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Date: Wed, 30 Nov 2016 11:47:24 +0100
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: Retrieving per-process environment block?
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References: <CAOTD34ZFH5E3r3AuDOXctss46e1hoU2f9pwE1mt4L674J2Ak_A@mail.gmail.com> <20161117140012.GA23664@calimero.vinschen.de> <CAOTD34Y9TRq2Qq8Mn2awTf9SCgz0qnbBa-a117pkSEvz9gaHKQ@mail.gmail.com> <98eb08bf-5012-fe14-b10c-241b427c4366@cs.umass.edu>
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On Nov 29 09:28, Eliot Moss wrote:
> On 11/29/2016 8:26 AM, Erik Bray wrote:
> > I could do this, if each process kept a copy of its environment block
> > in shared memory, which would in turn have to be updated every time
> > the process's environment is updated.  But I don't know what the
> > impact of that would be performance-wise.
>=20
> Sorry, no advice getting around this, but a thought about why it may have
> been hard -- it can be a security hole.

Using the mechanism outlined in my mail from 2 minutes ago, there's
no security problem.  Opening the signal pipe is only allowed to
same user processes or administrative processes.  Other will get a
/proc/$PID/environ content of "<defunct>"


Corinna

--=20
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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