5efaea4cc6
permitted by the University of Berkeley on July 22, 1999. Reviewed by: imp MFC after: 1 week
307 lines
7.5 KiB
Groff
307 lines
7.5 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. 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
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 22, 2011
|
|
.Dt TFTPD 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm tftpd
|
|
.Nd Internet Trivial File Transfer Protocol server
|
|
.Sh SYNOPSIS
|
|
.Nm tftpd
|
|
.Op Fl cdClnow
|
|
.Op Fl F Ar strftime-format
|
|
.Op Fl s Ar directory
|
|
.Op Fl u Ar user
|
|
.Op Fl U Ar umask
|
|
.Op Ar directory ...
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility is a server which supports the
|
|
Internet Trivial File Transfer
|
|
Protocol
|
|
.Pq Tn RFC 1350 .
|
|
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
|
|
will allow only publicly readable files to be
|
|
accessed.
|
|
Files containing the string
|
|
.Dq Li "/../"
|
|
or starting with
|
|
.Dq Li "../"
|
|
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
|
|
with a list of directories by including up to 20 pathnames
|
|
as server program arguments in
|
|
.Xr inetd.conf 5 .
|
|
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
|
|
.Fl s
|
|
option provides additional security by changing
|
|
the root directory of
|
|
.Nm ,
|
|
thereby prohibiting accesses to outside of the specified
|
|
.Ar directory .
|
|
Because
|
|
.Xr chroot 2
|
|
requires super-user privileges,
|
|
.Nm
|
|
must be run as
|
|
.Li root .
|
|
However, after performing the
|
|
.Xr chroot 2
|
|
call,
|
|
.Nm
|
|
will set its user ID to that of the specified
|
|
.Ar user ,
|
|
or
|
|
.Dq Li nobody
|
|
if no
|
|
.Fl u
|
|
option is specified.
|
|
.Pp
|
|
The options are:
|
|
.Bl -tag -width Ds
|
|
.It Fl c
|
|
Changes the default root directory of a connecting host via
|
|
.Xr chroot 2
|
|
based on the connecting IP address.
|
|
This prevents multiple clients from writing to the same file at the same time.
|
|
If the directory does not exist, the client connection is refused.
|
|
The
|
|
.Fl s
|
|
option is required for
|
|
.Fl c
|
|
and the specified
|
|
.Ar directory
|
|
is used as a base.
|
|
.It Fl C
|
|
Operates the same as
|
|
.Fl c
|
|
except it falls back to
|
|
.Ar directory
|
|
specified via
|
|
.Fl s
|
|
if a directory does not exist for the client's IP.
|
|
.It Fl F
|
|
Use this
|
|
.Xr strftime 3
|
|
compatible format string for the creation of the suffix if
|
|
.Fl W
|
|
is specified.
|
|
By default the string "%Y%m%d" is used.
|
|
.It Fl d, d Ar [value]
|
|
Enables debug output.
|
|
If
|
|
.Ar value
|
|
is not specified, then the debug level is increased by one
|
|
for each instance of
|
|
.Fl d
|
|
which is specified.
|
|
.Pp
|
|
If
|
|
.Ar value
|
|
is specified, then the debug level is set to
|
|
.Ar value .
|
|
The debug level is a bitmask implemented in
|
|
.Pa src/libexec/tftpd/tftp-utils.h .
|
|
Valid values are 0 (DEBUG_NONE), 1 (DEBUG_PACKETS), 2, (DEBUG_SIMPLE),
|
|
4 (DEBUG_OPTIONS), and 8 (DEBUG_ACCESS). Multiple debug values can be combined
|
|
in the bitmask by logically OR'ing the values. For example, specifying
|
|
.Fl d
|
|
.Ar 15
|
|
will enable all the debug values.
|
|
.It Fl l
|
|
Log all requests using
|
|
.Xr syslog 3
|
|
with the facility of
|
|
.Dv LOG_FTP .
|
|
.Sy Note :
|
|
Logging of
|
|
.Dv LOG_FTP
|
|
messages
|
|
must also be enabled in the syslog configuration file,
|
|
.Xr syslog.conf 5 .
|
|
.It Fl n
|
|
Suppress negative acknowledgement of requests for nonexistent
|
|
relative filenames.
