X509_VERIFY_PARAM_set_flags.pod revision 279264 
1=pod
2
3=head1 NAME
4
5X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose, X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth, X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_time, X509_VERIFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies - X509 verification parameters 
6
7=head1 SYNOPSIS
8
9 #include <openssl/x509_vfy.h>
10
11 int X509_VERIFY_PARAM_set_flags(X509_VERIFY_PARAM *param, unsigned long flags);
12 int X509_VERIFY_PARAM_clear_flags(X509_VERIFY_PARAM *param,
13							unsigned long flags);
14 unsigned long X509_VERIFY_PARAM_get_flags(X509_VERIFY_PARAM *param);
15
16 int X509_VERIFY_PARAM_set_purpose(X509_VERIFY_PARAM *param, int purpose);
17 int X509_VERIFY_PARAM_set_trust(X509_VERIFY_PARAM *param, int trust);
18
19 void X509_VERIFY_PARAM_set_time(X509_VERIFY_PARAM *param, time_t t);
20
21 int X509_VERIFY_PARAM_add0_policy(X509_VERIFY_PARAM *param,
22						ASN1_OBJECT *policy);
23 int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param, 
24					STACK_OF(ASN1_OBJECT) *policies);
25
26 void X509_VERIFY_PARAM_set_depth(X509_VERIFY_PARAM *param, int depth);
27 int X509_VERIFY_PARAM_get_depth(const X509_VERIFY_PARAM *param);
28
29=head1 DESCRIPTION
30
31These functions manipulate the B<X509_VERIFY_PARAM> structure associated with
32a certificate verification operation. 
33
34The X509_VERIFY_PARAM_set_flags() function sets the flags in B<param> by oring
35it with B<flags>. See the B<VERIFICATION FLAGS> section for a complete
36description of values the B<flags> parameter can take.
37
38X509_VERIFY_PARAM_get_flags() returns the flags in B<param>.
39
40X509_VERIFY_PARAM_clear_flags() clears the flags B<flags> in B<param>.
41
42X509_VERIFY_PARAM_set_purpose() sets the verification purpose in B<param>
43to B<purpose>. This determines the acceptable purpose of the certificate
44chain, for example SSL client or SSL server.
45
46X509_VERIFY_PARAM_set_trust() sets the trust setting in B<param> to 
47B<trust>.
48
49X509_VERIFY_PARAM_set_time() sets the verification time in B<param> to
50B<t>. Normally the current time is used.
51
52X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled
53by default) and adds B<policy> to the acceptable policy set.
54
55X509_VERIFY_PARAM_set1_policies() enables policy checking (it is disabled
56by default) and sets the acceptable policy set to B<policies>. Any existing
57policy set is cleared. The B<policies> parameter can be B<NULL> to clear
58an existing policy set.
59
60X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to B<depth>.
61That is the maximum number of untrusted CA certificates that can appear in a
62chain.
63
64=head1 RETURN VALUES
65
66X509_VERIFY_PARAM_set_flags(), X509_VERIFY_PARAM_clear_flags(), 
67X509_VERIFY_PARAM_set_purpose(), X509_VERIFY_PARAM_set_trust(),
68X509_VERIFY_PARAM_add0_policy() and X509_VERIFY_PARAM_set1_policies() return 1
69for success and 0 for failure. 
70
71X509_VERIFY_PARAM_get_flags() returns the current verification flags.
72
73X509_VERIFY_PARAM_set_time() and X509_VERIFY_PARAM_set_depth() do not return
74values.
75
76X509_VERIFY_PARAM_get_depth() returns the current verification depth.
77
78=head1 VERIFICATION FLAGS
79
80The verification flags consists of zero or more of the following flags
81ored together.
82
83B<X509_V_FLAG_CRL_CHECK> enables CRL checking for the certificate chain leaf
84certificate. An error occurs if a suitable CRL cannot be found. 
85
86B<X509_V_FLAG_CRL_CHECK_ALL> enables CRL checking for the entire certificate
87chain.
88
89B<X509_V_FLAG_IGNORE_CRITICAL> disabled critical extension checking. By default
90any unhandled critical extensions in certificates or (if checked) CRLs results
91in a fatal error. If this flag is set unhandled critical extensions are
92ignored. B<WARNING> setting this option for anything other than debugging
93purposes can be a security risk. Finer control over which extensions are
94supported can be performed in the verification callback.
95
96THe B<X509_V_FLAG_X509_STRICT> flag disables workarounds for some broken
97certificates and makes the verification strictly apply B<X509> rules.
98
99B<X509_V_FLAG_ALLOW_PROXY_CERTS> enables proxy certificate verification.
100
101B<X509_V_FLAG_POLICY_CHECK> enables certificate policy checking, by default
102no policy checking is peformed. Additional information is sent to the 
103verification callback relating to policy checking.
104
105B<X509_V_FLAG_EXPLICIT_POLICY>, B<X509_V_FLAG_INHIBIT_ANY> and
106B<X509_V_FLAG_INHIBIT_MAP> set the B<require explicit policy>, B<inhibit any
107policy> and B<inhibit policy mapping> flags respectively as defined in
108B<RFC3280>. Policy checking is automatically enabled if any of these flags
109are set.
110
111If B<X509_V_FLAG_NOTIFY_POLICY> is set and the policy checking is successful
112a special status code is set to the verification callback. This permits it
113to examine the valid policy tree and perform additional checks or simply
114log it for debugging purposes.
115
116By default some additional features such as indirect CRLs and CRLs signed by
117different keys are disabled. If B<X509_V_FLAG_EXTENDED_CRL_SUPPORT> is set
118they are enabled.
119
120If B<X509_V_FLAG_USE_DELTAS> ise set delta CRLs (if present) are used to
121determine certificate status. If not set deltas are ignored.
122
123B<X509_V_FLAG_CHECK_SS_SIGNATURE> enables checking of the root CA self signed
124cerificate signature. By default this check is disabled because it doesn't
125add any additional security but in some cases applications might want to
126check the signature anyway. A side effect of not checking the root CA
127signature is that disabled or unsupported message digests on the root CA
128are not treated as fatal errors.
129
130The B<X509_V_FLAG_CB_ISSUER_CHECK> flag enables debugging of certificate
131issuer checks. It is B<not> needed unless you are logging certificate
132verification. If this flag is set then additional status codes will be sent
133to the verification callback and it B<must> be prepared to handle such cases
134without assuming they are hard errors.
135
136=head1 NOTES
137
138The above functions should be used to manipulate verification parameters
139instead of legacy functions which work in specific structures such as
140X509_STORE_CTX_set_flags().
141
142=head1 BUGS
143
144Delta CRL checking is currently primitive. Only a single delta can be used and
145(partly due to limitations of B<X509_STORE>) constructed CRLs are not 
146maintained.
147
148If CRLs checking is enable CRLs are expected to be available in the
149corresponding B<X509_STORE> structure. No attempt is made to download
150CRLs from the CRL distribution points extension.
151
152=head1 EXAMPLE
153
154Enable CRL checking when performing certificate verification during SSL 
155connections associated with an B<SSL_CTX> structure B<ctx>:
156
157  X509_VERIFY_PARAM *param;
158  param = X509_VERIFY_PARAM_new();
159  X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_CRL_CHECK);
160  SSL_CTX_set1_param(ctx, param);
161  X509_VERIFY_PARAM_free(param);
162
163=head1 SEE ALSO
164
165L<X509_verify_cert(3)|X509_verify_cert(3)>
166
167=head1 HISTORY
168
169TBA
170
171=cut
172