5015048190
* Add ftpd.conf(5) directive `advertise'; change the address that is advertised to the client for PASV transfers. this may be useful in certain firewall/NAT environments. Feature requested in [bin/9606] by Scott Presnell. * Add -X option; syslog wu-ftpd style xferlog messages, prefixed with `xferlog: '. An example line from syslog (wrapped): Dec 16 18:50:24 odysseus ftpd[571]: xferlog: Sat Dec 16 18:50:24 2000 2 localhost 3747328 /pub/WLW2K601.EXE b _ o a lukem@ FTP 0 * c These messages can be converted to a wu-ftpd style xferlog file suitable for parsing with third-party tools with something like: grep 'xferlog: ' /var/log/xferlog | \ sed -e 's/^.*xferlog: //' >wuxferlog The format is the same as the wu-ftpd xferlog entries (with the leading syslog stuff), but different from the wu-ftpd syslogged xferlog entries because the latter is not as easy to convert into the standard xferlog file format. The choice to only syslog the xferlog messages rather than append to a /var/log/xferlog file was made because the latter doesn't work to well in the situation where the logfile is rotated and compressed and a long-running ftpd still has a file-descriptor to the now nonexistant xferlog file, and the log message will then get lost. Feature requested in [bin/11651] by Hubert Feyrer. Fixes: * In ftpd(8), clarify the -a and -c options. * More clarifications in ftpd.conf(5). * Ensure that all ftpd.conf commands set a parameter back to sane defaults if an argument of `none' or bad settings are given. * Support the `chroot' directive for `REAL' users too (for consistency). * For `GUEST' users, store the supplied password in pw->pw_passwd for use later in the xferlog. * If show_chdir_messages() is given a code of -1, flush the cache of visited directories. Invoke show_chdir_messages(-1) in end_login(). * Only syslog session stats if logging is requested. * Rename logcmd() -> logxfer(), and dolog() -> logremotehost(). * Use cprintf() instead of fprintf() where appropriate. * Minor KNF, and make a couple of functions static that were declared static.
834 lines
22 KiB
Groff
834 lines
22 KiB
Groff
.\" $NetBSD: ftpd.8,v 1.63 2000/12/18 02:32:51 lukem Exp $
|
|
.\"
|
|
.\" Copyright (c) 1997-2000 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Luke Mewburn.
|
|
.\"
|
|
.\" 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 NetBSD
|
|
.\" Foundation, Inc. and its contributors.
|
|
.\" 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
|
|
.\"
|
|
.\" Copyright (c) 1985, 1988, 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
|
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.\" SUCH DAMAGE.
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.\"
|
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.\" @(#)ftpd.8 8.2 (Berkeley) 4/19/94
|
|
.\"
|
|
.Dd December 18, 2000
|
|
.Dt FTPD 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ftpd
|
|
.Nd
|
|
Internet File Transfer Protocol server
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl dHlqQrsuUwWX
|
|
.Op Fl a Ar anondir
|
|
.Op Fl c Ar confdir
|
|
.Op Fl C Ar user
|
|
.Op Fl e Ar emailaddr
|
|
.Op Fl h Ar hostname
|
|
.Op Fl P Ar dataport
|
|
.Op Fl V Ar version
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
is the Internet File Transfer Protocol server process.
|
|
The server uses the
|
|
.Tn TCP
|
|
protocol and listens at the port specified in the
|
|
.Dq ftp
|
|
service specification; see
|
|
.Xr services 5 .
|
|
.Pp
|
|
Available options:
|
|
.Bl -tag -width Ds
|
|
.It Fl a Ar anondir
|
|
Define
|
|
.Ar anondir
|
|
as the directory to
|
|
.Xr chroot 2
|
|
into for anonymous logins.
|
|
Default is the home directory for the ftp user.
|
|
This can also be specified with the
|
|
.Xr ftpd.conf 5
|
|
.Sy chroot
|
|
directive.
|
|
.It Fl c Ar confdir
|
|
Change the root directory of the configuration files from
|
|
.Dq Pa /etc
|
|
to
|
|
.Ar confdir .
|
|
This changes the directory for the following files:
|
|
.Pa /etc/ftpchroot ,
|
|
.Pa /etc/ftpusers ,
|
|
.Pa /etc/ftpwelcome ,
|
|
.Pa /etc/motd ,
|
|
and the file specified by the
|
|
.Xr ftpd.conf 5
|
|
.Sy limit
|
|
directive.
