Provided by: libpam-ldap_184-4ubuntu2_i386 bug

NAME

       pam_ldap - LDAP pluggable authentication module

DESCRIPTION

       The  pam_ldap  module  is a Pluggable Authentication Module (PAM) which
       provides  for  authentication,  authorization  and  password   changing
       against LDAP servers.

       Features  of  the  PADL  pam_ldap  module include support for transport
       layer security, SASL authentication, directory server-enforced password
       policy, and host- and group- based logon authorization.

       The present version of pam_ldap supports AIX 5L, FreeBSD 3.x and above,
       HP-UX 11i, IRIX 6.x, Linux, Mac OS X 10.2 and above,  and  Solaris  2.6
       and   above.   Many  vendors  provide  their  own  LDAP  authentication
       providers, often also called pam_ldap.  This manual page applies to the
       PADL  pam_ldap  module only. If you are using a vendor provided module,
       consult the relevant documentation instead.

       When authenticating or authorizing a  user,  pam_ldap  first  maps  the
       user’s  login  name  to a distinguished name by searching the directory
       server. This must  be  possible  using  the  local  system’s  identity,
       specified in ldap.conf. (Note that presently only simple authentication
       is supported for authenticating in this initial step.)

       To authenticate a user, pam_ldap attempts  to  bind  to  the  directory
       server using the distinguished name of the user (retrieved previously).
       Both simple and SASL authentication mechanisms are  supported;  in  the
       former  case, one should take care to use transport security to prevent
       the user’s password being transmitted in the clear.

       A variety  of  authorization  primitives  are  supported  by  pam_ldap,
       discussed in the configuration section below.

       Finally,  pam_ldap  supports a number of password change protocols used
       by directory servers from  various  vendors.  (Some  directory  servers
       support more than one password change protocol.)

       Whilst  pam_ldap  is  generally  configured  in  the system LDAP naming
       configuration file (ldap.conf), some options can be configured  in  the
       PAM  configuration  file,  to  allow for per-service granularity. These
       options include the path to the LDAP naming configuration file to  use,
       so  in  effect  all  options  can be configured on a per-service basis.
       Options are listed below under PAM Configuration.

CONFIGURATION

       pam_ldap stores its configuration in the ldap.conf file. (It should  be
       noted  that  some  LDAP  client libraries, such as OpenLDAP, also use a
       configuration file of the same name.  pam_ldap  supports  many  of  the
       same  configuration  file options as OpenLDAP, but it adds several that
       are specific to the functionality it provides.  It  is  not  guaranteed
       that  pam_ldap  will continue to match the configuration file semantics
       of OpenLDAP.  You may wish to use different files.)

       Configuration file options consist of a keyword followed by a space and
       any arguments. The following options are supported by both pam_ldap and
       the PADL nss_ldap module:

       host <name:port ...>
              Specifies the name(s) or IP address(es) of the LDAP server(s) to
              connect  to.  In  the  case  that nss_ldap is used for host name
              resolution, each server should be specified as an IP address  or
              name  that can be resolved without using LDAP.  Multiple servers
              may be specified, each separated by a space.  The failover  time
              depends on whether the LDAP client library supports configurable
              network or connect timeouts (see bind_timelimit below).

       base <base>
              Specifies the default base distinguished name (DN)  to  use  for
              searches.

       uri <ldap[is]://[name[:port]] ...>
              For  LDAP client libraries that support it, specifies the URI(s)
              of the LDAP server(s) to connect to. The URI scheme may be ldap,
              ldapi,   or  ldaps,  specifying  LDAP  over  TCP,  IPC  and  SSL
              respectively. If applicable, a port number can be specified; the
              default  port  number  for  the  selected  protocol  is  used if
              omitted. This option takes precedence over the host  option;  it
              is not possible to combine the two.

       ldap_version <version>
              Specifies  the  version  of  the LDAP protocol to use. Presently
              version must be 2 or 3.  The  default  is  to  use  the  maximum
              version supported by the client library.

       binddn <binddn>
              Specifies  the  distinguished  name  with  which  to bind to the
              directory server(s). This option is optional; the default is  to
              bind anonymously.

       bindpw <bindpw>
              Specifies  the  cleartext  credentials  with which to bind. This
              option is only applicable  when  used  with  binddn  above.  The
              default  is  no credential (anonymous bind). When binding to the
              directory using SASL or other  authentication  mechanisms  apart
              from simple binds, this option is not used.

       rootbinddn <binddn>
              This  option has the same syntax and effect as the binddn option
              above, except it applies when the effective user ID is zero.  If
              not  specified,  then  the  identity specified in binddn is used
              instead. Because the configuration file may be readable by  many
              users,   the   root  bind  DN  credentials  are  stored  in  the
              ldap.secret file instead. This  file  is  usually  in  the  same
              directory as the configuration file.

