RFC1353
From RFC-Wiki
Network Working Group K. McCloghrie Request for Comments: 1353 Hughes LAN Systems, Inc.
J. Davin
MIT Laboratory for Computer Science
J. Galvin
Trusted Information Systems, Inc.
July 1992
Definitions of Managed Objects
for Administration of SNMP Parties
Status of this Memo
This document specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Abstract
This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it describes a representation of the SNMP parties defined in [8] as objects defined according to the Internet Standard SMI [1]. These definitions are consistent with the SNMP Security protocols set forth in [9].
Contents
The Network Management Framework
the Internet-standard Network Management Framework consists of three components. They are:
RFC 1155 which defines the SMI, the mechanisms used for describing and naming objects for the purpose of management. RFC 1212 defines a more concise description mechanism, which is wholly consistent with the SMI.
RFC 1156 which defines MIB-I, the core set of managed objects for the Internet suite of protocols. RFC 1213, defines MIB-II, an evolution of MIB-I based on implementation experience and new operational requirements.
RFC 1157 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.
Objects
Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) [5] defined in the SMI. In particular, each object has a name, a syntax, and an encoding. 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 language is used for this purpose. However, the SMI [1] purposely restricts the ASN.1 constructs which may be used. These restrictions are explicitly made for simplicity.
The encoding of an object type is simply how that object type is represented using the object type's syntax. Implicitly tied to the notion of an object type's syntax and encoding is how the object type is represented when being transmitted on the network.
The SMI specifies the use of the basic encoding rules of ASN.1 [6], subject to the additional requirements imposed by the SNMP.
Format of Definitions
Section 4 contains the specification of all object types contained in this MIB module. The object types are defined using the conventions defined in the SMI, as amended by the extensions specified in [7].
Overview
Structure
This MIB contains the definitions for four tables, a number of OBJECT IDENTIFIER assignments, and some conventions for initial use with some of the assignments. The four tables are the SNMP Party Public database, the SNMP Party Secrets database, the SNMP Access Control database, and the SNMP Views database.
The SNMP Party Public database and the SNMP Party Secrets database are defined as separate tables specifically for the purpose of positioning them in different parts of the MIB tree namespace. In particular, the SNMP Party Secrets database contains secret information, for which security demands that access to it be limited to parties which use both authentication and privacy. It is therefore positioned in a separate branch of the MIB tree so as to provide for the easiest means of accommodating the required limitation.
In contrast, the SNMP Party Public database contains public information about SNMP parties. In particular, it contains the parties' clocks which need to be read-able (but not write-able) by unauthenticated queries, since an unauthenticated query of a party's clock is the first step of the procedure to re-establish clock synchronization (see [9]).
The objects in this MIB are organized into four groups. All four of the groups are mandatory for those SNMP implementations that realize the security framework and mechanisms defined in [8] and [9].
Instance Identifiers
In all four of the tables in this MIB, the object instances are identified by values which have an underlying syntax of OBJECT IDENTIFIER. For the Party Public database and the Party Secrets database, the index variable is the party identifier. For the Access Control database and the Views database, two index variables are defined, both of which have a syntax of OBJECT IDENTIFIER. (See the INDEX clauses in the MIB definitions below for the specific variables.)
According to RFC 1212 [7], section 4.1.6, the syntax of the object(s) specified in an INDEX clause indicates how to form the instance- identifier. In particular, for each index object which is object identifier-valued, its contribution to the instance identifier is:
`n+1' sub-identifiers, where `n' is the number of sub-identifiers in the value (the first sub-identifier is `n' itself, following this, each sub-identifier in the value is copied).
Textual Conventions
The datatypes, Party, Clock, and TAddress, are used as textual conventions in this document. These textual conventions have NO effect on either the syntax nor the semantics of any managed object. Objects defined using these conventions are always encoded by means of the rules that define their primitive type. Hence, no changes to the SMI or the SNMP are necessary to accommodate these textual conventions which are adopted merely for the convenience of readers.
