mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-13 10:02:38 +00:00
cda3118c2e
Rexecd is a crock, it never should have been written, however make it so that people who have a need to run it don't hurt themselves so badly. Obtained from: Ideas obtained from logdaemon 4.3 from Wietse Venema
153 lines
5.1 KiB
Groff
153 lines
5.1 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)rexecd.8 8.2 (Berkeley) 12/11/93
|
|
.\"
|
|
.Dd September 23, 1994
|
|
.Dt REXECD 8
|
|
.Os BSD 4.2
|
|
.Sh NAME
|
|
.Nm rexecd
|
|
.Nd remote execution server
|
|
.Sh SYNOPSIS
|
|
.Nm rexecd
|
|
.Sh DESCRIPTION
|
|
.Nm Rexecd
|
|
is the server for the
|
|
.Xr rexec 3
|
|
routine. The server provides remote execution facilities
|
|
with authentication based on user names and
|
|
passwords.
|
|
.Pp
|
|
.Nm Rexecd
|
|
listens for service requests at the port indicated in
|
|
the ``exec'' service specification; see
|
|
.Xr services 5 .
|
|
When a service request is received the following protocol
|
|
is initiated:
|
|
.Bl -enum
|
|
.It
|
|
The server reads characters from the socket up
|
|
to a NUL
|
|
.Pq Ql \e0
|
|
byte. The resultant string is
|
|
interpreted as an
|
|
.Tn ASCII
|
|
number, base 10.
|
|
.It
|
|
If the number received in step 1 is non-zero,
|
|
it is interpreted as the port number of a secondary
|
|
stream to be used for the
|
|
.Em stderr .
|
|
A second connection is then created to the specified
|
|
port on the client's machine.
|
|
.It
|
|
A NUL terminated user name of at most 16 characters
|
|
is retrieved on the initial socket.
|
|
.It
|
|
A NUL terminated, unencrypted password of at most
|
|
16 characters is retrieved on the initial socket.
|
|
.It
|
|
A NUL terminated command to be passed to a
|
|
shell is retrieved on the initial socket. The length of
|
|
the command is limited by the upper bound on the size of
|
|
the system's argument list.
|
|
.It
|
|
.Nm Rexecd
|
|
then validates the user as is done at login time
|
|
and, if the authentication was successful, changes
|
|
to the user's home directory, and establishes the user
|
|
and group protections of the user.
|
|
If any of these steps fail the connection is
|
|
aborted with a diagnostic message returned.
|
|
.It
|
|
A NUL byte is returned on the initial socket
|
|
and the command line is passed to the normal login
|
|
shell of the user. The
|
|
shell inherits the network connections established
|
|
by
|
|
.Nm rexecd .
|
|
.El
|
|
.Sh CAVEATS
|
|
.Nm Rexecd
|
|
will no longer allow root logins, access for users listed in /etc/ftpusers,
|
|
or access for users with no passwords, which were all serious security holes.
|
|
The entire concept of rexec/rexecd is a major security hole and an example
|
|
of how not to do things.
|
|
.Nm Rexecd
|
|
is disabled by default in /etc/inetd.conf.
|
|
.Sh DIAGNOSTICS
|
|
Except for the last one listed below,
|
|
all diagnostic messages are returned on the initial socket,
|
|
after which any network connections are closed.
|
|
An error is indicated by a leading byte with a value of
|
|
1 (0 is returned in step 7 above upon successful completion
|
|
of all the steps prior to the command execution).
|
|
.Pp
|
|
.Bl -tag -width Ds
|
|
.It Sy username too long
|
|
The name is
|
|
longer than 16 characters.
|
|
.It Sy password too long
|
|
The password is longer than 16 characters.
|
|
.It Sy command too long
|
|
The command line passed exceeds the size of the argument
|
|
list (as configured into the system).
|
|
.It Sy Login incorrect.
|
|
No password file entry for the user name existed.
|
|
.It Sy Password incorrect.
|
|
The wrong password was supplied.
|
|
.It Sy \&No remote directory.
|
|
The
|
|
.Xr chdir
|
|
command to the home directory failed.
|
|
.It Sy Try again.
|
|
A
|
|
.Xr fork
|
|
by the server failed.
|
|
.It Sy <shellname>: ...
|
|
The user's login shell could not be started.
|
|
This message is returned
|
|
on the connection associated with the
|
|
.Em stderr ,
|
|
and is not preceded by a flag byte.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr rexec 3
|
|
.Sh BUGS
|
|
A facility to allow all data and password exchanges to be encrypted should be
|
|
present.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
command appeared in
|
|
.Bx 4.2 .
|