in.rlogind(1M) System Administration Commands in.rlogind(1M)NAME
in.rlogind, rlogind - remote login server
SYNOPSIS
/usr/sbin/in.rlogind [-k5eExXciPp] [-s tos] [-S keytab] [-M realm]
DESCRIPTIONin.rlogind is the server for the rlogin(1) program. The server pro‐
vides a remote login facility with authentication based on Kerberos V5
or privileged port numbers.
in.rlogind is invoked by inetd(1M) when a remote login connection is
established. When Kerberos V5 authentication is required (see option -k
below), the authentication sequence is as follows:
· Check Kerberos V5 authentication.
· Check authorization according to the rules in krb5_auth_rules(5).
· Prompt for a password if any checks fail and /etc/pam.conf is con‐
figured to do so.
In order for Kerberos authentication to work, a host/<FQDN> Kerberos
principal must exist for each Fully Qualified Domain Name associated
with the in.rlogind server. Each of these host/<FQDN> principals must
have a keytab entry in the /etc/krb5/krb5.keytab file on the in.rlogind
server. An example principal might be:
host/bigmachine.eng.example.com
See kadmin(1M) or gkadmin(1M) for instructions on adding a principal to
a krb5.keytab file. See System Administration Guide: Security Services
for a discussion of Kerberos authentication.
If Kerberos V5 authentication is not enabled, then the authentication
procedure follows the standard rlogin protocol:
· The server checks the client's source port. If the port is not in
the range 512-1023, the server aborts the connection.
· The server checks the client's source address. If an entry for the
client exists in both /etc/hosts and /etc/hosts.equiv, a user log‐
ging in from the client is not prompted for a password. If the
address is associated with a host for which no corresponding entry
exists in /etc/hosts, the user is prompted for a password, regard‐
less of whether or not an entry for the client is present in
/etc/hosts.equiv. See hosts(4) and hosts.equiv(4).
Once the source port and address have been checked, in.rlogind allo‐
cates a pseudo-terminal and manipulates file descriptors so that the
slave half of the pseudo-terminal becomes the stdin, stdout, and stderr
for a login process. The login process is an instance of the login(1)
program, invoked with the -r.
The login process then proceeds with the pam(3PAM) authentication
process. See SECURITY below. If automatic authentication fails, it
reprompts the user to login.
The parent of the login process manipulates the master side of the
pseudo-terminal, operating as an intermediary between the login process
and the client instance of the rlogin program. In normal operation, a
packet protocol is invoked to provide <Ctrl-S> and <Ctrl-Q> type facil‐
ities and propagate interrupt signals to the remote programs. The login
process propagates the client terminal's baud rate and terminal type,
as found in the environment variable, TERM.
OPTIONS
The following options are supported:
-5 Same as -k, for backwards compatibility.
-c Requires Kerberos V5 clients to present a cryptographic
checksum of initial connection information like the
name of the user that the client is trying to access
in the initial authenticator. This checksum provides
additionl security by preventing an attacker from
changing the initial connection information. This
option is mutually exclusive with the -i option.
-e Creates an encrypted session.
-E Same as -e, for backwards compatibility.
-i Ignores authenticator checksums if provided. This
option ignores authenticator checksums presented by
current Kerberos clients to protect initial connection
information. Option -i is the opposite of option -c.
-k Allows Kerberos V5 authentication with the .k5login
access control file to be trusted. If this authentica‐
tion system is used by the client and the authorization
check is passed, then the user is allowed to log in.
-M realm Uses the indicated Kerberos V5 realm. By default, the
daemon will determine its realm from the settings in
the krb5.conf(4) file.
-p Prompts for authentication only if other authentication
checks fail.
-P Prompts for a password in addition to other authentica‐
tion methods.
-s tos Sets the IP TOS option.
-S keytab Sets the KRB5 keytab file to use.
The/etc/krb5/krb5.keytab file is used by default.
-x Same as -e, for backwards compatibility.
-X Same as -e, for backwards compatibility.
