Internet DRAFT - draft-ietf-ipsecme-labeled-ipsec
draft-ietf-ipsecme-labeled-ipsec
Network P. Wouters
Internet-Draft Aiven
Intended status: Standards Track S. Prasad
Expires: 16 November 2023 Red Hat
15 May 2023
Labeled IPsec Traffic Selector support for IKEv2
draft-ietf-ipsecme-labeled-ipsec-12
Abstract
This document defines a new Traffic Selector (TS) Type for Internet
Key Exchange version 2 to add support for negotiating Mandatory
Access Control (MAC) security labels as a traffic selector of the
Security Policy Database (SPD). Security Labels for IPsec are also
known as "Labeled IPsec". The new TS type is TS_SECLABEL, which
consists of a variable length opaque field specifying the security
label.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on 16 November 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Traffic Selector clarification . . . . . . . . . . . . . 3
1.3. Security Label Traffic Selector negotiation . . . . . . . 4
2. TS_SECLABEL Traffic Selector Type . . . . . . . . . . . . . . 4
2.1. TS_SECLABEL payload format . . . . . . . . . . . . . . . 4
2.2. TS_SECLABEL properties . . . . . . . . . . . . . . . . . 5
3. Traffic Selector negotiation . . . . . . . . . . . . . . . . 5
3.1. Example TS negotiation . . . . . . . . . . . . . . . . . 6
3.2. Considerations for using multiple TS_TYPEs in a TS . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 7
6.1. Libreswan . . . . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
In computer security, Mandatory Access Control usually refers to
systems in which all subjects and objects are assigned a security
label. A security label is composed of a set of security attributes.
The security labels along with a system authorization policy
determine access. Rules within the system authorization policy
determine whether the access will be granted based on the security
attributes of the subject and object.
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Historically, security labels used by Multilevel Systems (MLS) are
comprised of a sensitivity level (or classification) field and a
compartment (or category) field, as defined in [FIPS188] and
[RFC5570]. As MAC systems evolved, other MAC models gained in
popularity. For example, SELinux, a Flux Advanced Security Kernel
(FLASK) implementation, has security labels represented as colon-
separated ASCII strings composed of values for identity, role, and
type. The security labels are often referred to as security
contexts.
Traffic Selector (TS) payloads specify the selection criteria for
packets that will be forwarded over the newly set up IPsec Security
Association (SA) as enforced by the Security Policy Database (SPD,
see [RFC4301]).
This document specifies a new Traffic Selector Type TS_SECLABEL for
IKEv2 that can be used to negotiate security labels as additional
selectors for the Security Policy Database (SPD) to further restrict
the type of traffic allowed to be sent and received over the IPsec
SA.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Traffic Selector clarification
The negotiation of Traffic Selectors is specified in Section 2.9 of
[RFC7296] where it defines two TS Types (TS_IPV4_ADDR_RANGE and
TS_IPV6_ADDR_RANGE). The Traffic Selector payload format is
specified in Section 3.13 of [RFC7296]. However, the term Traffic
Selector is used to denote the traffic selector payloads and
individual traffic selectors of that payload. Sometimes the exact
meaning can only be learned from context or if the item is written in
plural ("Traffic Selectors" or "TSs"). This section clarifies these
terms as follows:
A Traffic Selector (no acronym) is one selector for traffic of a
specific Traffic Selector Type (TS_TYPE). For example a Traffic
Selector of TS_TYPE TS_IPV4_ADDR_RANGE for UDP (protocol 17) traffic
in the IP network 198.51.100.0/24 covering all ports, is denoted as
(17, 0, 198.51.100.0-198.51.100.255)
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A Traffic Selector payload (TS) is a set of one or more Traffic
Selectors of the same or different TS_TYPEs. It typically contains
one or more of the TS_TYPE of TS_IPV4_ADDR_RANGE and/or
TS_IPV6_ADDR_RANGE. For example, the above Traffic Selector by
itself in a TS payload is denoted as TS((17, 0,
198.51.100.0-198.51.100.255))
1.3. Security Label Traffic Selector negotiation
The negotiation of Traffic Selectors is specified in Section 2.9 of
[RFC7296] and states that the TSi/TSr payloads MUST contain at least
one Traffic Selector type. This document adds a new TS_TYPE of
TS_SECLABEL that is valid only with at least one other type of
Traffic Selector. That is, it cannot be the only TS_TYPE present in
a TSi or TSr payload. It MUST be used along with an IP address
selector type such as TS_IPV4_ADDR_RANGE and/or TS_IPV6_ADDR_RANGE.
