Additionally
There are three kinds of FTP logins that wu-ftpd provides:
- anonymous FTP
- real FTP
- guest FTP
Anonymous FTP is well known; one logs in with the username 'anonymous'
and an email type password.
Real FTP is when someone logs in with a real username and password and
has access to the entire disk structure. This form of access can be
extremely dangerous to system security and should be avoided unless
absolutely necessary and well controlled.
Guest FTP is a form of real FTP; one logs in with a real user name and
password, but the user is chroot'ed to his home directory and cannot
escape from it. This is much safer, and it is a useful way for remote
clients to maintain their Web accounts.
If you want to learn more about 'chroot', the following two commands
should help, as should any good Unix text.
man chroot
There may be different man pages in sections 1, 2 and 8 (or others,
perhaps) depending on your operating system. ('man # chroot')
This howto will describe in detail the steps necessary to set up a
guest FTP account. It does not describe anonymous or real FTP setup,
though the procedures for setting up an operational 'ls' command will
apply equally to anonymous FTP because of the chroot'ed nature of
anonymous FTP.
The working example here will be as if it were a directory under a Web
tree, /home/web. The Web account will be maintained remotely by FTP. The
remote user is Mortimer. Mortimer's account name is "mort", group
"client".
(Yes, there is some droll humor here for the French speakers...)
Create Mort's entry in /etc/passwd and /etc/group. Do so manually,
or use adduser or whatever your Unix supports. If you use adduser,
you will probably have to make manual modifications to get the /./
information in the home path.
There are also entries to make in /etc/ftpaccess.
/etc/passwd:
mort:*:403:400:Mortimer Snerd:/home/web/mort/./:/etc/ftponly
^^^
The /./ sequence determines where the chroot() is done to. If you
want the chroot() done to the web directory and a chdir() to mort,
it would look like this:
mort:*:403:400:Mortimer Snerd:/home/web/./mort/:/etc/ftponly
^^^
--------> (make sure "/etc/ftponly" is in /etc/shells.)
/etc/group:
client::400:mort
Set Mort's password as you wish, or better yet use S/KEY.
The current releases of wu-ftpd come with /etc/ftpaccess enabled by
default. If your version does not do this for some reason, you must
do one of two thing to properly use /etc/ftpaccess:
- compile the source to use /etc/ftpaccess by default;
modify the source to set use_accessfile = 1;
OR
- run the daemon with the -a option.
/etc/ftpaccess:
class local real,guest,anonymous ......
... ^^^^^
... +----------- define 'guest' in the proper classes;
... this is site dependent.
...
...
delete no anonymous,guest # delete permission?
overwrite no anonymous,guest # overwrite permission?
rename no anonymous,guest # rename permission?
chmod no anonymous,guest # chmod permission?
umask no anonymous,guest # umask permission?
... ^^^^^
... +------ decide if guest should be in this
... permission list; this is site dependent.
...
...
path-filter guest /etc/pathmsg ^[-A-Za-z0-9_\.]*$ ^\. ^-
...
guestgroup client
...
- mkdir /home/web/mort
- chown mort.client /home/web/mort
- chmod 755 /home/web/mort
Create the /etc, /lib, and any other directory you need
in the directory that the chroot() is done into.
- cd /home/web/mort
- mkdir etc bin [dev lib] (dev and lib are optional and are OS dependent.)
- chown root.daemon etc bin
- chmod 111 etc bin
NOTE WELL: if you cannot see the directory contents after you login
as the guest user, the 'ls' program that you installed is not working.
If you use an 'ls' linked for dynamic libraries, and you do not have
the required libraries and/or devices installed properly in the guest
tree, 'ls' will not work and you will not see the contents of the
guest directory.
This is the single most FAQ on the wu-ftpd list. Repeating: if you
cannot see the contents of the directory, your installed 'ls' is not
working. The proper installation procedures for 'ls' vary by operating
system. There are some OS specific notes at the bottom of this howto
that may be of help.
Another problem that has been reported is that the chroot() directory
given in your /etc/passwd file for the guest account must be to the
directory where your ~/bin directory is located. That is, if your
chroot directory is /u01/ftp/ftptest/ and your /etc/passwd account is
yourftp:x:42:42:guest ftp account:/u01/ftp/./ftptest:/etc/ftponly
it will not work, as the ~/bin directory is not under the chroot()ed
directory. It must be set as follows.
yourftp:x:42:42:guest ftp account:/u01/ftp/ftptest/./:/etc/ftponly
There are additional resources to help if you still cannot see files
after an FTP login. See the FAQ and Resource Center and
http://www.wuftpd.org/ for more information.
USE STATIC LINKED COPIES OF ALL UTILITIES IF POSSIBLE.
You may get the source to build your own static 'ls' by downloading the
GNU fileutils source package from .
- cp /.../bin/ls bin
- chown root.bin bin/ls
- chmod 111 bin/ls
Optional for on the fly compression and tar:
- cp /.../bin/gzip bin
- cp /.../bin/tar bin
- chown root.bin bin/gzip
- chown root.bin bin/tar
- chmod 111 bin/gzip
- chmod 111 bin/tar
If the utilities are not static, create the necessary devices in ~/dev and
copy the necessary libraries into ~/lib. Check the man page for ftpd that
comes with your system; it may be of help.
REGARDING HARD AND SOFT/SYMBOLIC LINKS:
The chroot() obviates the use of soft links in this case. However, it
it is possible to make these hard links back to the master copy of the
utilities rather than copies. This can save some disk space if that is
a concern.
