1=pod 2 3=head1 NAME 4 5X509_STORE_CTX_new_ex, X509_STORE_CTX_new, X509_STORE_CTX_cleanup, 6X509_STORE_CTX_free, X509_STORE_CTX_init, X509_STORE_CTX_set0_trusted_stack, 7X509_STORE_CTX_set_cert, X509_STORE_CTX_set0_crls, 8X509_STORE_CTX_get0_param, X509_STORE_CTX_set0_param, 9X509_STORE_CTX_get0_untrusted, X509_STORE_CTX_set0_untrusted, 10X509_STORE_CTX_get_num_untrusted, 11X509_STORE_CTX_get0_chain, X509_STORE_CTX_set0_verified_chain, 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_ex(OSSL_LIB_CTX *libctx, const char *propq); 25 X509_STORE_CTX *X509_STORE_CTX_new(void); 26 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx); 27 void X509_STORE_CTX_free(X509_STORE_CTX *ctx); 28 29 int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *trust_store, 30 X509 *target, STACK_OF(X509) *untrusted); 31 32 void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk); 33 34 void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *target); 35 void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk); 36 37 X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(const X509_STORE_CTX *ctx); 38 void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param); 39 40 STACK_OF(X509)* X509_STORE_CTX_get0_untrusted(const X509_STORE_CTX *ctx); 41 void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk); 42 43 int X509_STORE_CTX_get_num_untrusted(const X509_STORE_CTX *ctx); 44 STACK_OF(X509) *X509_STORE_CTX_get0_chain(const X509_STORE_CTX *ctx); 45 void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *chain); 46 47 int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name); 48 typedef int (*X509_STORE_CTX_verify_fn)(X509_STORE_CTX *); 49 void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx, X509_STORE_CTX_verify_fn verify); 50 51 int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose); 52 int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust); 53 int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose, 54 int purpose, int trust); 55 56=head1 DESCRIPTION 57 58These functions initialise an B<X509_STORE_CTX> structure for subsequent use 59by L<X509_verify_cert(3)> or L<X509_STORE_CTX_verify(3)>. 60 61X509_STORE_CTX_new_ex() returns a newly initialised B<X509_STORE_CTX> 62structure associated with the specified library context I<libctx> and property 63query string I<propq>. Any cryptographic algorithms fetched while performing 64processing with the X509_STORE_CTX will use that library context and property 65query string. 66 67X509_STORE_CTX_new() is the same as X509_STORE_CTX_new_ex() except that 68the default library context and a NULL property query string are used. 69 70X509_STORE_CTX_cleanup() internally cleans up an B<X509_STORE_CTX> structure. 71It is used by X509_STORE_CTX_init() and X509_STORE_CTX_free(). 72 73X509_STORE_CTX_free() completely frees up I<ctx>. After this call I<ctx> 74is no longer valid. 75If I<ctx> is NULL nothing is done. 76 77X509_STORE_CTX_init() sets up I<ctx> for a subsequent verification operation. 78 79X509_STORE_CTX_init() initializes the internal state and resources of the 80given I<ctx>. Among others, it sets the verification parameters associcated 81with the method name C<default>, which includes the C<any> purpose, 82and takes over callback function pointers from I<trust_store> (unless NULL). 83It must be called before each call to L<X509_verify_cert(3)> or 84L<X509_STORE_CTX_verify(3)>, i.e., a context is only good for one verification. 85If you want to verify a further certificate or chain with the same I<ctx> 86then you must call X509_STORE_CTX_init() again. 87The trusted certificate store is set to I<trust_store> of type B<X509_STORE>. 88This may be NULL because there are no trusted certificates or because 89they are provided simply as a list using X509_STORE_CTX_set0_trusted_stack(). 90The certificate to be verified is set to I<target>, 91and a list of additional certificates may be provided in I<untrusted>, 92which will be untrusted but may be used to build the chain. 93Each of the I<trust_store>, I<target> and I<untrusted> parameters can be NULL. 94Yet note that L<X509_verify_cert(3)> and L<X509_STORE_CTX_verify(3)> 95will need a verification target. 96This can also be set using X509_STORE_CTX_set_cert(). 97For L<X509_STORE_CTX_verify(3)>, which takes by default the first element of the 98list of untrusted certificates as its verification target, 99this can be also set indirectly using X509_STORE_CTX_set0_untrusted(). 100 101X509_STORE_CTX_set0_trusted_stack() sets the set of trusted certificates of 102I<ctx> to I<sk>. This is an alternative way of specifying trusted certificates 103instead of using an B<X509_STORE> where its complexity is not needed 104or to make sure that only the given set I<sk> of certificates are trusted. 