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Date: Wed, 13 Jul 2005 15:22:26 -0400 (EDT)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: cygwin AT cygwin DOT com
cc: FischRon DOT external AT infineon DOT com
Subject: RE: ssh ceased to work after recreation of /etc/passwd
In-Reply-To: <6.2.1.2.0.20050713103256.09ae06c0@pop.prospeed.net>
Message-ID: <Pine.GSO.4.61.0507131501230.306@slinky.cs.nyu.edu>
References: <25F7D2213F14794A8767B88203EA2BC9240CBB AT mucse201 DOT eu DOT infineon DOT com>  <6 DOT 2 DOT 1 DOT 2 DOT 0 DOT 20050713103256 DOT 09ae06c0 AT pop DOT prospeed DOT net>
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On Wed, 13 Jul 2005, Larry Hall wrote:

> At 01:46 AM 7/13/2005, FischRon.external wrote:
>
> >So what I did is to manually edit /etc/passwd and set my user id back
> >to 400. Then I opened a new cygwin shell and, voila, ssh works again.
> >
> >Now the question is: What possible damage to my system could I have
> >introduced by manually changing the uid for my account in /etc/passwd?
> >After all, I'm always a bit reluctant to hack around in my passwd
> >file....
>
> I expect you won't want to keep it this way but doing this for now is
> fine. It just means the POSIX UID that Cygwin knows you as isn't the
> same as Windows.  This will mean that POSIX permissions that Cygwin
> creates on new files will be 400 instead of that of your domain user, so
> there may be more files to "fix" once your general permission issue is
> resolved.

Sorry, but no.  Cygwin simply converts POSIX permission bits to the
appropriate Windows ACLs.  The ACLs, of course, don't know anything about
the Cygwin UIDs, and go by the SID.  So, as long as the SID is the same,
nothing will change.

And now that I've authoritatively stated this, the *real* experts should
step in and bash me on the head if the above is misleading.

> But I expect that's not a problem for you.  The only thing you really
> don't want to edit in the passwd file is the Windows SUID, after the
> POSIX guid field.  The rest is fair game, though I temper that comment
> by saying that one shouldn't just start editing all these fields for fun
> (which I know is not the case for you).

FWIW, I find this slightly contradictory to what you said above (it agrees
with my "sorry, but no" comment).
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_		pechtcha AT cs DOT nyu DOT edu
ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

If there's any real truth it's that the entire multidimensional infinity
of the Universe is almost certainly being run by a bunch of maniacs. /DA

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