Definitions
RFC1353-MIB DEFINITIONS ::= BEGIN
IMPORTS
system, mib, private, internet FROM RFC1155-SMI
OBJECT-TYPE FROM RFC-1212;
snmpParties OBJECT IDENTIFIER ::= { mib-2 20 }
partyAdmin OBJECT IDENTIFIER ::= { snmpParties 1 }
partyPublic OBJECT IDENTIFIER ::= { snmpParties 2 }
snmpSecrets OBJECT IDENTIFIER ::= { mib-2 21 }
partyPrivate OBJECT IDENTIFIER ::= { snmpSecrets 1 }
partyAccess OBJECT IDENTIFIER ::= { snmpSecrets 2 }
partyViews OBJECT IDENTIFIER ::= { snmpSecrets 3 }
-- Textual Conventions
-- A textual convention denoting a SNMP party identifier:
Party ::= OBJECT IDENTIFIER
-- A party's authentication clock - a non-negative integer
-- which is incremented as specified/allowed by the party's
-- Authentication Protocol.
-- For noAuth, a party's authentication clock is unused and
-- its value is undefined.
-- For md5AuthProtocol, a party's authentication clock is a
-- relative clock with 1-second granularity.
Clock ::= INTEGER (0..2147483647)
-- A textual convention denoting a transport service
-- address.
-- For rfc1351Domain, a TAddress is 6 octets long,
-- the initial 4 octets containing the IP-address in
-- network-byte order and the last 2 containing the
-- UDP port in network-byte order.
TAddress ::= OCTET STRING
--- Definitions of Security Protocols
partyProtocols
OBJECT IDENTIFIER ::= { partyAdmin 1 }
noAuth -- The protocol without authentication
OBJECT IDENTIFIER ::= { partyProtocols 1 }
noPriv -- The protocol without privacy
OBJECT IDENTIFIER ::= { partyProtocols 3 }
desPrivProtocol -- The DES Privacy Protocol
OBJECT IDENTIFIER ::= { partyProtocols 4 }
md5AuthProtocol -- The MD5 Authentication Protocol
OBJECT IDENTIFIER ::= { partyProtocols 5 }
--- definitions of Transport Domains
transportDomains
OBJECT IDENTIFIER ::= { partyAdmin 2 }
rfc1351Domain --- RFC-1351 (SNMP over UDP, using SNMP Parties)
OBJECT IDENTIFIER ::= { transportDomains 1 }
--- definitions of Proxy Domains
proxyDomains
OBJECT IDENTIFIER ::= { partyAdmin 3 }
noProxy --- Local operation
OBJECT IDENTIFIER ::= { proxyDomains 1 }
--- Definition of Initial Party Identifiers
-- When devices are installed, they need to be configured
-- with an initial set of SNMP parties. The configuration
-- of SNMP parties requires (among other things) the
-- assignment of several OBJECT IDENTIFIERs. Any local
-- network administration can obtain the delegated
-- authority necessary to assign its own OBJECT
-- IDENTIFIERs. However, to provide for those
-- administrations who have not obtained the necessary
-- authority, this document allocates a branch of the
-- naming tree for use with the following conventions.
initialPartyId
OBJECT IDENTIFIER ::= { partyAdmin 4 }
-- Note these are identified as "initial" party identifiers
-- since these allow secure SNMP communication to proceed,
-- thereby allowing further SNMP parties to be configured
-- through use of the SNMP itself.
-- The following definitions identify a party identifier,
-- and specify the initial values of various object
-- instances indexed by that identifier. In addition,
-- the initial MIB view and access control parameters
-- assigned, by convention, to these parties are identified.
