Subject: re: Not-so-anonymous FTP

From: Quentin Fennessy <[email-masked]>
Date: Sat, 06 May 1995 01:57:52 -0500

Mark Spruiell <[email-masked]> asked:
> I've hacked up an ftpd to provide a hybrid real/anonymous account.  It
> uses an /etc/ftppasswd file, which looks just like an /etc/passwd
> file:
> 
>   username:password:uid:gid:gecos:homedir:shell
> 
> During the login process, ftpd checks /etc/ftppasswd for the account.
> If the account is found and the correct password is entered, ftpd behaves
> like anonymous FTP, in that it chroots to the specified home directory.
> All of the uids and gids in the /etc/ftppasswd file would be set to the
> same harmless account (e.g. nobody/nogroup).
> 
> 
> What do you all think?  Is there an easier way that I'm overlooking?

Hi Mark-
	I have similar requirements, and I think the guestgroup option
mentioned in the ftpaccess file will do the job for me.  Of course, I
still have to create real 'heavyweight' account with a real password
entry, and I do have to supply the chrooted universe including
~ftp/bin/ls and shared libraries, etc.

	I still like my approach because I did not have to hack ftpd--
I am using an existing facility.  Below I have compared your pros and
cons with mine:

Mark Spruiell <[email-masked]> continued:
> What I like about it:
> 
>   * We don't have to create real system accounts, but we still get
>     transfer records by username

I have to create real accounts, but the 'work' necessary is similar--
a *passwd account in a file somewhere.

>   * The user is operating in an isolated file-system, a la anonymous
>     FTP
Ditto.

>   * The /etc/ftppasswd file can be read-write root only, similar to a
>     shadow password file
Ditto.

>   * We have a library of routines for safely querying and modifying the
>     /etc/ftppasswd file
I am using AIX (aches) and it offers some facilities like this.  Other
OS's may lack them.

> What I don't like about it:
>  * It's a hack
Mine isn't-- I am using an existing facility.

> * We have to prepare each account's home directory with all of the
>   anonymous-FTP trappings, i.e. /dev, /bin/ls, /usr/lib, etc.
So do I.

Mark-
	The downside I see to my approach (guestgroup) is that I
am creating multiple UNIX accounts with the attendant security
'possibilities.'  It looks like all you have to worry about are your
modifications to ftpd and their security.

Quentin