical, X509v3_delete_ext,
7X509v3_add_ext, X509_get_ext_count, X509_get_ext,
8X509_get_ext_by_NID, X509_get_ext_by_OBJ, X509_get_ext_by_critical,
9X509_delete_ext, X509_add_ext, X509_CRL_get_ext_count, X509_CRL_get_ext,
10X509_CRL_get_ext_by_NID, X509_CRL_get_ext_by_OBJ, X509_CRL_get_ext_by_critical,
11X509_CRL_delete_ext, X509_CRL_add_ext, X509_REVOKED_get_ext_count,
12X509_REVOKED_get_ext, X509_REVOKED_get_ext_by_NID, X509_REVOKED_get_ext_by_OBJ,
13X509_REVOKED_get_ext_by_critical, X509_REVOKED_delete_ext,
14X509_REVOKED_add_ext - extension stack utility functions
15
16=head1 SYNOPSIS
17
18 #include <openssl/x509.h>
19
20 int X509v3_get_ext_count(const STACK_OF(X509_EXTENSION) *x);
21 X509_EXTENSION *X509v3_get_ext(const STACK_OF(X509_EXTENSION) *x, int loc);
22
23 int X509v3_get_ext_by_NID(const STACK_OF(X509_EXTENSION) *x,
24                           int nid, int lastpos);
25 int X509v3_get_ext_by_OBJ(const STACK_OF(X509_EXTENSION) *x,
26                           const ASN1_OBJECT *obj, int lastpos);
27 int X509v3_get_ext_by_critical(const STACK_OF(X509_EXTENSION) *x,
28                                int crit, int lastpos);
29 X509_EXTENSION *X509v3_delete_ext(STACK_OF(X509_EXTENSION) *x, int loc);
30 STACK_OF(X509_EXTENSION) *X509v3_add_ext(STACK_OF(X509_EXTENSION) **x,
31                                          X509_EXTENSION *ex, int loc);
32
33 int X509_get_ext_count(const X509 *x);
34 X509_EXTENSION *X509_get_ext(const X509 *x, int loc);
35 int X509_get_ext_by_NID(const X509 *x, int nid, int lastpos);
36 int X509_get_ext_by_OBJ(const X509 *x, const ASN1_OBJECT *obj, int lastpos);
37 int X509_get_ext_by_critical(const X509 *x, int crit, int lastpos);
38 X509_EXTENSION *X509_delete_ext(X509 *x, int loc);
39 int X509_add_ext(X509 *x, X509_EXTENSION *ex, int loc);
40
41 int X509_CRL_get_ext_count(const X509_CRL *x);
42 X509_EXTENSION *X509_CRL_get_ext(const X509_CRL *x, int loc);
43 int X509_CRL_get_ext_by_NID(const X509_CRL *x, int nid, int lastpos);
44 int X509_CRL_get_ext_by_OBJ(const X509_CRL *x, const ASN1_OBJECT *obj, int lastpos);
45 int X509_CRL_get_ext_by_critical(const X509_CRL *x, int crit, int lastpos);
46 X509_EXTENSION *X509_CRL_delete_ext(X509_CRL *x, int loc);
47 int X509_CRL_add_ext(X509_CRL *x, X509_EXTENSION *ex, int loc);
48
49 int X509_REVOKED_get_ext_count(const X509_REVOKED *x);
50 X509_EXTENSION *X509_REVOKED_get_ext(const X509_REVOKED *x, int loc);
51 int X509_REVOKED_get_ext_by_NID(const X509_REVOKED *x, int nid, int lastpos);
52 int X509_REVOKED_get_ext_by_OBJ(const X509_REVOKED *x, const ASN1_OBJECT *obj,
53                                 int lastpos);
54 int X509_REVOKED_get_ext_by_critical(const X509_REVOKED *x, int crit, int lastpos);
55 X509_EXTENSION *X509_REVOKED_delete_ext(X509_REVOKED *x, int loc);
56 int X509_REVOKED_add_ext(X509_REVOKED *x, X509_EXTENSION *ex, int loc);
57
58=head1 DESCRIPTION
59
60X509v3_get_ext_count() retrieves the number of extensions in B<x>.
