=pod

=head1 NAME

SSL_CTX_load_verify_locations - set default locations for trusted CA
certificates

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_CTX_load_verify_locations(SSL_CTX *ctx, const char *CAfile,
                                   const char *CApath);

=head1 DESCRIPTION

SSL_CTX_load_verify_locations() specifies the locations for B<ctx>, at
which CA certificates for verification purposes are located. The certificates
available via B<CAfile> and B<CApath> are trusted.

=head1 NOTES

If B<CAfile> is not NULL, it points to a file of CA certificates in PEM
format. The file can contain several CA certificates identified by

 -----BEGIN CERTIFICATE-----
 ... (CA certificate in base64 encoding) ...
 -----END CERTIFICATE-----

sequences. Before, between, and after the certificates text is allowed
which can be used e.g. for descriptions of the certificates.

The B<CAfile> is processed on execution of the SSL_CTX_load_verify_locations()
function.

If on an TLS/SSL server no special setting is perfomed using *client_CA_list()
functions, the certificates contained in B<CAfile> are listed to the client
as available CAs during the TLS/SSL handshake.

If B<CApath> is not NULL, it points to a directory containing CA certificates
in PEM format. The files each contain one CA certificate. The files are
looked up by the CA subject name hash value, which must hence be available.
Use the B<c_rehash> utility to create the necessary links.

The certificates in B<CAfile> are only looked up when required, e.g. when
building the certificate chain or when actually performing the verification
of a peer certificate.

On a server, the certificates in B<CApath> are not listed as available
CA certificates to a client during a TLS/SSL handshake.

=head1 EXAMPLES

Generate a CA certificate file with descriptive text from the CA certificates
ca1.pem ca2.pem ca3.pem:

 #!/bin/sh
 rm CAfile.pem
 for i in ca1.pem ca2.pem ca3.pem ; do
   openssl x509 -in $i -text >> CAfile.pem
 done

Prepare the directory /some/where/certs containing several CA certificates
for use as B<CApath>:

 cd /some/where/certs
 c_rehash

=head1 RETURN VALUES

The following return values can occur:

=over 4

=item 0

The operation failed because B<CAfile> and B<CApath> are NULL or the
processing at one of the locations specified failed. Check the error
stack to find out the reason.

=item 1

The operation succeeded.

=back

=head1 SEE ALSO

L<ssl(3)|ssl(3)>,
L<SSL_CTX_set_client_CA_list(3)|SSL_CTX_set_client_CA_list(3)>,
L<SSL_get_client_CA_list(3)|SSL_get_client_CA_list(3)>

=cut