-- Party Identifiers for use as initial SNMP parties
-- at IP address a.b.c.d
-- partyIdentity = { initialPartyId a b c d 1 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = a.b.c.d, 161
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { noAuth }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = h (the empty string)
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 0
-- partyPrivProtocol = { noPriv }
-- partySecretsPrivPrivate = h (the empty string)
-- partyPrivPublic = h (the empty string)
-- partyIdentity = { initialPartyId a b c d 2 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = assigned by local administration
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { noAuth }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = h (the empty string)
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 0
-- partyPrivProtocol = { noPriv }
-- partySecretsPrivPrivate = h (the empty string)
-- partyPrivPublic = h (the empty string)
-- partyIdentity = { initialPartyId a b c d 3 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = a.b.c.d, 161
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { md5AuthProtocol }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = assigned by local administration
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 300
-- partyPrivProtocol = { noPriv }
-- partySecretsPrivPrivate = h (the empty string)
-- partyPrivPublic = h (the empty string)
-- partyIdentity = { initialPartyId a b c d 4 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = assigned by local administration
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { md5AuthProtocol }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = assigned by local administration
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 300
-- partyPrivProtocol = { noPriv }
-- partySecretsPrivPrivate = h (the empty string)
-- partyPrivPublic = h (the empty string)
-- partyIdentity = { initialPartyId a b c d 5 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = a.b.c.d, 161
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { md5AuthProtocol }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = assigned by local administration
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 300
-- partyPrivProtocol = { desPrivProtocol }
-- partySecretsPrivPrivate = assigned by local administration
-- partyPrivPublic = h (the empty string)
-- partyIdentity = { initialPartyId a b c d 6 }
-- partyTDomain = { rfc1351Domain }
-- partyTAddress = assigned by local administration
-- partyProxyFor = { noProxy }
-- partyAuthProtocol = { md5AuthProtocol }
-- partyAuthClock = 0
-- partySecretsAuthPrivate = assigned by local administration
-- partyAuthPublic = h (the empty string)
-- partyAuthLifetime = 300
-- partyPrivProtocol = { desPrivProtocol }
-- partySecretsPrivPrivate = assigned by local administration
-- partyPrivPublic = h (the empty string)
-- The initial access control parameters assigned, by
-- convention, to these parties are:
-- aclTarget = { initialPartyId a b c d 1 }
-- aclSubject = { initialPartyId a b c d 2 }
-- aclPrivileges = 3 (Get & Get-Next)
-- aclTarget = { initialPartyId a b c d 2 }
-- aclSubject = { initialPartyId a b c d 1 }
-- aclPrivileges = 20 (GetResponse & Trap)
-- aclTarget = { initialPartyId a b c d 3 }
-- aclSubject = { initialPartyId a b c d 4 }
-- aclPrivileges = 11 (Get, Get-Next & Set)
-- aclTarget = { initialPartyId a b c d 4 }
-- aclSubject = { initialPartyId a b c d 3 }
-- aclPrivileges = 20 (GetResponse & Trap)
-- aclTarget = { initialPartyId a b c d 5 }
-- aclSubject = { initialPartyId a b c d 6 }
-- aclPrivileges = 11 (Get, Get-Next & Set)
-- aclTarget = { initialPartyId a b c d 6 }
-- aclSubject = { initialPartyId a b c d 5 }
-- aclPrivileges = 20 (GetResponse & Trap)
-- The initial MIB views assigned, by convention, to
-- these parties are:
-- viewParty = { initialPartyId a b c d 1 }
-- viewSubtree = { system }
-- viewStatus = { included }
-- viewMask = { h }
-- viewParty = { initialPartyId a b c d 1 }
-- viewSubtree = { snmpParties }
-- viewStatus = { included }
-- viewMask = { h }
-- viewParty = { initialPartyId a b c d 3 }
-- viewSubtree = { internet }
-- viewStatus = { included }
-- viewMask = { h }
-- viewParty = { initialPartyId a b c d 3 }
-- viewSubtree = { partyPrivate }
-- viewStatus = { excluded }
-- viewMask = { h }
-- viewParty = { initialPartyId a b c d 5 }
-- viewSubtree = { internet }
-- viewStatus = { included }
-- viewMask = { h }
-- The SNMP Party Public Database Group
--
-- The non-secret party information.
--
-- Implementation of the objects in this group is mandatory.
partyTable OBJECT-TYPE
SYNTAX SEQUENCE OF PartyEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The SNMP Party Public database.
An agent must ensure that there is, at all times,
a one-to-one correspondence between entries in
this table and entries in the partySecretsTable.
The creation/deletion of instances in this table
via SNMP Set-Requests is not allowed. Instead,
entries in this table are created/deleted as a
side-effect of the creation/deletion of
corresponding entries in the partySecretsTable.
