1X509_VERIFY_PARAM_set_flags(3)      OpenSSL     X509_VERIFY_PARAM_set_flags(3)
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NAME

6       X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags,
7       X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose,
8       X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth,
9       X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_time,
10       X509_VERIFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies,
11       X509_VERIFY_PARAM_set1_host, X509_VERIFY_PARAM_add1_host,
12       X509_VERIFY_PARAM_set_hostflags, X509_VERIFY_PARAM_get0_peername,
13       X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip,
14       X509_VERIFY_PARAM_set1_ip_asc - X509 verification parameters
15

SYNOPSIS

17        #include <openssl/x509_vfy.h>
18
19        int X509_VERIFY_PARAM_set_flags(X509_VERIFY_PARAM *param, unsigned long flags);
20        int X509_VERIFY_PARAM_clear_flags(X509_VERIFY_PARAM *param,
21                                                               unsigned long flags);
22        unsigned long X509_VERIFY_PARAM_get_flags(X509_VERIFY_PARAM *param);
23
24        int X509_VERIFY_PARAM_set_purpose(X509_VERIFY_PARAM *param, int purpose);
25        int X509_VERIFY_PARAM_set_trust(X509_VERIFY_PARAM *param, int trust);
26
27        void X509_VERIFY_PARAM_set_time(X509_VERIFY_PARAM *param, time_t t);
28
29        int X509_VERIFY_PARAM_add0_policy(X509_VERIFY_PARAM *param,
30                                                       ASN1_OBJECT *policy);
31        int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param,
32                                               STACK_OF(ASN1_OBJECT) *policies);
33
34        void X509_VERIFY_PARAM_set_depth(X509_VERIFY_PARAM *param, int depth);
35        int X509_VERIFY_PARAM_get_depth(const X509_VERIFY_PARAM *param);
36
37        int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
38                                        const char *name, size_t namelen);
39        int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
40                                        const char *name, size_t namelen);
41        void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,
42                                             unsigned int flags);
43        char *X509_VERIFY_PARAM_get0_peername(X509_VERIFY_PARAM *param);
44        int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,
45                                        const char *email, size_t emaillen);
46        int X509_VERIFY_PARAM_set1_ip(X509_VERIFY_PARAM *param,
47                                      const unsigned char *ip, size_t iplen);
48        int X509_VERIFY_PARAM_set1_ip_asc(X509_VERIFY_PARAM *param, const char *ipasc);
49

