deceptive mail

[L.M.McLoughlin]

In article <331 at uvm-cs.UUCP> hartley at uvm-cs.UUCP (Stephen J. Hartley) writes:
>Somebody here noticed the following "feature" of mail (4.2 BSD).  Under
>certain conditions, a user "xyzu" can do a "set user=abcd" and send mail
>to user "pqrs".  To "pqrs" it appears that "abcd" sent the mail (xyzu <>
>abcd).  This could cause misunderstandings or such if "xyzu" were malicious.
>Is this a feature or a bug?  Thanks.

I thought it was a bug.  When we switched to MMDF it agreed with me.
The From: line and who is posting the message must agree or mmdf tells
you to drop dead (to be honest it says something like invalid author spec).
So I change the rmail to ignore the USER enviroment variable and alway go by
uid.