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Diffstat (limited to 'openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod')
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diff --git a/openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod b/openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod new file mode 100644 index 0000000..5263fac --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod @@ -0,0 +1,359 @@ +=pod + +=head1 NAME + +X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, +X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose, +X509_VERIFY_PARAM_get_inh_flags, X509_VERIFY_PARAM_set_inh_flags, +X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth, +X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_auth_level, +X509_VERIFY_PARAM_get_auth_level, X509_VERIFY_PARAM_set_time, +X509_VERIFY_PARAM_get_time, +X509_VERIFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies, +X509_VERIFY_PARAM_set1_host, X509_VERIFY_PARAM_add1_host, +X509_VERIFY_PARAM_set_hostflags, X509_VERIFY_PARAM_get0_peername, +X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip, +X509_VERIFY_PARAM_set1_ip_asc +- X509 verification parameters + +=head1 SYNOPSIS + + #include <openssl/x509_vfy.h> + + int X509_VERIFY_PARAM_set_flags(X509_VERIFY_PARAM *param, + unsigned long flags); + int X509_VERIFY_PARAM_clear_flags(X509_VERIFY_PARAM *param, + unsigned long flags); + unsigned long X509_VERIFY_PARAM_get_flags(X509_VERIFY_PARAM *param); + + int X509_VERIFY_PARAM_set_inh_flags(X509_VERIFY_PARAM *param, + uint32_t flags); + uint32_t X509_VERIFY_PARAM_get_inh_flags(const X509_VERIFY_PARAM *param); + + int X509_VERIFY_PARAM_set_purpose(X509_VERIFY_PARAM *param, int purpose); + int X509_VERIFY_PARAM_set_trust(X509_VERIFY_PARAM *param, int trust); + + void X509_VERIFY_PARAM_set_time(X509_VERIFY_PARAM *param, time_t t); + time_t X509_VERIFY_PARAM_get_time(const X509_VERIFY_PARAM *param); + + int X509_VERIFY_PARAM_add0_policy(X509_VERIFY_PARAM *param, + ASN1_OBJECT *policy); + int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param, + STACK_OF(ASN1_OBJECT) *policies); + + void X509_VERIFY_PARAM_set_depth(X509_VERIFY_PARAM *param, int depth); + int X509_VERIFY_PARAM_get_depth(const X509_VERIFY_PARAM *param); + + void X509_VERIFY_PARAM_set_auth_level(X509_VERIFY_PARAM *param, + int auth_level); + int X509_VERIFY_PARAM_get_auth_level(const X509_VERIFY_PARAM *param); + + int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param, + const char *name, size_t namelen); + int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param, + const char *name, size_t namelen); + void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param, + unsigned int flags); + char *X509_VERIFY_PARAM_get0_peername(X509_VERIFY_PARAM *param); + int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param, + const char *email, size_t emaillen); + int X509_VERIFY_PARAM_set1_ip(X509_VERIFY_PARAM *param, + const unsigned char *ip, size_t iplen); + int X509_VERIFY_PARAM_set1_ip_asc(X509_VERIFY_PARAM *param, const char *ipasc); + +=head1 DESCRIPTION + +These functions manipulate the B<X509_VERIFY_PARAM> structure associated with +a certificate verification operation. + +The X509_VERIFY_PARAM_set_flags() function sets the flags in B<param> by oring +it with B<flags>. See the B<VERIFICATION FLAGS> section for a complete +description of values the B<flags> parameter can take. + +X509_VERIFY_PARAM_get_flags() returns the flags in B<param>. + +X509_VERIFY_PARAM_get_inh_flags() returns the inheritance flags in B<param> +which specifies how verification flags are copied from one structure to +another. X509_VERIFY_PARAM_set_inh_flags() sets the inheritance flags. +See the B<INHERITANCE FLAGS> section for a description of these bits. + +X509_VERIFY_PARAM_clear_flags() clears the flags B<flags> in B<param>. + +X509_VERIFY_PARAM_set_purpose() sets the verification purpose in B<param> +to B<purpose>. This determines the acceptable purpose of the certificate +chain, for example SSL client or SSL server. + +X509_VERIFY_PARAM_set_trust() sets