       port <port>
              Specifies  the  port to connect to; this option is used with the
              host option, and is ignored with the uri option.

       scope <sub|one|base>
              Specifies the search scope (subtree, one level or base  object).
              The  default scope is subtree; base scope is almost never useful
              for nameservice lookups.

       deref <never|searching|finding|always>
              Specifies the policy  for  dereferencing  aliases.  The  default
              policy is to never dereference aliases.

       timelimit <timelimit>
              Specifies  the  time  limit  (in seconds) to use when performing
              searches. A value of zero (0), which is the default, is to  wait
              indefinitely for searches to be completed.

       bind_timelimit <timelimit>
              Specifies  the time limit (in seconds) to use when connecting to
              the directory server. This  is  distinct  from  the  time  limit
              specified in timelimit and affects the initial server connection
              only. (Server connections are otherwise cached.) Only some  LDAP
              client  libraries have the underlying functionality necessary to
              support this option. The default bind timelimit is 30 seconds.

       referrals <yes|no>
              Specifies whether automatic referral chasing should be  enabled.
              The default behaviour is specifed by the LDAP client library.

       restart <yes|no>
              Specifies  whether  the  LDAP client library should restart the
              select(2) system call when  interrupted.  This  feature  is  not
              supported by all client libraries.

       logdir <directory>
              Specifies  the  directory  used  for  logging by the LDAP client
              library. This feature is not supported by all client  libraries.

       debug <level>
              Specifies  the  debug  level used for logging by the LDAP client
              library. This feature is not supported by all client  libraries,
              and  does  not  apply  to  the  nss_ldap  and  pam_ldap  modules
              themselves (debugging, if  any,  is  configured  separately  and
              usually at compile time).

       ssl <on|off|start_tls>
              Specifies whether to use SSL/TLS or not (the default is not to).
              If start_tls is specified then StartTLS is used rather than  raw
              LDAP  over  SSL.  Not all LDAP client libraries support both SSL
              and StartTLS, and all related configuration options.

       sslpath <cert7_path>
              For the Netscape and Mozilla LDAP client  libraries  only,  this
              specifies the path to the X.509 certificate database.

       tls_checkpeer <yes|no>
              Specifies  whether  to require and verify the server certificate
              or not, when using SSL/TLS with  the  OpenLDAP  client  library.
              The  default  is  to  use  the  default  behaviour of the client
              library; for OpenLDAP 2.0 and earlier it is "no",  for  OpenLDAP
              2.1  and  later  it  is "yes". At least one of tls_cacertdir and
              tls_cacertfile is required if peer verification is enabled.

       tls_cacertdir <certificate_dir>
              Specifies the directory containing X.509 certificates  for  peer
              authentication.

       tls_cacertfile <certificate_file>
              Specifies   the   path   to   the  X.509  certificate  for  peer
              authentication.

       tls_randfile <entropy_file>
              Specifies the path to an entropy source.

       tls_ciphers <ciphers>
              Specifies  the  ciphers  to  use   for   TLS.   See   your   TLS
              implementation’s documentation for further information.

       tls_cert <certificate_file>
              Specifies  the path to the file containing the local certificate
              for client TLS authentication.

       tls_key <key_file>
              Specifies the path to the file containing the  private  key  for
              client TLS authentication.

       The following configuration options apply to pam_ldap only:

       pam_login_attribute <attribute>
              Specifies  the  attribute to use when constructing the attribute
              value assertion for retrieving a directory entry  for  a  user’s
              login  name.   The  default is "uid", for compatibility with RFC
              2307.

       pam_filter <filter>
              Specifies a filter to use when retrieving user information.  The
              user   entry   must  match  the  attribute  value  assertion  of
              (pam_login_attribute=login_name) as well as any filter specified
              here. There is no default for this option.

       pam_lookup_policy <yes|no>
              Specifies  whether  to  search the root DSE for password policy.
              The default is "no".

       pam_check_host_attr <yes|no>
              Specifies whether the "host" attribute  should  be  checked  for
              logon authorization ("account" in the PAM stack). The default is
              not to.  If set to "yes" and a user has no value for the  "host"
              attribute, then the user will be unable to login.

       pam_check_service_attr <yes|no>
              Specifies  whether  the  "authorizedService" attribute should be
              checked for logon authorization ("account" in  the  PAM  stack).
              The  default  is not to. If set to "yes" and a user has no value
              for the "authorizedService" attribute, then  the  user  will  be
              unable to login.

       pam_groupdn <groupdn>
              Specifies the distinguished name of a group to which a user must
              belong for logon authorization to succeed.  pam_member_attribute
              <attribute> Specifies the attribute to use when testing a user’s
              membership of a group specified in the pam_groupdn option.

       pam_min_uid <uid>
              If specified, a user must have a POSIX user ID of at  least  uid
              in order for logon authorization to succeed.

