Internet Draft M. Condell, BBN
draft-ietf-ipsp-spsl-00.txt C. Lynn, BBN
Expires September 2000 J. Zao, BBN
March 10, 2000
Security Policy Specification Language
Status of this Memo
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Abstract
This document describes the Security Policy Specification Language
(SPSL), a language designed to express security policies, security
domains, and the entities that manage the policies and domains. The
syntax and semantics of the language are presented here. SPSL
currently supports policies for packet filtering, IP Security (IPsec),
and IKE exchanges. However, it may easily be extended to express
other types of policies.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Language Requirements . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Specification of Security Policies. . . . . . . . . . . . . 3
1.1.2 Node- and Domain-Based Models . . . . . . . . . . . . . . . 4
1.1.3 Multiple Distributed Policy Enforcement Points. . . . . . . 5
1.1.4 Authentication and Authorization Mechanisms . . . . . . . . 5
1.1.5 Language Flexibility and Extensibility. . . . . . . . . . . 5
1.2 Language Structure. . . . . . . . . . . . . . . . . . . . . . . 6
1.2.1 Categories. . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2.2 Class Design. . . . . . . . . . . . . . . . . . . . . . . . 7
1.2.3 Naming Scheme and Scope . . . . . . . . . . . . . . . . . . 8
1.2.4 $INCLUDE Extension. . . . . . . . . . . . . . . . . . . . . 8
1.2.5 File Structure. . . . . . . . . . . . . . . . . . . . . . . 8
2. Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Management Agent Classes . . . . . . . . . . . . . . . . . . . . . 11
3.1 mntner Class. . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 cert Class. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Network Entity Classes . . . . . . . . . . . . . . . . . . . . . . 15
4.1 node Class. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2 node-set Class. . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3 gateway Class . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.4 gateway-set Class . . . . . . . . . . . . . . . . . . . . . . . 17
4.5 polserv Class . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.6 domain Class. . . . . . . . . . . . . . . . . . . . . . . . . . 19
5. Policy Class . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1 policy Attribute (Short Format) . . . . . . . . . . . . . . . . 21
5.2 policy Attribute (Long Format). . . . . . . . . . . . . . . . . 23
5.3 ipsec-policy Class. . . . . . . . . . . . . . . . . . . . . . . 28
5.4 Selectors and Actions . . . . . . . . . . . . . . . . . . . . . 33
5.5 Policy Order. . . . . . . . . . . . . . . . . . . . . . . . . . 34
6. Security Considerations. . . . . . . . . . . . . . . . . . . . . . 34
6.1 Authenticate the Maintainer . . . . . . . . . . . . . . . . . . 34
6.2 Verify the Objects. . . . . . . . . . . . . . . . . . . . . . . 35
6.3 Protect File from Tampering . . . . . . . . . . . . . . . . . . 35
7. Remaining Issues . . . . . . . . . . . . . . . . . . . . . . . . . 35
8. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appendix A. BNF Form of SPSL . . . . . . . . . . . . . . . . . . . . 36
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Author Information. . . . . . . . . . . . . . . . . . . . . . . . . . 45
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1. Introduction
The Security Policy Specification Language (SPSL) is a vendor and
platform independent language for specifying communication security
policies, especially those controlling the use of IPsec and IKE
protocols. As the use of firewalls with strong authentication and
virtual private networks (VPNs) with level 2 and 3 encryption become
more popular, the need to manage these security services and devices
by means of security policies also becomes more acute. SPSL allows
the security policies to be specified in an interoperable language,
stored in common databases and processed by management systems
separate from the security devices. As such, SPSL is a main component
of a scalable policy based security management system [IPSP-PDA].
The syntax of SPSL and several of its supporting object classes were
derived from the Routing Policy Specification Language [RPSL].
However, the processing rules of SPSL are significantly different from
those of RPSL. Although the language was designed initially for
specifying IPsec and IKE policies, its flexible syntax allows it to
be used to express stateless and stateful packet filtering rules.
Moreover, the language is extensible: new object classes can be added
for the purpose of specifying policies of other security or
communication protocols.
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in RFC 2119 [Bra97].
1.1 Language Requirements
SPSL was designed to meet the following requirements:
* Support for IPsec/IKE and general communication security
policy specification,
* Support for both node- and domain-based policy models,
* Support for multiple distributed policy enforcement points,
* Support for authentication and authorization mechanisms to aid
policy management,
* Support for flexibility and extensibility of the language.
1.1.1 Specification of Security Policies
In SPSL, a policy is defined as a binding between a set of
communication conditions and a corresponding set of security actions.
This abstraction is used to specify communication security policies in
general and IPsec/IKE policies in particular. If an on-going
communication (or one to be established) matches one of the conditions
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then one of the prioritized alternative sets of actions must be taken
to protect the communication. This abstraction also captures current
policy enforcement practices.
The set of communication conditions in a policy are specified as one
or more tuples of selector values. This is because IPsec transports
and tunnels depend on security associations that are attached to
specific values of chosen communication parameters, known as the
selectors. SPSL supports all the selectors mentioned in IPsec
architecture document [Kent98] and a much extended collection as
described in Section 5.4.
The actions of a policy can affect different communication security
operations:
* They may specify simple packet filtering actions: discard the
packet, pass it, or forward it to a designated network entity.
* They may specify security proposals necessary for protecting
IKE exchanges.
* They may specify IPsec tunnels or transports for passing the
packets. The possible security mechanisms to protect the tunnels
and the transports are IKE proposals as specified in the IPsec
Domain of Interpretation [rfc2407].
SPSL supports the IPsec policy data model [PolMod] proposed by Pereira
and Bhattacharya in order to effect the last two types of actions.
1.1.2 Node- and Domain-Based Models
SPSL enables two ways to associate security policies with network
entities, known as the node-based and the domain-based policy
models.
In the node-based model, security policies are bound to individual
network nodes and security devices, e.g., firewalls, hosts, etc. The
policies associated with a network node specify the protection for the
communications to and from the node. These policies are expected to
be enforced by the node itself. The policies associated with a
security device (formally known as a policy enforcement point) specify
the protection for the communications passing through these agents.
Either the source or the destination of the communication must be
among the nodes that the agent is authorized/expected to protect. In
this model, both the network nodes and the security policy enforcement
agents manage their own policies.
In the domain-based model, security policies are bound to a security
domain. A security domain is defined as a connected set of network
entities that are protected by policy enforcement points (PEP) placed
on every communication path going through the perimeter of the domain.
Every policy enforcement point of the domain works to enforce the
common set of security policies associated with the domain. Security
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domains may be completely disjoint, contained in one another,
comprised of several sub-networks, or just hosts that enforce their
own policy. In this model, the policies associated with a domain are
managed by one or more special agents common to the entire domain.
These special agents act as policy servers. They may be distinct
network entities or co-located with the nodes or the policy
enforcement agents of the domain.
1.1.3 Multiple Distributed Policy Enforcement Points
SPSL allows explicit selection of enforcement points(s) of a security
policy. The choices can be interfaces of end nodes or en-route
security gateways (SG), e.g., firewalls, specified by IP addresses.
The explicit selection of an enforcement agent allows a system to
choose a communication path different than the one chosen by the
routing infrastructure. This facility is especially useful for tunnel
establishment and management.
1.1.4 Authentication and Authorization Mechanisms
SPSL has object classes to support the following security services:
1. data integrity, data origin authentication: every policy object
is protected using a public key signature. Both RSA [RSA]
and DSA [DSA] signature algorithms are supported. This also
offers non-repudiation proof of the issuer(s) of the policies.
2. authentication and authorization of policy management entities:
management objects such as maintainers have public key
certificates associated with them to allow authentication of
policies they issue and/or identify themselves to a security
management system for access control purposes.
With these services, users of SPSL policy specifications can always
verify the integrity and the origin of the policies and allow only
authorized personnel to maintain the policies.
1.1.5 Language Flexibility and Extensibility
SPSL is a flexible and extensible language. The language is flexible
because its present syntax enables it to specify policies for
different uses. For example, it can be used to specify
non-cryptographic stateless packet filtering rules as well as IPsec
tunnels for virtual private networks. It can also be used to effect
standard IPsec or fine grain selector matching. In addition, it
supports both node- and domain-based models.
The language is also extensible. It allows new object classes to be
created by following a syntactic rule similar to inheritance.
Consequently, the language can be extended for specifying policies of
different communication and security protocols or applications.
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1.2 Language Structure
SPSL uses the object paradigm although it is not an object-oriented
language. The language defines a small set of classes, which can
instantiate objects maintaining data relevant to policy specification.
The data are contained in the attributes defined in the object
classes. There are no executable methods in the classes nor do the
classes form types. Objects in an SPSL file are distinguished and
referred by the unique values of their first attribute, known as the
key attribute.
New classes can be created as needed based on a syntactic rule similar
to inheritance in object-oriented languages. For example, a sub-class
will have all the attributes of its parent class in addition to its
own attributes, except for the key attribute. The sub-class will have
to define its own key attribute. It will use the same syntax for the
"inherited" attributes as its parent does. However, the parent and
sub-classes are not related by type polymorphic relations because the
objects do not contain types. The only constraint on sub-classes
beyond the normal class rules is the inheritance of the parent's
attributes.
1.2.1 Categories
SPSL is comprised of the following four categories:
Primitive Data - contain basic or atomic data elements used in
policy specification, e.g., object-name, ipv4-address,
integer-range, date, etc.
Management Agents - contain information relevant to the management
entities; the existing classes in this category are maintainer
(mntner) and certificate (cert).
Network Entities - depict the network elements that are relevant
to policy specification; the existing classes are node,
node-set, gateway, gateway-set, polserver, and domain.
Policies - contain the policy specification; there are only two
classes at the moment: class policy specifies general packet
filtering rules and class ipsec-policy specifies IPsec
selectors and actions. Objects of the policy class may appear
in two forms for short or long policy specification.
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1.2.2 Class Design
Each class has a set of attributes which store information about the
objects of the class. Attributes can be mandatory (man) or optional
(opt). A mandatory attribute MUST be defined for all objects of the
class, and an optional attribute MAY be omitted. Attributes can also
be single valued (s-v) or multiple valued (m-v). A single valued
attribute MUST only appear once per object. A multiple valued
attribute MAY appear more than once per object. Each object is
uniquely identified by the key attribute of its class.
An SPSL object is textually represented as a list of attribute-value
pairs. All text within an SPSL object is case sensitive. An object's
representation begins with the class-key attribute-value pair. Each
attribute-value pair is written on a separate line. The attribute
name precedes the first colon, ":", and is followed by the value of
the attribute. An attribute-value pair may span multiple lines. A
"\" MUST be used as the last character of a line to indicate that the
line is continued. An object's representation ends when a blank line
(i.e., a line containing only whitespace characters such as spaces,
tabs, and carriage returns) or the end of file is encountered.