Thus, a SNMP Set-Request whose varbinds contain a
reference to a non-existent instance of a
partyTable object, but no reference to the
corresponding instance of a partySecretsTable
object, will be rejected."
::= { partyPublic 1 }
partyEntry OBJECT-TYPE
SYNTAX PartyEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Locally held non-secret information about a
particular SNMP party, which is available for
access by network management. Note that this does
not include all locally held information about a
party. In particular, it does not include the
'last-timestamp' (i.e., the timestamp of the last
authentic message received) or the 'nonce'
values."
INDEX { partyIdentity }
::= { partyTable 1 }
PartyEntry ::=
SEQUENCE {
partyIdentity
Party,
partyTDomain
OBJECT IDENTIFIER,
partyTAddress
TAddress,
partyProxyFor
Party,
partyAuthProtocol
OBJECT IDENTIFIER,
partyAuthClock
Clock,
partyAuthPublic
OCTET STRING,
partyAuthLifetime
INTEGER,
partyPrivProtocol
OBJECT IDENTIFIER,
partyPrivPublic
OCTET STRING,
partyMaxMessageSize
INTEGER,
partyStatus
INTEGER
}
partyIdentity OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A party identifier uniquely identifying a
particular SNMP party."
::= { partyEntry 1 }
partyTDomain OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"Indicates the kind of transport service by which
the party receives network management traffic. An
example of a transport domain is 'rfc1351Domain'
(SNMP over UDP)."
DEFVAL { rfc1351Domain }
::= { partyEntry 2 }
partyTAddress OBJECT-TYPE
SYNTAX TAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The transport service address by which the party
receives network management traffic, formatted
according to the corresponding value of
partyTDomain. For rfc1351Domain, partyTAddress is
formatted as a 4-octet IP Address concatenated
with a 2-octet UDP port number."
DEFVAL { '000000000000'h }
::= { partyEntry 3 }
partyProxyFor OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The identity of a second SNMP party or other
management entity with which interaction may be
necessary to satisfy received management requests.
In this context, the distinguished value { noProxy
} signifies that the party responds to received
management requests by entirely local mechanisms."
DEFVAL { noProxy }
::= { partyEntry 4 }
partyAuthProtocol OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The authentication protocol by which all messages
generated by the party are authenticated as to
origin and integrity. In this context, the value
{ noAuth } signifies that messages generated by
the party are not authenticated."
DEFVAL { md5AuthProtocol }
::= { partyEntry 5 }
partyAuthClock OBJECT-TYPE
SYNTAX Clock
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The authentication clock which represents the
local notion of the current time specific to the
party. This value must not be decremented unless
the party's secret information is changed
simultaneously, at which time the party's nonce
and last-timestamp values must also be reset to
zero, and the new value of the clock,
respectively."
DEFVAL { 0 }
::= { partyEntry 6 }
partyAuthPublic OBJECT-TYPE
SYNTAX OCTET STRING -- for md5AuthProtocol: (SIZE (0..16))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A publically-readable value for the party.
Depending on the party's authentication protocol,
this value may be needed to support the party's
authentication protocol. Alternatively, it may be
used by a manager during the procedure for
altering secret information about a party. (For
example, by altering the value of an instance of
this object in the same SNMP Set-Request used to
update an instance of partyAuthPrivate, a
subsequent Get-Request can determine if the Set-
Request was successful in the event that no
response to the Set-Request is received, see RFC
1352.)
The length of the value is dependent on the
party's authentication protocol. If not used by
the authentication protocol, it is recommended
that agents support values of any length up to and
including the length of the corresponding
partyAuthPrivate object."
DEFVAL { h } -- the empty string
::= { partyEntry 7 }
partyAuthLifetime OBJECT-TYPE
SYNTAX INTEGER (0..2147483647)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The lifetime (in units of seconds) which
represents an administrative upper bound on
acceptable delivery delay for protocol messages
generated by the party."
DEFVAL { 300 }
::= { partyEntry 8 }
partyPrivProtocol OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The privacy protocol by which all protocol
messages received by the party are protected from
disclosure. In this context, the value { noPriv }
signifies that messages received by the party are
not protected."
