*BSD News Article 76913


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From: j@ida.interface-business.de (J Wunsch)
Newsgroups: comp.unix.bsd.bsdi.misc,comp.unix.misc,comp.programming
Subject: Re: Perl Script Permissions
Date: 26 Aug 1996 09:33:06 GMT
Organization: interface business GmbH, Dresden
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References: <321E1027.58DB@he.net>
Reply-To: joerg_wunsch@interface-business.de (Joerg Wunsch)
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ShadowTech Enterprises <shadow@he.net> wrote:

(Btw., your message is what i consider `close to be unreadable'.  One
large blurb of text is not what people invites to read about your
problem.)

> directories are modified. What I am weak on, is the access
> permission structure of the BSD/OS system I am running on. The
> script runs fine for 'cd' using the 'chdir' perl command, and but
> when I try to implement 'chmod' using the perl command 'chmod' or a
> 'system' call or by using backticks I do not get any result other
> than a permission denied error for the perl command...

Perhaps you can elaborate more?

Since all this happens under your account, from a Unix point of view,
all files belong to you.  You are not even allowed to give away files
to other user IDs.

What might be your problem is that you are probably running a script
called by the Web server.  For security reasons, Webservers usually
run under the UID of `nobody'.  If this is your problem, suidperl
might solve your problems, but if your system manager is paranoid, he
hasn't installed it. :)  (There has been a recent vulnerability report
about suidperl, but there are indeed fixed versions that do also work.
The trick is to *not* use the ``Posix saved ID model''.)

With suidperl, you can make the script run on behalf of your identity.
Naturally, you gotta be very careful with what you're allowing and
what not.

-- 
J"org Wunsch					       Unix support engineer
joerg_wunsch@interface-business.de       http://www.interface-business.de/~j