2. TS_SECLABEL Traffic Selector Type
This document defines a new TS Type, TS_SECLABEL that contains a
single new opaque Security Label.
2.1. TS_SECLABEL payload format
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------------------------------+
| TS Type | Reserved | Selector Length |
+---------------+---------------+-------------------------------+
| |
~ Security Label* ~
| |
+---------------------------------------------------------------+
Figure 1: Labeled IPsec Traffic Selector
*Note: All fields other than TS Type and Selector Length depend on
the TS Type. The fields shown is for TS Type TS_SECLABEL, the
selector this document defines.
* TS Type (one octet) - Set to 10 for TS_SECLABEL,
* Selector Length (2 octets, unsigned integer) - Specifies the
length of this Traffic Selector substructure including the header.
* Security Label - An opaque byte stream of at least one octet.
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2.2. TS_SECLABEL properties
The TS_SECLABEL Traffic Selector Type does not support narrowing or
wildcards. It MUST be used as an exact match value.
The TS_SECLABEL Traffic Selector Type MUST NOT be the only TS_TYPE
present in the TS payload as TS_SECLABEL is complimentary to another
type of Traffic Selector. There MUST be an IP address Traffic
Selector type in addition to the TS_SECLABEL Traffic Selector type in
the Traffic Selector Payload. If a TS payload is received with only
TS_SECLABEL Traffic Selector types, the exchange MUST be aborted with
an Error Notify message containing TS_UNACCEPTABLE.
The Security Label contents are opaque to the IKE implementation.
That is, the IKE implementation might not have any knowledge of the
meaning of this selector, other than as a type and opaque value to
pass to the SPD.
A zero length Security Label MUST NOT be used. If a received TS
payload contains a TS_TYPE of TS_SECLABEL with a zero length Security
Label, that specific Traffic Selector MUST be ignored. If no other
Traffic Selector of TS_TYPE TS_SECLABEL can be selected, the exchange
MUST be aborted with a TS_UNACCEPTABLE Error Notify message. A zero
length Security Label MUST NOT be interpreted as a wildcard security
label.
If multiple Security Labels are allowed for a given IP protocol,
start and end address/port match, the initiator includes all of the
acceptable TS_SECLABEL's and the responder MUST select one of them.
A responder that selected a TS with TS_SECLABEL MUST use the Security
Label for all selector operations on the resulting TS. It MUST NOT
select a TS_SECLABEL without using the specified Security Label, even
if it deems the Security Label optional, as the initiator has
indicated (and expects) that Security Label will be set for all
traffic matching the negotiated TS.
3. Traffic Selector negotiation
If the TSi Payload contains a traffic selector for TS_TYPE of
TS_SECLABEL (along with another TS_TYPE), the responder MUST create
each TS response for the other TS_TYPEs using its normal rules
specified for each of those TS_TYPE, such as narrowing them following
the rules specified for that TS_TYPE, and then add exactly one for
the TS_TYPE of TS_SECLABEL to the TS Payload(s). If this is not
possible, it MUST return a TS_UNACCEPTABLE Error Notify payload.
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If the Security Label traffic selector is optional from a
configuration point of view, an initiator will add the TS_SECLABEL to
the TSi/TSr Payloads. If the responder replies with TSi/TSr Payloads
that include the TS_SECLABEL, then the Child SA MUST be created
including the negotiated Security Label. If the responder did not
include a TS_SECLABEL in its response, then the initiator (which
deemed the Security Label optional) will install the Child SA without
including any Security Label. If the initiator required the
TS_SECLABEL, it MUST NOT install the Child SA and it MUST send a
Delete notification for the Child SA so the responder can uninstall
its Child SA.
