[comp.mail.elm] elm and /usr/spool/mail

boehme@unvax.union.edu (Eric M. Boehm) (01/10/91)

Is there some compelling reason for /usr/spool/mail to be world
writable? Before I go changing things or altering the source code, I
would like to know if it is possible to have /usr/spool/mail mode 755
and still be able to use elm?


-- 
Eric M. Boehm
boehme@unvax.Union.EDU
BOEHME@UNION.BITNET

syd@DSI.COM (Syd Weinstein) (01/10/91)

boehme@unvax.union.edu (Eric M. Boehm) writes:
>Is there some compelling reason for /usr/spool/mail to be world
>writable? Before I go changing things or altering the source code, I
>would like to know if it is possible to have /usr/spool/mail mode 755
>and still be able to use elm?

Having /usr/spool/mail mode 755 means Elm would have to be setuid
to the owner of /usr/spool/mail, so it can do links and unlinks
to get the file copied back.  Not the best idea.  However, many
System V's make /usr/mail (their /usr/spool/mail) 775, group mail,
and in that mode Elm runs setgid.

If /usr/spool/mail is 1777 or 3777 in the BSD world, then only
the owner can remove the file, and the protections on the file
itself will prevent others from reading it.  This works quite well.

-- 
=====================================================================
Sydney S. Weinstein, CDP, CCP                   Elm Coordinator
Datacomp Systems, Inc.                          Voice: (215) 947-9900
syd@DSI.COM or dsinc!syd                        FAX:   (215) 938-0235