ident-like MIB for SNMP

Mike StJohns <stjohns@umd5.umd.edu> Sat, 11 April 1992 13:38 UTC

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To: ident@nri.reston.va.us
Subject: ident-like MIB for SNMP
Date: Sat, 11 Apr 1992 09:41:57 -0400
From: Mike StJohns <stjohns@umd5.umd.edu>
X-Mts: smtp

What follows is a MIB for SNMP that provides functionality
approximately equal to that of the "ident" protocol.  Marshall Rose
was kind enough to do the work to put this into a formal format.  In
addition, he's already modified his SNMP agent implementation (I think
its the one supplied in ISODE?) to return these variables.

For now, I'm going to ask for discussion of this MIB on the ident list
as many of the issues are the same.  (For ex - the character set issue
and the relationship of the userid to the opsys) If the list gets too
cluttered I'll ask to have a seperate list created.

This MIB is targeted to move onto the standards track.  It is NOT
meant to replace or prevent the ident draft from moving forward also.

Mike



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          Draft                     Ident MIB                     Apr 92


                                    Ident MIB

                             Fri Apr 10 23:01:59 1992


                                Michael St. Johns
                            U.S. Department of Defense
                               stjohns@UMD5.UMD.EDU


                                 Marshall T. Rose
                           Dover Beach Consulting, Inc.
                              mrose@dbc.mtview.ca.us






          1.  Status of this Memo

          This memo provides information for the Internet community.  It
          does not specify any standard.  Distribution of this memo is
          unlimited.  Please send comments to the authors.


          2.  Abstract

          This memo defines a MIB for use with identifying the users
          associated with TCP connections.  It provides functionality
          approximately equivalent to that provided by the protocol
          defined in RFC 931[1].


















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          Draft                     Ident MIB                     Apr 92


          3.  The Network Management Framework

          The Internet-standard Network Management Framework consists of
          three components.  They are:

          RFC 1155[2] which defines the SMI, the mechanisms used for
          describing and naming objects for the purpose of management.
          RFC 1212[3] defines a more concise description mechanism,
          which is wholly consistent with the SMI.

          RFC 1213[4] which defines MIB-II, the core set of managed
          objects for the Internet suite of protocols.

          RFC 1157[5] which defines the SNMP, the protocol used for
          network access to managed objects.

          The Framework permits new objects to be defined for the
          purpose of experimentation and evaluation.

          Managed objects are accessed via a virtual information store,
          termed the Management Information Base or MIB.  Within a given
          MIB module, objects are defined using RFC 1212's OBJECT-TYPE
          macro.  At a minimum, each object has a name, a syntax, an
          access-level, and an implementation-status.

          The name is an object identifier, an administratively assigned
          name, which specifies an object type.  The object type
          together with an object instance serves to uniquely identify a
          specific instantiation of the object.  For human convenience,
          we often use a textual string, termed the object descriptor,
          to also refer to the object type.

          The syntax of an object type defines the abstract data
          structure corresponding to that object type.  The ASN.1[6]
          language is used for this purpose.  However, RFC 1155
          purposely restricts the ASN.1 constructs which may be used.
          These restrictions are explicitly made for simplicity.

          The access-level of an object type defines whether it makes
          "protocol sense" to read and/or write the value of an instance
          of the object type.  (This access-level is independent of any
          administrative authorization policy.)

          The implementation-status of an object type indicates whether
          the object is mandatory, optional, obsolete, or deprecated.





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          Draft                     Ident MIB                     Apr 92


          4.  Ident MIB

          The Ident MIB defines a uniform set of objects useful for
          identifying users associated with TCP connections.














































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          Draft                     Ident MIB                     Apr 92


          5.  Definitions

          RFC-ident-MIB DEFINITIONS ::= BEGIN

          IMPORTS
              experimental
                  FROM RFC-1155
              OBJECT-TYPE
                  FROM RFC-1212
              tcpConnLocalAddress, tcpConnLocalPort,
              tcpConnRemAddress, tcpConnRemPort
                      FROM RFC1213-MIB;


          ident   OBJECT IDENTIFIER ::= { experimental 33 }


          -- conformance groups

          identInfo       OBJECT IDENTIFIER ::= { ident 1 }


          -- textual conventions

          -- none

























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          Draft                     Ident MIB                     Apr 92


          -- the ident information system group
          --
          -- implementation of this group is mandatory

          identTable OBJECT-TYPE
                  SYNTAX  SEQUENCE OF IdentEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                      "A table containing user information for TCP
                      connections.

