ldap_bind(3) — Linux manual page


LDAP_BIND(3)            Library Functions Manual            LDAP_BIND(3)

NAME         top

       ldap_bind, ldap_bind_s, ldap_simple_bind, ldap_simple_bind_s,
       ldap_sasl_bind, ldap_sasl_bind_s, ldap_sasl_interactive_bind_s,
       ldap_parse_sasl_bind_result, ldap_unbind, ldap_unbind_s,
       ldap_unbind_ext, ldap_unbind_ext_s, ldap_set_rebind_proc - LDAP
       bind routines

LIBRARY         top

       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS         top

       #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_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,
              LDAPControl *sctrls[], LDAPControl *cctrls[],
              unsigned flags, LDAP_SASL_INTERACT_PROC *interact,
              void *defaults);

       int ldap_sasl_interactive_bind(LDAP *ld, const char *dn,
              const char *mechs,
              LDAPControl *sctrls[], LDAPControl *cctrls[],
              unsigned flags, LDAP_SASL_INTERACT_PROC *interact,
              void *defaults, LDAPMessage *result,
              const char **rmechp, int *msgidp);

       int (LDAP_SASL_INTERACT_PROC)(LDAP *ld, unsigned flags, void *defaults, void *sasl_interact);

       int ldap_unbind(LDAP *ld);

       int ldap_unbind_s(LDAP *ld);

       int ldap_unbind_ext(LDAP *ld, LDAPControl *sctrls[],
              LDAPControl *cctrls[]);

       int ldap_unbind_ext_s(LDAP *ld, LDAPControl *sctrls[],
              LDAPControl *cctrls[]);

       int ldap_set_rebind_proc (LDAP *ld, LDAP_REBIND_PROC *ldap_proc, void *params);

       int (LDAP_REBIND_PROC)(LDAP *ld, LDAP_CONST char *url, ber_tag_t request, ber_int_t msgid, void *params);

DESCRIPTION         top

       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 three types of bind calls, ones providing simple
       authentication, ones providing SASL authentication, and general
       routines capable of doing either simple or SASL authentication.

       SASL (Simple Authentication and Security Layer) 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).


       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).  The ldap_sasl_bind_s() and
       asynchronous ldap_sasl_bind() functions can also be used to make
       a simple bind by using LDAP_SASL_SIMPLE as the SASL mechanism.


       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
       LDAP_AUTH_SIMPLE to select simple authentication.  ldap_bind()
       returns the message id of the request it initiates.
       ldap_bind_s() returns an LDAP error indication.


       For SASL binds the server always ignores any provided DN, so the
       dn parameter should always be NULL.  ldap_sasl_bind_s() sends a
       single SASL bind request with the given SASL mechanism and
       credentials in the cred parameter. The format of the credentials
       depends on the particular SASL mechanism in use. For mechanisms
       that provide mutual authentication the server's credentials will
       be returned in the servercredp parameter.  The routine returns an
       LDAP error indication (see ldap_error(3)).  The ldap_sasl_bind()
       call is asynchronous, taking the same parameters but only sending
       the request 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).  The result must be additionally parsed by
       ldap_parse_sasl_bind_result() to obtain any server credentials
       sent from the server.

       Any returned server credentials should be freed using

       Many SASL mechanisms require multiple message exchanges to
       perform a complete authentication. Applications should generally
       use ldap_sasl_interactive_bind_s() rather than calling the basic
       ldap_sasl_bind() functions directly. The mechs parameter should
       contain a space-separated list of candidate mechanisms to use. If
       this parameter is NULL or empty the library will query the
       supportedSASLMechanisms attribute from the server's rootDSE for
       the list of SASL mechanisms the server supports. The flags
       parameter controls the interaction used to retrieve any necessary
       SASL authentication parameters and should be one of:

              use defaults if available, prompt otherwise

              always prompt

              never prompt

       The interact function uses the provided defaults to handle
       requests from the SASL library for particular authentication
       parameters. There is no defined format for the defaults
       information; it is up to the caller to use whatever format is
       appropriate for the supplied interact function.  The
       sasl_interact parameter comes from the underlying SASL library.
       When used with Cyrus SASL this is an array of sasl_interact_t
       structures. The Cyrus SASL library will prompt for a variety of
       inputs, including:

              the realm for the authentication attempt

              the username to authenticate

              the password for the provided username

              the username to use for proxy authorization

              generic prompt for input with input echoing disabled

              generic prompt for input with input echoing enabled

              indicates the end of the array of prompts

       See the Cyrus SASL documentation for more details.