|
|
.It Fl o
|
|
Disable support for RFC2347 style TFTP Options.
|
|
.It Fl s Ar directory
|
|
Cause
|
|
.Nm
|
|
to change its root directory to
|
|
.Ar directory .
|
|
After doing that but before accepting commands,
|
|
.Nm
|
|
will switch credentials to an unprivileged user.
|
|
.It Fl u Ar user
|
|
Switch credentials to
|
|
.Ar user
|
|
(default
|
|
.Dq Li nobody )
|
|
when the
|
|
.Fl s
|
|
option is used.
|
|
The user must be specified by name, not a numeric UID.
|
|
.It Fl U Ar umask
|
|
Set the
|
|
.Ar umask
|
|
for newly created files.
|
|
The default is 022
|
|
.Pq Dv S_IWGRP | S_IWOTH .
|
|
.It Fl w
|
|
Allow write requests to create new files.
|
|
By default
|
|
.Nm
|
|
requires that the file specified in a write request exist.
|
|
Note that this only works in directories writable by the user
|
|
specified with
|
|
.Fl u
|
|
option
|
|
.It Fl W
|
|
As
|
|
.Fl w
|
|
but append a YYYYMMDD.nn sequence number to the end of the filename.
|
|
Note that the string YYYYMMDD can be changed with the
|
|
.Fl F
|
|
option.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr tftp 1 ,
|
|
.Xr chroot 2 ,
|
|
.Xr syslog 3 ,
|
|
.Xr inetd.conf 5 ,
|
|
.Xr services 5 ,
|
|
.Xr syslog.conf 5 ,
|
|
.Xr inetd 8
|
|
.Pp
|
|
The following RFC's are supported:
|
|
.Rs
|
|
.%T RFC 1350: The TFTP Protocol (Revision 2)
|
|
.Re
|
|
.Rs
|
|
.%T RFC 2347: TFTP Option Extension
|
|
.Re
|
|
.Rs
|
|
.%T RFC 2348: TFTP Blocksize Option
|
|
.Re
|
|
.Rs
|
|
.%T RFC 2349: TFTP Timeout Interval and Transfer Size Options
|
|
.Re
|
|
.Pp
|
|
The non-standard
|
|
.Cm rollover
|
|
and
|
|
.Cm blksize2
|
|
TFTP options are mentioned here:
|
|
.Rs
|
|
.%T Extending TFTP
|
|
.%U http://www.compuphase.com/tftp.htm
|
|
.Re
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
utility appeared in
|
|
.Bx 4.2 ;
|
|
the
|
|
.Fl s
|
|
option was introduced in
|
|
.Fx 2.2 ,
|
|
the
|
|
.Fl u
|
|
option was introduced in
|
|
.Fx 4.2 ,
|
|
the
|
|
.Fl c
|
|
option was introduced in
|
|
.Fx 4.3 ,
|
|
and the
|
|
.Fl F
|
|
and
|
|
.Fl W
|
|
options were introduced in
|
|
.Fx 7.4 .
|
|
.Pp
|
|
Support for Timeout Interval and Transfer Size Options (RFC2349)
|
|
was introduced in
|
|
.Fx 5.0 ,
|
|
support for the TFTP Blocksize Option (RFC2348) and the blksize2 option
|
|
was introduced in
|
|
.Fx 7.4 .
|
|
.Pp
|
|
Edwin Groothuis <edwin@FreeBSD.org> performed a major rewrite of the
|
|
.Nm
|
|
and
|
|
.Xr tftp 1
|
|
code to support RFC2348.
|
|
.Sh NOTES
|
|
Files larger than 33,553,919 octets (65535 blocks, last one <512
|
|
octets) cannot be correctly transferred without client and server
|
|
supporting blocksize negotiation (RFCs 2347 and 2348),
|
|
or the non-standard TFTP rollover option.
|
|
As a kludge,
|
|
.Nm
|
|
accepts a sequence of block number which wrap to zero after 65535,
|
|
even if the rollover option is not specified.
|
|
.Pp
|
|
Many tftp clients will not transfer files over 16,776,703 octets
|
|
(32767 blocks), as they incorrectly count the block number using
|
|
a signed rather than unsigned 16-bit integer.
|