K5LOGIN(5) MIT Kerberos K5LOGIN(5)
NAME
k5login - Kerberos V5 acl file for host access
DESCRIPTION
The .k5login file, which resides in a user's home directory, contains a
list of the Kerberos principals. Anyone with valid tickets for a prin-
cipal in the file is allowed host access with the UID of the user in
whose home directory the file resides. One common use is to place a
.k5login file in root's home directory, thereby granting system adminis-
trators remote root access to the host via Kerberos.
EXAMPLES
Suppose the user alice had a .k5login file in her home directory con-
taining just the following line:
bob@FOOBAR.ORG
This would allow bob to use Kerberos network applications, such as
ssh(1), to access alice's account, using bob's Kerberos tickets. In a
default configuration (with k5login_authoritative set to true in
krb5.conf(5)), this .k5login file would not let alice use those network
applications to access her account, since she is not listed! With no
.k5login file, or with k5login_authoritative set to false, a default
rule would permit the principal alice in the machine's default realm to
access the alice account.
Let us further suppose that alice is a system administrator. Alice and
the other system administrators would have their principals in root's
.k5login file on each host:
alice@BLEEP.COM
joeadmin/root@BLEEP.COM
This would allow either system administrator to log in to these hosts
using their Kerberos tickets instead of having to type the root pass-
word. Note that because bob retains the Kerberos tickets for his own
principal, bob@FOOBAR.ORG, he would not have any of the privileges that
require alice's tickets, such as root access to any of the site's hosts,
or the ability to change alice's password.
SEE ALSO
kerberos(1)
AUTHOR
MIT
COPYRIGHT
1985-2024, MIT
1.21.3 K5LOGIN(5)
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