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    SubjectRe: [PATCH] Add "-e" option to rpc.gssd to allow error on ticket expiry. Try 2 with added man pages.
    On 11/18/2011 09:33 PM, Trond Myklebust wrote:
    > On Fri, 2011-11-18 at 20:19 +0100, John Hughes wrote:
    >
    >> On 11/18/2011 07:35 PM, Trond Myklebust wrote:
    >>
    >>>
    >>> You need a big fat warning somewhere that enabling this option WILL
    >>> cause data corruption...
    >>>
    >>>
    >> Why?
    >>
    >> Because some process may get the EACCES error half way through it's
    >> operation.
    >>
    > No. Because the process can receive a reply to the write() syscall that
    > indicates that the data is safe,

    There is no reply from "write(2)" that says the data is safe.

    > but the EKEYEXPIRED error will cause
    > the data to be lost when the client tries to actually commit the data to
    > disk.
    >
    >
    >> The traditional Kerberos/AFS way was to behave the old way, and use
    >> krenew to keep the ticket from expiring if a process needed to be run
    >> overnight.
    >>
    > Which is just wrong: the general intention of kerberos security is to
    > ensure that the _user_ has ACKed an operation. Renewing tickets without
    > user input would circumvent that intention. If you need to have the job
    > run overnight, then ask for a longer lifetime for your ticket.
    >

    Ok, so no need for the hang on ticket expired then.

    (Although I don't think renewable tickets and krenew are a figment of my
    imagination).

    >
    >> What other way is there of fixing the problem if we are going to keep
    >> the "hang 'till a ticket turns up" behaviour? (rewrite gnome and kde
    >> seems kind of a big job).
    >>
    > Notify the kernel that a ticket is about to expire so that the kernel
    > can decide to block the process on the next NFS-related syscall.
    >
    >
    I don't understand. How is it a win to block processes *before* the
    ticket has expired?




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