The order of attributes within a signed object is significant. The
order of the written form of the attributes when signed must be
preserved until the object is validated or resigned. This ordering is
necessary to be able to verify signatures of objects. The class key
must always be the first attribute. If the 'char-set' attribute is
included, it must always precede any 'notes' attribute. The last
attribute in any object must be the 'signature' attribute(s). If
multiple 'policy' attributes are included in a single policy class
object then their ordering must be preserved, unless the policy is
being specifically changed. This is required since the ordering of
policies may affect how they are applied (section 5.5).
A value of an attribute may be a single data item or a list of data
items of the same type. A list is represented by separating the list
members by commas ",". Note that the options of having a list of
values and/or multiple values are two independent choices for an
attribute. A multiple valued attribute may appear multiple times
within an object, and the value in each occurrence may or may not be a
list. A single valued attribute may also have a list value.
The default character set is ISO 8859-1 (Latin-1) [ISO8859]. The
character set is an eight bit encoding where the lower 7 bits are
identical to the ASCII character set. This default MUST always be
used for all the attribute names and attribute values. The character
set for the notes attribute value MAY be overridden by using the
'char-set' attribute.
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An object's specification may contain comments. A comment may appear
anywhere in an object definition. It starts at the first "#"
character on a line and ends at the first end-of-line character. The
"\" character may be used to escape the comment character, so that it
will be used as a "#" character and not a comment. "\\" will be used
to represent the "\" character. Whitespace characters may be used to
improve readability.
1.2.3 Naming Scheme and Scope
Since an SPSL object is distinguished by and referenced by its key
attribute, the value of that attribute (which is usually a name) must
be unique in the entire policy specification file (SPSL file). The
actual scope of uniqueness may differ depending on the choice of
policy model. In the node-based model, the names must be unique
within a node or a policy enforcement point that owns the policies.
In the domain-based model, the names must be unique within the set of
security servers that manage the policies of one or more domains in a
primary-secondary server configuration. Note that the name of an
object must be unique among all classes, not merely among its own
class.
A recommended method for satisfying this uniqueness requirement
is to adopt the following hierarchical naming scheme. A
hierarchical object name is a sequence of names (usually, domain,
node, or gateway names) separated by colons ":". The names are
arranged following a descending order starting with the highest level
name. For example, SG-BAZ:SG-BAR:SG-FOO is a valid hierarchical
object name with SG-BAZ being the top level name.
1.2.4 $INCLUDE Extension
An SPSL file may actually consist of multiple files containing
complete SPSL objects. One SPSL file may be included as part of
another file using the following:
$INCLUDE <filename>
The contents of <filename> are included in the SPSL file at the
exact place where the $INCLUDE line is in the SPSL file. As with
SPSL objects, this line must be separated from other SPSL objects
by a blank line. The included SPSL file MUST contain at least one
object or $INCLUDE line.
1.2.5 File Structure
Besides the policy ordering constraints in section 5.5, there are few
constraints on the structure of an SPSL file. Some classes reference
other classes which are expected to exist for the referencing classes
to be meaningful. For example, all classes reference at least one
"mntner" object and the "domain" class references the other network
element objects.
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All SPSL files MUST contain at least one object or $INCLUDE line.
This is required to be able to verify that the file has not been
tampered with (see section 6.3).
2. Data Types
The following are the commonly used data types in SPSL. [Note: many
of these data types are identical to those specified in RPSL. [RPSL]]
<object-name> All SPSL objects are identified by a name. An
<object-name> is made up of letters, digits, the character
underscore "_", the character period ".", the character colon
":", and the character hyphen "-"; the first character of a name
must be a letter, and the last character of a name must be a
letter or a digit.
<filename> is made up of letters, digits, the character
underscore "_", the character period ".", the character colon
":", the character hyphen "-", the character slash "/", and
the character backslash "\". ("\\" must be used to represent
a single "\".)
<ipv4-address> An IPv4 address is represented as a sequence of four
integers in the range from 0 to 255 separated by the character
dot ".". For example, 172.17.128.5 represents a valid IPv4
address.
<ipv6-address> An IPv6 address is represented as a sequence of eight
hexadecimal integers in the range from 0 to FFFF separated by
the character colon ":". The last two hexadecimal integers may
be replaced with an <ipv4-address>. A single string of one or
more hexadecimal integers with value zero (0) may be omitted.
For example, 129:0:0:0:5:800:20C2:F35B,
129:0:0:0:5:800:32.194.243.91, and 129::5:800:32.194.243.91 all
represent valid IPv6 addresses, and all encode the same value.
<ip-address> An <ipv4-address> or <ipv6-address>.
<address-range> An address range is represented as an IP address
followed by the character dash "-" followed by a second IP
address, by an IP address followed by the keyword "mask"
followed by a second IP address, or by an IP address followed
by a slash "/" followed by an integer. The addresses MUST be
either both <ipv4-address>'s or both <ipv6-address>'s. The dash
form of an address range is inclusive. The following are valid
address ranges: 172.16.1.1-172.16.1.200, 172.16.1.1-172.16.3.33.
The mask form uses the second IP address to specify a bit mask.
One bits in the mask correspond to bits in the address that may
not vary. A valid masked address range is: 10.0.0.1 mask
255.255.0.255. The slash form uses the integer to indicate the
number of bits in the address, beginning from the
most-significant, that may not vary. A valid address range in
this form is: 192.168.2.0/24.
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<date> A date is represented as an eight digit integer of the form
YYYYMMDD where YYYY represents the year, MM represents the
month of the year (01 through 12), and DD represents the day of
the month (01 through 31). For example, June 24, 1996 is
represented as 19960624.
<integer-range> specifies an integer, minimum integer, maximum
integer, or inclusive range of integer values. It uses the
following syntax:
<integer> | min <integer> | max <integer> | <integer>-<integer>
The following are valid <integer-range>'s: 5, 67-100, min 50,
max 60. "min 50" means any value greater than or equal to "50".
<phone-number> is a phone or fax number. A phone number may
contain digits, spaces " ", plus "+", minus "-", and the letter
"x" to indicate extension numbers. The following are valid
<phone-number>s: +31 20 123-4676, +44 123 987654 x4711.
<email-address> is as described in RFC-822 [rfc822].
<dns-name> is as described in RFC-1034 [rfc1034].
<free-form> is a sequence of ASCII characters.
<X-name> is a name of an object of type X. That is <mntner-name>
is a name of a mntner object.
<oid> is an object identifier of type <object-name>.
<or-address> is an X.400 address of type <free-form>. See Appendix
in [PKIXP1] for further definition of the syntax.
<relative-distinguished-name> represents an X.500 distinguished
name of type <free-form>. See Appendix in [PKIXP1] for further
definition of the syntax.
<edi-party-name> EDI Party Name of type <free-form>. See Appendix
in [PKIXP1] for further definition of the syntax.
<uri> Uniform Resource Identifier of type <free-form>.
<general-name> is of the form <name-type> <name>. <name-type>
describes the type of name used in <name>. <name> is a string
that is the name. Its format depends upon the <name-type>. The
following name types and their corresponding <name> formats
have been defined as follows (based on CRL Distribution Points
extension in [PKIXP1]):
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<name-type> description of type <name> format
other Other Name <oid> <freeform>
n822 RFC 822 Name <email-address>
dns DNS Name <dns-name>
x400 X400 Address <or-address>
dirname Directory Name list of
<relative-distinguished-name>
ediname EDI Party Name <edi-party-name>
uri Uniform Resource Identifier <uri>
ipaddr IP Address <ip-address>
regid Registered ID <oid>
Lists of one or more data types may be defined as:
list of <data-type1>[, <data-type2>[...]]
This defines a list of elements of type <data-type1>. Optionally,
more than one data type may be included in the list separated by
commas, ",". If multiple data types are permitted, the list may
contain elements from any or all of those data types. The elements
of the list are not required to be sorted by data type.
3. Management Agent Classes
The classes mntner and cert and the attributes mnt-by and changed in
all classes contain information about the management agents of the
policy specification. Among them, the mntner class specifies what
entities can create, delete, and replace other objects. These classes
do not specify communications policies.
3.1 mntner Class
The mntner class defines entities that can create, delete, and replace
SPSL objects. A security administrator, before creating SPSL objects,
first needs to create a mntner object. The attributes of the mntner
class are shown in Figure 1.
Attribute Value Type (Sect. 1.2.2)
mntner: <mntner-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
auth: <scheme-id> <auth-info> man, m-v
address: <free-form> man, m-v
phone: <phone-number> man, m-v
fax-no: <phone-number> opt, m-v
email: <email-address> man, m-v
mnt-by: list of <mntner-name> man, m-v
certs: list of <cert-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description below man, m-v
Figure 1: mntner Class Attributes
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The 'mntner' attribute is mandatory and is the class key. Its
value is an SPSL name. The 'auth' attribute specifies the scheme that
will be used to identify and authenticate change requests from this
maintainer. It has the following syntax:
auth: <scheme-id> <auth-info>
E.g.,
auth: crypt-pw dhjsdfhruewf
The <scheme-id>'s currently defined are: "cert", "pgp", and
"crypt-pw". The <auth-info> is additional information required by a
particular scheme: in the case of "crypt-pw", it is a password in
UNIX(TM) crypt format; and in the case of "pgp", it is a PGP public
key; in the case of "cert", it is a list of <cert-name> of public key
certificates that may be used to authenticate the mntner. If multiple
'auth' attributes are specified, an update request satisfying any one
of them is authenticated to be from the maintainer.
The 'char-set' attribute identifies the name of the character set used
for the value of the notes attribute in this object. The 'char-set'
does not apply to the attribute names; the default character set is
always used for them. If this attribute is not included, then the
default character set is used for all attribute values.
The 'address', 'phone', 'fax-no', and 'email' attributes provide contact
information for the maintainer. The 'address' attribute SHOULD contain
one complete address per instance of the attribute.
The 'notes' attribute contains a free-form textual description of the
object and other notes about the object. The 'mnt-by' attribute is a
list of mntner object names. The authorization for replacement or
deletion of this object is governed by any of the maintainer objects
referenced. The 'changed' attribute documents who last changed this
object, and when the change was made. This attribute is multi-valued
so that a history of who made changes and when MAY be kept. Only the
most recent change MUST be kept. If multiple 'changed' attributes are
saved, then they MUST be ordered from most to least recent. The
<mntner> identifies who made the change. <date> is the date of the
change.
The 'certs' attribute lists certificate objects that point to the public
key certificates for this mntner.
