The pam_sm_chauthtok function is the service module's implementation
of the pam_chauthtok(3) interface.
This function is used to (re-)set the authentication token of the
Valid flags, which may be logically OR'd with PAM_SILENT, are:
Do not emit any messages.
This argument indicates to the module that the user's
authentication token (password) should only be changed if it has
expired. This flag is optional and must be combined with one of
the following two flags. Note, however, the following two options
are mutually exclusive.
This indicates that the modules are being probed as to their
ready status for altering the user's authentication token. If the
module requires access to another system over some network it
should attempt to verify it can connect to this system on
receiving this flag. If a module cannot establish it is ready to
update the user's authentication token it should return
PAM_TRY_AGAIN, this information will be passed back to the
If the control value sufficient is used in the password stack,
the PAM_PRELIM_CHECK section of the modules following that
control value is not always executed.
This informs the module that this is the call it should change
the authorization tokens. If the flag is logically OR'd with
PAM_CHANGE_EXPIRED_AUTHTOK, the token is only changed if it has
The PAM library calls this function twice in succession. The first
time with PAM_PRELIM_CHECK and then, if the module does not return
PAM_TRY_AGAIN, subsequently with PAM_UPDATE_AUTHTOK. It is only on
the second call that the authorization token is (possibly) changed.
The module was unable to obtain the new authentication token.
The module was unable to obtain the old authentication token.
Cannot change the authentication token since it is currently
Authentication token aging has been disabled.
Preliminary check was unsuccessful. Signals an immediate return
to the application is desired.
The authentication token was successfully updated.
User unknown to password service.
This page is part of the linux-pam (Pluggable Authentication Modules
for Linux) project. Information about the project can be found at
⟨https://fedorahosted.org/linux-pam/⟩. If you have a bug report for
this manual page, see ⟨https://fedorahosted.org/linux-pam/report⟩.
This page was obtained from the tarball Linux-PAM-1.3.0.tar.gz
fetched from ⟨http://www.linux-pam.org/library/⟩ on 2017-03-13. If
you discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page), send a
mail to email@example.com
Linux-PAM Manual 04/01/2016 PAM_SM_CHAUTHTOK(3)