1=pod
2
3=head1 NAME
4
5X509_STORE_CTX_new, X509_STORE_CTX_cleanup, X509_STORE_CTX_free,
6X509_STORE_CTX_init, X509_STORE_CTX_set0_trusted_stack, X509_STORE_CTX_set_cert,
7X509_STORE_CTX_set0_crls,
8X509_STORE_CTX_get0_chain, X509_STORE_CTX_set0_verified_chain,
9X509_STORE_CTX_get0_param, X509_STORE_CTX_set0_param,
10X509_STORE_CTX_get0_untrusted, X509_STORE_CTX_set0_untrusted,
11X509_STORE_CTX_get_num_untrusted,
12X509_STORE_CTX_set_default,
13X509_STORE_CTX_set_verify,
14X509_STORE_CTX_verify_fn,
15X509_STORE_CTX_set_purpose,
16X509_STORE_CTX_set_trust,
17X509_STORE_CTX_purpose_inherit
18- X509_STORE_CTX initialisation
19
20=head1 SYNOPSIS
21
22 #include <openssl/x509_vfy.h>
23
24 X509_STORE_CTX *X509_STORE_CTX_new(void);
25 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx);
26 void X509_STORE_CTX_free(X509_STORE_CTX *ctx);
27
28 int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store,
29                         X509 *x509, STACK_OF(X509) *chain);
30
31 void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk);
32
33 void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *x);
34 STACK_OF(X509) *X509_STORE_CTX_get0_chain(X509_STORE_CTX *ctx);
35 void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *chain);
36 void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk);
37
38 X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(X509_STORE_CTX *ctx);
39 void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param);
40 int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name);
41
42 STACK_OF(X509)* X509_STORE_CTX_get0_untrusted(X509_STORE_CTX *ctx);
43 void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk);
44
45 int X509_STORE_CTX_get_num_untrusted(X509_STORE_CTX *ctx);
46
47 typedef int (*X509_STORE_CTX_verify_fn)(X509_STORE_CTX *);
48 void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx, X509_STORE_CTX_verify_fn verify);
49
50 int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose);
51 int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust);
52 int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose,
53                                    int purpose, int trust);
54
55=head1 DESCRIPTION
56
57These functions initialise an B<X509_STORE_CTX> structure for subsequent use
58by X509_verify_cert().
59
60X509_STORE_CTX_new() returns a newly initialised B<X509_STORE_CTX> structure.
61
62X509_STORE_CTX_cleanup() internally cleans up an B<X509_STORE_CTX> structure.
63The context can then be reused with a new call to X509_STORE_CTX_init().
64
65X509_STORE_CTX_free() completely frees up B<ctx>. After this call B<ctx>
66is no longer valid.
67If B<ctx> is NULL nothing is done.
68
69X509_STORE_CTX_init() sets up B<ctx> for a subsequent verification operation.
70It must be called before each call to X509_verify_cert(), i.e. a B<ctx> is only
71good for one call to X509_verify_cert(); if you want to verify a second
72certificate with the same B<ctx> then you must call X509_STORE_CTX_cleanup()
73and then X509_STORE_CTX_init() again before the second call to
74X509_verify_cert(). The trusted certificate store is set to B<store>, the end
75entity certificate to be verified is set to B<x509> and a set of additional
76certificates (which will be untrusted but may be used to build the chain) in
77B<chain>. Any or all of the B<store>, B<x509> and B<chain> parameters can be
78B<NULL>.
79
80X509_STORE_CTX_set0_trusted_stack() sets the set of trusted certificates of
81B<ctx> to B<sk>. This is an alternative way of specifying trusted certificates
82instead of using an B<X509_STORE>.
83
84X509_STORE_CTX_set_cert() sets the certificate to be verified in B<ctx> to
85B<x>.
86
87X509_STORE_CTX_set0_verified_chain() sets the validated chain used
88by B<ctx> to be B<chain>.
