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 4 102 103=item 0 104 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. 108 109=item 1 110 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 125