The 'signature' attribute contains a signature of the object.
Signatures are computed over the textual representation of all the
attributes in the object, except any 'signature' attributes. For
purposes of the signature, all white-space is reduced to a single
space, except for new-line characters which are included in the
signature. Line continuation characters and the following carriage
return are included in the signature. Comma separated lists do not
have a space on either side of the comma "," for the signature. There
SHOULD be at least one 'signature' line for each <mntner-name> in
mnt-by. A maintainer that modifies the object MUST sign the object.
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When an object is modified, all signature attributes MUST either be
recomputed or removed from the object so that all signatures are
valid. The attribute has the following syntax:
signature: <mntner-name> <cert-name>
<signature-alg> <signature-data>
The <mntner-name> and <cert-name> identify which mntner signed this
object and which certificate was used. <signature-alg> is the
algorithm used to create the signature. Currently the following
signature algorithms are defined: "rsa-pkcs1", "dsa-sha1".
<signature-data> is a hexadecimal string of the signature generated
using the specified algorithm.
E.g.,
signature: XYZ-IR-MNT XYZ-X509-CERT rsa-pkcs1 \
8889a0efb2e72cdaaeb36708cda4315ded3c20e3a57b6ae4fca18c22 \
e27b8974971ef19b5d4df46b437648995dea264c21de55420186c7c3 \
9cf4c42973f2bc0b91e259eea56114af880a2a57d2d8d723afc03608 \
75d88f5327ad18ebf888ff916171b6823eb89bb74ee1c3a373ee4f4e \
c42d7224f166c56a704961f10bac3534
(Note that <signature-data> MAY be split across multiple lines.)
Figure 2 shows an example mntner object. In the example, "cert"
authentication is used.
mntner: XYZ-IR-MNT
notes: XYZ-IR Maintainer
auth: cert XYZ-IR-X509-CERT
address: XYZ Corp, 1 XYZ Place, Anytown, AS 12345, USA
phone: +1 617 5551234
email: jdoe@ir.xyz.com
mnt-by: XYZ-IR-MNT
certs: XYZ-IR-X509-CERT
changed: XYZ-IR-MNT 19970820
signature: XYZ-IR-MNT XYZ-IR-X509-CERT dsa-sha1 <signature-data>
Figure 2: An example mntner object.
The 'char-set', 'notes', 'mnt-by', 'changed', and 'signature'
attributes are attributes of all SPSL classes. Their syntax,
semantics, and type (mandatory, optional, multi-valued, or
single-valued) are the same for for all SPSL classes. They are not
discussed further in the remaining sections.
3.2 cert Class
The cert class identifies a public key certificate that may be used to
sign SPSL objects. A cert object either specifies a certificate or
the location of a certificate. The 'cert' attribute identifies the
name of the object.
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Internet Draft Security Policy Specification Language March 2000
Attribute Value Type (Sect. 1.2.2)
cert: <cert-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
certificate: see description below opt, s-v
certlocation: see description below opt, m-v
crllocation: see description below opt, s-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 3: cert class attributes
The 'certificate' attribute has the following syntax:
certificate: <cert-type> <cert-data>
<cert-type> describes the type of certificate represented. Currently
the following types are defined: "pkcs7", "pgp", "dnskey", "x509_sig",
"x509_ke", "kerberos", "spki". <cert-data> is the actual certificate
described by this object. The encoding depends upon <cert-type>,
which will be defined in future revisions of this draft.
certificate type description
pkcs7 PKCS #7 wrapped X.509 certificate
pgp PGP certificate
dnskey DNS signed key
x509_sig X.509 certificate - signature
x509_ke X.509 certificate - key exchange
kerberos Kerberos tokens
spki SPKI certificate
The 'certlocation' attribute has the following syntax:
certlocation: <cert-type> <fetch-protocol>
<general-name> | filename <filename> |
rdn <relative-distinguished-name>
<cert-type> is as defined above. <fetch-protocol> specifies the
preferred protocol that should be used to fetch the certificate from
this location. Currently the following protocols have been defined:
"cdp", "dns", "file". The location of the certificate is identified
either by using a <general-name> or a <relative-distinguished-name>
when fetching with CDP or DNS, or a <filename> when fetching from a
locally stored file.
The 'crllocation' attribute indicates where a certificate revocation
list (CRL) may be found for this certificate. It has the following
syntax:
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Internet Draft Security Policy Specification Language March 2000
crllocation: <crl-type> <fetch-protocol>
<general-name> | filename <filename> |
rdn <relative-distinguished-name>
This is similar to the certlocation attribute, except that <crl-type>
is used in place of <cert-type>. <crl-type> describes the type of CRL
that may be found at this location. Currently, the following CRL type
has been defined: "x509".
At least one 'certificate' or 'certlocation' attribute MUST be present
in a cert object. It is possible for a 'certificate' and a
'certlocation' attribute, or multiple 'certlocation' attributes to be
present in a single cert object, but they SHOULD all refer to the same
certificate, otherwise the wrong certificate may be used.
4. Network Entity Classes
4.1 node Class
The node class identifies a set of interfaces on a network entity that
may have communications policies associated with them. This
definition allows a single network entity to be represented by one or
more node objects. It also allows policies to be associated with
specific interfaces or addresses of a network entity.
Attribute Value Type (Sect. 1.2.2)
node: <node-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
name: <dns-name> man, s-v
alias: <dns-name> opt, m-v
ifaddr: <ip-address> man, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 4: node class attributes
The 'node' attribute is the class key, which uniquely identifies the
node object.
The 'name' attribute is a valid DNS name identifying the network entity
to which the interfaces in the object are attached. Each 'alias'
attribute, if present, should be a canonical DNS name of the network
entity. The 'ifaddr' attribute specifies the IP address of each
interface of the node.
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Figure 5 shows two examples of node objects.
node: SQUATCH
name: squatch.foo.com
ifaddr: 172.16.3.11
ifaddr: 192.168.1.83
node: SG-FOO-FIREWALL:COTTON
name: cotton.foo.com
ifaddr: 172.16.5.196
Figure 5: node object examples
4.2 node-set Class
The node-set class provides a means to group several nodes into one
object. The class may be used to group together the interfaces of a
single host or of multiple hosts. The nodes in a node-set object are
expected to contain the interfaces of a common set of network
entities.
The node-set class is defined below:
Attribute Value Type (Sect. 1.2.2)
node-set: <node-set-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
members: list of <node-names>, <node-set-names> man, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 6: node-set class attributes
The 'node-set' attribute is the class key, which uniquely identifies
the node-set object. The 'members' attribute is a list of the node
objects and node-set objects that are grouped by the node-set object.
4.3 gateway Class
The gateway class identifies a set of interfaces on a policy
enforcement agent, e.g., a security gateway, that can enforce the
security policies associated with the enforcement agent or the domain
for which it enforces policy.
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Attribute Value Type (Sect. 1.2.2)
gateway: <gateway-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
name: <dns-name> man, s-v
alias: <dns-name> opt, m-v
ifaddr: <ip-address> man, m-v
preference: <integer> man, s-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 7: gateway class attributes
The 'gateway' attribute is the class key, which uniquely identifies the
gateway object.
The 'name' attribute is a valid canonical DNS name identifying the
network entity on which the policy enforcement agent is implemented.
Each 'alias' attribute, if present, should be a canonical DNS name of
the network entity. The 'ifaddr' attribute specifies the IP address of
an interface.
The 'preference' attribute gives a hint as to the preference of routing
to use this gateway. 1 is the highest preference and the preference
decreases as the integer increases. This is only used for purposes of
the domain object and is explained further in section 4.6.
Figure 8 shows two examples of gateway objects.
gateway: SG-FOO-FIREWALL
name: foo-firewall.foo.com
ifaddr: 172.16.0.1
ifaddr: 192.168.1.83
preference: 1
gateway: SG-FOO-FIREWALL:SG-IS-FIREWALL
name: is-firewall.foo.com
ifaddr: 172.16.5.196
preference: 3
Figure 8: gateway object examples
4.4 gateway-set Class
The gateway-set class provides a means to group gateways. It can be
used to group together the interfaces of a single gateway or the
interfaces of multiple gateways spread across several gateway objects,
so that they may be referred to as a single object.
The gateway-set class is defined below:
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Internet Draft Security Policy Specification Language March 2000
Attribute Value Type (Sect. 1.2.2)
gateway-set: <gateway-set-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
members: list of <gateway-names>,
<gateway-set-names> man, s-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 9: gateway-set class attributes
The 'gateway-set' attribute is the class key, which uniquely identifies
the gateway-set object. The 'members' attribute is a list of gateway
objects and/or gateway-set objects which are grouped by the gateway-set
object.
4.5 polserv Class
The polserv class defines the policy servers that are capable of
managing security policies.
Attribute Value Type (Sect. 1.2.2)
polserv: <policy-server-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
name: <dns-name> man, s-v
alias: <dns-name> opt, m-v
ifaddr: <ip-address> man, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 10: polserv class attributes
The 'polserv' attribute is the class key, which uniquely identifies
the policy server object. The 'name' attribute is a valid DNS name
identifying the network entity on which the policy server is located.
Each 'alias' attribute, if present, should be a canonical DNS name of
the network entity. The 'ifaddr' attribute specifies the IP address of
an interface of the policy server.
Figure 11 shows a simple example of a policy server object.
polserv: PS-SECURITY
name: foo-pol-server.foo.com
ifaddr: 172.16.0.2
Figure 11: polserv object example
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Internet Draft Security Policy Specification Language March 2000
4.6 domain Class
The domain class provides a means to define a security domain, which
is a cluster of network entities protected by a common set of security
policies that are enforced by the policy enforcement points located at
the perimeter of the domain.
A security domain is the basic topological structure for a
domain-based security model [Section 1.1.2]. It consists of three
components:
1. Coverage - a security domain must be authorized to include a
specific set of network entities. That specification is provided
in the 'coverage' attribute, and can take the form of a list of IP
addresses, a list of IP address ranges, a list of nodes, and/or
a list of node-sets.
2. Policy Enforcement Points - the network entities included in a
security domain are protected by a set of policy enforcement
points located at the perimeter of the domain. The policy
enforcement points are specified by the 'gateways' attribute,
which may contain a list of gateways or gateway-sets. The
gateways in the list MAY be ordered using the 'gateways'
'preference' attribute.
3. Policy Servers - one or more policy servers are assigned to
the security domain to manage the security policies of the
domain. These servers are given in a list under the 'polservs'
attribute. The first member of the list MUST be the primary
server, and the rest are any secondary servers. The policy
servers are not included in the domain's coverage, unless
explicitly stated in the coverage component.
With these three components, the domain class is defined below.
