Subject: Term114 share patch
From: [email-masked] (Bill C. Riemers)
Date: Sun, 27 Mar 1994 18:51:37 GMT
Newsgroups: comp.os.linux.announce

[Term is a serial line multiplexor, providing some of the functionality
of SLIP. --mdw]

OK, the following instructions allow you to share your term connection without
allowing other users direct access to either the account on which term
was started, or the remote unix account.

Begin2
Title        Term114 share patches
Version      0.1
Desc1        These are patches for term114 that allow you to safely share
Desc2        a term connection with other users.
Author       Bill C. Riemers
AuthorEmail  [email-masked]
Site1        sunsite.unc.edu
Path1        /pub/Linux/apps/comm/termstuff/
File1        term114-share.tar.gz
FileSize1    9k
Required1    term114
Required2    Recommended: termncftp, termtelnet, fet
CopyPolicy1  Same as term114
Keywords     term patches share
Comment1     I've only tested this patch under Linux...  Undoubtably there
Comment2     will be some problems under other systems that should be worked
Comment3     out before I submitt these changes to Michael O'Reilly.
Entered      26MAR94
EnteredBy    Bill C. Riemers
End

The primary differences between the shareable and are unsharable commands is:
  - Sharable commands are set group ID programs.
  - the shared "term" directory is /usr/lib/term intead of ~/.term 
    (This is hardcoded for security reasons.  You can change it in the
    Makefile.)

The following summarizes which programs can be used in shared mode:
  Command:  Shared:     Comments:
  term      yes         Required to be shared
  tiptest   yes         A fairly safe test of remote hosts...
  tmon      yes         Why not?
  tredir    yes         Probably safe... as long as you don't start term as root
  txconn    yes         Probably safe... as long as you don't start term as root
  tupload   no          Don't make shared!
  trsh      no          Don't make shared!

The user who owns the connection may use all term commands normally.

If you want to make another command, such as foo sharable, then try:
  chgrp term foo
  chmod g+s foo
Then check to see if the command will either allow you to fork a shell
as with the 'id' of '... egid=16(term) ...'.  If so, it is a security
hole, and the source code should be modified.

Here are some of the programs I keep as sharable:
  Command:	Comment:
  termtelnet	Seems OK, so far
  termncftp	Major security hole (i.e. type !id ); modify the source
  termfinger	Seems OK
  xtmon		Why not?
  termMosaic	Probably a security hole...

As always, any ports you redirect will be useable by everyone.

                             Bill