SSL_CTX_SET_CLIENT_CA_LI(3) Library Functions ManualSSL_CTX_SET_CLIENT_CA_LI(3)
NAME
SSL_CTX_set_client_CA_list, SSL_set_client_CA_list, SSL_CTX_add_client_CA, SSL_add_client_CA — set list of CAs sent to the client when requesting a client certificate
SYNOPSIS
#include <openssl/ssl.h>
void
SSL_CTX_set_client_CA_list(SSL_CTX *ctx, STACK_OF(X509_NAME) *list);
void
SSL_set_client_CA_list(SSL *s, STACK_OF(X509_NAME) *list);
int
SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *cacert);
int
SSL_add_client_CA(SSL *ssl, X509 *cacert);
DESCRIPTION
SSL_CTX_set_client_CA_list() sets the list of CAs sent to the client when requesting a client certificate for ctx.
SSL_set_client_CA_list() sets the list of CAs sent to the client when requesting a client certificate for the chosen ssl, overriding the setting valid for ssl’s SSL_CTX object.
SSL_CTX_add_client_CA() adds the CA name extracted from cacert to the list of CAs sent to the client when requesting a client certificate for ctx.
SSL_add_client_CA() adds the CA name extracted from cacert to the list of CAs sent to the client when requesting a client certificate for the chosen ssl, overriding the setting valid for ssl’s SSL_CTX object.
When a TLS/SSL server requests a client certificate (see SSL_CTX_set_verify()), it sends a list of CAs for which it will accept certificates to the client.
This list must explicitly be set using SSL_CTX_set_client_CA_list() for ctx and SSL_set_client_CA_list() for the specific ssl. The list specified overrides the previous setting. The CAs listed do not become trusted (
list only contains the names, not the complete certificates ); use SSL_CTX_load_verify_locations(3) to additionally load them for verification.
If the list of acceptable CAs is compiled in a file, the SSL_load_client_CA_file(3) function can be used to help importing the necessary data.
SSL_CTX_add_client_CA() and SSL_add_client_CA() can be used to add additional items the list of client CAs. If no list was specified before using SSL_CTX_set_client_CA_list() or SSL_set_client_CA_list(), a new client CA list for ctx or ssl (as appropriate) is opened.
These functions are only useful for TLS/SSL servers.
RETURN VALUES
SSL_CTX_add_client_CA() and SSL_add_client_CA() have the following return values:
0
A failure while manipulating the STACK_OF(X509_NAME) object occurred or the X509_NAME could not be extracted from cacert. Check the error stack to find out the reason.
1
The operation succeeded.
EXAMPLES
Scan all certificates in CAfile and list them as acceptable CAs:
SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(CAfile));
SEE ALSO
ssl(3), SSL_CTX_load_verify_locations(3), SSL_get_client_CA_list(3), SSL_load_client_CA_file(3), X509_NAME_new(3)
HISTORY
SSL_CTX_set_client_CA_list(), SSL_set_client_CA_list(), SSL_CTX_add_client_CA(), and SSL_add_client_CA() first appeared in SSLeay 0.8.0 and have been available since OpenBSD 2.4. GNU March 30, 2020 SSL_CTX_SET_CLIENT_CA_LIST(3)