pam_sm_chauthtok(3PAM) PAM Library Functions pam_sm_chauthtok(3PAM)NAMEpam_sm_chauthtok - service provider implementation for pam_chauthtok
SYNOPSIS
cc [ flag ...] file ... -lpam [ library ... ]
#include <security/pam_appl.h>
#include <security/pam_modules.h>
int pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const
char **argv);
DESCRIPTION
In response to a call to pam_chauthtok() the PAM framework calls
pam_sm_chauthtok(3PAM) from the modules listed in the pam.conf(4) file.
The password management provider supplies the back-end functionality
for this interface function.
The pam_sm_chauthtok() function changes the authentication token asso‐
ciated with a particular user referenced by the authentication handle
pamh.
The following flag may be passed to pam_chauthtok():
PAM_SILENT The password service should not gener‐
ate any messages.
PAM_CHANGE_EXPIRED_AUTHTOK The password service should only update
those passwords that have aged. If this
flag is not passed, the password ser‐
vice should update all passwords.
PAM_PRELIM_CHECK The password service should only per‐
form preliminary checks. No passwords
should be updated.
PAM_UPDATE_AUTHTOK The password service should update
passwords.
Note that PAM_PRELIM_CHECK and PAM_UPDATE_AUTHTOK cannot be set at
the same time.
Upon successful completion of the call, the authentication token of the
user will be ready for change or will be changed, depending upon the
flag, in accordance with the authentication scheme configured within
the system.
The argc argument represents the number of module options passed in
from the configuration file pam.conf(4). The argv argument specifies
the module options, which are interpreted and processed by the password
management service. Please refer to the specific module man pages for
the various available options.
It is the responsibility of pam_sm_chauthtok() to determine if the new
password meets certain strength requirements. pam_sm_chauthtok() may
continue to re-prompt the user (for a limited number of times) for a
new password until the password entered meets the strength require‐
ments.
Before returning, pam_sm_chauthtok() should call
pam_get_item() and retrieve both PAM_AUTHTOK and PAM_OLDAUTHTOK. If
both are NULL, pam_sm_chauthtok() should set them to the new and old
passwords as entered by the user.
RETURN VALUES
Upon successful completion, PAM_SUCCESS must be returned. The follow‐
ing values may also be returned:
PAM_PERM_DENIED No permission.
PAM_AUTHTOK_ERR Authentication token manipulation
error.
PAM_AUTHTOK_RECOVERY_ERR Old authentication token cannot be
recovered.
PAM_AUTHTOK_LOCK_BUSY Authentication token lock busy.
PAM_AUTHTOK_DISABLE_AGING Authentication token aging disabled.
PAM_USER_UNKNOWN User unknown to password service.
PAM_TRY_AGAIN Preliminary check by password service
failed.
ATTRIBUTES
See attributes(5) for description of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │ Stable │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe with exceptions │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOping(1M), pam(3PAM), pam_chauthtok(3PAM), pam_get_data(3PAM),
pam_get_item(3PAM), pam_set_data(3PAM), libpam(3LIB), pam.conf(4),
attributes(5)NOTES
The PAM framework invokes the password services twice. The first time
the modules are invoked with the flag, PAM_PRELIM_CHECK. During this
stage, the password modules should only perform preliminary checks.
For example, they may ping remote name services to see if they are
ready for updates. If a password module detects a transient error such
as a remote name service temporarily down, it should return
PAM_TRY_AGAIN to the PAM framework, which will immediately return the
error back to the application. If all password modules pass the prelim‐
inary check, the PAM framework invokes the password services again with
the flag, PAM_UPDATE_AUTHTOK. During this stage, each password module
should proceed to update the appropriate password. Any error will
again be reported back to application.
If a service module receives the flag PAM_CHANGE_EXPIRED_AUTHTOK, it
should check whether the password has aged or expired. If the password
has aged or expired, then the service module should proceed to update
the password. If the status indicates that the password has not yet
aged or expired, then the password module should return PAM_IGNORE.
If a user's password has aged or expired, a PAM account module could
save this information as state in the authentication handle, pamh,
using pam_set_data(). The related password management module could
retrieve this information using pam_get_data() to determine whether or
not it should prompt the user to update the password for this particu‐
lar module.
The interfaces in libpam are MT-Safe only if each thread within the
multithreaded application uses its own PAM handle.
If the PAM_REPOSITORY item_type is set and a service module does not
recognize the type, the service module does not process any informa‐
tion, and returns PAM_IGNORE. If the PAM_REPOSITORY item_type is not
set, a service module performs its default action.
SunOS 5.10 18 Nov 2003 pam_sm_chauthtok(3PAM)