USAGE
rlogind and in.rlogind are IPv6-enabled. See ip6(7P). IPv6 is not cur‐
rently supported with Kerberos V5 authentication.
Typically, Kerberized rlogin service runs on port 543 (klogin) and Ker‐
berized, encrypted rlogin service runs on port 2105 (eklogin). The cor‐
responding FMRI entries are:
svc:/network/login:klogin (rlogin with kerberos)
svc:/network/login:eklogin (rlogin with kerberos and encryption)
SECURITYin.rlogind uses pam(3PAM) for authentication, account management, and
session management. The PAM configuration policy, listed through
/etc/pam.conf, specifies the modules to be used for in.rlogind. Here is
a partial pam.conf file with entries for the rlogin command using the
"rhosts" and UNIX authentication modules, and the UNIX account, session
management, and password management modules.
rlogin auth sufficient pam_rhosts_auth.so.1
rlogin auth requisite pam_authtok_get.so.1
rlogin auth required pam_dhkeys.so.1
rlogin auth required pam_unix_auth.so.1
rlogin account required pam_unix_roles.so.1
rlogin account required pam_unix_projects.so.1
rlogin account required pam_unix_account.so.1
rlogin session required pam_unix_session.so.1
With this configuration, the server checks the client's source address.
If an entry for the client exists in both /etc/hosts and
/etc/hosts.equiv, a user logging in from the client is not prompted for
a password. If the address is associated with a host for which no cor‐
responding entry exists in /etc/hosts, the user is prompted for a pass‐
word, regardless of whether or not an entry for the client is present
in /etc/hosts.equiv. See hosts(4) and hosts.equiv(4).
When running a Kerberized rlogin service (with or without the encryp‐
tion option), the pam service name that should be used is "krlogin".
If there are no entries for the rlogin service, then the entries for
the "other" service will be used. If multiple authentication modules
are listed, then the user may be prompted for multiple passwords.
Removing the pam_rhosts_auth.so.1 entry will disable the
/etc/hosts.equiv and ~/.rhosts authentication protocol and the user
would always be forced to type the password. The sufficient flag indi‐
cates that authentication through the pam_rhosts_auth.so.1 module is
sufficient to authenticate the user. Only if this authentication fails
is the next authentication module used.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWrcmds │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOlogin(1), svcs(1), rlogin(1), gkadmin(1M), in.rshd(1M), inetadm(1M),
inetd(1M), kadmin(1M), svcadm(1M), pam(3PAM), hosts(4), hosts.equiv(4),
krb5.conf(4), pam.conf(4), attributes(5), environ(5),
krb5_auth_rules(5), pam_authtok_check(5), pam_authtok_get(5), pam_auth‐
tok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5),
pam_unix_auth(5), pam_unix_session(5), smf(5)
System Administration Guide: Security Services
DIAGNOSTICS
All diagnostic messages are returned on the connection associated with
the stderr, after which any network connections are closed. An error is
indicated by a leading byte with a value of 1.
Hostname for your address unknown. No entry in the host name data‐
base existed for the client's
machine.
Try again. A fork by the server failed.
/usr/bin/sh: ... The user's login shell could
not be started.
NOTES
The authentication procedure used here assumes the integrity of each
client machine and the connecting medium. This is insecure, but it is
useful in an ``open'' environment.
A facility to allow all data exchanges to be encrypted should be
present.
The pam_unix(5) module is no longer supported. Similar functionality is
provided by pam_authtok_check(5), pam_authtok_get(5), pam_auth‐
tok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5),
pam_unix_auth(5), and pam_unix_session(5).
The in.rlogind service is managed by the service management facility,
smf(5), under the service identifier:
svc:/network/login:rlogin (rlogin)
svc:/network/login:klogin (rlogin with kerberos)
svc:/network/login:eklogin (rlogin with kerberos and encryption)
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(1M). Responsibility
for initiating and restarting this service is delegated to inetd(1M).
Use inetadm(1M) to make configuration changes and to view configuration
information for this service. The service's status can be queried using
the svcs(1) command.
SunOS 5.10 10 Nov 2005 in.rlogind(1M)
