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