61
62X509v3_get_ext() retrieves extension B<loc> from B<x>. The index B<loc>
63can take any value from B<0> to X509_get_ext_count(x) - 1. The returned
64extension is an internal pointer which B<must not> be freed up by the
65application.
66
67X509v3_get_ext_by_NID() and X509v3_get_ext_by_OBJ() look for an extension
68with B<nid> or B<obj> from extension stack B<x>. The search starts from the
69extension after B<lastpos> or from the beginning if <lastpos> is B<-1>. If
70the extension is found its index is returned otherwise B<-1> is returned.
71
72X509v3_get_ext_by_critical() is similar to X509v3_get_ext_by_NID() except it
73looks for an extension of criticality B<crit>. A zero value for B<crit>
74looks for a non-critical extension a nonzero value looks for a critical
75extension.
76
77X509v3_delete_ext() deletes the extension with index B<loc> from B<x>.
78The deleted extension is returned and must be freed by the caller.
79If B<loc> is in invalid index value B<NULL> is returned.
80
81X509v3_add_ext() adds extension B<ex> to stack B<*x> at position B<loc>. If
82B<loc> is B<-1> the new extension is added to the end. If B<*x> is B<NULL>
83a new stack will be allocated. The passed extension B<ex> is duplicated
84internally so it must be freed after use.
85
86X509_get_ext_count(), X509_get_ext(), X509_get_ext_by_NID(),
87X509_get_ext_by_OBJ(), X509_get_ext_by_critical(), X509_delete_ext()
88and X509_add_ext() operate on the extensions of certificate B<x> they are
89otherwise identical to the X509v3 functions.
90
91X509_CRL_get_ext_count(), X509_CRL_get_ext(), X509_CRL_get_ext_by_NID(),
92X509_CRL_get_ext_by_OBJ(), X509_CRL_get_ext_by_critical(),
93X509_CRL_delete_ext() and X509_CRL_add_ext() operate on the extensions of
94CRL B<x> they are otherwise identical to the X509v3 functions.
95
96X509_REVOKED_get_ext_count(), X509_REVOKED_get_ext(),
97X509_REVOKED_get_ext_by_NID(), X509_REVOKED_get_ext_by_OBJ(),
98X509_REVOKED_get_ext_by_critical(), X509_REVOKED_delete_ext() and
99X509_REVOKED_add_ext() operate on the extensions of CRL entry B<x>
100they are otherwise identical to the X509v3 functions.
101
102=head1 NOTES
103
104These functions are used to examine stacks of extensions directly. Many
105applications will want to parse or encode and add an extension: they should
106use the extension encode and decode functions instead such as
107X509_add1_ext_i2d() and X509_get_ext_d2i().
108
109Extension indices start from zero, so a zero index return value is B<not> an
110error. These search functions start from the extension B<after> the B<lastpos>
111parameter so it should initially be set to B<-1>, if it is set to zero the
112initial extension will not be checked.
113
114=head1 BUGS
115
116X509v3_delete_ext() and its variants are a bit counter-intuitive
117because these functions do not free the extension they delete.
118
119=head1 RETURN VALUES
120
121X509v3_get_ext_count() returns the extension count.
122
123X509v3_get_ext(), X509v3_delete_ext() and X509_delete_ext() return an
124B<X509_EXTENSION> pointer or B<NULL> if an error occurs.
125
126X509v3_get_ext_by_NID() X509v3_get_ext_by_OBJ() and
127X509v3_get_ext_by_critical() return the an extension index or B<-1> if an
128error occurs.
129
130X509v3_add_ext() returns a stack of extensions or B<NULL> on error.
131
132X509_add_ext() returns 1 on success and 0 on error.
133
134=head1 SEE ALSO
135
136L<X509V3_get_d2i(3)>
137
138=head1 COPYRIGHT
139
140Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.
141
142Licensed under the Apache License 2.0 (the "License").  You may not use
143this file except in compliance with the License.  You can obtain a copy
144in the file LICENSE in the source distribution or at
145L<https://www.openssl.org/source/license.html>.
146
147=cut
148