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SubjectRe: 2.3.30 linuxNFS import is broken (Screwed up NFS/RPC credentials)
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Alexander Viro <viro@math.psu.edu> said:
> On Tue, 21 Dec 1999, Trond Myklebust wrote:
> > Let me explain: The problem is that NFS relies on the user sending the
> > RPC authentication each and every time we access data on the
> > server. In order not to get a permissions error suddenly if the user
> > changes euid while s/he is reading/writing to the open file, we
> > therefore want to use the same RPC authentication info throughout the
> > file's lifetime. Ideally that means taking the RPC auth info that was
> > valid when opening the file (since this is more or less in line with a
> > POSIX filesystem's behaviour with permission checking at file open
> > only) and caching it somewhere.

What if several people open the same file (from different machines, even)?
The permissions might have changed in between... AFAIKS, you need one such
cookie for each time the file has been open(2)ed via NFS, and that gets
ugly.

What do "others" do in such a case?
--
Dr. Horst H. von Brand mailto:vonbrand@inf.utfsm.cl
Departamento de Informatica Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria +56 32 654239
Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513

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