SSL_CTX_LOAD_VERIFY_LOCATIONSOpenSSL_CTX_LOAD_VERIFY_LOCATIONS(3)NAMESSL_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);
DESCRIPTIONSSL_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 certifi-
cates in PEM format. The file can contain several CA certi-
ficates 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 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 exten-
sion number, regardless of other properties of the certifi-
cates. 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
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SSL_CTX_LOAD_VERIFY_LOCATIONSOpenSSL_CTX_LOAD_VERIFY_LOCATIONS(3)
do not match, the next certificate will be tried. If a first
certificate matching the parameters is found, the verifica-
tion 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 con-
tents 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 identif-
ier, 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 dif-
ferent expiration dates. If a "certificate expired" verifi-
cation 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.
MirOS BSD #10-current 2005-02-05 2
SSL_CTX_LOAD_VERIFY_LOCATIONSOpenSSL_CTX_LOAD_VERIFY_LOCATIONS(3)SEE ALSOssl(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)MirOS BSD #10-current 2005-02-05 3