Individual domain objects are uniquely identified by the 'domain'
attribute, which is the class key.
Attribute Value Type (Sect. 1.2.2)
domain: <domain-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
coverage: list of <ip-address >, <address-range>,
<node-name>, <node-set-name> man, m-v
gateways: list of <gateway-name>,
<gateway-set-name> man, s-v
polservs: list of <policy-server-names> man, s-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 12: domain class attributes
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5. Policy Class
A policy class object specifies a binding between a set of
communication conditions and a set of actions.
In the current version of SPSL, two policy classes are defined. The
general class described in sections 5.1 and 5.2 defines the conditions
and a transfer action that allows specification of packet filtering
rules. The class described in Section 5.3 is to be used to specify
IPsec and IKE policies.
Moreover, objects of the general policy class may take one of two
possible formats. The short format expresses the policy in a single
'policy' attribute and the long format expresses each part of a policy
in a distinct attribute. Each of the two formats is appropriate for
different applications. They will be discussed in the next two
sections, along with comments on their strengths and weaknesses.
Both formats of the policy class share three attributes. Figure 13
shows the class definition (in short format) in order to display the
common attributes. Among them, 'policy-name' gives the name of the
policy. The 'cache-expiry' attribute indicates, in seconds, the maximum
time that this policy should be cached. It can be regarded as a hint
to any entities that may cache this policy. If the attribute is
absent or has a value of zero then no expiration time is suggested.
The 'association' attribute specifies the names of one or more nodes,
gateways, or domains that own the policy. If a node-based or
domain-based policy model is being used, strict rules of association
must be observed depending on the model. In the node-based model, a
policy can be associated with an object from the node, node-set,
gateway, or gateway-set classes but never with a domain object. In
the domain-based model, a policy can be associated with an object from
the node, node-set, or domain classes but not with a gateway or
gateway-set object. This is because the policy associated with a
gateway or gateway-set object will be enforced by that particular
object instead of by all of the enforcement agents of a specific
domain. However, a node or node-set object is allowed its own
policies in a domain-based association because the object may be
regarded as a single/multiple node domain.
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5.1 policy Attribute (Short Format)
The short format of the policy class specifies the policy in a
single 'policy' attribute that is structured as follows:
Attribute Value Type (Sect. 1.2.2)
policy-name: <policy-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
association: <node-name> | <node-set-name>
| <gateway-name> | <gateway-set-name>
| <domain-name> man, s-v
cache-expiry: <integer> opt, s-v
policy: as described below opt, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 13: policy class attributes, short format
policy: dst * | any | [not] list of <ip-address>, <address-range>
[port (* | opaque | any |
[not] list of <port>, <port-range>)
[dynamic [<port-range>]]]
[src * | any | [not] list of <ip-address>, <address-range>
[port (* | opaque | any |
[not] list of <port>, <port-range>)
[dynamic [<port-range>]]]]
[xport-proto * | opaque | any |
[not] list of <proto>, <proto-range>]
[direction (inbound | outbound) [, symmetric]]
permit [, forward <dest> [<proto> <port>]]
| deny [, forward <dest> [<proto> <port>]]
The "dst" tag specifies a list of <ip-address>s or <address-range>s to
which this policy does (or does not) apply. The address may be
specified as "any" or the wildcard, "*", to indicate this applies to
traffic destined to all addresses. Otherwise, the address is a list
of individual IP addresses, or address ranges specified by a minimum
and maximum address (inclusive), or address ranges specified using an
address and mask.
An address list may be preceded by the qualifier "not" to indicate
that the address from a packet must not be the one specified. When a
list is preceded by a "not" qualifier each element would be
interpreted as being preceded by a "not". The interpretation of "not
X, Y, Z is "not X and not Y and not Z". Note that we do not permit
some list members with the "not" qualifier and some without it since
it is redundant. For example, for a distinct X and Y, an expression
"X or not Y" is equivalent to just "not Y". An expression "X and not
Y" is equivalent to just "X". Similar reasoning is used wherever the
rule "[not] list of <element>" occurs.
Condell, Lynn, Zao [page 21]
Internet Draft Security Policy Specification Language March 2000
Attribute "dst" may optionally be followed by "port" and a list of
destination port numbers or ranges of port numbers to which this
policy does (or does not) apply. Additionally, "port" may be followed
by the tag "dynamic" and an optional range of port numbers. This
specifies that a connection established by using one of the port
numbers following the "port" tag, may then use dynamic ports for the
rest of the communications using that connection. If a range of port
numbers follows the dynamic tag, then dynamic ports are only allowed
within that specified range. If the range is not specified, the port
range defaults to "*". If the dynamic tag is not used, then dynamic
ports are excluded from this policy.
A source address and port(s) may optionally be specified in a similar
manner using the "src" tag. The source address and source and
destination ports default to "*" if they are not specified.
The transport protocol may be specified using the optional tag
"xport-proto", which defaults to "*" if not specified. The transport
protocol may be specified as a single transport protocol number, a
list of protocol numbers, or a range of protocol numbers in the form
<number>-<number>. It may also be specified as "*", "any", or
"opaque". Note that when a port is specified as described in the
previous two paragraphs, then the protocol associated with those ports
must be specified using the "xport-proto" phrase.
The "direction" specification is used to specify whether a packet is
entering the domain associated with the policy (inbound) or exiting it
(outbound). If the optional qualifier "symmetric" is present, a
second policy will automatically be created with the direction
sensitive fields -- "src" and "dst", src port and dst port, and
direction -- switched. Once the second rule is created, the symmetric
tag SHOULD be dropped. For example, the policy:
policy: dst 192.168.3.47 port 23 src 192.168.2.21
direction inbound, symmetric permit
is replaced by two rules:
policy: dst 192.168.3.47 port 23 src 192.168.2.21
direction inbound permit
policy: dst 192.168.2.21 src 192.168.3.47 port 23
direction outbound permit
The direction MUST be specified here or in the 'direction' attribute
of the long form.
The transfer action of "permit" or "deny" must be specified to
indicate whether packets that match this policy should be passed or
dropped, respectively. The transfer action may additionally specify
that a copy of the the matching packets be forwarded to a specified
destination, e.g., a policy server in addition to the packet either
being allowed or dropped. The destination may be specified by either
a DNS name, preceded by "dns", or by an IP address. The destination
may optionally include a specific transport protocol and port number.
Condell, Lynn, Zao [page 22]
Internet Draft Security Policy Specification Language March 2000
policy-name: foo
association: sg-bar
policy: dst 172.16.0.0-172.16.255.255
src 192.168.100.0-192.168.100.255
xport-proto 6 permit
policy: dst 172.16.0.0-172.16.255.255 deny
Figure 14: policy object example, short format
In this example, this policy denies all packets destined to IP
addresses from 172.16.0.0 to 172.16.255.255, unless they are from
addresses 192.168.100.0 to 192.168.100.255 and use TCP. Note that the
ordering of the 'policy' attributes is important (see section 5.5).
5.2 policy Attribute (Long Format)
The long format policy class makes each part of the policy attribute an
explicit attribute.
Attribute Value Type (Sect. 1.2.2)
policy-name: <policy-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
association: <node-name> | <node-set-name>
| <gateway-name> | <gateway-set-name>
| <domain-name> man, s-v
cache-expiry: <integer> opt, s-v
valid-period: list of <valid-time> opt, m-v
dst: see below opt, m-v
src: see below opt, m-v
xport-proto: see below opt, m-v
direction: (inbound | outbound) [, symmetric] opt, s-v
userid: * | any | [not] list of n822 <email-addr>,
dn <distinguished-name> opt, m-v
systemname: * | any | [not] list of <general-name>,
dn <distinguished-name> opt, m-v
ipv6-class: * | any | [not] list of <integer-range> opt, m-v
ipv6-flow: * | any | [not] list of <integer-range> opt, m-v
ipv4-tos: * | any | [not] list of <integer-range> opt, m-v
seclabel: * | any | [not] list of <seclabel> opt, m-v
see Section 5.4 for additional selectors opt, m-v
tfr-action: see below opt, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 15: policy class attributes, long format
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The attributes are specified as follows:
dst: * | any | [not] list of <ip-address>, <address-range>
[port (* | opaque | any | [not] list of <port>, <port-range>)
[dynamic [<port-range>]]]
src: * | any | [not] list of <ip-address>, <address-range>
[port (* | opaque | any | [not] list of <port>, <port-range>)
[dynamic [<port-range>]]]
xport-proto: * | opaque | any | [not] list of <proto>, <proto-range>
tfr-action: permit [, forward <dest> [<proto> <port>]]
| deny [, forward <dest> [<proto> <port>]]
<valid-time>: [year yyyy-yyyy] [month 000000000000]
[day-of-month 0000000000000000000000000000000]
[reverse-day-of-month 0000000000000000000000000000000]
[day-of-week 0000000] [time [not] hh:mm:ss-hh:mm:ss]
The 'valid-period' attribute describes one or more time periods in
which the policy is valid. If more than one time period is expressed
in an object, then the periods are related by a logical OR. Each
<valid-time> consists optionally of a range of years, "zero-one mask"
of months, "zero-one mask" of days-of-the-month, "zero-one mask" of
reverse-days-of-the-month and day-of-the-week, and a period of time
within a day. These fields of a time period are related by a logical
AND. A "zero-one mask" is used instead of an integer bitmask for
human readability. For the rest of this discussion we will use "bit"
to refer to one element of the zero-one mask.
The "year" is a range of years to which the policy applies. The
"month" is a 12-bit zero-one mask of the months with January as the
first bit and December the last bit. If a bit is set to 1, the policy
is valid during that month, if 0, it is not valid during that month.
The "day-of-month" is a 31-bit zero-one mask of the days-of-the-month
with day 1 as the first bit and day 31 the last bit. The
"reverse-day-of-month" is also a 31-bit zero-one mask of the
days-of-the-month, however, the days are represented in reverse order
relative to the last day of the month. If a bit is set to 1, the
policy is valid during that day, if 0, it is not valid during that
day. The "day-of-week" is a 7-bit zero-one mask of the
days-of-the-week with Sunday as the first bit and Saturday the last
bit. If a bit is set to 1, the policy is valid during that
day-of-the-week, if 0, it is not valid during that day. The "time"
describes a range of time during which the policy is (or is not)
valid. The times use a 24-hour clock and their values MUST be
expressed in UTC. If any period is not described that field is
interpreted as "any."
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Attributes 'dst', 'src', 'xport-proto', 'direction', and 'tfr-action'
(transfer action) are similar to their counterparts in the short
format of the policy class. Note that the interpretation of a single
selector attribute with a list value is similar to having each
list member be a separate instance of the selector attribute since
multiple occurrences of these selectors (unlike the 'policy' selector)
are interpreted as logical ORs.
