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, 7X509_STORE_CTX_init_rpk, 8X509_STORE_CTX_set0_trusted_stack, 9X509_STORE_CTX_set_cert, X509_STORE_CTX_set0_crls, 10X509_STORE_CTX_set0_rpk, 11X509_STORE_CTX_get0_param, X509_STORE_CTX_set0_param, 12X509_STORE_CTX_get0_untrusted, X509_STORE_CTX_set0_untrusted, 13X509_STORE_CTX_get_num_untrusted, 14X509_STORE_CTX_get0_chain, X509_STORE_CTX_set0_verified_chain, 15X509_STORE_CTX_get0_rpk, 16X509_STORE_CTX_set_default, 17X509_STORE_CTX_set_verify, 18X509_STORE_CTX_verify_fn, 19X509_STORE_CTX_set_purpose, 20X509_STORE_CTX_set_trust, 21X509_STORE_CTX_purpose_inherit 22- X509_STORE_CTX initialisation 23 24=head1 SYNOPSIS 25 26 #include <openssl/x509_vfy.h> 27 28 X509_STORE_CTX *X509_STORE_CTX_new_ex(OSSL_LIB_CTX *libctx, const char *propq); 29 X509_STORE_CTX *X509_STORE_CTX_new(void); 30 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx); 31 void X509_STORE_CTX_free(X509_STORE_CTX *ctx); 32 33 int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *trust_store, 34 X509 *target, STACK_OF(X509) *untrusted); 35 int X509_STORE_CTX_init_rpk(X509_STORE_CTX *ctx, X509_STORE *trust_store, 36 EVP_PKEY *rpk); 37 38 void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk); 39 40 void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *target); 41 void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk); 42 void X509_STORE_CTX_set0_rpk(X509_STORE_CTX *ctx, EVP_PKEY *target); 43 44 X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(const X509_STORE_CTX *ctx); 45 void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param); 46 47 STACK_OF(X509)* X509_STORE_CTX_get0_untrusted(const X509_STORE_CTX *ctx); 48 void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk); 49 50 int X509_STORE_CTX_get_num_untrusted(const X509_STORE_CTX *ctx); 51 STACK_OF(X509) *X509_STORE_CTX_get0_chain(const X509_STORE_CTX *ctx); 52 void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *chain); 53 EVP_PKEY *X509_STORE_CTX_get0_rpk(const X509_STORE_CTX *ctx); 54 55 int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name); 56 typedef int (*X509_STORE_CTX_verify_fn)(X509_STORE_CTX *); 57 void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx, X509_STORE_CTX_verify_fn verify); 58 59 int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose); 60 int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust); 61 int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose, 62 int purpose, int trust); 63 64=head1 DESCRIPTION 65 66These functions initialise an B<X509_STORE_CTX> structure for subsequent use 67by L<X509_verify_cert(3)> or L<X509_STORE_CTX_verify(3)>. 68 69X509_STORE_CTX_new_ex() returns a newly initialised B<X509_STORE_CTX> 70structure associated with the specified library context I<libctx> and property 71query string I<propq>. Any cryptographic algorithms fetched while performing 72processing with the X509_STORE_CTX will use that library context and property 73query string. 74 75X509_STORE_CTX_new() is the same as X509_STORE_CTX_new_ex() except that 76the default library context and a NULL property query string are used. 77 78X509_STORE_CTX_cleanup() internally cleans up an B<X509_STORE_CTX> structure. 79It is used by X509_STORE_CTX_init() and X509_STORE_CTX_free(). 80 81X509_STORE_CTX_free() completely frees up I<ctx>. After this call I<ctx> 82is no longer valid. 83If I<ctx> is NULL nothing is done. 84 85X509_STORE_CTX_init() sets up I<ctx> for a subsequent verification operation. 86 87X509_STORE_CTX_init() initializes the internal state and resources of the 88X509_STORE_CTX, and must be called before each call to L<X509_verify_cert(3)> or 89L<X509_STORE_CTX_verify(3)>, i.e., a context is only good for one verification. 90If you want to verify a further certificate or chain with the same I<ctx> 91then you must call X509_STORE_CTX_init() again. 92The trusted certificate store is set to I<trust_store> of type B<X509_STORE>. 93This may be NULL because there are no trusted certificates or because 94they are provided simply as a list using X509_STORE_CTX_set0_trusted_stack(). 