sample procmailrc:
SHELL=/bin/bash
LOGFILE=$HOME/procmail.log
VERBOSE=yes
:0
* ^Subject: envdump please$
{
LOG="`id`"
:0
/dev/null
}
/etc/group file contains (note the other usernames are vain attempts to make this work):
someuser:x:504:
s3:x:505:someuser,someotheruser,postfix,postdrop,mail,root
If I run as "someuser" the command id
:
[someuser@lixyz-pqr ~]$ id
uid=504(someuser) gid=504(someuser) groups=504(someuser),505(s3)
However when I run procmail by sending an email with the subject "envdump please", the 505/s3 group disappears (this is in procmail.log):
procmail: [17618] Mon Dec 19 17:39:50 2011
procmail: Match on "^Subject: envdump please$"
procmail: Executing "id"
procmail: Assigning "LOG=uid=504(someuser) gid=504(someuser) groups=504(someuser)"
uid=504(someuser) gid=504(someuser) groups=504(someuser)procmail: Assigning "LASTFOLDER=/dev/null"
this server is running Fedora 14 with Postfix 2.7.5
Procmail wasn't installed setuid.
for background, it should look like:
[root@li321-238 postfix]# ls -l /usr/bin/procmail
-rwsr-sr-x. 1 root mail 92816 Jul 28 2009 /usr/bin/procmail
which you can set up via:
chmod ug+s /usr/bin/procmail