FreeBSD manual
download PDF document: auth_ttyok.3.pdf
LOGIN_OK(3) FreeBSD Library Functions Manual LOGIN_OK(3)
NAME
auth_ttyok, auth_hostok, auth_timeok - functions for checking login class
based login restrictions
LIBRARY
System Utilities Library (libutil, -lutil)
SYNOPSIS
#include <sys/types.h>
#include <time.h>
#include <login_cap.h>
int
auth_ttyok(login_cap_t *lc, const char *tty);
int
auth_hostok(login_cap_t *lc, const char *host, char const *ip);
int
auth_timeok(login_cap_t *lc, time_t t);
DESCRIPTION
This set of functions checks to see if login is allowed based on login
class capability entries in the login database, login.conf(5).
The auth_ttyok() function checks to see if the named tty is available to
users of a specific class, and is either in the ttys.allow access list,
and not in the ttys.deny access list. An empty ttys.allow list (or if no
such capability exists for the given login class) logins via any tty
device are allowed unless the ttys.deny list exists and is non-empty, and
the device or its tty group (see ttys(5)) is not in the list. Access to
ttys may be allowed or restricted specifically by tty device name, a
device name which includes a wildcard (e.g. ttyD* or cuaD*), or may name
a ttygroup, when group=<name> tags have been assigned in /etc/ttys.
Matching of ttys and ttygroups is case sensitive. Passing a NULL or
empty string as the tty parameter causes the function to return a non-
zero value.
The auth_hostok() function checks for any host restrictions for remote
logins. The function checks on both a host name and IP address (given in
its text form, typically n.n.n.n) against the host.allow and host.deny
login class capabilities. As with ttys and their groups, wildcards and
character classes may be used in the host allow and deny capability
records. The fnmatch(3) function is used for matching, and the matching
on hostnames is case insensitive. Note that this function expects that
the hostname is fully expanded (i.e., the local domain name added if
necessary) and the IP address is in its canonical form. No hostname or
address lookups are attempted.
It is possible to call this function with either the hostname or the IP
address missing (i.e. NULL) and matching will be performed only on the
basis of the parameter given. Passing NULL or empty strings in both
parameters will result in a non-zero return value.
The auth_timeok() function checks to see that a given time value is
within the times.allow login class capability and not within the
times.deny access lists. An empty or non-existent times.allow list
access is granted. A zero return value means either that the item being
tested is not in the allow access list, or is within the deny access
list.
SEE ALSO
getcap(3), login_cap(3), login_class(3), login_times(3), login.conf(5),
termcap(5)
HISTORY
The functions auth_ttyok(), auth_hostok()
and auth_timeok() functions first appeared in FreeBSD 2.1.5.
FreeBSD 14.0-RELEASE-p11 May 10, 2020 FreeBSD 14.0-RELEASE-p11