DEFVAL { noPriv }
::= { partyEntry 9 }
partyPrivPublic OBJECT-TYPE
SYNTAX OCTET STRING -- for desPrivProtocol: (SIZE (0..16))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A publically-readable value for the party.
Depending on the party's privacy protocol, this
value may be needed to support the party's privacy
protocol. Alternatively, it may be used by a
manager as a part of its procedure for altering
secret information about a party. (For example,
by altering the value of an instance of this
object in the same SNMP Set-Request used to update
an instance of partyPrivPrivate, a subsequent
Get-Request can determine if the Set-Request was
successful in the event that no response to the
Set-Request is received, see RFC 1352.)
The length of the value is dependent on the
party's privacy protocol. If not used by the
privacy protocol, it is recommended that agents
support values of any length up to and including
the length of the corresponding partyPrivPrivate
object."
DEFVAL { h } -- the empty string
::= { partyEntry 10 }
partyMaxMessageSize OBJECT-TYPE
SYNTAX INTEGER (484..65507)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The maximum length in octets of a SNMP message
which this party will accept. For parties which
execute at an agent, the agent initializes this
object to the maximum length supported by the
agent, and does not let the object be set to any
larger value. For parties which do not execute at
the agent, the agent must allow the manager to set
this object to any legal value, even if it is
larger than the agent can generate."
DEFVAL { 484 }
::= { partyEntry 11 }
partyStatus OBJECT-TYPE
SYNTAX INTEGER { valid(1), invalid(2) }
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The status of the locally-held information on a
particular SNMP party.
The instance of this object for a particular party
and the instance of partySecretsStatus for the
same party always have the same value.
This object will typically provide unrestricted
read-only access to the status of parties. In
contrast, partySecretsStatus will typically
provide restricted read-write access to the status
of parties."
::= { partyEntry 12 }
-- The SNMP Party Secrets Database Group
-- The secret party information
--
-- Implementation of the objects in this group is mandatory.
partySecretsTable OBJECT-TYPE
SYNTAX SEQUENCE OF PartySecretsEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The SNMP Party Secrets database."
::= { partyPrivate 1 }
partySecretsEntry OBJECT-TYPE
SYNTAX PartySecretsEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Locally held secret information about a
particular SNMP party, which is available for
access by network management.
When a SNMP Set-Request is used to update the
values of instances of objects in this table, it
is recommended that the same SNMP Set-Request also
alter the value of a non-secret object instance
(e.g., an instance of partyAuthPublic or
partyPrivPublic). This allows a Get-Request of
that non-secret object instance to determine if
the Set-Request was successful in the event that
no response which matches the Set-Request is
received, see RFC 1352."
INDEX { partySecretsIdentity }
::= { partySecretsTable 1 }
PartySecretsEntry ::=
SEQUENCE {
partySecretsIdentity
Party,
partySecretsAuthPrivate
OCTET STRING,
partySecretsPrivPrivate
OCTET STRING,
partySecretsStatus
INTEGER
}
partySecretsIdentity OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A party identifier uniquely identifying a
particular SNMP party."
::= { partySecretsEntry 1 }
partySecretsAuthPrivate OBJECT-TYPE
SYNTAX OCTET STRING -- for md5AuthProtocol: (SIZE (16))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An encoding of the party's private authentication
key which may be needed to support the
authentication protocol. Although the value of
this variable may be altered by a management
operation (e.g., a SNMP Set-Request), its value
can never be retrieved by a management operation:
when read, the value of this variable is the zero
length OCTET STRING.
The private authentication key is NOT directly
represented by the value of this variable, but
rather it is represented according to an encoding.
This encoding is the bitwise exclusive-OR of the
old key with the new key, i.e., of the old private
authentication key (prior to the alteration) with
the new private authentication key (after the
alteration). Thus, when processing a received
protocol Set operation, the new private
authentication key is obtained from the value of
this variable as the result of a bitwise
exclusive-OR of the variable's value and the old
private authentication key. In calculating the
exclusive-OR, if the old key is shorter than the
new key, zero-valued padding is appended to the
old key. If no value for the old key exists, a
zero-length OCTET STRING is used in the
calculation."
