[vox-tech] Running a suid root perl script

[Ken Herron]

--On Monday, May 05, 2003 11:37:20 -0700 Henry House 
<hajhouse@houseag.com> wrote:

> #!/usr/bin/suidperl -T
> $ENV{'PATH'} = '/bin:/usr/bin';
> delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
> $ENV{'HOME'} = '/root';
> open(BOGOFILTER, "|ssh root\@mail.internal bogofilter -Nsv");
> while ($line = <STDIN>) { print BOGOFILTER $line }
> close(BOGOFILTER);
> exit

My guess is that you're being tripped up by the real ID being different 
from the effective ID. Ssh is pretty strict about security and not every 
thing it checks is described in the documentation.

However, would recommend you implement this process in another way. First 
of all, the script will fail rather badly if the open() step fails for 
any reason. Second, you're apparently using a general-purpose ssh key 
which can be used to run any kind of command on the remote system, with 
the script being the only protection. You should set up a special key 
which can only be used to run "bogofilter -Nsv" on the remote host. 
Third, there's no good reason to be using the root ID for this, at least 
on the local side.

Personally I wouldn't have the user launching ssh interactively at all. 
I'd probably just write the mail to a file in a directory somewhere, then 
use a cron job to periodically copy the directory contents to the remote 
system. Maybe you trust your users, but the script you've posted here 
would make me nervous.

For example, bogofilter has to lock its wordlist files to guard against 
simultaneous access. If bogofilter is part of the normal mail delivery 
process, then someone running

	sleep 999999 | /usr/local/bin/spamlearn

might be able to halt normal mail delivery.

-- 
Kenneth Herron  Kherron@newsguy.com     916-366-7338