- cd /home/web/mort
- touch .rhosts .forward
- chown root.root .rhosts .forward
- chmod 400 .rhosts .forward
You should now be the proud owner of a working guest group FTP login.
Connect to the machine via FTP and login as "mort". You should end up in
Mort's account with a current directory of "/".
If not, go over it carefully again, as there is a lot of detail here. If
you still can't get it to work, yell for help on
wu-ftpd@wugate.wustl.edu.
Linux does not need a ~/dev dir. It does need the ~/lib dir if the
utilities in ~/bin are dynamically linked.
Use the 'ldd' command to find out what libraries are necessary for a given
dynamically linked utility.
LINUX REDHAT 6.1: (reported by Steven Schramm <sws@lacasa.com>)
I found the following steps for the lib directory critical to my
success:
- create the lib directory with mode 111
- cd lib
- cp /lib/ld-2.1.1.so .
- cp /lib/libc-2.1.1.so .
- ln -s ld-2.1.1.so ld-linux.so.2
- ln -s libc-2.1.1.so libc.so.6
- chmod 111 ld-2.1.1.so
- chmod 555 libc-2.1.1.so
Solaris can't handle SETPROCTITLE, so turn the compile time option off.
(The following was culled from a post by Tom Leach to the wu-ftpd list.)
>For people who are having problems with ls -al and dir on solaris 2.x
>systems, you might try the following to find out what's missing...
>truss -f chroot ~ftp /bin/ls
>This will run the ls command in the same chroot'd environment that
>anonymous FTP runs in. The truss will show you what
>files/libraries/devices are accessed and where the ls is looking for them.
>Tom Leach
>leach@oce.orst.edu
Create a ~dev/zero and ~dev/tcp device for the FTP directory as follows.
Run the following 'ls' command, then create the devices in the ~/dev
directory with the 'mknod' command, using the major and minor numbers
from the 'ls' results (thanks to Jim Davis
<jdavis@cs.arizona.edu>).
ls -lL /dev/zero /dev/tcp
cd dev
mknod zero c <major> <minor>
mknod tcp c <major> <minor>
cd ..
chmod 555 dev
You may also wish to use the following method to create the device,
per Ian Willis <ianw@sco.com>; repeat this command for each device
(zero, tcp, etc.).
find /dev/zero -print | cpio -pd ~ftp
Also, you probably need the following shared libraries:
- ~lib/ld.so
- ~lib/libc.so
- ~lib/libdl.so
Set 555 protections on the ~ftp/shlib and its contents if shared libraries
are used.
From Darci Chapman (minerva@phix.com):
The following directories and files need to be created in whatever
directory/ies are being chrooted to (~ftp for anon ftp or for whatever
directory guest users are chrooted):
dr-xr-xr-x root/wheel 0 Nov 3 01:43 1995 bin/
-r-xr-xr-x root/wheel 12288 Nov 3 01:43 1995 bin/compress
-r-xr-xr-x root/wheel 45056 Nov 3 01:43 1995 bin/gzip
-r-xr-xr-x root/wheel 12288 Nov 3 01:43 1995 bin/ls
-r-xr-xr-x root/wheel 65536 Nov 3 01:43 1995 bin/pax
dr-xr-xr-x root/wheel 0 Nov 3 01:43 1995 etc/
-r--r--r-- root/wheel 793 Nov 3 01:43 1995 etc/group
-r--r--r-- root/wheel 817 Nov 3 01:43 1995 etc/localtime
-r--r--r-- root/wheel 40960 Nov 3 01:43 1995 etc/pwd.db
dr-xr-xr-x root/wheel 0 Feb 3 12:34 1995 pub/
dr-xr-xr-x root/wheel 0 Nov 3 01:43 1995 shlib/
-r-xr-xr-x root/wheel 298407 Nov 3 01:43 1995 shlib/libc_s.2.0
From Frans Stekelenburg <gjs@knmi.nl>:
(as in SUN 4.1.x, but without /dev/tcp)
Create a ~dev/zero and ~dev/tcp device for the FTP directory as follows.
(tip: search on 'dev/zero' in your IRIX systems' Online Books.)
Run the following 'ls' command, then create the devices in the ~/dev
directory with the 'mknod' command, using the major and minor numbers
from the 'ls' results (thanks to Jim Davis
<jdavis@cs.arizona.edu>).
ls -lL /dev/zero
cd dev
mknod zero c <major> <minor>
cd ..
chmod 555 dev
You may also wish to use the following method to create the device,
per Ian Willis <ianw@sco.com>;
repeat this command for each device
(zero, etc.).
find /dev/zero -print | cpio -pd ~ftp
Also, you probably need the following shared libraries:
- ~lib/rld
- ~lib/libc.so.1
- (found in /lib)
Also read the manpages on FTPD, or look in the IRIX Insight Library
(Online Books) in the book/chapter "IRIX Admin: Networking and Mail"
for the paragraph 'How to Set Up a Proper Anonymous FTP Account'
(search helps:-)) on your IRIX system.
Per Chuque Berry
<chuque@ns2.tiba.net>
and Joseph Matusiewicz
<Joseph.Matusiewicz@noaa.gov>,
AIX needs the following files for
the external ls to work:
- ~lib/libc.a
- ~lib/libcurses.a (???)
You may also need:
For tips on security of anonymous FTP see CERT documents:
Also, check out Christopher Klaus's older Anonymous FTP FAQ.