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Date: Wed, 31 Dec 2008 22:38:30 -0500
From: Christopher Faylor <cgf-use-the-mailinglist-please@cygwin.com>
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Subject: Re: [BUG 1.7] Read-only files are not.
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On Thu, Jan 01, 2009 at 12:06:40AM +0000, Eric Blake wrote:
>David Rothenberger <daveroth <at> acm.org> writes:
>>It seems that read-only files in Cygwin 1.7 are not truly read-only.
>>The sequence of steps below shows that "chmod 444 file1" does not make
>>the file read-only in Cygwin 1.7, while it does in Cygwin 1.5.  It may
>>have something to do with the Read Only DOS attribute.  This is set by
>>Cygwin 1.5 but not by Cygwin 1.7.  If I manually set it for Cygwin 1.7,
>>the file does become read-only.
>
>Are you perchance running as an Administrator, and therefore you have
>backup privileges?  If so, then you have root-like power, and cygwin
>exposes that by opening files with intent to backup even when the ACLs
>would otherwise make the file unreadable.  Therefore, even though none
>of S_IRUSR, S_IRGRP, S_IROTH are set in the posixy st_mode bits,
>access(file, R_OK) returns 0 and open() is able to exploit your
>root-like powers to read that file.
>
>I thought Corinna mentioned this in the release notes.

Ah, right.  I remember when Corinna removed the "DOS" read-only bit.

I am running with Administrator privileges so I guess this behavior
makes sense.

cgf

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