DESCRIPTION

51       These functions manipulate the X509_VERIFY_PARAM structure associated
52       with a certificate verification operation.
53
54       The X509_VERIFY_PARAM_set_flags() function sets the flags in param by
55       oring it with flags. See the VERIFICATION FLAGS section for a complete
56       description of values the flags parameter can take.
57
58       X509_VERIFY_PARAM_get_flags() returns the flags in param.
59
60       X509_VERIFY_PARAM_clear_flags() clears the flags flags in param.
61
62       X509_VERIFY_PARAM_set_purpose() sets the verification purpose in param
63       to purpose. This determines the acceptable purpose of the certificate
64       chain, for example SSL client or SSL server.
65
66       X509_VERIFY_PARAM_set_trust() sets the trust setting in param to trust.
67
68       X509_VERIFY_PARAM_set_time() sets the verification time in param to t.
69       Normally the current time is used.
70
71       X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled
72       by default) and adds policy to the acceptable policy set.
73
74       X509_VERIFY_PARAM_set1_policies() enables policy checking (it is
75       disabled by default) and sets the acceptable policy set to policies.
76       Any existing policy set is cleared. The policies parameter can be NULL
77       to clear an existing policy set.
78
79       X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to
80       depth.  That is the maximum number of untrusted CA certificates that
81       can appear in a chain.
82
83       X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to name
84       clearing any previously specified host name or names.  If name is NULL,
85       or empty the list of hostnames is cleared, and name checks are not
86       performed on the peer certificate.  If name is NUL-terminated, namelen
87       may be zero, otherwise namelen must be set to the length of name.  When
88       a hostname is specified, certificate verification automatically invokes
89       X509_check_host(3) with flags equal to the flags argument given to
90       X509_VERIFY_PARAM_set_hostflags() (default zero).  Applications are
91       strongly advised to use this interface in preference to explicitly
92       calling X509_check_host(3), hostname checks are out of scope with the
93       DANE-EE(3) certificate usage, and the internal check will be suppressed
94       as appropriate when DANE support is added to OpenSSL.
95
96       X509_VERIFY_PARAM_add1_host() adds name as an additional reference
97       identifer that can match the peer's certificate.  Any previous names
98       set via X509_VERIFY_PARAM_set1_host() or X509_VERIFY_PARAM_add1_host()
99       are retained, no change is made if name is NULL or empty.  When
100       multiple names are configured, the peer is considered verified when any
101       name matches.
102
103       X509_VERIFY_PARAM_get0_peername() returns the DNS hostname or subject
104       CommonName from the peer certificate that matched one of the reference
105       identifiers.  When wildcard matching is not disabled, or when a
106       reference identifier specifies a parent domain (starts with ".")
107       rather than a hostname, the peer name may be a wildcard name or a sub-
108       domain of the reference identifier respectively.  The return string is
109       allocated by the library and is no longer valid once the associated
110       param argument is freed.  Applications must not free the return value.
111
112       X509_VERIFY_PARAM_set1_email() sets the expected RFC822 email address
113       to email.  If email is NUL-terminated, emaillen may be zero, otherwise
114       emaillen must be set to the length of email.  When an email address is
115       specified, certificate verification automatically invokes
116       X509_check_email(3).
117
118       X509_VERIFY_PARAM_set1_ip() sets the expected IP address to ip.  The ip
119       argument is in binary format, in network byte-order and iplen must be
120       set to 4 for IPv4 and 16 for IPv6.  When an IP address is specified,
121       certificate verification automatically invokes X509_check_ip(3).
122
123       X509_VERIFY_PARAM_set1_ip_asc() sets the expected IP address to ipasc.
124       The ipasc argument is a NUL-terminal ASCII string: dotted decimal quad
125       for IPv4 and colon-separated hexadecimal for IPv6.  The condensed "::"
126       notation is supported for IPv6 addresses.
127

RETURN VALUES

129       X509_VERIFY_PARAM_set_flags(), X509_VERIFY_PARAM_clear_flags(),
130       X509_VERIFY_PARAM_set_purpose(), X509_VERIFY_PARAM_set_trust(),
131       X509_VERIFY_PARAM_add0_policy() X509_VERIFY_PARAM_set1_policies(),
132       X509_VERIFY_PARAM_set1_host(), X509_VERIFY_PARAM_set_hostflags(),
133       X509_VERIFY_PARAM_set1_email(), X509_VERIFY_PARAM_set1_ip() and
134       X509_VERIFY_PARAM_set1_ip_asc() return 1 for success and 0 for failure.
135
136       X509_VERIFY_PARAM_get_flags() returns the current verification flags.
137
138       X509_VERIFY_PARAM_set_time() and X509_VERIFY_PARAM_set_depth() do not
139       return values.
140
141       X509_VERIFY_PARAM_get_depth() returns the current verification depth.
142