95The certificate to be verified is set to I<target>, 96and a list of additional certificates may be provided in I<untrusted>, 97which will be untrusted but may be used to build the chain. 98The I<target> certificate is not copied (its reference count is not updated), 99and the caller must not free it before verification is complete. 100Each of the I<trust_store>, I<target> and I<untrusted> parameters can be NULL. 101Yet note that L<X509_verify_cert(3)> and L<X509_STORE_CTX_verify(3)> 102will need a verification target. 103This can also be set using X509_STORE_CTX_set_cert(). 104For L<X509_STORE_CTX_verify(3)>, which takes by default the first element of the 105list of untrusted certificates as its verification target, 106this can be also set indirectly using X509_STORE_CTX_set0_untrusted(). 107 108X509_STORE_CTX_init_rpk() sets up I<ctx> for a subsequent verification 109operation for the I<target> raw public key. 110It behaves similarly to X509_STORE_CTX_init(). 111The I<target> raw public key can also be supplied separately, via 112X509_STORE_CTX_set0_rpk(). 113The I<target> public key is not copied (its reference count is not updated), 114and the caller must not free it before verification is complete. 115 116X509_STORE_CTX_set0_trusted_stack() sets the set of trusted certificates of 117I<ctx> to I<sk>. This is an alternative way of specifying trusted certificates 118instead of using an B<X509_STORE> where its complexity is not needed 119or to make sure that only the given set I<sk> of certificates are trusted. 120 121X509_STORE_CTX_set_cert() sets the target certificate to be verified in I<ctx> 122to I<target>. 123The target certificate is not copied (its reference count is not updated), 124and the caller must not free it before verification is complete. 125 126X509_STORE_CTX_set0_rpk() sets the target raw public key to be verified in I<ctx> 127to I<target>, a non-NULL raw public key preempts any target certificate, which 128is then ignored. 129The I<target> public key is not copied (its reference count is not updated), 130and the caller must not free it before verification is complete. 131 132X509_STORE_CTX_set0_verified_chain() sets the validated chain to I<chain>. 133Ownership of the chain is transferred to I<ctx>, 134and so it should not be free'd by the caller. 135 136X509_STORE_CTX_get0_chain() returns the internal pointer used by the 137I<ctx> that contains the constructed (output) chain. 138 139X509_STORE_CTX_get0_rpk() returns the internal pointer used by the 140I<ctx> that contains the raw public key. 141 142X509_STORE_CTX_set0_crls() sets a set of CRLs to use to aid certificate 143verification to I<sk>. These CRLs will only be used if CRL verification is 144enabled in the associated B<X509_VERIFY_PARAM> structure. This might be 145used where additional "useful" CRLs are supplied as part of a protocol, 146for example in a PKCS#7 structure. 147 148X509_STORE_CTX_get0_param() retrieves an internal pointer 149to the verification parameters associated with I<ctx>. 150 151X509_STORE_CTX_set0_param() sets the internal verification parameter pointer 152to I<param>. After this call B<param> should not be used. 153 154X509_STORE_CTX_get0_untrusted() retrieves an internal pointer to the 155stack of untrusted certificates associated with I<ctx>. 156 157X509_STORE_CTX_set0_untrusted() sets the internal pointer to the stack 158of untrusted certificates associated with I<ctx> to I<sk>. 159X509_STORE_CTX_verify() will take the first element, if any, 160as its default target if the target certificate is not set explicitly. 161 162X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates 163that were used in building the chain. 164This is can be used after calling L<X509_verify_cert(3)> and similar functions. 165With L<X509_STORE_CTX_verify(3)>, this does not count the first chain element. 166 167X509_STORE_CTX_get0_chain() returns the internal pointer used by the 168I<ctx> that contains the validated chain. 