SSL_CTX_load_verify_locations(3) OpenSSL SSL_CTX_load_verify_locations(3)
NAME
SSL_CTX_load_verify_locations - 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);
DESCRIPTION
SSL_CTX_load_verify_locations() specifies the locations for ctx, at which CA certificates for
verification purposes are located. The certificates available via CAfile and CApath are trusted.
NOTES
If 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-----... CERTIFICATE----...
... (CA certificate in base64 encoding) ...
-----END CERTIFICATE-----sequences. CERTIFICATE----sequences.
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 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. If more than one CA 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 CA 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 CA 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 CA
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 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 CApath:
cd /some/where/certs
c_rehash .
RETURN VALUES
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.
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)
0.9.7l 2001-09-06 SSL_CTX_load_verify_locations(3)
|