105 106X509_STORE_CTX_set_cert() sets the target certificate to be verified in I<ctx> 107to I<target>. 108 109X509_STORE_CTX_set0_verified_chain() sets the validated chain to I<chain>. 110Ownership of the chain is transferred to I<ctx>, 111and so it should not be free'd by the caller. 112 113X509_STORE_CTX_get0_chain() returns the internal pointer used by the 114I<ctx> that contains the constructed (output) chain. 115 116X509_STORE_CTX_set0_crls() sets a set of CRLs to use to aid certificate 117verification to I<sk>. These CRLs will only be used if CRL verification is 118enabled in the associated B<X509_VERIFY_PARAM> structure. This might be 119used where additional "useful" CRLs are supplied as part of a protocol, 120for example in a PKCS#7 structure. 121 122X509_STORE_CTX_get0_param() retrieves an internal pointer 123to the verification parameters associated with I<ctx>. 124 125X509_STORE_CTX_set0_param() sets the internal verification parameter pointer 126to I<param>. After this call B<param> should not be used. 127 128X509_STORE_CTX_get0_untrusted() retrieves an internal pointer to the 129stack of untrusted certificates associated with I<ctx>. 130 131X509_STORE_CTX_set0_untrusted() sets the internal pointer to the stack 132of untrusted certificates associated with I<ctx> to I<sk>. 133X509_STORE_CTX_verify() will take the first element, if any, 134as its default target if the target certificate is not set explicitly. 135 136X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates 137that were used in building the chain. 138This is can be used after calling L<X509_verify_cert(3)> and similar functions. 139With L<X509_STORE_CTX_verify(3)>, this does not count the first chain element. 140 141X509_STORE_CTX_get0_chain() returns the internal pointer used by the 142I<ctx> that contains the validated chain. 143 144Details of the chain building and checking process are described in 145L<openssl-verification-options(1)/Certification Path Building> and 146L<openssl-verification-options(1)/Certification Path Validation>. 147 148X509_STORE_CTX_set0_verified_chain() sets the validated chain used 149by I<ctx> to be I<chain>. 150Ownership of the chain is transferred to I<ctx>, 151and so it should not be free'd by the caller. 152 153X509_STORE_CTX_set_default() looks up and sets the default verification method. 154This uses the function X509_VERIFY_PARAM_lookup() to find 155the set of parameters associated with the given verification method I<name>. 156Among others, the parameters determine the trust model and verification purpose. 157More detail, including the list of currently predefined methods, 158is described for the B<-verify_name> command-line option 159in L<openssl-verification-options(1)/Verification Options>. 160 161X509_STORE_CTX_set_verify() provides the capability for overriding the default 162verify function. This function is responsible for verifying chain signatures and 163expiration times. 164 165A verify function is defined as an X509_STORE_CTX_verify type which has the 166following signature: 167 168 int (*verify)(X509_STORE_CTX *); 169 170This function should receive the current X509_STORE_CTX as a parameter and 171return 1 on success or 0 on failure. 172 173X509 certificates may contain information about what purposes keys contained 174within them can be used for. For example "TLS WWW Server Authentication" or 175"Email Protection". This "key usage" information is held internally to the 176certificate itself. In addition the trust store containing trusted certificates 177can declare what purposes we trust different certificates for. This "trust" 178information is not held within the certificate itself but is "meta" information 179held alongside it. This "meta" information is associated with the certificate 180after it is issued and could be determined by a system administrator. For 181example a certificate might declare that it is suitable for use for both 182"TLS WWW Server Authentication" and "TLS Client Authentication", but a system 183administrator might only trust it for the former. An X.509 certificate extension 184exists that can record extended key usage information to supplement the purpose 185information described above. This extended mechanism is arbitrarily extensible 186and not well suited for a generic library API; applications that need to 187validate extended key usage information in certificates will need to define a 188custom "purpose" (see below) or supply a nondefault verification callback 189(L<X509_STORE_set_verify_cb_func(3)>). 