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Annotation of 43BSD/contrib/X/doc/Usenix/naming.t, revision 1.1

1.1     ! root        1: .SH
        !             2: Resource Location and Authentication
        !             3: .PP
        !             4: At this time, 
        !             5: .UX
        !             6: lacks good network authentication and resource location.
        !             7: The only example of a real name server in widespread use is the
        !             8: internet name server.
        !             9: As 
        !            10: .UX
        !            11: moves toward a distributed systems environment,
        !            12: questions of distributed resource location become important.
        !            13: X at this time does little to solve this problem,
        !            14: relying on either command line arguments or an environment variable to
        !            15: specify the host and display you want the application to use.
        !            16: In reality, it should be closely tied to the user's name, since
        !            17: the name of a machine is basically irrelevant as users often move.
        !            18: X seems to highlight some issues in the future design of such servers
        !            19: that may not be widely appreciated.
        !            20: .PP
        !            21: The model used to best describe distributed computing goes under the
        !            22: name of the ``client/server'' model.
        !            23: That is, a client program connects to a ``server'' which provides a service
        !            24: somewhere in the network.
        !            25: The additional twist is that the window system is a ``server'' in this
        !            26: model, and other network services may become ``clients'' of the X server.
        !            27: For example,
        !            28: one can envision using services that want to interact with the user's display.
        !            29: The result is that the ``name'' 
        !            30: of the X server must somehow propagate
        !            31: through such service requests, along with whatever authentication information
        !            32: may be required to connect the X server in the future.
        !            33: This ``cascaded'' services problem has not been well explored.
        !            34: .PP
        !            35: The access control currently in X requires no authentication, but is
        !            36: only adequate for workstations, and fails badly in an environment
        !            37: which includes timesharing systems.
        !            38: X can be told to only accept connections from a list of machines.
        !            39: Unfortunately, if any of them are timesharing machines,
        !            40: and you allow access from
        !            41: that machine, then anyone on that machine may manipulate your display
        !            42: arbitrarily.
        !            43: This has the unfortunate side effect of making it trivial to
        !            44: write password grabbers (across the net!) or otherwise disturb the
        !            45: display if access is left open.
        !            46: .PP
        !            47: The ``name'' of the user's
        !            48: display server also comes and goes with some frequency,
        !            49: as each time you log out, any previously authenticated connection
        !            50: information needs to be invalidated, so no background process from a previous
        !            51: user will disturb the user's display.
        !            52: It is also not uncommon that a single user may  use multiple displays,
        !            53: possibly on multiple machines simultaneously.
        !            54: This might be common, for example, in a laboratory environment.
        !            55: Interesting questions arise as to which display to use on what machine.
        !            56: (For example, the user may initiate a request on a black and white display
        !            57: that really works better on a color display; which display on what machine
        !            58: should be used?)
        !            59: We do not believe these issues, 
        !            60: in particular the transient and cascading nature of such display services and
        !            61: authentication information,
        !            62: have been properly taken into account in the design of resource location
        !            63: and authentication
        !            64: servers.

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