|
|
.It Fl C Ar user
|
|
Check whether
|
|
.Ar user
|
|
would be granted access under
|
|
the restrictions given in
|
|
.Xr ftpusers 5
|
|
and exit without attempting a connection.
|
|
.Nm
|
|
exits with an exit code of 0 if access would be granted, or 1 otherwise.
|
|
This can be useful for testing configurations.
|
|
.It Fl d
|
|
Debugging information is written to the syslog using a facility of
|
|
.Dv LOG_FTP .
|
|
.It Fl e Ar emailaddr
|
|
Use
|
|
.Ar emailaddr
|
|
for the
|
|
.Dq "\&%E"
|
|
escape sequence (see
|
|
.Sx Display file escape sequences )
|
|
.It Fl h Ar hostname
|
|
Explicitly set the hostname to advertise as to
|
|
.Ar hostname .
|
|
The default is the hostname associated with the IP address that
|
|
.Nm
|
|
is listening on.
|
|
This ability (with or without
|
|
.Fl h ) ,
|
|
in conjunction with
|
|
.Fl c Ar confdir ,
|
|
is useful when configuring
|
|
.Sq virtual
|
|
.Tn FTP
|
|
servers, each listening on separate addresses as separate names.
|
|
Refer to
|
|
.Xr inetd.conf 5
|
|
for more information on starting services to listen on specific IP addresses.
|
|
.It Fl H
|
|
Equivalent to
|
|
.Do
|
|
-h
|
|
`hostname`
|
|
.Dc .
|
|
.It Fl l
|
|
Each successful and failed
|
|
.Tn FTP
|
|
session is logged using syslog with a facility of
|
|
.Dv LOG_FTP .
|
|
If this option is specified more than once, the retrieve (get), store (put),
|
|
append, delete, make directory, remove directory and rename operations and
|
|
their file name arguments are also logged.
|
|
.It Fl P Ar dataport
|
|
Use
|
|
.Ar dataport
|
|
as the data port, overriding the default of using the port one less
|
|
that the port
|
|
.Nm
|
|
is listening on.
|
|
.It Fl q
|
|
Enable the use of pid files for keeping track of the number of logged-in
|
|
users per class.
|
|
This is the default.
|
|
.It Fl Q
|
|
Disable the use of pid files for keeping track of the number of logged-in
|
|
users per class.
|
|
This may reduce the load on heavily loaded
|
|
.Tn FTP
|
|
servers.
|
|
.It Fl r
|
|
Permanently drop root privileges once the user is logged in.
|
|
The use of this option may result in the server using a port other
|
|
than the (listening-port - 1) for
|
|
.Sy PORT
|
|
style commands, which is contrary to the
|
|
.Cm RFC 959
|
|
specification, but in practice very few clients rely upon this behaviour.
|
|
See
|
|
.Sx SECURITY CONSIDERATIONS
|
|
below for more details.
|
|
.It Fl s
|
|
Require a secure authentication mechanism like Kerberos or S/Key to be used.
|
|
.It Fl u
|
|
Log each concurrent
|
|
.Tn FTP
|
|
session to
|
|
.Pa /var/run/utmp ,
|
|
making them visible to commands such as
|
|
.Xr who 1 .
|
|
.It Fl U
|
|
Don't log each concurrent
|
|
.Tn FTP
|
|
session to
|
|
.Pa /var/run/utmp .
|
|
This is the default.
|
|
.It Fl V Ar version
|
|
Use
|
|
.Ar version
|
|
as the version to advertise in the login banner and in the output of
|
|
.Sy STAT
|
|
and
|
|
.Sy SYST
|
|
instead of the default version information.
|
|
If
|
|
.Ar version
|
|
is empty or
|
|
.Sq -
|
|
then don't display any version information.
|
|
.It Fl w
|
|
Log each
|
|
.Tn FTP
|
|
session to
|
|
.Pa /var/log/wtmp ,
|
|
making them visible to commands such as
|
|
.Xr last 1 .
|
|
This is the default.
|
|
.It Fl W
|
|
Don't log each
|
|
.Tn FTP
|
|
session to
|
|
.Pa /var/log/wtmp .
