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Date: Fri, 28 Aug 2009 20:37:54 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
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Subject: Re: [1.7] Admins can write to readonly files
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On Aug 28 19:57, Christian Franke wrote:
> Dave Korn wrote:
>> Christian Franke wrote:
>>   
>>> For members of Admin group, Cygwin 1.7 allows to overwrite files without
>>> write permission, but Cygwin 1.5 does not.
>>>     
>>
>>   You are the root user, this is Unix.  Of course you can overwrite files
>> without write permission.
>>
>>   
>
> This is not true when 'chmod -w ...' was done before the upgrade to 1.7.
> Cygwin 1.5 sets R/O attribute, then open for write fails with permission  
> denied also on 1.7.

That's why 1.7 tries not to set the R/O DOS attribute anymore.  But yes,
that's not quite consistent.  open(2) should open these files for writing
as well.  Unfortunately this requires to remove the R/O attribute before
trying to open the file for writing.  There's no atomic way to accomplish
this.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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