169 170Details of the chain building and checking process are described in 171L<openssl-verification-options(1)/Certification Path Building> and 172L<openssl-verification-options(1)/Certification Path Validation>. 173 174X509_STORE_CTX_set0_verified_chain() sets the validated chain used 175by I<ctx> to be I<chain>. 176Ownership of the chain is transferred to I<ctx>, 177and so it should not be free'd by the caller. 178 179X509_STORE_CTX_set_default() looks up and sets the default verification 180method to I<name>. This uses the function X509_VERIFY_PARAM_lookup() to 181find an appropriate set of parameters from the purpose identifier I<name>. 182Currently defined purposes are C<sslclient>, C<sslserver>, C<nssslserver>, 183C<smimesign>, C<smimeencrypt>, C<crlsign>, C<ocsphelper>, C<timestampsign>, 184and C<any>. 185 186X509_STORE_CTX_set_verify() provides the capability for overriding the default 187verify function. This function is responsible for verifying chain signatures and 188expiration times. 189 190A verify function is defined as an X509_STORE_CTX_verify type which has the 191following signature: 192 193 int (*verify)(X509_STORE_CTX *); 194 195This function should receive the current X509_STORE_CTX as a parameter and 196return 1 on success or 0 on failure. 197 198X509 certificates may contain information about what purposes keys contained 199within them can be used for. For example "TLS WWW Server Authentication" or 200"Email Protection". This "key usage" information is held internally to the 201certificate itself. In addition the trust store containing trusted certificates 202can declare what purposes we trust different certificates for. This "trust" 203information is not held within the certificate itself but is "meta" information 204held alongside it. This "meta" information is associated with the certificate 205after it is issued and could be determined by a system administrator. For 206example a certificate might declare that it is suitable for use for both 207"TLS WWW Server Authentication" and "TLS Client Authentication", but a system 208administrator might only trust it for the former. An X.509 certificate extension 209exists that can record extended key usage information to supplement the purpose 210information described above. This extended mechanism is arbitrarily extensible 211and not well suited for a generic library API; applications that need to 212validate extended key usage information in certificates will need to define a 213custom "purpose" (see below) or supply a nondefault verification callback 214(L<X509_STORE_set_verify_cb_func(3)>). 215 216X509_STORE_CTX_set_purpose() sets the purpose for the target certificate being 217verified in the I<ctx>. Built-in available values for the I<purpose> argument 218are B<X509_PURPOSE_SSL_CLIENT>, B<X509_PURPOSE_SSL_SERVER>, 219B<X509_PURPOSE_NS_SSL_SERVER>, B<X509_PURPOSE_SMIME_SIGN>, 220B<X509_PURPOSE_SMIME_ENCRYPT>, B<X509_PURPOSE_CRL_SIGN>, B<X509_PURPOSE_ANY>, 221B<X509_PURPOSE_OCSP_HELPER>, B<X509_PURPOSE_TIMESTAMP_SIGN> and 222B<X509_PURPOSE_CODE_SIGN>. It is also 223possible to create a custom purpose value. Setting a purpose requests that 224the key usage and extended key usage (EKU) extensions optionally declared within 225the certificate and its chain are verified to be consistent with that purpose. 226For SSL client, SSL server, and S/MIME purposes, the EKU is checked also for the 227CA certificates along the chain, including any given trust anchor certificate. 228Potentially also further checks are done (depending on the purpose given). 229Every purpose also has an associated default trust value, which will also be set 230at the same time. During verification, this trust setting will be verified 231to check whether it is consistent with the trust set by the system administrator 232for certificates in the chain. 