|
|
.It Fl X
|
|
Log
|
|
.Tn wu-ftpd
|
|
style
|
|
.Sq xferlog
|
|
entries to the syslog, prefixed with
|
|
.Dq "xferlog:\ " ,
|
|
using a facility of
|
|
.Dv LOG_FTP .
|
|
These syslog entries can be converted to a
|
|
.Tn wu-ftpd
|
|
style
|
|
.Pa xferlog
|
|
file suitable for input into a third-party log analysis tool with a command
|
|
similar to:
|
|
.Dl "grep 'xferlog: ' /var/log/xferlog | \e"
|
|
.Dl "\ \ \ sed -e 's/^.*xferlog: //' > wuxferlog"
|
|
.El
|
|
.Pp
|
|
The file
|
|
.Pa /etc/nologin
|
|
can be used to disable
|
|
.Tn FTP
|
|
access.
|
|
If the file exists,
|
|
.Nm
|
|
displays it and exits.
|
|
If the file
|
|
.Pa /etc/ftpwelcome
|
|
exists,
|
|
.Nm
|
|
prints it before issuing the
|
|
.Dq ready
|
|
message.
|
|
If the file
|
|
.Pa /etc/motd
|
|
exists (under the chroot directory if applicable),
|
|
.Nm
|
|
prints it after a successful login.
|
|
This may be changed with the
|
|
.Xr ftpd.conf 5
|
|
directive
|
|
.Sy motd .
|
|
.Pp
|
|
The
|
|
.Nm
|
|
server currently supports the following
|
|
.Tn FTP
|
|
requests.
|
|
The case of the requests is ignored.
|
|
.Bl -column "Request" -offset indent
|
|
.It Sy Request Ta Sy Description
|
|
.It ABOR Ta "abort previous command"
|
|
.It ACCT Ta "specify account (ignored)"
|
|
.It ALLO Ta "allocate storage (vacuously)"
|
|
.It APPE Ta "append to a file"
|
|
.It CDUP Ta "change to parent of current working directory"
|
|
.It CWD Ta "change working directory"
|
|
.It DELE Ta "delete a file"
|
|
.It EPSV Ta "prepare for server-to-server transfer"
|
|
.It EPRT Ta "specify data connection port"
|
|
.It FEAT Ta "list extra features that are not defined in" Cm "RFC 959"
|
|
.It HELP Ta "give help information"
|
|
.It LIST Ta "give list files in a directory" Pq Dq Li "ls -lA"
|
|
.It LPSV Ta "prepare for server-to-server transfer"
|
|
.It LPRT Ta "specify data connection port"
|
|
.It MLSD Ta "list contents of directory in a machine-processable form"
|
|
.It MLST Ta "show a pathname in a machine-processable form"
|
|
.It MKD Ta "make a directory"
|
|
.It MDTM Ta "show last modification time of file"
|
|
.It MODE Ta "specify data transfer" Em mode
|
|
.It NLST Ta "give name list of files in directory"
|
|
.It NOOP Ta "do nothing"
|
|
.It OPTS Ta "define persistent options for a given command"
|
|
.It PASS Ta "specify password"
|
|
.It PASV Ta "prepare for server-to-server transfer"
|
|
.It PORT Ta "specify data connection port"
|
|
.It PWD Ta "print the current working directory"
|
|
.It QUIT Ta "terminate session"
|
|
.It REST Ta "restart incomplete transfer"
|
|
.It RETR Ta "retrieve a file"
|
|
.It RMD Ta "remove a directory"
|
|
.It RNFR Ta "specify rename-from file name"
|
|
.It RNTO Ta "specify rename-to file name"
|
|
.It SITE Ta "non-standard commands (see next section)"
|
|
.It SIZE Ta "return size of file"
|
|
.It STAT Ta "return status of server"
|
|
.It STOR Ta "store a file"
|
|
.It STOU Ta "store a file with a unique name"
|
|
.It STRU Ta "specify data transfer" Em structure
|
|
.It SYST Ta "show operating system type of server system"
|
|
.It TYPE Ta "specify data transfer" Em type
|
|
.It USER Ta "specify user name"
|
|
.It XCUP Ta "change to parent of current working directory (deprecated)"
|
|
.It XCWD Ta "change working directory (deprecated)"
|
|
.It XMKD Ta "make a directory (deprecated)"
|
|
.It XPWD Ta "print the current working directory (deprecated)"
|
|
.It XRMD Ta "remove a directory (deprecated)"
|
|
.El
|
|
.Pp
|
|
The following non-standard or
|
|
.Ux
|
|
specific commands are supported by the SITE request.
