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Re: [BUG 1.7] Read-only files are not.
- From: Eric Blake <ebb9 at byu dot net>
- To: cygwin at cygwin dot com
- Date: Thu, 1 Jan 2009 00:06:40 +0000 (UTC)
- Subject: Re: [BUG 1.7] Read-only files are not.
- References: <495C00DF.5020208@acm.org>
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.
>
> (This issue was brought to my attention by a failing subversion test
> after building for 1.7.)
The findutils testsuite also had to make accomodations to skip certain tests
when run with root-like privileges.
--
Eric Blake
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