DEFVAL { h } -- the empty string
::= { partySecretsEntry 2 }
partySecretsPrivPrivate OBJECT-TYPE
SYNTAX OCTET STRING -- for desPrivProtocol: (SIZE (16))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An encoding of the party's private encryption key
which may be needed to support the privacy
protocol. Although the value of this variable may
be altered by a management operation (e.g., a SNMP
Set-Request), its value can never be retrieved by
a management operation: when read, the value of
this variable is the zero length OCTET STRING.
The private encryption key is NOT directly
represented by the value of this variable, but
rather it is represented according to an encoding.
This encoding is the bitwise exclusive-OR of the
old key with the new key, i.e., of the old private
encryption key (prior to the alteration) with the
new private encryption key (after the alteration).
Thus, when processing a received protocol Set
operation, the new private encryption key is
obtained from the value of this variable as the
result of a bitwise exclusive-OR of the variable's
value and the old private encryption key. In
calculating the exclusive-OR, if the old key is
shorter than the new key, zero-valued padding is
appended to the old key. If no value for the old
key exists, a zero-length OCTET STRING is used in
the calculation."
DEFVAL { h } -- the empty string
::= { partySecretsEntry 3 }
partySecretsStatus OBJECT-TYPE
SYNTAX INTEGER { valid(1), invalid(2) }
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of the locally-held information on a
particular SNMP party.
Setting an instance of this object to the value
'valid(1)' has the effect of ensuring that valid
local knowledge exists for the corresponding
party. For valid local knowledge to exist, there
must be corresponding instances of each object in
this table and in the partyTable. Thus, the
creation of instances in the partyTable (but not
in the aclTable or viewTable) occurs as a direct
result of the creation of instances in this table.
Setting an instance of this object to the value
'invalid(2)' has the effect of invalidating all
local knowledge of the corresponding party,
including the invalidating of any/all entries in
the partyTable, the partySecretsTable, the
aclTable, and the viewTable which reference said
party.
It is an implementation-specific matter as to
whether the agent removes an invalidated entry
from the table. Accordingly, management stations
must be prepared to receive from agents tabular
information corresponding to entries not currently
in use. Proper interpretation of such entries
requires examination of the relevant
partySecretsStatus object."
DEFVAL { valid }
::= { partySecretsEntry 4 }
-- The SNMP Access Privileges Database Group
-- This group of objects allows the SNMP itself to be used to
-- configure new SNMP parties, or to manipulate the access
-- privileges of existing parties.
--
-- Implementation of the objects in this group is mandatory.
aclTable OBJECT-TYPE
SYNTAX SEQUENCE OF AclEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The access privileges database."
::= { partyAccess 1 }
aclEntry OBJECT-TYPE
SYNTAX AclEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The access privileges for a particular requesting
SNMP party in accessing a particular target SNMP
party."
INDEX { aclTarget, aclSubject }
::= { aclTable 1 }
AclEntry ::=
SEQUENCE {
aclTarget
Party,
aclSubject
Party,
aclPrivileges
INTEGER,
aclStatus
INTEGER
}
aclTarget OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The target SNMP party whose performance of
management operations is constrained by this set
of access privileges."
::= { aclEntry 1 }
aclSubject OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The subject SNMP party whose requests for
management operations to be performed is
constrained by this set of access privileges."
::= { aclEntry 2 }
aclPrivileges OBJECT-TYPE
SYNTAX INTEGER (0..31)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The access privileges which govern what
management operations a particular target party
may perform when requested by a particular subject
party. These privileges are specified as a sum of
values, where each value specifies a SNMP PDU type
by which the subject party may request a permitted
operation. The value for a particular PDU type is
computed as 2 raised to the value of the ASN.1
context-specific tag for the appropriate SNMP PDU
type. The values (for the tags defined in RFC
1157) are defined in RFC 1351 as:
Get : 1
GetNext : 2
GetResponse : 4
Set : 8
Trap : 16
The null set is represented by the value zero."