|
|
.Pp
|
|
.Bl -column Request -offset indent
|
|
.It Sy Request Ta Sy Description
|
|
.It CHMOD Ta "change mode of a file, e.g. ``SITE CHMOD 755 filename''"
|
|
.It HELP Ta "give help information."
|
|
.It IDLE Ta "set idle-timer, e.g. ``SITE IDLE 60''"
|
|
.It RATEGET Ta "set maximum get rate throttle in bytes/second, e.g. ``SITE RATEGET 5k''"
|
|
.It RATEPUT Ta "set maximum put rate throttle in bytes/second, e.g. ``SITE RATEPUT 5k''"
|
|
.It UMASK Ta "change umask, e.g. ``SITE UMASK 002''"
|
|
.El
|
|
.Pp
|
|
The following
|
|
.Tn FTP
|
|
requests (as specified in
|
|
.Cm RFC 959 )
|
|
are recognized, but are not implemented:
|
|
.Sy ACCT ,
|
|
.Sy SMNT ,
|
|
and
|
|
.Sy REIN .
|
|
.Sy MDTM
|
|
and
|
|
.Sy SIZE
|
|
are not specified in
|
|
.Cm RFC 959 ,
|
|
but will appear in the
|
|
next updated
|
|
.Tn FTP
|
|
RFC.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
server will abort an active file transfer only when the
|
|
.Sy ABOR
|
|
command is preceded by a Telnet "Interrupt Process" (IP)
|
|
signal and a Telnet "Synch" signal in the command Telnet stream,
|
|
as described in Internet
|
|
.Cm RFC 959 .
|
|
If a
|
|
.Sy STAT
|
|
command is received during a data transfer, preceded by a Telnet IP
|
|
and Synch, transfer status will be returned.
|
|
.Pp
|
|
.Nm
|
|
interprets file names according to the
|
|
.Dq globbing
|
|
conventions used by
|
|
.Xr csh 1 .
|
|
This allows users to utilize the metacharacters
|
|
.Dq Li \&*?[]{}~ .
|
|
.Sh User authentication
|
|
.Pp
|
|
.Nm
|
|
authenticates users according to five rules.
|
|
.Pp
|
|
.Bl -enum -offset indent
|
|
.It
|
|
The login name must be in the password data base,
|
|
.Pa /etc/pwd.db ,
|
|
and not have a null password.
|
|
In this case a password must be provided by the client before any
|
|
file operations may be performed.
|
|
If the user has an S/Key key, the response from a successful
|
|
.Sy USER
|
|
command will include an S/Key challenge.
|
|
The client may choose to respond with a
|
|
.Sy PASS
|
|
command giving either
|
|
a standard password or an S/Key one-time password.
|
|
The server will automatically determine which type of password it
|
|
has been given and attempt to authenticate accordingly.
|
|
See
|
|
.Xr skey 1
|
|
for more information on S/Key authentication.
|
|
S/Key is a Trademark of Bellcore.
|
|
.It
|
|
The login name must be allowed based on the information in
|
|
.Xr ftpusers 5 .
|
|
.It
|
|
The user must have a standard shell returned by
|
|
.Xr getusershell 3 .
|
|
If the user's shell field in the password database is empty, the
|
|
shell is assumed to be
|
|
.Pa /bin/sh .
|
|
.It
|
|
If directed by the file
|
|
.Xr ftpchroot 5
|
|
the session's root directory will be changed by
|
|
.Xr chroot 2
|
|
to the directory specified in the
|
|
.Xr ftpd.conf 5
|
|
.Sy chroot
|
|
directive (if set),
|
|
or to the home directory of the user.
|
|
However, the user must still supply a password.
|
|
This feature is intended as a compromise between a fully anonymous account
|
|
and a fully privileged account.
|
|
The account should also be set up as for an anonymous account.
|
|
.It
|
|
If the user name is
|
|
.Dq anonymous
|
|
or
|
|
.Dq ftp ,
|
|
an
|
|
anonymous
|
|
.Tn FTP
|
|
account must be present in the password
|
|
file (user
|
|
.Dq ftp ) .
|
|
In this case the user is allowed
|
|
to log in by specifying any password (by convention an email address for
|
|
the user should be used as the password).
