SSL_CTX_set_default_verify_paths (3)

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NAME

SSL_CTX_load_verify_locations, SSL_CTX_set_default_verify_paths, SSL_CTX_set_default_verify_dir, SSL_CTX_set_default_verify_file - set default locations for trusted CA certificates

SYNOPSIS

 #include <openssl/ssl.h>

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

 int SSL_CTX_set_default_verify_paths(SSL_CTX *ctx);

 int SSL_CTX_set_default_verify_dir(SSL_CTX *ctx);

 int SSL_CTX_set_default_verify_file(SSL_CTX *ctx);

DESCRIPTION

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

SSL_CTX_set_default_verify_paths() specifies that the default locations from which

certificates are loaded should be used. There is one default directory and one default file. The default certificates directory is called ``certs'' in the default OpenSSL directory. Alternatively the environment variable can be defined to override this location. The default certificates file is called ``cert.pem'' in the default OpenSSL directory. Alternatively the environment variable can be defined to override this location.

SSL_CTX_set_default_verify_dir() is similar to SSL_CTX_set_default_verify_paths() except that just the default directory is used.

SSL_CTX_set_default_verify_file() is similar to SSL_CTX_set_default_verify_paths() except that just the default file is used.

NOTES

If CAfile is not it points to a file of certificates in format. The file can contain several 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 CAfile is processed on execution of the SSL_CTX_load_verify_locations() function.

If CApath is not

it points to a directory containing certificates in format. The files each contain one certificate. The files are looked up by the subject name hash value, which must hence be available. If more than one certificate with the same name hash value exist, the extension must be different (e.g. 9d66eef0.0, 9d66eef0.1 etc). The search is performed in the ordering of the extension number, regardless of other properties of the certificates. Use the c_rehash utility to create the necessary links.

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

When looking up

certificates, the OpenSSL library will first search the certificates in CAfile, then those in CApath. Certificate matching is done based on the subject name, the key identifier (if present), and the serial number as taken from the certificate to be verified. If these data do not match, the next certificate will be tried. If a first certificate matching the parameters is found, the verification process will be performed; no other certificates for the same parameters will be searched in case of failure.

In server mode, when requesting a client certificate, the server must send the list of CAs of which it will accept client certificates. This list is not influenced by the contents of CAfile or CApath and must explicitly be set using the SSL_CTX_set_client_CA_list(3) family of functions.

When building its own certificate chain, an OpenSSL client/server will try to fill in missing certificates from CAfile/CApath, if the certificate chain was not explicitly specified (see SSL_CTX_add_extra_chain_cert(3), SSL_CTX_use_certificate(3).

WARNINGS

If several certificates matching the name, key identifier, and serial number condition are available, only the first one will be examined. This may lead to unexpected results if the same certificate is available with different expiration dates. If a ``certificate expired'' verification error occurs, no other certificate will be searched. Make sure to not have expired certificates mixed with valid ones.

EXAMPLES

Generate a certificate file with descriptive text from the 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

certificates for use as CApath:

 cd /some/where/certs
 c_rehash .

RETURN VALUES

For SSL_CTX_load_verify_locations the following return values can occur:

0

The operation failed because CAfile and CApath are

NULL

or the processing at one of the locations specified failed. Check the error stack to find out the reason.

1

The operation succeeded.

SSL_CTX_set_default_verify_paths(), SSL_CTX_set_default_verify_dir() and SSL_CTX_set_default_verify_file() all return 1 on success or 0 on failure. A missing default location is still treated as a success.

SEE ALSO

ssl(3), SSL_CTX_set_client_CA_list(3), SSL_get_client_CA_list(3), SSL_CTX_use_certificate(3), SSL_CTX_add_extra_chain_cert(3), SSL_CTX_set_cert_store(3), SSL_CTX_set_client_CA_list(3)

COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the ``License''). You may not use this file except in compliance with the License. You can obtain a copy in the file

in the source distribution or at <www.openssl.org/source/license.html>.