DEFVAL { 3 } -- Get & Get-Next
::= { aclEntry 3 }
aclStatus OBJECT-TYPE
SYNTAX INTEGER { valid(1), invalid(2) }
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of the access privileges for a
particular requesting SNMP party in accessing a
particular target SNMP party. Setting an instance
of this object to the value 'invalid(2)' has the
effect of invalidating the corresponding access
privileges.
It is an implementation-specific matter as to
whether the agent removes an invalidated entry
from the table. Accordingly, management stations
must be prepared to receive from agents tabular
information corresponding to entries not currently
in use. Proper interpretation of such entries
requires examination of the relevant aclStatus
object."
DEFVAL { valid }
::= { aclEntry 4 }
-- The MIB View Database Group
-- This group of objects allows the SNMP itself to be used to
-- configure new SNMP parties, or to manipulate the MIB
-- MIB views of existing parties.
--
-- Implementation of the objects in this group is mandatory.
viewTable OBJECT-TYPE
SYNTAX SEQUENCE OF ViewEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The table contained in the local database which
defines local MIB views. Each SNMP party has a
single MIB view which is defined by two
collections of view subtrees: the included view
subtrees, and the excluded view subtrees. Every
such subtree, both included and excluded, is
defined in this table.
To determine if a particular object instance is in
a particular SNMP party's MIB view, compare the
object instance's Object Identifier with each
entry (for this party) in this table. If none
match, then the object instance is not in the MIB
view. If one or more match, then the object
instance is included in, or excluded from, the MIB
view according to the value of viewStatus in the
entry whose value of viewSubtree has the most
sub-identifiers. If multiple entries match and
have the same number of sub-identifiers, then the
lexicographically greatest instance of viewStatus
determines the inclusion or exclusion.
An object instance's Object Identifier X matches
an entry in this table when the number of sub-
identifiers in X is at least as many as in the
value of viewSubtree for the entry, and each sub-
identifier in the value of viewSubtree matches its
corresponding sub-identifier in X. Two sub-
identifiers match either if the corresponding bit
of viewMask is zero (the 'wild card' value), or if
they are equal.
Due to this 'wild card' capability, we introduce
the term, a 'family' of view subtrees, to refer to
the set of subtrees defined by a particular
combination of values of viewSubtree and viewMask.
In the case where no 'wild card' is defined in
viewMask, the family of view subtrees reduces to a
single view subtree."
::= { partyViews 1 }
viewEntry OBJECT-TYPE
SYNTAX ViewEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Information on a particular family of view
subtrees included in or excluded from a particular
SNMP party's MIB view."
INDEX { viewParty, viewSubtree }
::= { viewTable 1 }
ViewEntry ::=
SEQUENCE {
viewParty
Party,
viewSubtree
OBJECT IDENTIFIER,
viewStatus
INTEGER,
viewMask
OCTET STRING
}
viewParty OBJECT-TYPE
SYNTAX Party
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The SNMP party whose single MIB view includes or
excludes a particular family of view subtrees."
::= { viewEntry 1 }
viewSubtree OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The view subtree which, in combination with the
corresponding instance of viewMask, defines a
family of view subtrees. This family is included
in, or excluded from the particular SNMP party's
MIB view, according to the value of the
corresponding instance of viewStatus."
::= { viewEntry 2 }
viewStatus OBJECT-TYPE
SYNTAX INTEGER {
included(1),
excluded(2),
invalid(3)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The status of a particular family of view
subtrees within the particular SNMP party's MIB
view. The value 'included(1)' indicates that the
corresponding instances of viewSubtree and
viewMask define a family of view subtrees included
in the MIB view. The value 'excluded(2)'
indicates that the corresponding instances of
viewSubtree and viewMask define a family of view
subtrees excluded from the MIB view.
Setting an instance of this object to the value
'invalid(3)' has the effect of invalidating the
presence or absence of the corresponding family of
view subtrees in the corresponding SNMP party's
MIB view.
It is an implementation-specific matter as to
whether the agent removes an invalidated entry
from the table. Accordingly, management stations
must be prepared to receive from agents tabular
information corresponding to entries not currently
in use. Proper interpretation of such entries
requires examination of the relevant viewStatus
object."