|
|
.Pp
|
|
The server performs a
|
|
.Xr chroot 2
|
|
to the directory specified in the
|
|
.Xr ftpd.conf 5
|
|
.Sy chroot
|
|
directive (if set),
|
|
the
|
|
.Fl a Ar anondir
|
|
directory (if set),
|
|
or to the home directory of the
|
|
.Dq ftp
|
|
user.
|
|
.Pp
|
|
The server then performs a
|
|
.Xr chdir 2
|
|
to the directory specified in the
|
|
.Xr ftpd.conf 5
|
|
.Sy homedir
|
|
directive (if set), otherwise to
|
|
.Pa / .
|
|
.Pp
|
|
If other restrictions are required (such as disabling of certain
|
|
commands and the setting of a specific umask), then appropriate
|
|
entries in
|
|
.Xr ftpd.conf 5
|
|
are required.
|
|
.Pp
|
|
If the first character of the password supplied by an anonymous user
|
|
is
|
|
.Dq - ,
|
|
then the verbose messages displayed at login and upon a
|
|
.Sy CWD
|
|
command are suppressed.
|
|
.El
|
|
.Sh Display file escape sequences
|
|
.Pp
|
|
When
|
|
.Nm
|
|
displays various files back to the client (such as
|
|
.Pa /etc/ftpwelcome
|
|
and
|
|
.Pa /etc/motd ) ,
|
|
various escape strings are replaced with information pertinent
|
|
to the current connection.
|
|
.Pp
|
|
The supported escape strings are:
|
|
.Bl -tag -width "Escape" -offset indent -compact
|
|
.It Sy "Escape"
|
|
.Sy Description
|
|
.It "\&%c"
|
|
Class name.
|
|
.It "\&%C"
|
|
Current working directory.
|
|
.It "\&%E"
|
|
Email address given with
|
|
.Fl e .
|
|
.It "\&%L"
|
|
Local hostname.
|
|
.It "\&%M"
|
|
Maximum number of users for this class.
|
|
Displays
|
|
.Dq unlimited
|
|
if there's no limit.
|
|
.It "\&%N"
|
|
Current number of users for this class.
|
|
.It "\&%R"
|
|
Remote hostname.
|
|
.It "\&%s"
|
|
If the result of the most recent
|
|
.Dq "\&%M"
|
|
or
|
|
.Dq "\&%N"
|
|
was not
|
|
.Dq Li 1 ,
|
|
print an
|
|
.Dq s .
|
|
.It "\&%S"
|
|
If the result of the most recent
|
|
.Dq "\&%M"
|
|
or
|
|
.Dq "\&%N"
|
|
was not
|
|
.Dq Li 1 ,
|
|
print an
|
|
.Dq S .
|
|
.It "\&%T"
|
|
Current time.
|
|
.It "\&%U"
|
|
User name.
|
|
.It "\&%\&%"
|
|
A
|
|
.Dq \&%
|
|
character.
|
|
.El
|
|
.Sh Setting up a restricted ftp subtree
|
|
.Pp
|
|
In order that system security is not breached, it is recommended
|
|
that the
|
|
subtrees for the
|
|
.Dq ftp
|
|
and
|
|
.Dq chroot
|
|
accounts be constructed with care, following these rules
|
|
(replace
|
|
.Dq ftp
|
|
in the following directory names
|
|
with the appropriate account name for
|
|
.Sq chroot
|
|
users):
|
|
.Bl -tag -width "~ftp/incoming" -offset indent
|
|
.It Pa ~ftp
|
|
Make the home directory owned by
|
|
.Dq root
|
|
and unwritable by anyone.
|
|
.It Pa ~ftp/bin
|
|
Make this directory owned by
|
|
.Dq root
|
|
and unwritable by anyone (mode 555).
|
|
Generally any conversion commands should be installed
|
|
here (mode 111).
|
|
.It Pa ~ftp/etc
|
|
Make this directory owned by
|
|
.Dq root
|
|
and unwritable by anyone (mode 555).
|
|
The files
|
|
.Pa pwd.db
|
|
(see
|
|
.Xr passwd 5 )
|
|
and
|
|
.Pa group
|
|
(see
|
|
.Xr group 5 )
|
|
must be present for the
|
|
.Sy LIST
|
|
command to be able to display owner and group names instead of numbers.