the trust setting in B<param> to +B<trust>. + +X509_VERIFY_PARAM_set_time() sets the verification time in B<param> to +B<t>. Normally the current time is used. + +X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled +by default) and adds B<policy> to the acceptable policy set. + +X509_VERIFY_PARAM_set1_policies() enables policy checking (it is disabled +by default) and sets the acceptable policy set to B<policies>. Any existing +policy set is cleared. The B<policies> parameter can be B<NULL> to clear +an existing policy set. + +X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to B<depth>. +That is the maximum number of intermediate CA certificates that can appear in a +chain. +A maximal depth chain contains 2 more certificates than the limit, since +neither the end-entity certificate nor the trust-anchor count against this +limit. +Thus a B<depth> limit of 0 only allows the end-entity certificate to be signed +directly by the trust-anchor, while with a B<depth> limit of 1 there can be one +intermediate CA certificate between the trust-anchor and the end-entity +certificate. + +X509_VERIFY_PARAM_set_auth_level() sets the authentication security level to +B<auth_level>. +The authentication security level determines the acceptable signature and public +key strength when verifying certificate chains. +For a certificate chain to validate, the public keys of all the certificates +must meet the specified security level. +The signature algorithm security level is not enforced for the chain's I<trust +anchor> certificate, which is either directly trusted or validated by means other +than its signature. +See L<SSL_CTX_set_security_level(3)> for the definitions of the available +levels. +The default security level is -1, or "not set". +At security level 0 or lower all algorithms are acceptable. +Security level 1 requires at least 80-bit-equivalent security and is broadly +interoperable, though it will, for example, reject MD5 signatures or RSA keys +shorter than 1024 bits. + +X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to +B<name> clearing any previously specified host name or names. If +B<name> is NULL, or empty the list of hostnames is cleared, and +name checks are not performed on the peer certificate. If B<name> +is NUL-terminated, B<namelen> may be zero, otherwise B<namelen> +must be set to the length of B<name>. When a hostname is specified, +certificate verification automatically invokes L<X509_check_host(3)> +with flags equal to the B<flags> argument given to +X509_VERIFY_PARAM_set_hostflags() (default zero). Applications +are strongly advised to use this interface in preference to explicitly +calling L<X509_check_host(3)>, hostname checks are out of scope +with the DANE-EE(3) certificate usage, and the internal check will +be suppressed as appropriate when DANE support is added to OpenSSL. + +X509_VERIFY_PARAM_add1_host() adds B<name> as an additional reference +identifier that can match the peer's certificate. Any previous names +set via X509_VERIFY_PARAM_set1_host() or X509_VERIFY_PARAM_add1_host() +are retained, no change is made if B<name> is NULL or empty. When +multiple names are configured, the peer is considered verified when +any name matches. + +X509_VERIFY_PARAM_get0_peername() returns the DNS hostname or subject +CommonName from the peer certificate that matched one of the reference +identifiers. When wildcard matching is not disabled, or when a +reference identifier specifies a parent domain (starts with ".") +rather than a hostname, the peer name may be a wildcard name or a +sub-domain of the reference identifier respectively. The return +string is allocated by the library and is no longer valid once the +associated B<param> argument is freed. Applications must not free +the return value. + +X509_VERIFY_PARAM_set1_email() sets the expected RFC822 email address to +B<email>. If B<email> is NUL-terminated, B<emaillen> may be zero, otherwise +B<emaillen> must be set to the length of B<email>. When an email address +is specified, certificate verification automatically invokes +L<X509_check_email(3)>. + +X509_VERIFY_PARAM_set1_ip() sets the expected IP address to B<ip>. +The B<ip> argument is in binary format, in network byte-order and +B<iplen> must be set to 4 for IPv4 and 16 for IPv6. When an IP +address is specified, certificate verification automatically invokes +L<X509_check_ip(3)>. + +X509_VERIFY_PARAM_set1_ip_asc() sets the expected IP address to +B<ipasc>. The B<ipasc> argument is a NUL-terminal ASCII string: +dotted decimal quad for IPv4 and colon-separated hexadecimal for +IPv6. The condensed "::" notation is supported for IPv6 addresses. + +=head1 RETURN VALUES + +X509_VERIFY_PARAM_set_flags(), X509_VERIFY_PARAM_clear_flags(), +X509_VERIFY_PARAM_set_inh_flags(), +X509_VERIFY_PARAM_set_purpose(), X509_VERIFY_PARAM_set_trust(), +X509_VERIFY_PARAM_add0_policy() X509_VERIFY_PARAM_set1_policies(), +X509_VERIFY_PARAM_set1_host(), X509_VERIFY_PARAM_add1_host(), +X509_VERIFY_PARAM_set1_email(), X509_VERIFY_PARAM_set1_ip() and +X509_VERIFY_PARAM_set1_ip_asc() return 1 for success and 0 for +failure. + +X509_VERIFY_PARAM_get_flags() returns the current verification flags. + +X509_VERIFY_PARAM_get_inh_flags() returns the current inheritance flags. + +X509_VERIFY_PARAM_set_time() and X509_VERIFY_PARAM_set_depth() do not return +values. + +X509_VERIFY_PARAM_get_depth() returns the current verification depth. + +X509_VERIFY_PARAM_get_auth_level() returns the current authentication security +level. + +=head1 VERIFICATION FLAGS + +The verification flags consists of zero or more of the following flags +ored together. + +B<X509_V_FLAG_CRL_CHECK> enables CRL checking for the certificate chain leaf +certificate. An error occurs if a suitable CRL cannot be found. + +B<X509_V_FLAG_CRL_CHECK_ALL> enables CRL checking for the entire certificate +chain. + +B<X509_V_FLAG_IGNORE_CRITICAL> disabled critical extension checking. By default +any unhandled critical extensions in certificates or (if checked) CRLs results +in a fatal error. If this flag is set unhandled critical extensions are +ignored. B<WARNING> setting this option for anything other than debugging +purposes can be a security risk. Finer control over which extensions are +supported can be performed in the verification callback. + +The B<X509_V_FLAG_X509_STRICT> flag disables workarounds for some broken +certificates and makes the verification strictly apply B<X509> rules. + +B<X509_V_FLAG_ALLOW_PROXY_CERTS> enables proxy certificate verification. + +B<X509_V_FLAG_POLICY_CHECK> enables certificate policy checking, by default +no policy checking is performed. Additional information is sent to the +verification callback relating to policy checking. + +B<X509_V_FLAG_EXPLICIT_POLICY>, B<X509_V_FLAG_INHIBIT_ANY> and +B<X509_V_FLAG_INHIBIT_MAP> set the B<require explicit policy>, B<inhibit any +policy> and B<inhibit policy mapping> flags respectively as defined in +B<RFC3280>. Policy checking is automatically enabled if any of these flags +are set. + +If B<X509_V_FLAG_NOTIFY_POLICY> is set and the policy checking is successful +a special status code is set to the verification callback. This permits it +to examine the valid policy tree and perform additional checks or simply +log it for debugging purposes. + +By default some additional features such as indirect CRLs and CRLs signed by +different keys are disabled. If B<X509_V_FLAG_EXTENDED_CRL_SUPPORT> is set +they are enabled. + +If B<X509_V_FLAG_USE_DELTAS> is set delta CRLs (if present) are used to +determine certificate status. If not set deltas are ignored. + +B<X509_V_FLAG_CHECK_SS_SIGNATURE> enables checking of the root CA self signed +certificate signature. By default this check is disabled because it doesn't +add any additional security but in some cases applications might want to +check the signature anyway. A side effect of not checking the root CA +signature is that disabled or unsupported message digests on the root CA +are not treated as fatal errors. + +When B<X509_V_FLAG_TRUSTED_FIRST> is set, construction of the certificate chain +in L<X509_verify_cert(3)> will search the trust