3.1. Example TS negotiation
An initiator could send:
TSi = ((17,24233,198.51.100.12-198.51.100.12),
(0,0,198.51.100.0-198.51.100.255),
(0,0,192.0.2.0-192.0.2.255),
TS_SECLABEL1, TS_SECLABEL2)
TSr = ((17,53,203.0.113.1-203.0.113.1),
(0,0,203.0.113.0-203.0.113.255),
TS_SECLABEL1, TS_SECLABEL2)
Figure 2: initiator TS payloads example
The responder could answer with the following example:
TSi = ((0,0,198.51.100.0-198.51.100.255),
TS_SECLABEL1)
TSr = ((0,0,203.0.113.0-203.0.113.255),
TS_SECLABEL1)
Figure 3: responder TS payloads example
3.2. Considerations for using multiple TS_TYPEs in a TS
It would be unlikely that the traffic for TSi and TSr would have a
different Security Label, but this specification does allow this to
be specified. If the initiator does not support this, and wants to
prevent the responder from picking different labels for the TSi / TSr
payloads, it should attempt a Child SA negotiation with only the
first Security Label first, and upon failure retry a new Child SA
negotiation with only the second Security Label.
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If different IP ranges can only use different specific Security
Labels, then these should be negotiated in two different Child SA
negotiations. If in the example above, the initiator only allows
192.0.2.0/24 with TS_SECLABEL1, and 198.51.100.0/24 with
TS_SECLABEL2, than it MUST NOT combine these two ranges and security
labels into one Child SA negotiation.
4. Security Considerations
It is assumed that the Security Label can be matched by the IKE
implementation to its own configured value, even if the IKE
implementation itself cannot interpret the Security Label value.
A packet that matches an SPD entry for all components except the
Security Label would be treated as "not matching". If no other SPD
entries match, the (mis-labeled) traffic might end up being
transmitted in the clear. It is presumed that other Mandatory Access
Control methods are in place to prevent mis-labeled traffic from
reaching the IPsec subsystem, or that the IPsec subsystem itself
would install a REJECT/DISCARD rule in the SPD to prevent unlabeled
traffic otherwise matching a labeled security SPD rule from being
transmitted without IPsec protection.
5. IANA Considerations
This document defines one new entry in the IKEv2 Traffic Selector
Types registry:
[Note to RFC Editor (please remove before publication): This value
has already been added via Early Allocation.]
Value TS Type Reference
----- --------------------------- -----------------
10 TS_SECLABEL [this document]
Figure 4
6. Implementation Status
[Note to RFC Editor: Please remove this section and the reference to
[RFC7942] before publication.]
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
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here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
Authors are requested to add a note to the RFC Editor at the top of
this section, advising the Editor to remove the entire section before
publication, as well as the reference to [RFC7942].
6.1. Libreswan
Organization: The Libreswan Project
Name: https://lists.libreswan.org/mailman/listinfo/swan-dev/
Description: Implementation was introduced in 4.4, but 4.6 or newer
should be used
Level of maturity: beta
Coverage: Implements the entire draft using SElinux based labels
Licensing: GPLv2
Implementation experience: No interop testing has been done yet.
The code works including different labeled on-demand kernel
ACQUIRES.
Contact: Libreswan Development: swan-dev@libreswan.org
7. Acknowledgements
A large part of the introduction text was taken verbatim from
[draft-jml-ipsec-ikev2-security-label] whose authors are J Latten, D.
Quigley and J. Lu. Valery Smyslov provided valuable input regarding
IKEv2 Traffic Selector semantics.
8. References
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8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
8.2. Informative References
[draft-jml-ipsec-ikev2-security-label]
Latten, J., Quigley, D., and J. Lu, "Security Label
Extension to IKE", 28 January 2011.
[FIPS188] NIST, "National Institute of Standards and Technology,
"Standard Security Label for Information Transfer"",
Federal Information Processing Standard (FIPS) Publication
188, September 1994,
<https://csrc.nist.gov/publications/detail/fips/188/
archive/1994-09-06>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC5570] StJohns, M., Atkinson, R., and G. Thomas, "Common
Architecture Label IPv6 Security Option (CALIPSO)",
RFC 5570, DOI 10.17487/RFC5570, July 2009,
<https://www.rfc-editor.org/info/rfc5570>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
Authors' Addresses
Paul Wouters
Aiven
Email: paul.wouters@aiven.io
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Sahana Prasad
Red Hat
Email: sahana@redhat.com
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