|
|
The password field in
|
|
.Xr passwd 5
|
|
is not used, and should not contain real passwords.
|
|
The file
|
|
.Pa motd ,
|
|
if present, will be printed after a successful login.
|
|
These files should be mode 444.
|
|
.It Pa ~ftp/pub
|
|
This directory and the subdirectories beneath it should be owned
|
|
by the users and groups responsible for placing files in them,
|
|
and be writable only by them (mode 755 or 775).
|
|
They should
|
|
.Em not
|
|
be owned or writable by ftp or its group.
|
|
.It Pa ~ftp/incoming
|
|
This directory is where anonymous users place files they upload.
|
|
The owners should be the user
|
|
.Dq ftp
|
|
and an appropriate group.
|
|
Members of this group will be the only users with access to these
|
|
files after they have been uploaded; these should be people who
|
|
know how to deal with them appropriately.
|
|
If you wish anonymous
|
|
.Tn FTP
|
|
users to be able to see the names of the
|
|
files in this directory the permissions should be 770, otherwise
|
|
they should be 370.
|
|
.Pp
|
|
The following
|
|
.Xr ftpd.conf 5
|
|
directives should be used:
|
|
.Dl "modify guest off"
|
|
.Dl "umask guest 0707"
|
|
.Pp
|
|
This will result in anonymous users being able to upload files to this
|
|
directory, but they will not be able to download them, delete them, or
|
|
overwrite them, due to the umask and disabling of the commands mentioned
|
|
above.
|
|
.It Pa ~ftp/tmp
|
|
This directory is used to create temporary files which contain
|
|
the error messages generated by a conversion or
|
|
.Sy LIST
|
|
command.
|
|
The owner should be the user
|
|
.Dq ftp .
|
|
The permissions should be 300.
|
|
.Pp
|
|
If you don't enable conversion commands, or don't want anonymous users
|
|
uploading files here (see
|
|
.Pa ~ftp/incoming
|
|
above), then don't create this directory.
|
|
However, error messages from conversion or
|
|
.Sy LIST
|
|
commands won't be returned to the user.
|
|
(This is the traditional behaviour.)
|
|
Note that the
|
|
.Xr ftpd.conf 5
|
|
directive
|
|
.Sy upload
|
|
can be used to prevent users uploading here.
|
|
.El
|
|
.Pp
|
|
To set up "ftp-only" accounts that provide only
|
|
.Tn FTP ,
|
|
but no valid shell
|
|
login, you can copy/link
|
|
.Pa /sbin/nologin
|
|
to
|
|
.Pa /sbin/ftplogin ,
|
|
and enter
|
|
.Pa /sbin/ftplogin
|
|
to
|
|
.Pa /etc/shells
|
|
to allow logging-in via
|
|
.Tn FTP
|
|
into the accounts, which must have
|
|
.Pa /sbin/ftplogin
|
|
as login shell.
|
|
.Sh FILES
|
|
.Bl -tag -width /etc/ftpwelcome -compact
|
|
.It Pa /etc/ftpchroot
|
|
List of normal users who should be
|
|
.Xr chroot 2 ed.
|
|
.It Pa /etc/ftpd.conf
|
|
Configure file conversions and other settings.
|
|
.It Pa /etc/ftpusers
|
|
List of unwelcome/restricted users.
|
|
.It Pa /etc/ftpwelcome
|
|
Welcome notice before login.
|
|
.It Pa /etc/motd
|
|
Welcome notice after login.
|
|
.It Pa /etc/nologin
|
|
If it exists, displayed and access is refused.
|
|
.It Pa /var/run/ftpd.pids-CLASS
|
|
State file of logged-in processes for the
|
|
.Nm
|
|
class
|
|
.Sq CLASS .
|
|
.It Pa /var/run/utmp
|
|
List of logged-in users on the system.
|
|
.It Pa /var/log/wtmp
|
|
Login history database.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ftp 1 ,
|
|
.Xr skey 1 ,
|
|
.Xr who 1 ,
|
|
.Xr getusershell 3 ,
|
|
.Xr ftpd.conf 5 ,
|
|
.Xr ftpchroot 5 ,
|
|
.Xr ftpusers 5 ,
|
|
.Xr syslogd 8
|
|
.Sh STANDARDS
|
|
.Nm
|
|
recognizes all commands in
|
|
.Cm RFC 959 ,
|
|
follows the guidelines in
|
|
.Cm RFC 1123 ,
|
|
recognizes all commands in
|
|
.Cm RFC 2228
|
|
(although they are not supported yet),
|
|
and supports the extensions from
|
|
.Cm RFC 2389 ,
|
|
.Cm RFC 2428
|
|
and
|
|
.Cm draft-ietf-ftpext-mlst-11 .