DEFVAL { included }
::= { viewEntry 3 }
viewMask OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..16))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The bit mask which, in combination with the
corresponding instance of viewSubtree, defines a
family of view subtrees.
Each bit of this bit mask corresponds to a sub-
identifier of viewSubtree, with the most
significant bit of the i-th octet of this octet
string value (extended if necessary, see below)
corresponding to the (8*i - 7)-th sub-identifier,
and the least significant bit of the i-th octet of
this octet string corresponding to the (8*i)-th
sub-identifier, where i is in the range 1 through
16.
Each bit of this bit mask specifies whether or not
the corresponding sub-identifiers must match when
determining if an Object Identifier is in this
family of view subtrees; a '1' indicates that an
exact match must occur; a '0' indicates 'wild
card', i.e., any sub-identifier value matches.
Thus, the Object Identifier X of an object
instance is contained in a family of view subtrees
if the following criteria are met:
for each sub-identifier of the value of
viewSubtree, either:
the i-th bit of viewMask is 0, or
the i-th sub-identifier of X is equal to
the i-th sub-identifier of the value of
viewSubtree.
If the value of this bit mask is M bits long and
there are more than M sub-identifiers in the
corresponding instance of viewSubtree, then the
bit mask is extended with 1's to be the required
length.
Note that when the value of this object is the
zero-length string, this extension rule results in
a mask of all-1's being used (i.e., no 'wild
card'), and the family of view subtrees is the one
view subtree uniquely identified by the
corresponding instance of viewSubtree."
DEFVAL { h }
::= { viewEntry 4 }
END
Acknowledgments
This document was produced on behalf of the SNMP Security Working Group of the Internet Engineering Task Force. The authors wish to thank the members of the working group, and others who contributed to this effort.
References
[1] Rose, M., and K. McCloghrie, "Structure and Identification of
Management Information for TCP/IP based internets", RFC 1155, Performance Systems International, Hughes LAN Systems, May 1990.
[2] McCloghrie, K., and M. Rose, "Management Information Base for
Network Management of TCP/IP-based Internets", RFC 1156, Hughes LAN Systems and Performance Systems International, May 1990.
[3] Case, J., M. Fedor, M. Schoffstall, and J. Davin, The Simple
Network Management Protocol", RFC 1157, University of Tennessee at Knoxville, Performance Systems International, Performance Systems International, and the MIT Laboratory for Computer Science, May 1990.
[4] McCloghrie K., and M. Rose, Editors, "Management Information Base
for Network Management of TCP/IP-based internets", RFC 1213, Performance Systems International, March 1991.
[5] Information processing systems - Open Systems Interconnection -
Specification of Abstract Syntax Notation One (ASN.1), International Organization for Standardization, International Standard 8824, December 1987.
[6] Information processing systems - Open Systems Interconnection -
Specification of Basic Encoding Rules for Abstract Notation One (ASN.1), International Organization for Standardization, International Standard 8825, December 1987.
[7] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
RFC 1212, Performance Systems International, Hughes LAN Systems, March 1991.
[8] Davin, J., Galvin, J., and K. McCloghrie, "SNMP Administrative
Model", RFC 1351, MIT Laboratory for Computer Science, Trusted Information Systems, Inc., Hughes LAN Systems, Inc., July 1992.
[9] Galvin, J., McCloghrie, K., and J. Davin, "SNMP Security
Protocols", RFC 1352, Trusted Information Systems, Inc., Hughes LAN Systems, Inc., MIT Laboratory for Computer Science, July
1992.
Security Considerstions
Security issues are discussed in section 3.1. and in RFCs 1351 and 1352.
Authors' Addresses
Keith McCloghrie Hughes LAN Systems, Inc. Mountain View, CA 94043
Phone: (415) 966-7934 EMail: [email protected]
James R. Davin MIT Laboratory for Computer Science 545 Technology Square Cambridge, MA 02139
Phone: (617) 253-6020 EMail: [email protected]
James M. Galvin Trusted Information Systems, Inc. 3060 Washington Road, Route 97 Glenwood, MD 21738
Phone: (301) 854-6889 EMail: [email protected]
