freebsd-dev/libexec/tftpd/tftpd.8
Warner Losh 8ea3178507 Reviewed by: Bill Fenner <fennder@parc.xerox.com>
Reviewed by:	Garrett Wollman <wollman@freebsd.org>
Submitted by:	Warner Losh <imp@village.org>
Close PR bin/1145:
	Add -s flag to tftpd.  This enables the so-called secure mode
of tftpd where it chroots to a given directory before allowing access
to the files.  In addition, it runs as nobody when in this mode.
Reviewed a long time ago by Bill and Garrett.  Apply my patch from the
pr, and close the PR.
1996-09-22 04:19:27 +00:00

122 lines
4.0 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.
.\"
.\" @(#)tftpd.8 8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt TFTPD 8
.Os BSD 4.2
.Sh NAME
.Nm tftpd
.Nd
Internet Trivial File Transfer Protocol server
.Sh SYNOPSIS
.Nm tftpd
.Op Fl l
.Op Fl n
.Op Fl s Ar directory
.Op Ar directory ...
.Sh DESCRIPTION
.Nm Tftpd
is a server which supports the
Internet Trivial File Transfer
Protocol (\c
.Tn RFC 783).
The
.Tn TFTP
server operates
at the port indicated in the
.Ql tftp
service description;
see
.Xr services 5 .
The server is normally started by
.Xr inetd 8 .
.Pp
The use of
.Xr tftp 1
does not require an account or password on the remote system.
Due to the lack of authentication information,
.Nm tftpd
will allow only publicly readable files to be
accessed.
Files containing the string ``/\|\fB.\|.\fP\|/'' are not allowed.
Files may be written only if they already exist and are publicly writable.
Note that this extends the concept of
.Dq public
to include
all users on all hosts that can be reached through the network;
this may not be appropriate on all systems, and its implications
should be considered before enabling tftp service.
The server should have the user ID with the lowest possible privilege.
.Pp
Access to files may be restricted by invoking
.Nm tftpd
with a list of directories by including up to 20 pathnames
as server program arguments in
.Pa /etc/inetd.conf .
In this case access is restricted to files whose
names are prefixed by the one of the given directories.
The given directories are also treated as a search path for
relative filename requests.
.Pp
The chroot option provides additional security by restricting access
of tftpd to only a chroot'd file system. This is useful when moving
from an OS that supported
.Nm -s
as a boot server. Because chroot is restricted to root, you must run
tftpd as root. However, if you chroot, then
.Nm tftpd
will set its user id to nobody.
.Pp
The options are:
.Bl -tag -width Ds
.It Fl l
Logs all requests using
.Xr syslog 3 .
.It Fl n
Suppresses negative acknowledgement of requests for nonexistent
relative filenames.
.It Fl s Ar directory
Causes tftpd to chroot to
.Pa directory
before accepting commands. In addition, the user id is set to
nobody.
.El
.Sh SEE ALSO
.Xr tftp 1 ,
.Xr inetd 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .