105186eeee
(Including all changes for FreeBSD - importing the original eBones distribution would be too complex at this stage, since I don't have access to Piero's CVS.) (If you want to include eBones in your system, don't forget to include MAKE_EBONES in /etc/make.conf.) (This stuff is now also suppable from braae.ru.ac.za.) Bones originally from MIT SIPB. Original port to FreeBSD 1.x by Piero Serini. Moved to FreeBSD 2.0 by Doug Rabson and Geoff Rehmet. Nice bug fixes from Doug Rabson.
153 lines
4.5 KiB
Groff
153 lines
4.5 KiB
Groff
.\" from: kshd.8,v 4.1 89/01/23 11:39:41 jtkohl Exp $
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.\" $Id: kshd.8,v 1.2 1994/07/19 19:27:50 g89r4222 Exp $
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.\"
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.\" Copyright (c) 1983 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms are permitted
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.\" provided that the above copyright notice and this paragraph are
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.\" duplicated in all such forms and that any documentation,
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.\" advertising materials, and other materials related to such
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.\" distribution and use acknowledge that the software was developed
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.\" by the University of California, Berkeley. The name of the
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.\" University may not be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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.\" WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" @(#)rshd.8 6.5 (Berkeley) 9/19/88
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.\"
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.TH KSHD 8 "Kerberos Version 4.0" "MIT Project Athena"
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.UC 5
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.SH NAME
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kshd \- remote shell server
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.SH SYNOPSIS
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.B /usr/etc/kshd
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.SH DESCRIPTION
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.I Kshd
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is the server for the
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.IR kcmd (3)
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routine and, consequently, for the
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.IR rsh (1)
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program. The server provides remote execution facilities
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with authentication based on Kerberos.
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.PP
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.I Kshd
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listens for service requests at the port indicated in
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the ``kshell'' service specification; see
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.IR services (5).
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When a service request is received the following protocol
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is initiated:
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.IP 1)
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The server reads characters from the socket up
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to a null (`\e0') byte. The resultant string is
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interpreted as an ASCII number, base 10.
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.IP 2)
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If the number received in step 1 is non-zero,
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it is interpreted as the port number of a secondary
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stream to be used for the
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.BR stderr .
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A second connection is then created to the specified
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port on the client's machine.
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.IP 3)
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The server checks the client's source address
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and requests the corresponding host name (see
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.IR gethostbyaddr (3N),
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.IR hosts (5)
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and
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.IR named (8)).
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If the hostname cannot be determined,
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the dot-notation representation of the host address is used.
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.IP 4)
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A Kerberos ticket/authenticator pair are retrieved on the initial socket.
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.IP 5)
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A null terminated user name of at most 16 characters
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is retrieved on the initial socket. This user name
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is interpreted as a user identity to use on the
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.BR server 's
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machine.
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.IP 6)
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A null terminated command to be passed to a
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shell is retrieved on the initial socket. The length of
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the command is limited by the upper bound on the size of
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the system's argument list.
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.IP 7)
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.I Kshd
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then validates the user according to the following steps.
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The local (server-end) user name is looked up in the password file
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and a
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.I chdir
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is performed to the user's home directory. If either
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the lookup or
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.I chdir
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fail, the connection is terminated. The \&.klogin file in the home
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directory is used to mediate access to the account (via \fIkuserok\fP(3))
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by the Kerberos principal named in the ticket/authenticator. If this
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authorization check fails, the connection is terminated.
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.IP 8)
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A null byte is returned on the initial socket
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and the command line is passed to the normal login
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shell of the user. The
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shell inherits the network connections established
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by
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.IR kshd .
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.SH DIAGNOSTICS
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Except for the last one listed below,
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all diagnostic messages
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are returned on the initial socket,
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after which any network connections are closed.
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An error is indicated by a leading byte with a value of
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1 (0 is returned in step 8 above upon successful completion
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of all the steps prior to the execution of the login shell).
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.PP
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.B ``remuser too long''
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.br
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The name of the user on the remote machine is
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longer than 16 characters.
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.PP
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.B ``command too long ''
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.br
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The command line passed exceeds the size of the argument
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list (as configured into the system).
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.PP
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.B ``Login incorrect.''
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.br
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No password file entry for the user name existed.
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.PP
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.B ``No remote directory.''
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.br
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The
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.I chdir
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command to the home directory failed.
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.PP
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.B ``Permission denied.''
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.br
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The authorization procedure described above failed.
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.PP
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.B ``Can't make pipe.''
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.br
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The pipe needed for the
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.BR stderr ,
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wasn't created.
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.PP
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.B ``Try again.''
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.br
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A
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.I fork
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by the server failed.
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.PP
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.B ``<shellname>: ...''
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.br
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The user's login shell could not be started. This message is returned
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on the connection associated with the
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.BR stderr ,
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and is not preceded by a flag byte.
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.SH SEE ALSO
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rsh(1), kerberos(3), kuserok(3)
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.SH BUGS
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A facility to allow all data exchanges to be encrypted should be
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present.
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.PP
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A more extensible protocol should be used.
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