The direction MUST be specified either in the 'policy' attribute or the
'direction' attribute. The 'tfr-action' attribute specifies an action
that MUST be taken, as specified above.
The 'user-id' attribute specifies either a fully qualified email
address (e.g. user@foo.bar.net) or a distinguished name to identify a
particular user. The 'systemname' attribute uses a DNS name, an X.500
general name, or an X.500 distinguished name to identify a particular
system.
The 'seclabel' attribute is used to identify an implementation specific
security label. This should correspond to the implementation of the
security level selector in IPsec. This attribute is a good example of
the difference between "*" and "any". When "any" is used, the packet
MUST contain the field which contains the selector value. When "*" is
used, the packet does not have to have that field. Thus "any" means
that the packet must specify a security label, but its value is not of
interest. A "*" would mean that a packet need not contain any
security label. The value "opaque" is used to match packets for which
a selector field cannot be found, typically due to compression,
fragmentation, or confidentiality.
Attributes 'ipv6-flow' and 'ipv6-class' specify a list of integers or
integer ranges, optionally preceded by "not", corresponding to the
IPv6 flow label and transport class fields in the IPv6 header.
'ipv4-tos' is a list of integers or integer ranges, optionally
preceded by "not", corresponding to the IPv4 type of service field in
an IPv4 header. These attributes default to "*" if they are not
included. The 'tfr-action' and 'dst' attributes are mandatory, if the
policy class is used in the long format.
In order to represent the policies described in the above example
(Figure 14), two policy objects must be created. Note that the
ordering of the policy objects is important (see section 5.5).
Condell, Lynn, Zao [page 25]
Internet Draft Security Policy Specification Language March 2000
policy-name: baz
association: sg-bar
dst: 172.16.0.0-172.16.255.255
src: 192.168.100.0-192.168.100.255
xport-proto: 6
tfr-action: permit
policy-name: foo
association: sg-bar
dst: 172.16.0.0-172.16.255.255
tfr-action: deny
Figure 16: policy object example, long format
Generally, policy objects will use one of the two formats, but it is
possible to combine the features of both. The combined policy class
looks as follows:
Attribute Value Type (Sect. 1.2.2)
policy-name: <policy-name> man, s-v, key
char-set: <char-set> opt, s-v
notes: <free-form> opt, m-v
association: <node-name> | <node-set-name>
| <gateway-name> | <gateway-set-name>
| <domain-name> man, s-v
cache-expiry: <integer> opt, s-v
valid-period: list of <valid-time> opt, m-v
policy: as described above opt, m-v
dst: as described above opt, m-v
src: as described above opt, m-v
xport-proto: as described above opt, m-v
direction: (inbound | outbound) [',' symmetric] opt, s-v
userid: * | any | [not] list of n822 <email-addr>,
dn <distinguished-name> opt, m-v
systemname: * | any | [not] list of <general-name>,
dn <distinguished-name> opt, m-v
ipv6-class: * | any | [not] list of <integer-range> opt, m-v
ipv6-flow: * | any | [not] list of <integer-range> opt, m-v
ipv4-tos: * | any | [not] list of <integer-range> opt, m-v
seclabel: * | any | [not] list of <seclabel> opt, m-v
see Section 5.4 for additional selectors opt, m-v
tfr-action: as described above opt, m-v
mnt-by: list of <mntner-name> man, m-v
changed: <mntner-name> <date> man, m-v
signature: see description in Section 3.1 man, m-v
Figure 17: policy class attributes, combined format
If the 'policy' attribute is specified and any of the long-form
attributes are also specified, those others apply to all the policy
lines in this object. This holds true for sub-classes of the policy
class, too.
Condell, Lynn, Zao [page 26]
Internet Draft Security Policy Specification Language March 2000
Figure 18 illustrates the combination of the two formats. The first
policy object uses the combined format of the policy class. It has
two 'policy' attributes and an 'xport-proto' attribute. The
'xport-proto' attribute is applied as part of the policy described by
each of the 'policy' lines. This is equivalent to explicitly listing
the 'xport-proto' attribute in each policy line, as shown in the
second policy object.
policy-name: tcp-foo
association: sg-bar
policy: dst 172.16.0.0-172.16.255.255
src 192.168.100.0-192.168.100.255 permit
policy: dst 172.16.0.0-172.16.255.255 deny
xport-proto: 6
This is equivalent to:
policy-name: tcp-foo
association: sg-bar
policy: dst 172.16.0.0-172.16.255.255
src 192.168.100.0-192.168.100.255
xport-proto 6 permit
policy: dst 172.16.0.0-172.16.255.255 xport-proto 6 deny
Figure 18: policy object example, combined format
If an attribute is specified both in the policy attribute and one of
the long form attributes they should attempt to be merged. Values
of long form attributes should be considered logically "ORed" with the
value in the policy attribute. Figure 19 shows such a merge.
policy-name: tcp-foo
association: sg-bar
dst: 172.17.0.1
policy: dst 172.16.0.0-172.16.255.255
src 192.168.100.0-192.168.100.255 permit
xport-proto: 6
This is equivalent to:
policy-name: tcp-foo
association: sg-bar
policy: dst 172.16.0.0-172.16.255.255, 172.17.0.1
src 192.168.100.0-192.168.100.255
xport-proto 6 permit
Figure 19: policy object example, merging attributes
If a policy object has an unresolvable conflict between a part of the
policy attribute and one of the other attributes specified, it is an
invalid policy object. If an SPSL file has any invalid objects, the
parsed policies SHOULD not be used until the objects are fixed.
Figure 20 shows a conflict in the tfr-action attribute.
Condell, Lynn, Zao [page 27]
Internet Draft Security Policy Specification Language March 2000
policy-name: tcp-foo
association: sg-bar
policy: dst 172.16.0.0-172.16.255.255
src 192.168.100.0-192.168.100.255 permit
tfr-action: deny
Figure 20: policy object example, merging conflict
While both formats allow the same policies to be specified, they each
have their advantages and disadvantages. The short format allows
uncomplicated policies, such as general default policies, to be
specified in a compact format since it allows multiple policies to be
defined in a single object. The short format, however, is not capable
of specifying complex policies. The long format allows complex
policies to be specified in a more straightforward manner. Also, the
ability to combine both formats of the policy class, allows greater
flexibility in how policies may be defined. Correct specification of
policies is made easier by being able to specify those policies in a
straightforward manner.
5.3 ipsec-policy Class
The ipsec-policy class is a sub-class of the policy class. It is used
to state IPsec policies specifying whether or not AH or ESP are
required for a particular communication, and the choice of security
mechanisms to be used with IPsec protocols. It also specifies the
security mechanisms that may be negotiated by IKE using the IPsec DOI
[rfc2407]. Since it is a sub-class of the general policy class, it
inherits attributes from the policy class. The inherited attributes
are marked with an "*" in Figure 21 below.
Condell, Lynn, Zao [page 28]
Internet Draft Security Policy Specification Language March 2000
Attribute Value Type (Sect. 1.2.2)
ipsec-policy-name: <ipsec-policy-name> man, s-v, key
*char-set: <char-set> opt, s-v
*notes: <free-form> opt, m-v
*association: <node-name> | <node-set-name>
| <gateway-name> | <gateway-set-name>
| <domain-name> man, s-v
*cache-expiry: <integer> opt, s-v
*valid-period: list of <valid-time> opt, m-v
*policy: as described above opt, m-v
*dst: as described above opt, m-v
*src: as described above opt, m-v
*xport-proto: as described above opt, m-v
*direction: (inbound | outbound) [',' symmetric] opt, s-v
*userid: * | any | [not] list of n822 <email-addr>,
dn <distinguished-name> opt, m-v
*systemname: * | any | [not] list of <general-name>,
dn <distinguished-name> opt, m-v
*ipv6-class: * | any | [not] list of <integer-range> opt, m-v
*ipv6-flow: * | any | [not] list of <integer-range> opt, m-v
*ipv4-tos: * | any | [not] list of <integer-range> opt, m-v
*seclabel: * | any | [not] list of <seclabel> opt, m-v
* see Section 5.4 for additional selectors opt, m-v
*tfr-action: as described above opt, m-v
ipsec-action: see below opt, m-v
ike-action: see below opt, m-v
*mnt-by: list of <mntner-name> man, m-v
*changed: <mntner-name> <date> man, m-v
*signature: see description in Section 3.1 man, m-v
Figure 21: ipsec-policy class attributes
Condell, Lynn, Zao [page 29]
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ike-action: ikemode <ikemode> pfs <usepfs>
auth <auth-method>
cipher <ikecipher> hash <hashalg>
[group-desc <group-desc> |
group-type <group-type> <hex-string> <hex-string>
<hex-string> <hex-string> <hex-string> <hex-string>]
[prf <integer>] [field <integer>]
expiry ( seconds | kilobytes ) <integer-range>
where <ikemode> is one of: "aggressive", "main", "quick"
<usepfs> is either "false" or "true"
<auth-method> is one of "any", "pre-shared", "dss",
"rsa", "rsa-encrypt", "rsa-revised" or an
<integer> as defined in [rfc2409]. The list
is optionally preceded by "not".
<ikecipher> is a list of one or more of:
<ikecipheralg> [keylen <integer-range>]
<ikecipheralg> is one of "any", "blowfish", "cast",
"des", "des3", "idea", "rc5", or an
<integer> as defined in [rfc2409]. The list
is optionally preceded by "not".
<hashalg> is "any", or one or more of: "md5", "sha1", "tiger",
or an <integer> as defined in [rfc2409]. The list
is optionally preceded by "not".
<group-desc> is one of: "modp-768", "modp-1024", "ec2n-155",
"ec2n-185", or an <integer> as defined in [rfc2409].
<group-type> is one of: "modp", "ecp", "ec2n", or an
<integer> as defined in [rfc2409].
ipsec-action: [ esp <proposal-choice> cipher <ipseccipher>
[integrity <ipsecintegrity>]
[expiry ( seconds | kilobytes ) <integer-range>]
[tunnel | transport]
[from <location> [, <location>]]
[to <location> [, <location>]]
]
[ ah <proposal-choice> integrity <ipsecintegrity>
[expiry ( seconds | kilobytes ) <integer-range>]
[tunnel | transport]
[from <location> [, <location>]]
[to <location> [, <location>]]
]
[ ipcomp <proposal-choice> <ipcompalg> ]
Condell, Lynn, Zao [page 30]
Internet Draft Security Policy Specification Language March 2000
where <proposal-choice> is one of "req", "opt"
<ipseccipher> is a list of one or more of:
<ipseccipheralg> [keylen <integer-range>]
[rounds <integer-range>]. The list
is optionally preceded by "not".