       pam_max_uid <uid>
              If  specified,  a  user  must have a POSIX user ID of no greater
              than uid in order for logon authorization to succeed.

       pam_template_login_attribute <attribute>
              When  using  template  users   (not   supported   by   all   PAM
              applications),  specifies  the  attribute  containing the user’s
              actual login name.  The pam_ldap module will set PAM_USER to the
              value  of  this  attribute  if  present  in  the  user’s  entry,
              otherwise  it  defaults   to   the   user   specified   in   the
              pam_template_login option.

       pam_template_login <user>
              When   using   template   users   (not   supported  by  all  PAM
              applications), pam_ldap will set PAM_USER to the value  of  this
              option  if the user does not contain a template login attribute.

       pam_password <protocol>
              Specifies the password change protocol  to  use.  The  following
              protocols are supported:

              clear  Change  password  using  an LDAPModify request, replacing
                     the userPassword value with the new cleartext password.

              clear_remove_old
                     Change  password  using  an  LDAPModify  request,   first
                     removing   the  userPassword  value  containing  the  old
                     cleartext password,  and  then  adding  the  userPassword
                     value  with  the new cleartext password. This protocol is
                     necessary for use with Novell NDS and IBM RACF.

              crypt  Change  password  using  an  LDAPModify  request,   first
                     generating  a  one  way  hash  of  the new password using
                     crypt(3) and then replacing userPassword value  with  the
                     new hashed password.

              md5    Change   password  using  an  LDAPModify  request,  first
                     generating a one way hash of the new password  using  MD5
                     and then replacing userPassword value with the new hashed
                     password.

              nds    This is an alias for clear_remove_old.

              racf   This is an alias for clear_remove_old.

              ad     Change password using an LDAPModify  request,  using  the
                     Active   Directory  Services  Interface  (ADSI)  password
                     change protocol.

              exop   Change  password  using  the  RFC  3062  password  modify
                     extended operation (only the new password is sent).

              exop_send_old
                     Change  password  using  the  RFC  3062  password  modify
                     extended operation (both the old and  new  passwords  are
                     sent).

       pam_password_prohibit_message <message>
              Specifies  a  message to send to users indicating that passwords
              cannot be changed. This could  be  used  to  redirect  users  to
              another means of changing passwords.

       pam_sasl_mech <mechanism>
              Specifies the SASL mechanism to use for PAM authentication. This
              requires  SASL  libraries  be  installed.   Support   for   this
              functionality   presently  experimental  and  does  not  support
              password policy controls.

PAM CONFIGURATION

       It is possible to configure some aspects of pam_ldap on  a  per-service
       basis,  in  the  PAM configuration file (this is usually /etc/pam.conf;
       for PAM  implementations  based  on  Linux-PAM,  per-service  files  in
       /etc/pam.d are also supported).

       The  following  options  may  be specified as arguments to the pam_ldap
       module:

       config=<path>
              Specifies that pam_ldap should use  the  configuration  file  in
              path  instead of ldap.conf to retrieve its global configuration.
              Configuring multiple instances of pam_ldap for the same  service
              with different configuration files is not supported, because the
              configuration information is cached.

       use_first_pass
              Specifies that pam_ldap should always  use  the  first  password
              provided in the authentication stack.

       try_first_pass
              Specifies  that  pam_ldap  should  first  try the first password
              provided in the authentication stack, and then prompt  the  user
              for their LDAP password if authentication fails.

       ignore_unknown_user
              Specifies  that pam_ldap should return PAM_IGNORE for users that
              are not present in LDAP.   This  forces  the  PAM  framework  to
              ignore  the pam_ldap module. This option is useful where certain
              accounts do not reside in LDAP, but one wishes to make  pam_ldap
              "required"  for  all accounts in the directory. In this case one
              would make both pam_ldap and  the  other  module  (for  example,
              pam_unix)  "required" and enable the ignore_unknown_user option.
              (For this to work, the other module must  behave  similarly  for
              users in the directory; in the case of a module such as pam_unix
              that uses the system accounts database, using nss_ldap(5) should
              be sufficient to meet this requirement.)

       ignore_authinfo_unavail
              Specifies  that  pam_ldap  should return PAM_IGNORE if it cannot
              contact the LDAP server. This option forces the PAM framework to
              ignore the pam_ldap module in this case.

       no_warn
              Specifies  that warning messages should not be propagated to the
              PAM application.

       use_authtok
              Analogous to use_first_pass for password changing only.

       debug  This option is recognized by pam_ldap but is presently  ignored.

AUTHOR

       The   pam_ldap   module   was   developed  by  PADL  Software  Pty  Ltd
       (www.padl.com).

FILES

       /etc/ldap.conf, /etc/ldap.secret, /etc/pam.conf

SEE ALSO

       pam(8)

                                                                   pam_ldap(5)