pam_sm_chauthtok - PAM service function for authentication token
int flags, int argc,
const char **argv);
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,
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
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
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)
The module was unable to obtain the new authentication
The module was unable to obtain the old authentication
Cannot change the authentication token since it is
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.