store for issuer certificates +before searching the provided untrusted certificates. +Local issuer certificates are often more likely to satisfy local security +requirements and lead to a locally trusted root. +This is especially important when some certificates in the trust store have +explicit trust settings (see "TRUST SETTINGS" in L<x509(1)>). +As of OpenSSL 1.1.0 this option is on by default. + +The B<X509_V_FLAG_NO_ALT_CHAINS> flag suppresses checking for alternative +chains. +By default, unless B<X509_V_FLAG_TRUSTED_FIRST> is set, when building a +certificate chain, if the first certificate chain found is not trusted, then +OpenSSL will attempt to replace untrusted certificates supplied by the peer +with certificates from the trust store to see if an alternative chain can be +found that is trusted. +As of OpenSSL 1.1.0, with B<X509_V_FLAG_TRUSTED_FIRST> always set, this option +has no effect. + +The B<X509_V_FLAG_PARTIAL_CHAIN> flag causes intermediate certificates in the +trust store to be treated as trust-anchors, in the same way as the self-signed +root CA certificates. +This makes it possible to trust certificates issued by an intermediate CA +without having to trust its ancestor root CA. +With OpenSSL 1.1.0 and later and <X509_V_FLAG_PARTIAL_CHAIN> set, chain +construction stops as soon as the first certificate from the trust store is +added to the chain, whether that certificate is a self-signed "root" +certificate or a not self-signed intermediate certificate. +Thus, when an intermediate certificate is found in the trust store, the +verified chain passed to callbacks may be shorter than it otherwise would +be without the B<X509_V_FLAG_PARTIAL_CHAIN> flag. + +The B<X509_V_FLAG_NO_CHECK_TIME> flag suppresses checking the validity period +of certificates and CRLs against the current time. If X509_VERIFY_PARAM_set_time() +is used to specify a verification time, the check is not suppressed. + +=head1 INHERITANCE FLAGS + +These flags specify how parameters are "inherited" from one structure to +another. + +If B<X509_VP_FLAG_ONCE> is set then the current setting is zeroed +after the next call. + +If B<X509_VP_FLAG_LOCKED> is set then no values are copied. This overrides +all of the following flags. + +If B<X509_VP_FLAG_DEFAULT> is set then anything set in the source is copied +to the destination. Effectively the values in "to" become default values +which will be used only if nothing new is set in "from". This is the +default. + +If B<X509_VP_FLAG_OVERWRITE> is set then all value are copied across whether +they are set or not. Flags is still Ored though. + +If B<X509_VP_FLAG_RESET_FLAGS> is set then the flags value is copied instead +of ORed. + +=head1 NOTES + +The above functions should be used to manipulate verification parameters +instead of legacy functions which work in specific structures such as +X509_STORE_CTX_set_flags(). + +=head1 BUGS + +Delta CRL checking is currently primitive. Only a single delta can be used and +(partly due to limitations of B<X509_STORE>) constructed CRLs are not +maintained. + +If CRLs checking is enable CRLs are expected to be available in the +corresponding B<X509_STORE> structure. No attempt is made to download +CRLs from the CRL distribution points extension. + +=head1 EXAMPLE + +Enable CRL checking when performing certificate verification during SSL +connections associated with an B<SSL_CTX> structure B<ctx>: + + X509_VERIFY_PARAM *param; + param = X509_VERIFY_PARAM_new(); + X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_CRL_CHECK); + SSL_CTX_set1_param(ctx, param); + X509_VERIFY_PARAM_free(param); + +=head1 SEE ALSO + +L<X509_verify_cert(3)>, +L<X509_check_host(3)>, +L<X509_check_email(3)>, +L<X509_check_ip(3)>, +L<x509(1)> + +=head1 HISTORY + +The B<X509_V_FLAG_NO_ALT_CHAINS> flag was added in OpenSSL 1.1.0 +The legacy B<X509_V_FLAG_CB_ISSUER_CHECK> flag is deprecated as of +OpenSSL 1.1.0, and has no effect. + +=head1 COPYRIGHT + +Copyright 2009-2018 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +L<https://www.openssl.org/source/license.html>. + +=cut |