Is procmail chrooted or limited in using linux commands?

Question

im using procmail to forward emails to different folders in my Maildir. I use these two lines to get the FROM and TO from the mail, which works pretty fine.

FROM=`formail -x"From:"`
TO=`formail -x"To:"`

These two commands return the whole line without the From: and To: prefix. So i get something like:

Firstname Lastname <firstname.lastname@mail-domain.com>

Now i want to extract the email between < and >. For this i pipe the variable FROM and TO grepping it like this.

FROM_PARSED=`echo $FROM | grep -o '[[:alnum:]+\.\_\-]*@[[:alnum:]+\.\_\-]*'`
TO_PARSED=`echo $TO | grep -o '[[:alnum:]+\.\_\-]*@[[:alnum:]+\.\_\-]*'`

But when i print FROM_PARSED into the procmail log by using LOG=FROM_PARSED, i get an empty string in FROM_PARSED and TO_PARSED.

But if i run these commands on my console, all works fine. I tried many other grepping methods, using grep, egrep, sed and even cut (cutting < and >). All working on console, but i use it in procmail it just returns nothing.

Is it possible that procmail is not allowed to use grep and sed commands? Something like a chroot?

I dont get any error logs in my procmail log. I just want to extract the valid email address from the FROM and TO line. Extracting with formail works, but parsing it with grep or sed fails, even if expression is correct.

Could somebody help? Maybe i need to setup procmail somehow.

Answer 1

Strange.

I added this to the users .procmailrc file

SHELL=/bin/bash

The users shell was set to /bin/false, which is correct because its a mail user, no ssh access at all.

Answer 2

You should properly quote "$FROM" and "$TO".

You will also need to prefix grep with LC_ALL=POSIX to ensure [:alnum:] will actually match the 26 well-known characters + 10 digits of the English alphabet.

Answer 3

You already solved this, but to answer your actual question, it is possible to run procmail in a chroot, but this is certainly not done by Procmail itself. Sendmail used to come with something called the Sendmail Restricted Shell (originally called rsh but renamed to remsh) which allowed system administrators to chroot the delivery process. But to summarize, this is a feature of the MTA, not of Procmail.