<ipseccipheralg> is one of "*", "any", "blowfish", "cast",
"des", "des3", "idea", "idea3", "null", "rc4",
"rc5", "rfc1829-iv32", "rfc1829-iv64", or an
<integer> as defined in [rfc2407].
<ipsecintegrity> is a list of one or more of:
<integrityalg> [keylen <integer-range>].
The list is optionally preceded by "not".
<integrityalg> is one of "any", "hmacdes","hmacmd5",
"hmacsha1", "kpdk", or an <integer> as defined
in [rfc2407].
<ipcompalg> is "any", or one or more of: "deflate", "lzs",
"oui", or an <integer> as defined in [rfc2407].
The list is optionally preceded by "not".
<location> is "any", or one or more of: "dest", "host",
"local-sg", "remote-sg", <ip-address>,
"dns" <dns-name>
Two action attributes, 'ipsec-action' and 'ike-action', in addition to
the policy class attributes, form the ipsec-policy class.
The 'ipsec-action' attribute specifies ESP, AH, and IP compression
proposals that must be used to protect this communication. Each
proposal may be either a required, "req," or optional, "opt," part of
the specified communication. If a proposal is not included in the
'ipsec-action' it is prohibited.
If an ESP proposal is specified, the cipher algorithm to use is
specified by the "cipher" tag and "*", "any", a string describing a
cipher algorithm, or a number corresponding to a cipher algorithm as
defined in [rfc2407]. Each cipher algorithm may be further defined by
an optional key length and number of rounds, if the cipher requires
it. "any" specifies all the cipher algorithms, except "null" are
included, while "*" specifies all the cipher algorithms included in
any, plus the "null" algorithm. An integrity algorithm and its key
length may optionally be specified. It defaults to "any" if not
specified. Values are defined in [rfc2409]. The SA life type and
life time may be specified with the "expiry" tag. If not used, the
values default as described in section 4.5 of [rfc2407]. Tunnel or
transport mode may be specified with the "tunnel" or "transport" tags.
If neither are specified, either may be used. The end points of the
SA may be specified with the "to" and "from" tags which are described
in detail below.
Condell, Lynn, Zao [page 31]
Internet Draft Security Policy Specification Language March 2000
If an AH proposal is specified, the integrity algorithm to use is
specified by the "integrity" tag and "any", a string describing an
integrity algorithm, or a number corresponding to an integrity
algorithm as defined in [rfc2407]. Values are defined in [rfc2409].
The key length for each algorithm may also be specified. The SA life
type and life time may be specified with the "expiry" tag. If not
used, the values default as described in section 4.5 of [rfc2407].
Tunnel or transport mode may be specified with the "tunnel" or
"transport" tags. If neither are specified, either may be used. The
end points of the SA may be specified with the "to" and "from" tags
which are described in detail below.
If an IP compression proposal is specified, the compression algorithm
to use is specified by the "ipcomp" tag and "any", a string describing
a compression algorithm, or a number corresponding to a compression
algorithm as defined in [rfc2407]. The SA life type and life time may
be specified with the "expiry" tag. If not used, the values default
as described in section 4.5 of [rfc2407].
The "to" and "from" tags identify the endpoints (policy enforcement
points) of the security association that the proposal describes. A
network node may be explicitly specified as an endpoint using either
its IP address or its DNS name. This node MUST be used as the
specified endpoint of the SA. The endpoints of the SA may also be
specified using a generic specification that allows the policy
decision points to determine at which enforcement point to end the SA.
"any" allows any enforcement point to be chosen as long as it is not
the same as the other endpoint. "host" specifies the appropriate
(i.e. source or destination) endpoint of the communication. "dest",
"local-sg" and "remote-sg" still need further thought and
definition. If the SA endpoints are not specified, they default to the
source and destination endpoints specified in the policy object.
The 'ike-action' attribute specifies attributes that may be negotiated
during IKE phase one and whether perfect forward secrecy must be used
in quick mode. The "ikemode" tag specifies whether IKE should use
this specification in main, aggressive, or quick mode. The "pfs" tag
specifies if perfect forward secrecy should be used. "auth",
"cipher", and "hash" describe the authentication method, encryption
algorithm, and hash algorithm to be used. These may be specified by
"any", a string describing the appropriate algorithm, or a number
corresponding to an algorithm as defined in [rfc2409]. A key length
for the encryption algorithm may optionally be specified with each
cipher algorithm using the "keylen" tag. A predefined group or a
user-defined group may optionally be specified. A predefined group
uses the "group-desc" tag followed by a string describing the group,
or a number corresponding to a group as defined in [rfc2409]. A
user-defined group uses the "group-type" tag followed by the string or
number describing a group type (as defined in [rfc2409]) and the group
description: the group prime/irreducible polynomial, group generator
1, group generator 2, group curve A, group curve B, and group order.
A pseudo-random function may be specified with "prf" and the field
Condell, Lynn, Zao [page 32]
Internet Draft Security Policy Specification Language March 2000
size of a Diffie Hellman group may be specified with "field" and the
size in bits. Finally, the life time and life type must be specified
using the "expiry" tag.
If multiple 'ipsec-action' attributes or multiple 'ike-action'
attributes are specified, they should be taken as logical ORs.
5.4 Selectors and Actions
SPSL policies all contain two types of attributes: selectors and
actions. Selectors are the policy attributes that are used to match
packets with a particular policy. Currently, all the selectors that
are defined are contained in the base policy class, though sub-classes
may also contain additional selectors. The selectors currently
defined in the IPsec DOI are:
src dst
src-port dst-port
xport-proto userid
systemname ipv6-class
ipv6-flow ipv4-tos
seclabel direction
An extended list of selectors supported by SPSL includes:
ah-nhdr ipv4-dst rhv1-phop
direction ipv4-frgm seclabel
dop-nhdr ipv4-frgo src
dst ipv4-hlen src-port
dst-port ipv4-id systemname
esp-nhdr ipv4-opt-lsrr-dst tcp-ack
frag-nhdr ipv4-opt-ssrr-dst tcp-dato
hop-nhdr ipv4-prot tcp-dst-port
icmp4-code ipv4-src tcp-fin
icmp4-gwy ipv4-tlen tcp-psh
icmp4-id ipv4-tos tcp-rst
icmp4-mtu ipv4-ttl tcp-src-port
icmp4-seq ipv6-class tcp-syn
icmp4-type ipv6-dst tcp-urg
icmp6-code ipv6-flow tcp-urgp
icmp6-gwy ipv6-nhdr udp-cks
icmp6-id ipv6-src udp-dst-port
icmp6-mtu ipver udp-id
icmp6-seq rh-nhdr udp-src-port
icmp6-type rh-vers userid
ipcomp-nhdr rhv1-dst xport-proto
iphdr rhv1-nhop
Condell, Lynn, Zao [page 33]
Internet Draft Security Policy Specification Language March 2000
Actions are the policy attributes that are applied to outbound packets
and are used to decide whether or not to permit inbound packets. The
actions currently defined in SPSL are:
tfr-action ipsec-action ike-action
5.5 Policy Order
Multiple policy objects and attributes are likely to apply to a
particular communication. For example, most systems will have a
default policy to deny all inbound communications. There will then be
some more policies to permit specific inbound communications. A set
of selector values (see section 5.4) that match one of the specific
policies will also match the general default policy. SPSL must
establish a rule so that the correct policy is applied to the
communication. The rule must always provide the same answer when
applied to the same set of policies, otherwise inconsistent policy
enforcement may occur.
SPSL uses a simple rule to determine which policy should be applied to
the on-going communication - physical ordering of the policies. The
policy applied should always be the first policy that matches all the
selectors of the communication. This ordering holds for both the
ordering of the policy objects and the ordering of 'policy' attributes
within policy objects, if the long format of the policy class is used.
The physical ordering is the ordering of the policies in a file of
SPSL policy objects. This ordering must be maintained by the parser
and other applications that use the SPSL objects.
6. Security Considerations
SPSL is used to define a set of security policies for a host or a
domain. It is necessary to insure that the policies are only modified
by authorized maintainers, so that the intended policies are enforced.
The language provides the mechanisms to insure this and the integrity
of the policies, however the mechanisms must be used to secure them.
6.1 Authenticate the Maintainer
Tools that create and modify SPSL objects MUST use the 'auth'
attribute in the mntner object to authenticate the maintainer before
permitting any objects to be modified. When defining the maintainer
initially, the relative strengths of the provided authentication
mechanisms SHOULD be considered before using a particular one. The
integrity of an SPSL policy file is only as strong as the weakest
'auth' mechanism provided.
Condell, Lynn, Zao [page 34]
Internet Draft Security Policy Specification Language March 2000
6.2 Verify the Objects
Tools that modify or use SPSL objects SHOULD verify the signatures on
the objects before using them. A successful verification indicates
that the policy was written or modified by an authorized maintainer.
If the policy fails verification, it is suspect and SHOULD NOT be
used.
6.3 Protect File from Tampering
While SPSL provides the means to authenticate maintainers and verify
that objects are only modified by authorized maintainers, it does not
protect against some other attacks to the file. It is possible for an
attacker to delete or reorder objects in the file. It is also
possible for an attacker to replace the policy file with an empty
file. Since SPSL mechanisms are only on a per-object basis, it can
not protect against these attacks.
The maintainer or tools used to access and modify SPSL files SHOULD
sign each SPSL file or provide some other mechanism that can be used
to verify that objects have not been moved or reordered by an
unauthorized entity. SPSL requires that each SPSL file contain at
least one object so an authorization check will return meaningful
results.
7. Remaining Issues
The following issues are not resolved in this draft of language
definition. Solutions will be developed and included in the
subsequent revisions of the document.
* Certificate encodings must be defined.
* More thought should be put into signatures on objects,
especially on resigning objects when changes are made. Might
want to consider an attribute to specify the minimum number
of signatures that must be put in the object when it is
modified.
* General SA endpoints need to be thought out more, as noted in
the document.
* We are considering adding support for DNS names as policy
endpoints and for domain coverage in addition to IP addresses.
* We may want to define a packet description language and
selectors that use the language.
Condell, Lynn, Zao [page 35]
Internet Draft Security Policy Specification Language March 2000
8. Acknowledgments
The authors thank Luis Sanchez, David Mankins, Alden Jackson, and
Steve Kent for their help in reviewing early drafts of this document
and suggesting changes to the language. We thank Rajesh Krishnan,
Matt Fredette, and Thomas Fries, and Kai Martius for suggesting
changes to the language and helping clarify the draft.
