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_get0_host,
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_get0_email,
X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip,
X509_VERIFY_PARAM_get1_ip_asc, X509_VERIFY_PARAM_set1_ip_asc - X509
verification parameters
#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(const 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);
char *X509_VERIFY_PARAM_get0_host(X509_VERIFY_PARAM *param, int n);
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(const X509_VERIFY_PARAM *param);
char *X509_VERIFY_PARAM_get0_email(X509_VERIFY_PARAM *param);
int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,
const char *email, size_t emaillen);
char *X509_VERIFY_PARAM_get1_ip_asc(X509_VERIFY_PARAM *param);
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);
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 "VERIFICATION FLAGS" 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
X509_PURPOSE_SSL_CLIENT. The purpose
requirement is cleared if
purpose is 0.
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() adds
policy to the acceptable
policy set. Contrary to preexisting documentation of this function it does not
enable policy checking.
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_get0_host() returns the
nth expected DNS
hostname that has been set using
X509_VERIFY_PARAM_set1_host() or
X509_VERIFY_PARAM_add1_host(). To obtain all names start with
n
= 0 and increment
n as long as no NULL pointer is returned.
X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to
name clearing any previously specified hostname. 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_get0_email() returns the expected RFC822 email address.
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_get1_ip_asc() returns the expected IP address as a
string. The caller is responsible for freeing it.
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.
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_get0_host(),
X509_VERIFY_PARAM_get0_email(), and
X509_VERIFY_PARAM_get1_ip_asc(), return the string pointer specified
above or NULL if the respective value has not been set or on error.
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.
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 disables critical extension checking. By
default any unhandled critical extensions in certificates or (if checked) CRLs
result 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, which is always the case since
OpenSSL 1.1.0, construction of the certificate chain in
X509_verify_cert(3) searches 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
openssl-x509(1)).
The
X509_V_FLAG_NO_ALT_CHAINS flag could have been used before OpenSSL
1.1.0 to suppress 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 non-self-signed certificates in
the trust store to be treated as trust anchors, in the same way as self-signed
root CA certificates. This makes it possible to trust self-issued certificates
as well as certificates issued by an intermediate CA without having to trust
their 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 contained in the trust store is added to the chain, whether
that certificate is a self-signed "root" certificate or a not
self-signed "intermediate" or self-issued 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.
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.
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.
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.
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);
X509_verify_cert(3),
X509_check_host(3),
X509_check_email(3),
X509_check_ip(3),
openssl-x509(1)
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.
The
X509_VERIFY_PARAM_get0_host(),
X509_VERIFY_PARAM_get0_email(),
and
X509_VERIFY_PARAM_get1_ip_asc() functions were added in OpenSSL
3.0.
The function
X509_VERIFY_PARAM_add0_policy() was historically documented
as enabling policy checking however the implementation has never done this.
The documentation was changed to align with the implementation.
Copyright 2009-2023 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.