ldap_bind

LDAP_BIND(3)               Library Functions Manual               LDAP_BIND(3)

NAME
       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_un-
       bind_ext, ldap_unbind_ext_s, ldap_set_rebind_proc - 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_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
       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 at-
       tempted  over the connection.  An LDAP bind is required when using Ver-
       sion 2 of the LDAP protocol; it is optional for Version 3 but  is  usu-
       ally needed due to security considerations.

       There  are three types of bind calls, ones providing simple authentica-
       tion, 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 asynchro-
       nous  versions of each variant of the bind call are provided.  All rou-
       tines take ld as their first parameter, as returned from ldap_init(3).

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 en-
       try in passwd.  It returns  an  LDAP  error  indication  (see  ldap_er-
       ror(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.

GENERAL AUTHENTICATION
       The ldap_bind() and ldap_bind_s() routines can be used when the authen-
       tication 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.

SASL AUTHENTICATION
       For SASL binds the server always ignores any provided DN, so the dn pa-
       rameter  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.

       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  parame-
       ter 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:

       LDAP_SASL_AUTOMATIC
              use defaults if available, prompt otherwise

       LDAP_SASL_INTERACTIVE
              always prompt

       LDAP_SASL_QUIET
              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:

       SASL_CB_GETREALM
              the realm for the authentication attempt

       SASL_CB_AUTHNAME
              the username to authenticate

       SASL_CB_PASS
              the password for the provided username

       SASL_CB_USER
              the username to use for proxy authorization

       SASL_CB_NOECHOPROMPT
              generic prompt for input with input echoing disabled

       SASL_CB_ECHOPROMPT
              generic prompt for input with input echoing enabled

       SASL_CB_LIST_END
              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_re-
       sult() must be passed in the result parameter.  This parameter must  be
       NULL  when  initiating a new Bind. The caller must free the result mes-
       sage after each  call  using  ldap_msgfree().   The  ldap_sasl_interac-
       tive_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 server.

REBINDING
       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 ap-
       plication 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  arbi-
       trary  data like state information which the client might need to prop-
       erly 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) func-
       tion to parse the string into its components.

       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 authen-
       tication information such as, user name,  password,  and  certificates.
       The rebind function must use a synchronous bind method.

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 synchro-
       nous in nature.

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

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.

NOTES
       If  an  anonymous  bind  is  sufficient for the application, the rebind
       process need not be provided. The LDAP libraries with the  LDAP_OPT_RE-
       FERRALS  option set to ON (default value) will automatically follow re-
       ferrals 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
       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/)

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

OpenLDAP                          2020/01/30                      LDAP_BIND(3)
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