89Ownership of the chain is transferred to B<ctx> and should not be
90free'd by the caller.
91X509_STORE_CTX_get0_chain() returns the internal pointer used by the
92B<ctx> that contains the validated chain.
93
94X509_STORE_CTX_set0_crls() sets a set of CRLs to use to aid certificate
95verification to B<sk>. These CRLs will only be used if CRL verification is
96enabled in the associated B<X509_VERIFY_PARAM> structure. This might be
97used where additional "useful" CRLs are supplied as part of a protocol,
98for example in a PKCS#7 structure.
99
100X509_STORE_CTX_get0_param() retrieves an internal pointer
101to the verification parameters associated with B<ctx>.
102
103X509_STORE_CTX_get0_untrusted() retrieves an internal pointer to the
104stack of untrusted certificates associated with B<ctx>.
105
106X509_STORE_CTX_set0_untrusted() sets the internal point to the stack
107of untrusted certificates associated with B<ctx> to B<sk>.
108
109X509_STORE_CTX_set0_param() sets the internal verification parameter pointer
110to B<param>. After this call B<param> should not be used.
111
112X509_STORE_CTX_set_default() looks up and sets the default verification
113method to B<name>. This uses the function X509_VERIFY_PARAM_lookup() to
114find an appropriate set of parameters from B<name>.
115
116X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates
117that were used in building the chain following a call to X509_verify_cert().
118
119X509_STORE_CTX_set_verify() provides the capability for overriding the default
120verify function. This function is responsible for verifying chain signatures and
121expiration times.
122
123A verify function is defined as an X509_STORE_CTX_verify type which has the
124following signature:
125
126 int (*verify)(X509_STORE_CTX *);
127
128This function should receive the current X509_STORE_CTX as a parameter and
129return 1 on success or 0 on failure.
130
131X509 certificates may contain information about what purposes keys contained
132within them can be used for. For example "TLS WWW Server Authentication" or
133"Email Protection". This "key usage" information is held internally to the
134certificate itself. In addition the trust store containing trusted certificates
135can declare what purposes we trust different certificates for. This "trust"
136information is not held within the certificate itself but is "meta" information
137held alongside it. This "meta" information is associated with the certificate
138after it is issued and could be determined by a system administrator. For
139example a certificate might declare that it is suitable for use for both
140"TLS WWW Server Authentication" and "TLS Client Authentication", but a system
141administrator might only trust it for the former. An X.509 certificate extension
142exists that can record extended key usage information to supplement the purpose
143information described above. This extended mechanism is arbitrarily extensible
144and not well suited for a generic library API; applications that need to
145validate extended key usage information in certifiates will need to define a
146custom "purpose" (see below) or supply a nondefault verification callback
147(L<X509_STORE_set_verify_cb_func(3)>).
148
149X509_STORE_CTX_set_purpose() sets the purpose for the target certificate being
150verified in the I<ctx>. Built-in available values for the I<purpose> argument
151are B<X509_PURPOSE_SSL_CLIENT>, B<X509_PURPOSE_SSL_SERVER>,
152B<X509_PURPOSE_NS_SSL_SERVER>, B<X509_PURPOSE_SMIME_SIGN>,
153B<X509_PURPOSE_SMIME_ENCRYPT>, B<X509_PURPOSE_CRL_SIGN>, B<X509_PURPOSE_ANY>,
154B<X509_PURPOSE_OCSP_HELPER> and B<X509_PURPOSE_TIMESTAMP_SIGN>. It is also
155possible to create a custom purpose value. Setting a purpose will ensure that
156the key usage declared within certificates in the chain being verified is
157consistent with that purpose as well as, potentially, other checks. Every
158purpose also has an associated default trust value which will also be set at the
159same time. During verification this trust setting will be verified to check it
160is consistent with the trust set by the system administrator for certificates in
161the chain.