233 234X509_STORE_CTX_set_trust() sets the trust value for the target certificate 235being verified in the I<ctx>. Built-in available values for the I<trust> 236argument are B<X509_TRUST_COMPAT>, B<X509_TRUST_SSL_CLIENT>, 237B<X509_TRUST_SSL_SERVER>, B<X509_TRUST_EMAIL>, B<X509_TRUST_OBJECT_SIGN>, 238B<X509_TRUST_OCSP_SIGN>, B<X509_TRUST_OCSP_REQUEST> and B<X509_TRUST_TSA>. It is 239also possible to create a custom trust value. Since X509_STORE_CTX_set_purpose() 240also sets the trust value it is normally sufficient to only call that function. 241If both are called then X509_STORE_CTX_set_trust() should be called after 242X509_STORE_CTX_set_purpose() since the trust setting of the last call will be 243used. 244 245It should not normally be necessary for end user applications to call 246X509_STORE_CTX_purpose_inherit() directly. Typically applications should call 247X509_STORE_CTX_set_purpose() or X509_STORE_CTX_set_trust() instead. Using this 248function it is possible to set the purpose and trust values for the I<ctx> at 249the same time. 250Both I<ctx> and its internal verification parameter pointer must not be NULL. 251The I<def_purpose> and I<purpose> arguments can have the same 252purpose values as described for X509_STORE_CTX_set_purpose() above. The I<trust> 253argument can have the same trust values as described in 254X509_STORE_CTX_set_trust() above. Any of the I<def_purpose>, I<purpose> or 255I<trust> values may also have the value 0 to indicate that the supplied 256parameter should be ignored. After calling this function the purpose to be used 257for verification is set from the I<purpose> argument unless the purpose was 258already set in I<ctx> before, and the trust is set from the I<trust> argument 259unless the trust was already set in I<ctx> before. 260If I<trust> is 0 then the trust value will be set from 261the default trust value for I<purpose>. If the default trust value for the 262purpose is I<X509_TRUST_DEFAULT> and I<trust> is 0 then the default trust value 263associated with the I<def_purpose> value is used for the trust setting instead. 264 265=head1 NOTES 266 267The certificates and CRLs in a store are used internally and should B<not> 268be freed up until after the associated B<X509_STORE_CTX> is freed. 269 270=head1 BUGS 271 272The certificates and CRLs in a context are used internally and should B<not> 273be freed up until after the associated B<X509_STORE_CTX> is freed. Copies 274should be made or reference counts increased instead. 275 276=head1 RETURN VALUES 277 278X509_STORE_CTX_new() returns a newly allocated context or NULL if an 279error occurred. 280 281X509_STORE_CTX_init() and X509_STORE_CTX_init_rpk() return 1 for success 282or 0 if an error occurred. 283 284X509_STORE_CTX_get0_param() returns a pointer to an B<X509_VERIFY_PARAM> 285structure or NULL if an error occurred. 286 287X509_STORE_CTX_get0_rpk() returns a pointer to an B<EVP_PKEY> structure if 288present, or NULL if absent. 289 290X509_STORE_CTX_cleanup(), X509_STORE_CTX_free(), 291X509_STORE_CTX_set0_trusted_stack(), 292X509_STORE_CTX_set_cert(), 293X509_STORE_CTX_set0_crls() and X509_STORE_CTX_set0_param() do not return 294values. 295 296X509_STORE_CTX_set_default() returns 1 for success or 0 if an error occurred. 297 298X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates 299used. 300 301=head1 SEE ALSO 302 303L<X509_verify_cert(3)>, L<X509_STORE_CTX_verify(3)>, 304L<X509_VERIFY_PARAM_set_flags(3)> 305 306=head1 HISTORY 307 308The X509_STORE_CTX_set0_crls() function was added in OpenSSL 1.0.0. 309The X509_STORE_CTX_get_num_untrusted() function was added in OpenSSL 1.1.0. 310The X509_STORE_CTX_new_ex() function was added in OpenSSL 3.0. 311The X509_STORE_CTX_init_rpk(), X509_STORE_CTX_get0_rpk(), and 312X509_STORE_CTX_set0_rpk() functions were added in OpenSSL 3.2. 313 314There is no need to call X509_STORE_CTX_cleanup() explicitly since OpenSSL 3.0. 315 316=head1 COPYRIGHT 317 318Copyright 2009-2024 The OpenSSL Project Authors. All Rights Reserved. 319 320Licensed under the Apache License 2.0 (the "License"). You may not use 321this file except in compliance with the License. You can obtain a copy 322in the file LICENSE in the source distribution or at 323L<https://www.openssl.org/source/license.html>. 324 325=cut 326