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
command appeared in
|
|
.Bx 4.2 .
|
|
.Pp
|
|
Various features such as the
|
|
.Xr ftpd.conf 5
|
|
functionality,
|
|
.Cm RFC 2389 ,
|
|
and
|
|
.Cm draft-ietf-ftpext-mlst-11
|
|
support was implemented in
|
|
.Nx 1.3
|
|
and later releases by Luke Mewburn <lukem@netbsd.org>.
|
|
.Sh BUGS
|
|
The server must run as the super-user to create sockets with
|
|
privileged port numbers (i.e, those less than
|
|
.Dv IPPORT_RESERVED ,
|
|
which is 1024).
|
|
If
|
|
.Nm
|
|
is listening on a privileged port
|
|
it maintains an effective user id of the logged in user, reverting
|
|
to the super-user only when binding addresses to privileged sockets.
|
|
The
|
|
.Fl r
|
|
option can be used to override this behaviour and force privileges to
|
|
be permanently revoked; see
|
|
.Sx SECURITY CONSIDERATIONS
|
|
below for more details.
|
|
.Pp
|
|
.Nm
|
|
may have trouble handling connections from scoped IPv6 addresses, or
|
|
IPv4 mapped addresses
|
|
.Po
|
|
IPv4 connection on
|
|
.Dv AF_INET6
|
|
socket
|
|
.Pc .
|
|
For the latter case, running two daemons,
|
|
one for IPv4 and one for IPv6, will avoid the problem.
|
|
.Sh SECURITY CONSIDERATIONS
|
|
.Cm RFC 959
|
|
provides no restrictions on the
|
|
.Sy PORT
|
|
command, and this can lead to security problems, as
|
|
.Nm
|
|
can be fooled into connecting to any service on any host.
|
|
With the
|
|
.Dq checkportcmd
|
|
feature of the
|
|
.Xr ftpd.conf 5 ,
|
|
.Sy PORT
|
|
commands with different host addresses, or TCP ports lower than
|
|
.Dv IPPORT_RESERVED
|
|
will be rejected.
|
|
This also prevents
|
|
.Sq third-party proxy ftp
|
|
from working.
|
|
Use of this option is
|
|
.Em strongly
|
|
recommended, and enabled by default.
|
|
.Pp
|
|
By default
|
|
.Nm
|
|
uses a port that is one less than the port it is listening on to
|
|
communicate back to the client for the
|
|
.Sy EPRT ,
|
|
.Sy LPRT ,
|
|
and
|
|
.Sy PORT
|
|
commands, unless overridden with
|
|
.Fl P Ar dataport .
|
|
As the default port for
|
|
.Nm
|
|
(21) is a privileged port below
|
|
.Dv IPPORT_RESERVED ,
|
|
.Nm
|
|
retains the ability to switch back to root privileges to bind these
|
|
ports.
|
|
In order to increase security by reducing the potential for a bug in
|
|
.Nm
|
|
providing a remote root compromise,
|
|
.Nm
|
|
will permanently drop root privileges if one of the following is true:
|
|
.Bl -enum -offset indent
|
|
.It
|
|
.Nm
|
|
is running on a port greater than
|
|
.Dv IPPORT_RESERVED
|
|
and the user has logged in as a
|
|
.Sq guest
|
|
or
|
|
.Sq chroot
|
|
user.
|
|
.It
|
|
.Nm
|
|
was invoked with
|
|
.Fl r .
|
|
.El
|
|
.Pp
|
|
Don't create
|
|
.Pa ~ftp/tmp
|
|
if you don't want anonymous users to upload files there.
|
|
That directory is only necessary if you want to display the error
|
|
messages of conversion commands to the user.
|
|
Note that if uploads are disabled with the
|
|
.Xr ftpd.conf 5
|
|
directive
|
|
.Sy upload ,
|
|
then this directory cannot be abused by the user in this way, so it
|
|
should be safe to create.
|