pam_authenticate(3PAM) PAM Library Functions pam_authenticate(3PAM)NAMEpam_authenticate - perform authentication within the PAM framework
SYNOPSIS
cc [ flag ... ] file ... -lpam [ library ... ]
#include <security/pam_appl.h>
int pam_authenticate(pam_handle_t *pamh, int flags);
DESCRIPTION
The pam_authenticate() function is called to authenticate the current
user. The user is usually required to enter a password or similar
authentication token depending upon the authentication service config‐
ured within the system. The user in question should have been specified
by a prior call to pam_start() or pam_set_item().
The following flags may be set in the flags field:
PAM_SILENT Authentication service should not gen‐
erate any messages.
PAM_DISALLOW_NULL_AUTHTOK The authentication service should
return PAM_AUTH_ERR if the user has a
null authentication token.
RETURN VALUES
Upon successful completion, PAM_SUCCESS is returned. In addition to
the error return values described in pam(3PAM), the following values
may be returned:
PAM_AUTH_ERR Authentication failure.
PAM_CRED_INSUFFICIENT Cannot access authentication data due
to insufficient credentials.
PAM_AUTHINFO_UNAVAIL Underlying authentication service can‐
not retrieve authentication informa‐
tion.
PAM_USER_UNKNOWN User not known to the underlying
authentication module.
PAM_MAXTRIES An authentication service has main‐
tained a retry count which has been
reached. No further retries should be
attempted.
ATTRIBUTES
See attributes(5) for description of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │ Stable │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe with exceptions │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOpam(3PAM), pam_open_session(3PAM), pam_set_item(3PAM), pam_set‐
cred(3PAM), pam_start(3PAM), libpam(3LIB), attributes(5)NOTES
In the case of authentication failures due to an incorrect username or
password, it is the responsibility of the application to retry
pam_authenticate() and to maintain the retry count. An authentication
service module may implement an internal retry count and return an
error PAM_MAXTRIES if the module does not want the application to
retry.
If the PAM framework cannot load the authentication module, then it
will return PAM_ABORT. This indicates a serious failure, and the
application should not attempt to retry the authentication.
For security reasons, the location of authentication failures is hidden
from the user. Thus, if several authentication services are stacked
and a single service fails, pam_authenticate() requires that the user
re-authenticate each of the services.
A null authentication token in the authentication database will result
in successful authentication unless PAM_DISALLOW_NULL_AUTHTOK was spec‐
ified. In such cases, there will be no prompt to the user to enter an
authentication token.
The interfaces in libpam are MT-Safe only if each thread within the
multithreaded application uses its own PAM handle.
SunOS 5.10 27 Jan 2005 pam_authenticate(3PAM)