162
163X509_STORE_CTX_set_trust() sets the trust value for the target certificate
164being verified in the I<ctx>. Built-in available values for the I<trust>
165argument are B<X509_TRUST_COMPAT>, B<X509_TRUST_SSL_CLIENT>,
166B<X509_TRUST_SSL_SERVER>, B<X509_TRUST_EMAIL>, B<X509_TRUST_OBJECT_SIGN>,
167B<X509_TRUST_OCSP_SIGN>, B<X509_TRUST_OCSP_REQUEST> and B<X509_TRUST_TSA>. It is
168also possible to create a custom trust value. Since X509_STORE_CTX_set_purpose()
169also sets the trust value it is normally sufficient to only call that function.
170If both are called then X509_STORE_CTX_set_trust() should be called after
171X509_STORE_CTX_set_purpose() since the trust setting of the last call will be
172used.
173
174It should not normally be necessary for end user applications to call
175X509_STORE_CTX_purpose_inherit() directly. Typically applications should call
176X509_STORE_CTX_set_purpose() or X509_STORE_CTX_set_trust() instead. Using this
177function it is possible to set the purpose and trust values for the I<ctx> at
178the same time.
179Both I<ctx> and its internal verification parameter pointer must not be NULL.
180The I<def_purpose> and I<purpose> arguments can have the same
181purpose values as described for X509_STORE_CTX_set_purpose() above. The I<trust>
182argument can have the same trust values as described in
183X509_STORE_CTX_set_trust() above. Any of the I<def_purpose>, I<purpose> or
184I<trust> values may also have the value 0 to indicate that the supplied
185parameter should be ignored. After calling this function the purpose to be used
186for verification is set from the I<purpose> argument unless the purpose was
187already set in I<ctx> before, and the trust is set from the I<trust> argument
188unless the trust was already set in I<ctx> before.
189If I<trust> is 0 then the trust value will be set from
190the default trust value for I<purpose>. If the default trust value for the
191purpose is I<X509_TRUST_DEFAULT> and I<trust> is 0 then the default trust value
192associated with the I<def_purpose> value is used for the trust setting instead.
193
194=head1 NOTES
195
196The certificates and CRLs in a store are used internally and should B<not>
197be freed up until after the associated B<X509_STORE_CTX> is freed.
198
199=head1 BUGS
200
201The certificates and CRLs in a context are used internally and should B<not>
202be freed up until after the associated B<X509_STORE_CTX> is freed. Copies
203should be made or reference counts increased instead.
204
205=head1 RETURN VALUES
206
207X509_STORE_CTX_new() returns a newly allocated context or B<NULL> if an
208error occurred.
209
210X509_STORE_CTX_init() returns 1 for success or 0 if an error occurred.
211
212X509_STORE_CTX_get0_param() returns a pointer to an B<X509_VERIFY_PARAM>
213structure or B<NULL> if an error occurred.
214
215X509_STORE_CTX_cleanup(), X509_STORE_CTX_free(),
216X509_STORE_CTX_set0_trusted_stack(),
217X509_STORE_CTX_set_cert(),
218X509_STORE_CTX_set0_crls() and X509_STORE_CTX_set0_param() do not return
219values.
220
221X509_STORE_CTX_set_default() returns 1 for success or 0 if an error occurred.
222
223X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates
224used.
225
226=head1 SEE ALSO
227
228L<X509_verify_cert(3)>
229L<X509_VERIFY_PARAM_set_flags(3)>
230
231=head1 HISTORY
232
233The X509_STORE_CTX_set0_crls() function was added in OpenSSL 1.0.0.
234The X509_STORE_CTX_get_num_untrusted() function was added in OpenSSL 1.1.0.
235
236=head1 COPYRIGHT
237
238Copyright 2009-2022 The OpenSSL Project Authors. All Rights Reserved.
239
240Licensed under the OpenSSL license (the "License").  You may not use
241this file except in compliance with the License.  You can obtain a copy
242in the file LICENSE in the source distribution or at
243L<https://www.openssl.org/source/license.html>.
244
245=cut
246