       Applications which need to manage connections asynchronously may
       use ldap_sasl_interactive_bind() instead of the synchronous
       version.  A valid mechs parameter must be supplied, otherwise the
       library will be forced to query the server for a list of
       supported mechanisms, and this query will be performed
       synchronously.  The other parameters are the same as for the
       synchronous function, with three additional parameters.  The
       actual SASL mechanism that was used, and the message ID for use
       with ldap_result() will be returned in rmechp and msgidp,
       respectively.  The value in rmechp must not be modified by the
       caller and must be passed back on each subsequent call. The
       message obtained from ldap_result() must be passed in the result
       parameter.  This parameter must be NULL when initiating a new
       Bind. The caller must free the result message after each call
       using ldap_msgfree().  The ldap_sasl_interactive_bind() function
       returns an LDAP result code. If the code is
       LDAP_SASL_BIND_IN_PROGRESS then the Bind is not complete yet, and
       this function must be called again with the next result from the

REBINDING         top

       The ldap_set_rebind_proc function() sets the process to use for
       binding when an operation returns a referral. This function is
       used when an application needs to bind to another server in order
       to follow a referral or search continuation reference.

       The function takes ld, the rebind function, and the params, the
       arbitrary data like state information which the client might need
       to properly rebind.  The LDAP_OPT_REFERRALS option in the ld must
       be set to ON for the libraries to use the rebind function. Use
       the ldap_set_option function to set the value.

       The rebind function parameters are as follows:

       The ld parameter must be used by the application when binding to
       the referred server if the application wants the libraries to
       follow the referral.

       The url parameter points to the URL referral string received from
       the LDAP server.  The LDAP application can use the
       ldap_url_parse(3) function to parse the string into its

       The request parameter specifies the type of request that
       generated the referral.

       The msgid parameter specifies the message ID of the request
       generating the referral.

       The params parameter is the same value as passed originally to
       the ldap_set_rebind_proc() function.

       The LDAP libraries set all the parameters when they call the
       rebind function. The application should not attempt to free
       either the ld or the url structures in the rebind function.

       The application must supply to the rebind function the required
       authentication information such as, user name, password, and
       certificates. The rebind function must use a synchronous bind

UNBINDING         top

       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.

       The ldap_unbind_ext() and ldap_unbind_ext_s() allows the
       operations to specify  controls.

ERRORS         top

       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

NOTES         top

       If an anonymous bind is sufficient for the application, the
       rebind process need not be provided. The LDAP libraries with the
       LDAP_OPT_REFERRALS option set to ON (default value) will
       automatically follow referrals using an anonymous bind.

       If the application needs stronger authentication than an
       anonymous bind, you need to provide a rebind process for that
       authentication method.  The bind method must be synchronous.

SEE ALSO         top

       ldap(3), ldap_error(3), ldap_open(3), ldap_set_option(3),
       ldap_url_parse(3) RFC 4422 (http://www.rfc-editor.org), Cyrus
       SASL (http://asg.web.cmu.edu/sasl/)


       OpenLDAP Software is developed and maintained by The OpenLDAP
       Project <http://www.openldap.org/>.  OpenLDAP Software is derived
       from the University of Michigan LDAP 3.3 Release.

COLOPHON         top

       This page is part of the OpenLDAP (an open source implementation
       of the Lightweight Directory Access Protocol) project.
       Information about the project can be found at 
       ⟨http://www.openldap.org/⟩.  If you have a bug report for this
       manual page, see ⟨http://www.openldap.org/its/⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://git.openldap.org/openldap/openldap.git⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-19.)  If you discover any rendering
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       (which is not part of the original manual page), send a mail to

OpenLDAP LDVERSION             RELEASEDATE                  LDAP_BIND(3)

Pages that refer to this page: ldappasswd(1)ldap(3)ldap_open(3)