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Date: Sat, 7 Jun 2003 11:52:08 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: Re: 1.3.22: child real uid gets parent's effective uid
Message-ID: <20030607095208.GC18350@cygbert.vinschen.de>
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References: <4C37CF2D8DF07E4CA6357BAD5EB9A5D705B05A27 AT oh0012itsa1 DOT cb DOT lucent DOT com>
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On Fri, Jun 06, 2003 at 04:20:43PM -0400, Snively, John P (John) wrote:
> 
> I changed the effective uid of my app's process using seteuid, and printed
> out the real and effective uid's obtained via getuid and geteuid.  No
> surprises, until I tested running a child process via system() and printing
> ITS real and effective uid's.  The effective AND real uid of the child are
> set to the effective uid of the parent -- ouch:
> 
> before changing euid:
> child: euid: 25313 ruid: 25313
> parent: euid: 25313 ruid: 25313
> 
> setting euid to 500
> child: euid: 500 ruid: 500
> parent: euid: 500 ruid: 25313
> 
> Any way around this?

Not easily. The difference between real and effective uid is just plain
fake.  Windows doesn't support that difference, there's just one uid
(better: owner SID) attached to a process.  So each new process begins
its life with euid == ruid.

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin AT cygwin DOT com
Red Hat, Inc.

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