VERIFICATION FLAGS

144       The verification flags consists of zero or more of the following flags
145       ored together.
146
147       X509_V_FLAG_CRL_CHECK enables CRL checking for the certificate chain
148       leaf certificate. An error occurs if a suitable CRL cannot be found.
149
150       X509_V_FLAG_CRL_CHECK_ALL enables CRL checking for the entire
151       certificate chain.
152
153       X509_V_FLAG_IGNORE_CRITICAL disabled critical extension checking. By
154       default any unhandled critical extensions in certificates or (if
155       checked) CRLs results in a fatal error. If this flag is set unhandled
156       critical extensions are ignored. WARNING setting this option for
157       anything other than debugging purposes can be a security risk. Finer
158       control over which extensions are supported can be performed in the
159       verification callback.
160
161       THe X509_V_FLAG_X509_STRICT flag disables workarounds for some broken
162       certificates and makes the verification strictly apply X509 rules.
163
164       X509_V_FLAG_ALLOW_PROXY_CERTS enables proxy certificate verification.
165
166       X509_V_FLAG_POLICY_CHECK enables certificate policy checking, by
167       default no policy checking is peformed. Additional information is sent
168       to the verification callback relating to policy checking.
169
170       X509_V_FLAG_EXPLICIT_POLICY, X509_V_FLAG_INHIBIT_ANY and
171       X509_V_FLAG_INHIBIT_MAP set the require explicit policy, inhibit any
172       policy and inhibit policy mapping flags respectively as defined in
173       RFC3280. Policy checking is automatically enabled if any of these flags
174       are set.
175
176       If X509_V_FLAG_NOTIFY_POLICY is set and the policy checking is
177       successful a special status code is set to the verification callback.
178       This permits it to examine the valid policy tree and perform additional
179       checks or simply log it for debugging purposes.
180
181       By default some additional features such as indirect CRLs and CRLs
182       signed by different keys are disabled. If
183       X509_V_FLAG_EXTENDED_CRL_SUPPORT is set they are enabled.
184
185       If X509_V_FLAG_USE_DELTAS ise set delta CRLs (if present) are used to
186       determine certificate status. If not set deltas are ignored.
187
188       X509_V_FLAG_CHECK_SS_SIGNATURE enables checking of the root CA self
189       signed cerificate signature. By default this check is disabled because
190       it doesn't add any additional security but in some cases applications
191       might want to check the signature anyway. A side effect of not checking
192       the root CA signature is that disabled or unsupported message digests
193       on the root CA are not treated as fatal errors.
194
195       The X509_V_FLAG_CB_ISSUER_CHECK flag enables debugging of certificate
196       issuer checks. It is not needed unless you are logging certificate
197       verification. If this flag is set then additional status codes will be
198       sent to the verification callback and it must be prepared to handle
199       such cases without assuming they are hard errors.
200
201       The X509_V_FLAG_NO_ALT_CHAINS flag suppresses checking for alternative
202       chains. By default, when building a certificate chain, if the first
203       certificate chain found is not trusted, then OpenSSL will continue to
204       check to see if an alternative chain can be found that is trusted. With
205       this flag set the behaviour will match that of OpenSSL versions prior
206       to 1.0.2b.
207
208       The X509_V_FLAG_TRUSTED_FIRST flag causes chain construction to look
209       for issuers in the trust store before looking at the untrusted
210       certificates provided as part of the the peer chain.  Though it is not
211       on by default in OpenSSL 1.0.2, applications should generally set this
212       flag.  Local issuer certificates are often more likely to satisfy local
213       security requirements and lead to a locally trusted root.  This is
214       especially important When some certificates in the trust store have
215       explicit trust settings (see "TRUST SETTINGS" in x509(1)).
216
217       The X509_V_FLAG_PARTIAL_CHAIN flag causes intermediate certificates in
218       the trust store to be treated as trust-anchors, in the same way as the
219       self-signed root CA certificates.  This makes it possible to trust
220       certificates issued by an intermediate CA without having to trust its
221       ancestor root CA.  With OpenSSL 1.0.2, chain construction continues as
222       long as there are additional trusted issuers in the trust store, and
223       the last trusted issuer becomes the trust-anchor.  Thus, even when an
224       intermediate certificate is found in the trust store, the verified
225       chain passed to callbacks may still be anchored by a root CA.
226

NOTES

228       The above functions should be used to manipulate verification
229       parameters instead of legacy functions which work in specific
230       structures such as X509_STORE_CTX_set_flags().
231

BUGS

233       Delta CRL checking is currently primitive. Only a single delta can be
234       used and (partly due to limitations of X509_STORE) constructed CRLs are
235       not maintained.
236
237       If CRLs checking is enable CRLs are expected to be available in the
238       corresponding X509_STORE structure. No attempt is made to download CRLs
239       from the CRL distribution points extension.
240

EXAMPLE

242       Enable CRL checking when performing certificate verification during SSL
243       connections associated with an SSL_CTX structure ctx:
244
245         X509_VERIFY_PARAM *param;
246         param = X509_VERIFY_PARAM_new();
247         X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_CRL_CHECK);
248         SSL_CTX_set1_param(ctx, param);
249         X509_VERIFY_PARAM_free(param);
250

SEE ALSO

252       X509_verify_cert(3), X509_check_host(3), X509_check_email(3),
253       X509_check_ip(3), x509(1)
254

HISTORY

256       The X509_V_FLAG_NO_ALT_CHAINS flag was added in OpenSSL 1.0.2b
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259
2601.0.2o                            2019-09-10    X509_VERIFY_PARAM_set_flags(3)
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