gpg im CGI Script

[Stefan Suurmeijer]

On Thu, 6 Jul 2000, Werner Koch wrote:

> >From my understanding about the problem this code (from 1.0.1h)
> 
>         if( setuid( uid ) || getuid() != geteuid() || !setuid(0) )
>             log_fatal("failed to reset uid: %s\n", strerror(errno));
> 
> is a safeguard against the faulty setcap implementation.  The
> term "|| !setuid(0)" should always we false unless someone tries 
> the setcap exploit in whichcase the setuid(0) will succeed.  Note,
> this code is note used when running as root.
>

Hmm. Am I reading this wrong? I'm no C expert, but shouldn't the negation
be removed ( || setuid(0) as opposed to || !setuid(0)) ? If the setcap
exploit is used and setuid(0) succeeds, you want the if loop to be TRUE,
right? I just tried to implement the sendmail solution (see below) into
secmem.c (BTW, this didn't include the above check, although I downloaded
my current version just two weeks ago. When did 1.0.1h become available?)


---> snip

 The sendmail patch attempts a setuid(0) after a setuid(getuid());
        under normal circumstances this should fail (unless of course
        the real uid is root).  If this setuid(0) succeeds, then the>
        kernel has failed to properly give up permissions and sendmail>
        will refuse to continue running. 


---> endsnip

> -- 
> Werner Koch				OpenPGP key 621CC013
> OpenIT GmbH                             tel +49 211 239577-0
> Birkenstr. 12                           email   wk@OpenIT.de
> D-40233 Duesseldorf                     http://www.OpenIT.de
> 
> 

Stefan


==========================================
Stefan Suurmeijer
Network Specialist
University of Groningen
tel: (+31) 50 363 3423
fax: (+31) 50 363 7272
E-mail (business): s.m.suurmeijer@let.rug.nl
E-mail (private):  stefan@symbolica.nl
==========================================

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