Appendix A. BNF Form of SPSL
spsl-file -> spslobjlist
spslobjlist -> spslobjlist spslobj | spslobj
spslobj -> "mntner:" objectname line-term mntner-attributes obj-term
| "cert:" objectname line-term cert-attributes obj-term
| "node:" objectname line-term node-attributes obj-term
| "node-set:" objectname line-term node-set-attributes obj-term
| "gateway:" objectname line-term gateway-attributes obj-term
| "gateway-set:" objectname line-term gateway-set-attributes
obj-term
| "domain:" objectname line-term domain-attributes obj-term
| "polserv:" objectname line-term polserv-attributes obj-term
| "policy-name:" objectname line-term policy-attributes obj-term
| "ipsec-policy-name:" objectname line-term
ipsec-policy-attributes obj-term
| line-term
# checking for mandatory attributes is necessary after parsing
mntner-attributes -> mntner-attributes mntner-attribute
| mntner-attribute
cert-attributes -> cert-attributes cert-attribute | cert-attribute
node-attributes -> node-attributes node-attribute | node-attribute
node-set-attributes -> node-set-attributes node-set-attribute
| node-set-attribute
gateway-attributes -> gateway-attributes gateway-attribute
| gateway-attribute
gateway-set-attributes -> gateway-set-attributes gateway-set-attribute
| gateway-set-attribute
domain-attributes -> domain-attributes domain-attribute
| domain-attribute
polserv-attributes -> polserv-attributes polserv-attribute
| polserv-attribute
policy-attributes -> policy-attributes policy-attribute
| policy-attribute
ipsec-policy-attributes -> ipsec-policy-attributes
ipsec-policy-attribute | ipsec-policy-attribute
mntner-attribute -> shared-attribute | "auth:" auth-info line-term
| "address:" string line-term | "phone:" phonenum line-term
| "fax-no:" phonenum line-term | "email:" emailaddr line-term
| "certs:" objectnamelist line-term
Condell, Lynn, Zao [page 36]
Internet Draft Security Policy Specification Language March 2000
cert-attribute -> shared-attribute
| "certificate:" certtype hexstring line-term
| "certlocation:" certtype fetchproto locname line-term
| "crllocation:" crltype fetchproto locname line-term
node-attribute -> shared-attribute | "name:" dnsname line-term
| "alias:" dnsname line-term | "ifaddr:" ipaddress line-term
node-set-attribute -> shared-attribute
| "members:" objectnamelist line-term
gateway-attribute -> shared-attribute | "name:" dnsname line-term
| "alias:" dnsname line-term | "ifaddr:" ipaddress line-term
| "preference:" integer line-term
gateway-set-attribute -> shared-attribute
| "members:" objectnamelist line-term
domain-attribute -> shared-attribute
| "coverage:" domaincover line-term
| "gateways:" objectnamelist line-term
| "polservs:" objectnamelist line-term
polserv-attribute -> shared-attribute | "name:" dnsname line-term
| "alias:" dnsname line-term | "ifaddr:" ipaddress line-term
policy-attribute -> shared-attribute
| "association:" objectnamelist line-term
| "cache-expiry:" integer line-term | condition-attribute
| action-attribute
ipsec-policy-attribute -> policy-attribute
| ipsec-attribute
shared-attribute -> "char-set:" charset line-term
| "notes:" string line-term | "mnt-by:" objectnamelist line-term
| "changed:" objectname date line-term
| "signature:" objectname objectname signature-alg
signature-data line-term
| comments blankline
condition-attribute -> "policy:" "dst" addresslist ports-opt src-opt
xport-opt dir-opt actiontype line-term
| "valid-period:" valid-period-list line-term
| "dst:" addresslist ports-opt line-term
| "src:" addresslist ports-opt line-term
| "xport-proto:" integerlist line-term
| "direction:" dirtype symmetric-opt line-term
| "userid:" user-namelist line-term
| "systemname:" system-namelist line-term
| "ipv6-class:" integerlist line-term
| "ipv6-flow:" integerlist line-term
| "ipv4-tos:" integerlist line-term
| "seclabel:" seclabellist line-term
Condell, Lynn, Zao [page 37]
Internet Draft Security Policy Specification Language March 2000
| "ipver:" integerlist line-term
| "ipv4-hlen:" integerlist line-term
| "ipv4-tlen:" integerlist line-term
| "ipv4-id:" integerlist line-term
| "ipv4-frgm:" zeroone line-term
| "ipv4-frgo:" integerlist line-term
| "ipv4-ttl:" integerlist line-term
| "ipv4-prot:" integerlist line-term
| "ipv4-src:" ipv4list line-term
| "ipv4-dst:" ipv4list line-term
| "ipv4-opt-lsrr-dst:" ipv4list line-term
| "ipv4-opt-ssrr-dst:" ipv4list line-term
| "ipv6-dst:" ipv6list line-term
| "ipv6-src:" ipv6list line-term
| "ipv6-nhdr:" integerlist line-term
| "rh-nhdr:" integerlist line-term
| "rh-vers:" integerlist line-term
| "rhv1-dst:" ipv6list line-term
| "rhv1-nhop:" ipv6list line-term
| "rhv1-phop:" ipv6list line-term
| "ah-nhdr:" integerlist line-term
| "dop-nhdr:" integerlist line-term
| "esp-nhdr:" integerlist line-term
| "frag-nhdr:" integerlist line-term
| "hop-nhdr:" integerlist line-term
| "ipcomp-nhdr:" integerlist line-term
| "tcp-ack:" zeroone line-term
| "tcp-dato:" integerlist line-term
| "tcp-dst-port:" integerlist line-term
| "tcp-fin:" zeroone line-term
| "tcp-psh:" zeroone line-term
| "tcp-rst:" zeroone line-term
| "tcp-src-port:" integerlist line-term
| "tcp-syn:" zeroone line-term
| "tcp-urg:" zeroone line-term
| "tcp-urgp:" integerlist line-term
| "udp-cks:" integerlist line-term
| "udp-dst-port:" integerlist line-term
| "udp-id:" integerlist line-term
| "udp-src-port:" integerlist line-term
| "icmp4-code:" integerlist line-term
| "icmp4-gwy:" ipv4list line-term
| "icmp4-id:" integerlist line-term
| "icmp4-mtu:" integerlist line-term
| "icmp4-seq:" integerlist line-term
| "icmp4-type:" integerlist line-term
| "icmp6-code:" integerlist line-term
| "icmp6-gwy:" ipv6list line-term
| "icmp6-id:" integerlist line-term
| "icmp6-mtu:" integerlist line-term
| "icmp6-seq:" integerlist line-term
| "icmp6-type:" integerlist line-term
Condell, Lynn, Zao [page 38]
Internet Draft Security Policy Specification Language March 2000
action-attribute -> "tfr-action:" actiontype line-term
actiontype -> actionpd | actionpd "," actionfwd
actionpd -> "permit" | "deny"
actionfwd -> "forward" actionfwd-dst actionport-opt
actionfwd-dst -> "dns" dnsname | ipaddress
actionport-opt -> integer integer | (empty)
addresslist -> not-opt ipaddrlist | "any" | "*"
auth-info -> "crypt-pw" string | "pgp" hexstring
| "cert" objectnamelist
certtype -> "dnskey" | "kerberos" | "pgp" | "pkcs7" | "spki"
| "x509_ke" | "x509_sig"
crltype -> "x509"
date -> digit digit digit digit digit digit digit digit
dir-opt -> "direction" dirtype symmetric-opt | (empty)
dirtype -> "inbound" | "outbound"
symmetric-opt -> "," "symmetric" | (empty)
dn -> # see rfc 1779
# DNS name based on RFC 1034
dnsnamelist -> dnsnamelist "," dnsnamecomp
dnsnamecomp -> dnsname
dnsname -> dnsname "." label | label
label -> letter label-end-opt
label-end-opt -> ldh-string letdig | (empty)
ldh-string -> ldh-string letdighyph | (empty)
letdighyph -> letter | digit | "-"
letdig -> letter | digit
domaincover -> domaincomp | domaincover "," domaincomp
domaincomp -> ipcomp | objectname
edipn -> string
# email address from rfc 822
emailaddr -> username "@" dnsname
expiry-opt -> expiry | (empty)
expiry -> "expiry" expiry-type integerrange
expiry-type -> "seconds" | "kilobytes"
fetchproto -> "cdp" | "dns" | "file"
field-opt -> "field" integer | (empty)
filename -> filename filechar | (empty)
filechar -> alphanum | "_" | "-" | ":" | "." | "/" | "\"
genname -> "dirname" rdnlist | "dns" dnsname | "ediname" edipn
| "ipaddr" ipaddress | "n822" emailaddr | "other" oid string
| "regid" oid | "uri" uri | "x400" or-address
Condell, Lynn, Zao [page 39]
Internet Draft Security Policy Specification Language March 2000
signature-alg -> "dsa-sha1" | "rsa-pkcs1"
integerlist -> not-opt integerslist | "any" | "opaque" | "*"
integerslist -> integerslist "," integerrange | integerrange
integerrange -> "min" integer | "max" integer
| integer "-" integer | integer
integer -> integer digit | digit
ipaddress -> ipv4address | ipv6address
ipv4address -> two55 "." two55 "." two55 "." two55
ipv6address -> v6digit ":" v6digit ":" v6digit ":" v6digit ":"
v6digit ":" v6digit ":" v6digit ":" v6digit
v6digit -> hexdigit | hexdigit hexdigit | hexdigit hexdigit hexdigit
| hexdigit hexdigit hexdigit hexdigit | (empty)
ipaddrlist -> ipaddrlist "," ipcomp | ipcomp
ipcomp -> ipv4comp | ipv6comp
ipv4list -> ipv4list "," ipv4comp | ipv4comp
ipv4comp -> ipv4address | ipv4address-range
ipv4address-range -> ipv4address "-" ipv4address
| ipv4address "mask" ipv4address
| ipv4address "/" integer
ipv6list -> ipv6list "," ipv6comp | ipv6comp
ipv6comp -> ipv6address | ipv6address-range
ipv6address-range -> ipv6address "-" ipv6address
| ipv6address "mask" ipv6address
| ipv6address "/" integer
ipsec-attribute -> "ipsec-action:" ipsec-action line-term
| "ike-action:" ike-action line-term
ipsec-action -> ipsec_action_esp_opt ipsec_action_ah_opt
ipsec_action_ipcomp_opt
ipsec_action_esp_opt -> esp-proposal ipsectype ipsecloc | (empty)
ipsec_action_ah_opt -> ah-proposal ipsectype ipsecloc | (empty)
ipsec_action_ipcomp_opt -> ipcomp-proposal | (empty)
ipsectype -> "tunnel" | "transport" | (empty)
usepfs -> "true" | "false"
proposal-choice -> "req" | "opt"
ah-proposal -> "ah" proposal-choice "integrity"
integrity-alg-any expiry-opt | "ah" "proh"