                      Note that this table contains entries only for TCP
                      connections in the ESTABLISHED state.  Hence, a
                      management protocol retrieval operation on a
                      column which does not correspond to a TCP
                      connection in the ESTABLISHED state will result in
                      a `noSuchName' error."
                  ::= { identInfo 1 }

          identEntry OBJECT-TYPE
                  SYNTAX  IdentEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                      "User information about a particular TCP
                      connection."
                  INDEX   { tcpConnLocalAddress, tcpConnLocalPort,
                            tcpConnRemAddress, tcpConnRemPort }
                  ::= { identTable 1 }

          IdentEntry ::=
              SEQUENCE {
                  identStatus     INTEGER,
                  identOpSys      OBJECT IDENTIFIER,
                  identUserid     OCTET STRING,
                  identMisc       OCTET STRING
              }

          identStatus OBJECT-TYPE
                  SYNTAX  INTEGER {
                              noError(1),
                              unknownError(2)
                          }
                  ACCESS  read-only





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          Draft                     Ident MIB                     Apr 92


                  STATUS  mandatory
                  DESCRIPTION
                      "Indicates whether user information for the
                      associated TCP connection can be determined.  A
                      value of `noError(1)' indicates that user
                      information is available.  A value of
                      `unknownError(2)' indicates that user information
                      is not available."
                  ::= { identEntry 1 }

          identOpSys OBJECT-TYPE
                  SYNTAX  OBJECT IDENTIFIER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                      "Indicates the type of operating system in use.
                      In addition to identifying an operating system,
                      each assignment made for this purpose also
                      (implicitly) identifies the syntax, maximum size,
                      and repertoire of the corresponding identUserid
                      and identMisc objects.

                      The `identSystems' subtree may be used for
                      assignments."
                  ::= { identEntry 2 }

          identUserid OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                      "Indicates the user's identity.  Interpretation of
                      this object requires examination of the
                      corresponding value of the identOpSys object."
                  ::= { identEntry 3 }

          identMisc OBJECT-TYPE
                  SYNTAX  OCTET STRING (SIZE (0..255))
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                      "Indicates the user's identity.  Interpretation of
                      this object requires examination of the
                      corresponding value of the identOpSys object."
                  ::= { identEntry 4 }





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          Draft                     Ident MIB                     Apr 92


          -- operating system assignments, used for identOpSys

          identSystems    OBJECT IDENTIFIER ::= { ident 2 }

          -- when the Assigned Numbers "system name" is UNIX
          identSysUnix    OBJECT IDENTIFIER ::= { identSystems 1 }
          -- when identOpSys has the value identSysUnix:
          --
          --      identUserid corresponds to the UNIX username (pw_name)
          --          of length 1 to 8 octets
          --          from the NVT ASCII repertoire
          --
          --      the syntax (and length) of identMisc is a local matter,
          --          but the NVT ASCII repertoire is used


          END

































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          6.  Security Considerations

          The information available through this MIB is at most as
          trustworthy as the host providing it OR the organization
          operating the host.  For example, a PC in an open lab has few
          if any controls on it to prevent a user from having an SNMP
          query return any identifier the user wants.  Likewise, if the
          host has been compromised the information returned may be
          completely erroneous and misleading.

          This portion of the MIB space should only be used to gain
          hints as to who "owns" a particular TCP connection --
          information returned should NOT be considered authoritative
          for at least the reasons described above.  At best, this MIB
          provides some additional auditing information with respect to
          TCP connections.  At worse it can provide misleading,
          incorrect or maliciously incorrect information.  UNDER NO
          CIRCUMSTANCES should information returned from this MIB space
          be used to make access control decisions -- either as the
          primary method (i.e., no other checks) or as an adjunct to
          other methods.

          This MIB provides access to information that some systems
          might consider privacy-related.  The information accessible
          through this MIB is roughly as revealing as that returned by
          the "finger" server and protocol[7].  Access to this portion
          of the MIB tree may be controlled under the normal methods
          available through SNMP agent implementations.






















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          Draft                     Ident MIB                     Apr 92


          7.  References

          [1]  M. St. Johns, Authentication Server.  Request for
               Comments 931, (May, 1990).

          [2]  M.T. Rose and K. McCloghrie, Structure and Identification
               of Management Information for TCP/IP-based internets.
               Request for Comments 1155, (May, 1990).

          [3]  M.T. Rose and K. McCloghrie, Concise MIB Definitions.
               Request for Comments 1212, (March, 1991).

          [4]  K. McCloghrie and M.T. Rose, Management Information Base
               for Network Management of TCP/IP-based internets: MIB-II.
               Request for Comments 1213, (March, 1991).

          [5]  J.D. Case, M.S. Fedor, M.L. Schoffstall, and J.R. Davin,
               Simple Network Management Protocol.  Request for Comments
               1157, (May, 1990).

          [6]  Information processing systems - Open Systems
               Interconnection - Specification of Abstract Syntax
               Notation One (ASN.1), International Organization for
               Standardization.  International Standard 8824, (December,
               1987).

          [7]  D.P. Zimmerman, Finger User Information Protocol.
               Request for Comments 1288, (December, 1991).






















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          Draft                     Ident MIB                     Apr 92


          Table of Contents


          1 Status of this Memo ...................................    1
          2 Abstract ..............................................    1
          3 The Network Management Framework ......................    2
          4 Ident MIB .............................................    3
          5 Definitions ...........................................    4
          5.1 Conformance Groups ..................................    4
          5.2 Textual Conventions .................................    4
          5.3 The Ident information Group .........................    5
          5.4 Operating System Assignments ........................    7
          5.4.1 identSysUnix ......................................    7
          6 Security Considerations ...............................    8
          7 References ............................................    9



































          St. Johns, Rose                                      [Page 10]





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