190 191X509_STORE_CTX_set_purpose() sets the purpose for the target certificate being 192verified in the I<ctx>. Built-in available values for the I<purpose> argument 193are B<X509_PURPOSE_SSL_CLIENT>, B<X509_PURPOSE_SSL_SERVER>, 194B<X509_PURPOSE_NS_SSL_SERVER>, B<X509_PURPOSE_SMIME_SIGN>, 195B<X509_PURPOSE_SMIME_ENCRYPT>, B<X509_PURPOSE_CRL_SIGN>, B<X509_PURPOSE_ANY>, 196B<X509_PURPOSE_OCSP_HELPER> and B<X509_PURPOSE_TIMESTAMP_SIGN>. It is also 197possible to create a custom purpose value. Setting a purpose will ensure that 198the key usage declared within certificates in the chain being verified is 199consistent with that purpose as well as, potentially, other checks. Every 200purpose also has an associated default trust value which will also be set at the 201same time. During verification this trust setting will be verified to check it 202is consistent with the trust set by the system administrator for certificates in 203the chain. 204 205X509_STORE_CTX_set_trust() sets the trust value for the target certificate 206being verified in the I<ctx>. Built-in available values for the I<trust> 207argument are B<X509_TRUST_COMPAT>, B<X509_TRUST_SSL_CLIENT>, 208B<X509_TRUST_SSL_SERVER>, B<X509_TRUST_EMAIL>, B<X509_TRUST_OBJECT_SIGN>, 209B<X509_TRUST_OCSP_SIGN>, B<X509_TRUST_OCSP_REQUEST> and B<X509_TRUST_TSA>. It is 210also possible to create a custom trust value. Since X509_STORE_CTX_set_purpose() 211also sets the trust value it is normally sufficient to only call that function. 212If both are called then X509_STORE_CTX_set_trust() should be called after 213X509_STORE_CTX_set_purpose() since the trust setting of the last call will be 214used. 215 216It should not normally be necessary for end user applications to call 217X509_STORE_CTX_purpose_inherit() directly. Typically applications should call 218X509_STORE_CTX_set_purpose() or X509_STORE_CTX_set_trust() instead. Using this 219function it is possible to set the purpose and trust values for the I<ctx> at 220the same time. 221Both I<ctx> and its internal verification parameter pointer must not be NULL. 222The I<def_purpose> and I<purpose> arguments can have the same 223purpose values as described for X509_STORE_CTX_set_purpose() above. The I<trust> 224argument can have the same trust values as described in 225X509_STORE_CTX_set_trust() above. Any of the I<def_purpose>, I<purpose> or 226I<trust> values may also have the value 0 to indicate that the supplied 227parameter should be ignored. After calling this function the purpose to be used 228for verification is set from the I<purpose> argument unless the purpose was 229already set in I<ctx> before, and the trust is set from the I<trust> argument 230unless the trust was already set in I<ctx> before. 231If I<trust> is 0 then the trust value will be set from 232the default trust value for I<purpose>. If the default trust value for the 233purpose is I<X509_TRUST_DEFAULT> and I<trust> is 0 then the default trust value 234associated with the I<def_purpose> value is used for the trust setting instead. 235 236=head1 NOTES 237 238The certificates and CRLs in a store are used internally and should B<not> 239be freed up until after the associated B<X509_STORE_CTX> is freed. 240 241=head1 BUGS 242 243The certificates and CRLs in a context are used internally and should B<not> 244be freed up until after the associated B<X509_STORE_CTX> is freed. Copies 245should be made or reference counts increased instead. 246 247=head1 RETURN VALUES 248 249X509_STORE_CTX_new() returns a newly allocated context or NULL if an 250error occurred. 251 252X509_STORE_CTX_init() returns 1 for success or 0 if an error occurred. 253 254X509_STORE_CTX_get0_param() returns a pointer to an B<X509_VERIFY_PARAM> 255structure or NULL if an error occurred. 256 257X509_STORE_CTX_cleanup(), X509_STORE_CTX_free(), 258X509_STORE_CTX_set0_trusted_stack(), 259X509_STORE_CTX_set_cert(), 260X509_STORE_CTX_set0_crls() and X509_STORE_CTX_set0_param() do not return 261values. 262 263X509_STORE_CTX_set_default() returns 1 for success or 0 if an error occurred. 264 265X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates 266used. 267 268=head1 SEE ALSO 269 270L<X509_verify_cert(3)>, L<X509_STORE_CTX_verify(3)>, 271L<X509_VERIFY_PARAM_set_flags(3)> 272 273=head1 HISTORY 274 275The X509_STORE_CTX_set0_crls() function was added in OpenSSL 1.0.0. 276The X509_STORE_CTX_get_num_untrusted() function was added in OpenSSL 1.1.0. 277The X509_STORE_CTX_new_ex() function was added in OpenSSL 3.0. 278 279There is no need to call X509_STORE_CTX_cleanup() explicitly since OpenSSL 3.0. 280 281=head1 COPYRIGHT 282 283Copyright 2009-2023 The OpenSSL Project Authors. All Rights Reserved. 284 285Licensed under the Apache License 2.0 (the "License"). You may not use 286this file except in compliance with the License. You can obtain a copy 287in the file LICENSE in the source distribution or at 288L<https://www.openssl.org/source/license.html>. 289 290=cut 291