X509_VERIFY_PARAM_SET_FLAGS(3) OpenSSL X509_VERIFY_PARAM_SET_FLAGS(3)
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_get_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
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);
unsigned int X509_VERIFY_PARAM_get_hostflags(const X509_VERIFY_PARAM *param);
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);
DESCRIPTION
These functions manipulate the X509_VERIFY_PARAM structure associated
with a certificate verification operation.
The X509_VERIFY_PARAM_set_flags() function sets the flags in param by
oring it with flags. See the VERIFICATION FLAGS section for a complete
description of values the flags parameter can take.
X509_VERIFY_PARAM_get_flags() returns the flags in param.
X509_VERIFY_PARAM_get_inh_flags() returns the inheritance flags in
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 INHERITANCE FLAGS section for a description
of these bits.
X509_VERIFY_PARAM_clear_flags() clears the flags flags in param.
X509_VERIFY_PARAM_set_purpose() sets the verification purpose in param
to 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 param to trust.
X509_VERIFY_PARAM_set_time() sets the verification time in param to t.
Normally the current time is used.
X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled
by default) and adds 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 policies.
Any existing policy set is cleared. The policies parameter can be NULL
to clear an existing policy set.
X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to
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 depth limit of 0
only allows the end-entity certificate to be signed directly by the
trust-anchor, while with a 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 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 trust anchor
certificate, which is either directly trusted or validated by means
other than its signature. See 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 name
clearing any previously specified hostname or names. If name is NULL,
or empty the list of hostnames is cleared, and name checks are not
performed on the peer certificate. If name is NUL-terminated, namelen
may be zero, otherwise namelen must be set to the length of name.
When a hostname is specified, certificate verification automatically
invokes X509_check_host(3) with flags equal to the flags argument given
to X509_VERIFY_PARAM_set_hostflags() (default zero). Applications are
strongly advised to use this interface in preference to explicitly
calling X509_check_host(3), hostname checks may be out of scope with
the DANE-EE(3) certificate usage, and the internal check will be
suppressed as appropriate when DANE verification is enabled.
When the subject CommonName will not be ignored, whether as a result of
the X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT host flag, or because no DNS
subject alternative names are present in the certificate, any DNS name
constraints in issuer certificates apply to the subject CommonName as
well as the subject alternative name extension.
When the subject CommonName will be ignored, whether as a result of the
X509_CHECK_FLAG_NEVER_CHECK_SUBJECT host flag, or because some DNS
subject alternative names are present in the certificate, DNS name
constraints in issuer certificates will not be applied to the subject
DN. As described in X509_check_host(3) the
X509_CHECK_FLAG_NEVER_CHECK_SUBJECT flag takes precedence over the
X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT flag.
X509_VERIFY_PARAM_get_hostflags() returns any host flags previously set
via a call to X509_VERIFY_PARAM_set_hostflags().
X509_VERIFY_PARAM_add1_host() adds 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 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
param argument is freed. Applications must not free the return value.
X509_VERIFY_PARAM_set1_email() sets the expected RFC822 email address
to email. If email is NUL-terminated, emaillen may be zero, otherwise
emaillen must be set to the length of email. When an email address is
specified, certificate verification automatically invokes
X509_check_email(3).
X509_VERIFY_PARAM_set1_ip() sets the expected IP address to ip. The ip
argument is in binary format, in network byte-order and iplen must be
set to 4 for IPv4 and 16 for IPv6. When an IP address is specified,
certificate verification automatically invokes X509_check_ip(3).
X509_VERIFY_PARAM_set1_ip_asc() sets the expected IP address to ipasc.
The 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.
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_hostflags() returns any current host 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.
VERIFICATION FLAGS
The verification flags consists of zero or more of the following flags
ored together.
X509_V_FLAG_CRL_CHECK enables CRL checking for the certificate chain
leaf certificate. An error occurs if a suitable CRL cannot be found.
X509_V_FLAG_CRL_CHECK_ALL enables CRL checking for the entire
certificate chain.
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. 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 X509_V_FLAG_X509_STRICT flag disables workarounds for some broken
certificates and makes the verification strictly apply X509 rules.
X509_V_FLAG_ALLOW_PROXY_CERTS enables proxy certificate verification.
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.
X509_V_FLAG_EXPLICIT_POLICY, X509_V_FLAG_INHIBIT_ANY and
X509_V_FLAG_INHIBIT_MAP set the require explicit policy, inhibit any
policy and inhibit policy mapping flags respectively as defined in
RFC3280. Policy checking is automatically enabled if any of these flags
are set.
If 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
X509_V_FLAG_EXTENDED_CRL_SUPPORT is set they are enabled.
If X509_V_FLAG_USE_DELTAS is set delta CRLs (if present) are used to
determine certificate status. If not set deltas are ignored.
X509_V_FLAG_CHECK_SS_SIGNATURE requests checking the signature of the
last certificate in a chain if the certificate is supposedly self-
signed. This is prohibited and will result in an error if it is a non-
conforming CA certificate with key usage restrictions not including the
keyCertSign bit. 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 self-
signature of such a certificate is that disabled or unsupported message
digests used for the signature are not treated as fatal errors.
When X509_V_FLAG_TRUSTED_FIRST is set, construction of the certificate
chain in 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 x509(1)). As of
OpenSSL 1.1.0 this option is on by default.
The X509_V_FLAG_NO_ALT_CHAINS flag suppresses checking for alternative
chains. By default, unless 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 X509_V_FLAG_TRUSTED_FIRST always set, this
option has no effect.
The 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
X509_V_FLAG_PARTIAL_CHAIN flag.
The 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.
INHERITANCE FLAGS
These flags specify how parameters are "inherited" from one structure
to another.
If X509_VP_FLAG_ONCE is set then the current setting is zeroed after
the next call.
If X509_VP_FLAG_LOCKED is set then no values are copied. This
overrides all of the following flags.
If 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 X509_VP_FLAG_OVERWRITE is set then all value are copied across
whether they are set or not. Flags is still Ored though.
If X509_VP_FLAG_RESET_FLAGS is set then the flags value is copied
instead of ORed.
NOTES
The above functions should be used to manipulate verification
parameters instead of functions which work in specific structures such
as X509_STORE_CTX_set_flags() which are likely to be deprecated in a
future release.
BUGS
Delta CRL checking is currently primitive. Only a single delta can be
used and (partly due to limitations of X509_STORE) constructed CRLs are
not maintained.
If CRLs checking is enable CRLs are expected to be available in the
corresponding X509_STORE structure. No attempt is made to download CRLs
from the CRL distribution points extension.
EXAMPLES
Enable CRL checking when performing certificate verification during SSL
connections associated with an SSL_CTX structure 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);
SEE ALSO
X509_verify_cert(3), X509_check_host(3), X509_check_email(3),
X509_check_ip(3), x509(1)
HISTORY
The X509_V_FLAG_NO_ALT_CHAINS flag was added in OpenSSL 1.1.0. The
flag X509_V_FLAG_CB_ISSUER_CHECK was deprecated in OpenSSL 1.1.0 and
has no effect.
The X509_VERIFY_PARAM_get_hostflags() function was added in OpenSSL
1.1.0i.
COPYRIGHT
Copyright 2009-2020 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
<https://www.openssl.org/source/license.html>;.
1.1.1k 2021-03-25 X509_VERIFY_PARAM_SET_FLAGS(3)
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