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Command: SSL_CTX_load_verify_locations | Section: 3 | Source: OpenBSD | File: SSL_CTX_load_verify_locations.3
SSL_CTX_LOAD_VERIFY_LOCATIONS(3) FreeBSD Library Functions Manual
NAME
SSL_CTX_load_verify_locations, SSL_CTX_set_default_verify_paths - 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);
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.
SSL_CTX_set_default_verify_paths() specifies that the default locations
from which CA certificates are loaded should be used. There is one
default directory and one default file. The default CA certificates
directory is called certs in the default OpenSSL directory. The default
CA certificates file is called cert.pem in the default OpenSSL directory.
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
sequences of:
-----BEGIN CERTIFICATE-----
... (CA certificate in base64 encoding) ...
-----END CERTIFICATE-----
Before, between, and after the certificates arbitrary 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.
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) and SSL_CTX_use_certificate(3)).
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() returns 1 on success or 0 on failure.
A missing default location is still treated as a success.
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
$ rm -f *.[0-9]* *.r[0-9]*
$ for c in *.pem; do
> [ "$c" = "*.pem" ] && continue
> hash=$(openssl x509 -noout -hash -in "$c")
> if egrep -q -- '-BEGIN( X509 | TRUSTED | )CERTIFICATE-' "$c"; then
> suf=0
> while [ -e $hash.$suf ]; do suf=$(( $suf + 1 )); done
> ln -s "$c" $hash.$suf
> fi
> if egrep -q -- '-BEGIN X509 CRL-' "$c"; then
> suf=0
> while [ -e $hash.r$suf ]; do suf=$(( $suf + 1 )); done
> ln -s "$c" $hash.r$suf
> fi
> done
SEE ALSO
ssl(3), SSL_CTX_add_extra_chain_cert(3), SSL_CTX_set_cert_store(3),
SSL_CTX_set_client_CA_list(3), SSL_CTX_use_certificate(3),
SSL_get_client_CA_list(3)
HISTORY
SSL_CTX_load_verify_locations() and SSL_CTX_set_default_verify_paths()
first appeared in SSLeay 0.8.0 and have been available since OpenBSD 2.4.
CAVEATS
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.
FreeBSD 14.1-RELEASE-p8 March 27, 2018 FreeBSD 14.1-RELEASE-p8