Date: Thu, 1 May 1997 08:46:25 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: pius@ienet.com Cc: freebsd-fs@freebsd.org, terryl@ienet.com Subject: Re: nfs cache permissions problem? Message-ID: <Pine.BSF.3.95q.970501084257.289I-100000@herring.nlsystems.com> In-Reply-To: <199704302151.OAA04610@iago.ienet.com>
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On Wed, 30 Apr 1997 pius@ienet.com wrote: > > On Wed, 30 Apr 1997, dfr@nlsystems.com wrote: > > I know about this problem and there is an open PR for it. I don't know > > what the right fix for it is though. I can't do an ACCESS rpc for every > > cache read (apart from the performance, NFSv2 doesn't have an ACCESS rpc). > > The best I have come up with so far is to somehow associate a cred with > > each buf in the cache and only allow accesses which are allowed by the > > cred. Failures will invalidate the buf and attempt the READ rpc, allowing > > the server to do the check. > > Oops, sorry, I should have checked the PRs first. > > So the fix provided by the originator of kern/2635 would significantly > affect performance? Or perhaps it has other problems? The problem in 2635 is less severe and the fix is probably OK. The nasty one is accessing normal file data from read/write. I don't want to add an extra rpc to that case if I don't have to. > > Does the NFSv3 implementation fix this? How do other NFS implementations > handle this case (e.g. OpenBSD, NetBSD, Linux, Solaris)? I haven't looked yet. I would expect most BSDs to have the same behaviour as FreeBSD since the NFS code has a common ancestor. > Anyways, thanks very much for your help, You're welcome. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 951 1891
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