LDAP_BIND(3)

NAME
ldap_bind, ldap_bind_s, ldap_simple_bind, ldap_simple_bind_s, ldap_kerberos_bind_s, ldap_kerberos_bind1, ldap_kerberos_bind1_s, ldap_kerberos_bind2, ldap_kerberos_bind2_s, ldap_sasl_bind, ldap_sasl_bind_s, ldap_sasl_interactive_bind_s, ldap_parse_sasl_bind_result, ldap_unbind, ldap_unbind_s - LDAP bind routines

LIBRARY
OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS
#include <ldap.h>

int ldap_bind(LDAP *ld, const char *who, const char *cred,
    int method);

int ldap_bind_s(LDAP *ld, const char *who, const char *cred,
    int method);

int ldap_simple_bind(LDAP *ld, const char *who, const char *passwd);

int ldap_simple_bind_s(LDAP *ld, const char *who, const char *passwd);

int ldap_kerberos_bind_s(LDAP *ld, const char *who);

int ldap_kerberos_bind1(LDAP *ld, const char *who);

int ldap_kerberos_bind1_s(LDAP *ld, const char *who);

int ldap_kerberos_bind2(LDAP *ld, const char *who);

int ldap_kerberos_bind2_s(LDAP *ld, const char *who);

int ldap_sasl_bind(LDAP *ld, const char *dn, const char *mechanism,
    struct berval *cred, LDAPControl *sctrls[],
    LDAPControl *cctrls[], int *msgidp);

int ldap_sasl_bind_s(LDAP *ld, const char *dn, const char *mechanism,
    struct berval *cred, LDAPControl *sctrls[],
    LDAPControl *cctrls[], struct berval **servercredp);

int ldap_parse_sasl_bind_result(LDAP *ld, LDAPMessage *res,
    struct berval **servercredp, int freeit);

int ldap_sasl_interactive_bind_s(LDAP *ld, const char *dn,
    const char *mechs, struct berval *cred,
    LDAPControl *sctrls[], LDAPControl *cctrls[],
    unsigned flags, LDAP_SASL_INTERACT_PROC *interact,
    void *defaults);

int ldap_unbind(LDAP *ld);

int ldap_unbind_s(LDAP *ld);

DESCRIPTION

These routines provide various interfaces to the LDAP bind operation. After an association with an LDAP server is made using ldap_init(3), an LDAP bind operation should be performed before other operations are attempted over the connection. An LDAP bind is required when using Version 2 of the LDAP protocol; it is optional for Version 3 but is usually needed due to security considerations.

There are many types of bind calls, providing simple authentication, Kerberos version 4 authentication, and general routines to do either one, as well as calls using SASL (Simple Authentication and Security Layer) that can negotiate one of many different kinds of authentication. Both synchronous and asynchronous versions of each variant of the bind call are provided. All routines take ld as their first parameter, as returned from ldap_init(3).

Kerberos version 4 has been superseded by Kerberos version 5, and the Kerberos version 4 support is only provided for backward compatibility. The SASL interfaces should be used for new applications. SASL provides a general interface for using Kerberos versions 4 and 5 and many other security systems.

SIMPLE AUTHENTICATION
The simplest form of the bind call is ldap_simple_bind_s(). It takes the DN to bind as in who, and the userPassword associated with the entry in passwd. It returns an LDAP error indication (see ldap_error(3)). The ldap_simple_bind() call is asynchronous, taking the same parameters but only initiating the bind operation and returning the message id of the request it sent. The result of the operation can be obtained by a subsequent call to ldap_result(3).

KERBEROS AUTHENTICATION
If the LDAP library and LDAP server being contacted have been compiled with the KERBEROS option defined, Kerberos version 4 authentication can be performed. As mentioned above, these Kerberos routines are provided only for backward compatibility.

These routines assume the user already has obtained a ticket granting ticket. The routines take who, the DN of the entry to bind as. The ldap_kerberos_bind_s() routine does both steps of the Kerberos binding process synchronously. The ldap_kerberos_bind1_s() and ldap_kerberos_bind2_s() routines allow synchronous access to the individual steps, authenticating to the LDAP server and X.500 DSA, respectively. The ldap_kerberos_bind1() and ldap_kerberos_bind2() routines provide equivalent asynchronous access.

The ldap_kerberos_bind_s() routine is used to perform both authentication steps when contacting an LDAP server that is a gateway to an X.500 DSA. This kind of server configuration is only supported in the (very old) University of Michigan LDAP release. The OpenLDAP package no longer provides this gateway server. The standalone LDAP server provided in OpenLDAP may still be configured with Kerberos version 4 support, but it only requires one authentication step, and will return an error if the second step is attempted. Therefore, only the ldap_kerberos_bind1() routine or its synchronous equivalent may be used when contacting an OpenLDAP server.

GENERAL AUTHENTICATION
The ldap_bind() and ldap_bind_s() routines can be used when the authentication method to use needs to be selected at runtime. They both take an extra method parameter selecting the authentication method to use. It should be set to one of LDAP_AUTH_SIMPLE, LDAP_AUTH_KRBV41, or LDAP_AUTH_KRBV42, to select simple authentication, Kerberos authentication to the LDAP server, or Kerberos authentication to the X.500 DSA, respectively. ldap_bind() returns the message id of the request it initiates. ldap_bind_s() returns an LDAP error indication.

SASL AUTHENTICATION
Description still under construction...

UNBINDING
The ldap_unbind() call is used to unbind from the directory, terminate the current association, and free the resources contained in the ld structure. Once it is called, the connection to the LDAP server is closed, and the ld structure is invalid. The ldap_unbind_s() call is just another name for ldap_unbind(); both of these calls are synchronous in nature.

ERRORS
Asynchronous routines will return -1 in case of error, setting the ld_errno parameter of the ld structure. Synchronous routines return whatever ld_errno is set to. See ldap_error(3) for more information.

SEE ALSO
ldap(3), ldap_error(3), ldap_open(3), RFC 2222 (http://www.ietf.org), Cyrus SASL (http://asg.web.cmu.edu/sasl/)

ACKNOWLEDGEMENTS
OpenLDAP is developed and maintained by The OpenLDAP Project (http://www.openldap.org/). OpenLDAP is derived from University of Michigan LDAP 3.3 Release.