Date: Thu, 30 Oct 2008 15:16:54 -0400 From: Coleman Kane <cokane@FreeBSD.org> To: David Schultz <das@FreeBSD.ORG> Cc: Edward Tomasz Napierala <trasz@FreeBSD.ORG>, freebsd-arch@FreeBSD.ORG Subject: Re: Directory rename semantics. Message-ID: <1225394214.5610.6.camel@localhost> In-Reply-To: <20081028161855.GA45129@zim.MIT.EDU> References: <20081027193545.GA95872@pin.if.uz.zgora.pl> <20081028161855.GA45129@zim.MIT.EDU>
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[-- Attachment #1 --] On Tue, 2008-10-28 at 12:18 -0400, David Schultz wrote: > On Mon, Oct 27, 2008, Edward Tomasz Napierala wrote: > > Let's say we have two directories, "A/" and "B/". We also have a > > file, "A/F". To remove that file, we need write access to "A/". > > To move that file to "B/", we need write access to both "A/" and > > "B/". Now, assume we have a directory, "A/D". To remove that > > directory, we need write access to "A/". To move that directory > > to "B/", we need write access to "A/", "B/", _and "A/D"_. > > > > I'd like to remove the last check (requirement to have write access > > to a directory we want to move somewhere else). Reason for this > > is that it doesn't seem very logical, and many systems - including > > SunOS, and our ZFS - behave differently. In other words, we have > > different semantics on UFS and ZFS. > > No comment on other operating systems or standards, but I wanted > to point out that there is some logic to FreeBSD's present behavior: > When you move A/D, you must be able to write to D, because you are > modifying D's ".." entry to point to B instead of A. > > >From a practical point of view, I think either behavior is fine, > but we should consider whether any security-critical applications > rely on the current behavior before changing it. I was always mystified by the reason for this behavior until now... As for my input, I think the change sounds fine (perhaps allowing revert to old behavior via a sysctl). -- Coleman Kane [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEUEABECAAYFAkkKCCIACgkQcMSxQcXat5fmygCXZqwgMnp9NvJjhOt1sn/gXfGP EQCfekwNaPCCSePdMfDxOOgpQr1b4WY= =HMe3 -----END PGP SIGNATURE-----
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