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Annotation of 43BSD/contrib/X/doc/Usenix/naming.t, revision 1.1.1.1

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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