integrity-alg-any -> "any" keylen-opt | not-opt integrity-alg-list
integrity-alg-list -> integrity-alg-list "," integrity-alg
keylen-opt | integrity-alg keylen-opt
integrity-alg -> "hmacdes" | "hmacmd5" | "hmacsha1"
| "kpdk" | integer
Condell, Lynn, Zao [page 40]
Internet Draft Security Policy Specification Language March 2000
esp-proposal -> "esp" proposal-choice "cipher" ipsec-cipher-alg-any
integrity-opt expiry-opt | "esp" "proh"
ipsec-cipher-alg-any -> "any" keylen-opt rounds-opt
| "*" keylen-opt rounds-opt
| not-opt ipsec-cipher-alg-list
ipsec-cipher-alg-list ->
ipsec-cipher-alg-list "," ipsec-cipher-alg keylen-opt
rounds-opt | ipsec-cipher-alg keylen-opt rounds-opt
ipsec-cipher-alg -> "blowfish" | "cast" | "des" | "des3" | "idea"
| "idea3" | "null" | "rc4" | "rc5" | "rfc1829-iv32"
| "rfc1829-iv64" | integer
rounds-opt -> "rounds" integerrange | (empty)
integrity-opt -> "integrity" integrity-alg-any | (empty)
ipcomp-proposal -> "ipcomp" proposal-choice ipcomp-alg-any
| "ipcomp" "proh"
ipcomp-alg-any -> "any" | not-opt ipcomp-alg-list
ipcomp-alg-list -> ipcomp-alg-list "," ipcomp-alg
| ipcomp-alg
ipcomp-alg -> "deflate" | "lzs" | "oui" | integer
ike-action -> "ikemode" ikemode "pfs" usepfs
"auth" ike-auth-method-any
"cipher" ike-cipher-alg-any "hash" ike-hash-alg-any
ike-group-opt prf-opt field-opt expiry
ikemode -> "main" | "aggressive" | "quick"
ike-auth-method-any -> "any" | not-opt ike-auth-method-list
ike-auth-method-list -> ike-auth-method-list "," ike-auth-method
| ike-auth-method
ike-auth-method -> "pre-shared" | "dss" | "rsa" | "rsa-encrypt"
| "rsa-revised" | integer
ike-cipher-alg-any -> "any" keylen-opt | not-opt ike-cipher-alg-list
ike-cipher-alg-list -> ike-cipher-alg-list "," ike-cipher-alg
keylen-opt | ike-cipher-alg keylen-opt
ike-cipher-alg -> "blowfish" | "cast" | "des" | "des3" | "idea"
| "rc5" | integer
ike-hash-alg-any -> "any" | not-opt ike-hash-alg-list
ike-hash-alg-list -> ike-hash-alg-list "," ike-hash-alg
| ike-hash-alg
ike-hash-alg -> "md5" | "sha1" | "tiger" | integer
ike-group-opt -> "group-desc" ike-group-desc |
"group-type" ike-group-type | (empty)
ike-group-desc -> "modp-768" | "modp-1024" | "ec2n-155"
| "ec2n-185" | integer
ike-group-type -> ike-group-name hexstring hexstring hexstring
hexstring hexstring hexstring
ike-group-name -> "modp" | "ecp" | "ec2n" | integer
Condell, Lynn, Zao [page 41]
Internet Draft Security Policy Specification Language March 2000
ipsecloc -> from-opt to-opt
from-opt -> "from" anylocation | (empty)
to-opt -> "to" anylocation | (empty)
anylocation -> "any" | locations
locations -> locations "," location | location
location -> "dest" | "host" | "local-sg" | "remote-sg" | ipaddress
| "dns" dnsname
keylen-opt -> "keylen" integerrange | (empty)
locname -> genname | "rdn" rdn | "filename" filename
not-opt -> "not" | (empty)
objectnamelist -> objectnamelist "," objectname | objectname
objectname -> extletter objectinternals alphanum | extletter alphanum
| extletter
objectinternals -> objectinternals objectinternal | (empty)
objectinternal -> alphanum | "_" | "-" | ":" | "."
oid -> objectname
or-address -> string
phonenum -> phonenum phonenum | digit | " " | "+" | "-" | "x"
ports-opt -> "port" integerlist dynamic-opt | (empty)
dynamic-opt -> "dynamic" portrange-opt | (empty)
portrange-opt -> integerrange | (empty)
prf-opt -> "prf" integer | (empty)
rdnlist -> rdnlist rdn | rdn
rdn -> # see rfc 1779
src-opt -> "src" addresslist ports-opt | (empty)
seclabellist -> not-opt seclabelslist | "*" | "opaque" | "any"
seclabelslist -> seclabelslist "," seclabel | seclabel
seclabel -> hexstring
signature-data -> hexstring
system-namelist -> not-opt system-nameslist | "*" | "any"
system-nameslist -> system-nameslist "," system-name
| system-name
system-name -> genname | "dn" dn
uri -> # see definition in RFC 2396
username -> # see definition in RFC 822
user-namelist -> not-opt user-nameslist | "*" | "any"
user-nameslist -> user-nameslist "," user-name
| user-name
user-name -> "n822" emailaddr | "dn" dn
valid-period-list -> valid-period-list "," valid-period
| valid-period
valid-period -> year-opt month-opt dayof-month-opt
rev-dayof-month-opt dayof-week-opt time-opt
Condell, Lynn, Zao [page 42]
Internet Draft Security Policy Specification Language March 2000
year-opt -> "year" integer "-" integer | (empty)
month-opt -> "month" bitstring | (empty)
dayof-month-opt -> "day-of-month" bitstring | (empty)
dayof-week-opt -> "day-of-week" bitstring | (empty)
time-opt -> "time" not-opt time "-" time | (empty)
time -> integer ":" integer ":" integer
rev-dayof-month-opt -> "reverse-day-of-month" bitstring | (empty)
xport-opt -> "xport-proto" integerlist | (empty)
alphanum -> extletter | digit
charset -> string
digit -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
extletter -> A..Z | a..z | #140 | #156 | #192..#214
| #216..#246 | #248..#255
letter -> A..Z | a..z
two55 -> [0-9] | [0-9][0-9] | 1[0-9][0-9] | 2[0-4][0-9] | 25[0-5]
hexstring -> hexstring hexdigit | hexdigit
hexdigit -> [0-9] | a | A | b | B | c | C | d | D | e | E | f | F
string -> string char | (empty)
zeroone -> 0 | 1
bitstring -> bitstring zeroone | zeroone
line-term -> comments blankline | blankline
comments -> comments comment | comment
comment -> "#" string
obj-term -> blankline | EOF
blankline -> whitespace LF
whitespace -> whitespace whitechar | (empty)
whitechar -> tab | " " | ff
char -> any character in ISO 8859-1 (Latin-1) except special
characters ("#" and "\") which must be replaced by their
escaped versions ("\#" and "\\").
References
[Bra97] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Level," RFC-2119, March 1997.
[rfc2407] D. Piper, "The Internet IP Security Domain of
Interpretation for ISAKMP", RFC 2407, November 1998.
[DSA] Federal Information Processing Standards Publication
(FIPS PUB) 186, Digital Signature Standard, 18 May 1994.
[ISO8859] Information Processing - 8-bit Single-Byte Coded Graphic
Character Sets. Part1: Latin Alphabet Number 1, ISO 8859-1,
1987.
[Kent98] S. Kent, R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998.
Condell, Lynn, Zao [page 43]
Internet Draft Security Policy Specification Language March 2000
[PKIXP1] R. Housley, W. Ford, W. Polk, D. Solo, "Internet X.509
Public Key Infrastructure Certificate and CRL Profile",
RFC 2459, January 1999.
[PolMod] R. Pereira, P. Bhattacharya, "IPSec Policy Data Model",
Internet Draft draft-ietf-ipsec-policy-model-00, February 1998.
[rfc822] D. Crocker, "Standard for the Format of ARPA Internet
Text Messages", RFC 822, August 1982.
[rfc1034] P. Mockapetris, "Domain Names - Concepts and Facilities",
RFC 1034, November 1987.
[rfc1779] S. Kille, "A String Representation of Distinguished
Names", RFC 1779, March 1995.
[rfc2396] T. Berners-Lee, R. Fielding, L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[rfc2409] D. Harkins, D. Carrel, "The Internet Key Exchange (IKE)",
RFC 2409, November 1998.
[RPSL] C. Alaettinouglu, T. Bates, E. Gerich, D. Karrenberg, D.
Meyer, M. Terpstra, and C. Villamizer. "Routing Policy
Specification Language (RPSL)". RFC 2280. January 1998.
[RSA] PKCS #1: RSA Encryption Standard, Version 1.4, RSA Data
Security, Inc., 3 June 1991.
[IPSP-PDA] A. Keromytis, M. Richardson, L. Sanchez, "IPsec Policy
Discovery Architecture", Working Draft
draft-keromytis-ipsp-arch-00.txt, October 1999.
Condell, Lynn, Zao [page 44]
Internet Draft Security Policy Specification Language March 2000
Disclaimer
The views and specification here are those of the authors and are
not necessarily those of their employers. The authors and their
employers specifically disclaim responsibility for any problems
arising from correct or incorrect implementation or use of this
specification.
Copyright (C) The Internet Society (2000). All
Rights Reserved.
This document and translations of it may be copied and furnished
to others, and derivative works that comment on or otherwise
explain it or assist in its implementation may be prepared, copied,
published and distributed, in whole or in part, without
restriction of any kind, provided that the above copyright notice
and this paragraph are included on all such copies and derivative
works. However, this document itself may not be modified in any
way, such as by removing the copyright notice or references to the
Internet Society or other Internet organizations, except as needed
for the purpose of developing Internet standards in which case the
procedures for copyrights defined in the Internet Standards
process must be followed, or as required to translate it into
languages other than English. The limited permissions granted above
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This document and the information contained herein is provided on
an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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Author Information
Matthew Condell Charles Lynn
BBN Technologies BBN Technologies
10 Moulton Street 10 Moulton Street
Cambridge, MA 02138 Cambridge, MA 02138
USA USA
Email: mcondell@bbn.com Email: clynn@bbn.com
Telephone: +1 (617) 873-6203 Telephone: +1 (617) 873-3367
John Zao
BBN Technologies
10 Fawcett Street
Cambridge, MA 02138
USA
Email: jzao@bbn.com
Telephone: +1 (617) 873-2438
Condell, Lynn, Zao [page 45]
