Import OpenSSL-1.0.1h.
[dragonfly.git] / crypto / openssl / doc / ssl / SSL_CTX_load_verify_locations.pod
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1=pod
2
3=head1 NAME
4
5SSL_CTX_load_verify_locations - set default locations for trusted CA
6certificates
7
8=head1 SYNOPSIS
9
10 #include <openssl/ssl.h>
11
12 int SSL_CTX_load_verify_locations(SSL_CTX *ctx, const char *CAfile,
13 const char *CApath);
14
15=head1 DESCRIPTION
16
17SSL_CTX_load_verify_locations() specifies the locations for B<ctx>, at
18which CA certificates for verification purposes are located. The certificates
19available via B<CAfile> and B<CApath> are trusted.
20
21=head1 NOTES
22
23If B<CAfile> is not NULL, it points to a file of CA certificates in PEM
24format. The file can contain several CA certificates identified by
25
26 -----BEGIN CERTIFICATE-----
27 ... (CA certificate in base64 encoding) ...
28 -----END CERTIFICATE-----
29
30sequences. Before, between, and after the certificates text is allowed
31which can be used e.g. for descriptions of the certificates.
32
33The B<CAfile> is processed on execution of the SSL_CTX_load_verify_locations()
34function.
35
36If B<CApath> is not NULL, it points to a directory containing CA certificates
37in PEM format. The files each contain one CA certificate. The files are
38looked up by the CA subject name hash value, which must hence be available.
39If more than one CA certificate with the same name hash value exist, the
40extension must be different (e.g. 9d66eef0.0, 9d66eef0.1 etc). The search
41is performed in the ordering of the extension number, regardless of other
42properties of the certificates.
43Use the B<c_rehash> utility to create the necessary links.
44
45The certificates in B<CApath> are only looked up when required, e.g. when
46building the certificate chain or when actually performing the verification
47of a peer certificate.
48
49When looking up CA certificates, the OpenSSL library will first search the
50certificates in B<CAfile>, then those in B<CApath>. Certificate matching
51is done based on the subject name, the key identifier (if present), and the
52serial number as taken from the certificate to be verified. If these data
53do not match, the next certificate will be tried. If a first certificate
54matching the parameters is found, the verification process will be performed;
55no other certificates for the same parameters will be searched in case of
56failure.
57
58In server mode, when requesting a client certificate, the server must send
59the list of CAs of which it will accept client certificates. This list
60is not influenced by the contents of B<CAfile> or B<CApath> and must
61explicitly be set using the
62L<SSL_CTX_set_client_CA_list(3)|SSL_CTX_set_client_CA_list(3)>
63family of functions.
64
65When building its own certificate chain, an OpenSSL client/server will
66try to fill in missing certificates from B<CAfile>/B<CApath>, if the
67certificate chain was not explicitly specified (see
68L<SSL_CTX_add_extra_chain_cert(3)|SSL_CTX_add_extra_chain_cert(3)>,
69L<SSL_CTX_use_certificate(3)|SSL_CTX_use_certificate(3)>.
70
71=head1 WARNINGS
72
73If several CA certificates matching the name, key identifier, and serial
74number condition are available, only the first one will be examined. This
75may lead to unexpected results if the same CA certificate is available
76with different expiration dates. If a "certificate expired" verification
77error occurs, no other certificate will be searched. Make sure to not
78have expired certificates mixed with valid ones.
79
80=head1 EXAMPLES
81
82Generate a CA certificate file with descriptive text from the CA certificates
83ca1.pem ca2.pem ca3.pem:
84
85 #!/bin/sh
86 rm CAfile.pem
87 for i in ca1.pem ca2.pem ca3.pem ; do
88 openssl x509 -in $i -text >> CAfile.pem
89 done
90
91Prepare the directory /some/where/certs containing several CA certificates
92for use as B<CApath>:
93
94 cd /some/where/certs
95 c_rehash .
96
97=head1 RETURN VALUES
98
99The following return values can occur:
100
101=over 4
102
4bb195ec 103=item Z<>0
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104
105The operation failed because B<CAfile> and B<CApath> are NULL or the
106processing at one of the locations specified failed. Check the error
107stack to find out the reason.
108
4bb195ec 109=item Z<>1
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110
111The operation succeeded.
112
113=back
114
115=head1 SEE ALSO
116
117L<ssl(3)|ssl(3)>,
118L<SSL_CTX_set_client_CA_list(3)|SSL_CTX_set_client_CA_list(3)>,
119L<SSL_get_client_CA_list(3)|SSL_get_client_CA_list(3)>,
120L<SSL_CTX_use_certificate(3)|SSL_CTX_use_certificate(3)>,
121L<SSL_CTX_add_extra_chain_cert(3)|SSL_CTX_add_extra_chain_cert(3)>,
122L<SSL_CTX_set_cert_store(3)|SSL_CTX_set_cert_store(3)>
123
124=cut