Internet DRAFT - draft-ietf-ippm-ioam-data-integrity
draft-ietf-ippm-ioam-data-integrity
ippm F. Brockners
Internet-Draft Cisco
Intended status: Standards Track S. Bhandari
Expires: 18 April 2024 Thoughtspot
T. Mizrahi
Huawei
J. Iurman
ULiege
16 October 2023
Integrity of In-situ OAM Data Fields
draft-ietf-ippm-ioam-data-integrity-07
Abstract
In-situ Operations, Administration, and Maintenance (IOAM) records
operational and telemetry information in the packet while the packet
traverses a path in the network. IETF protocols require features to
ensure their security. This document describes the integrity
protection of IOAM-Data-Fields.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 18 April 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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
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and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4
3. Threat Analysis . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Modification: IOAM-Data-Fields . . . . . . . . . . . . . 5
3.2. Modification: IOAM Option-Type Headers . . . . . . . . . 5
3.3. Injection: IOAM-Data-Fields . . . . . . . . . . . . . . . 6
3.4. Injection: IOAM Option-Type Headers . . . . . . . . . . . 6
3.5. Replay . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.6. Management and Exporting . . . . . . . . . . . . . . . . 6
3.7. Delay . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.8. Threat Summary . . . . . . . . . . . . . . . . . . . . . 7
4. Integrity Protected Option-Types . . . . . . . . . . . . . . 8
4.1. Integrity Protected Trace Option-Types . . . . . . . . . 9
4.1.1. Header fields for integrity protection . . . . . . . 10
4.2. Integrity Protected POT Option-Type . . . . . . . . . . . 10
4.2.1. Header fields for integrity protection . . . . . . . 11
4.3. Integrity Protected E2E Option-Type . . . . . . . . . . . 11
4.3.1. Header fields for integrity protection . . . . . . . 12
4.4. Integrity Protected DEX Option-Type . . . . . . . . . . . 12
4.4.1. Header fields for integrity protection . . . . . . . 12
5. Integrity Protection Method . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
6.1. IOAM Option-Types . . . . . . . . . . . . . . . . . . . . 14
6.2. IOAM Integrity Protection Signature Suite . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
9.1. Normative References . . . . . . . . . . . . . . . . . . 16
9.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
"In-situ" Operations, Administration, and Maintenance (IOAM) records
OAM information within the packet while the packet traverses a
particular network domain. The term "in-situ" refers to the fact
that the OAM data is added to the data packets rather than being sent
within packets specifically dedicated to OAM. IOAM is to complement
mechanisms such as Ping or Traceroute. In terms of "active" or
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"passive" OAM, "in-situ" OAM can be considered a hybrid OAM type.
"In-situ" mechanisms do not require extra packets to be sent. IOAM
adds information to the already available data packets and therefore
cannot be considered passive. In terms of the classification given
in [RFC7799], IOAM could be portrayed as Hybrid Type I. IOAM
mechanisms can be leveraged where mechanisms using, e.g., ICMP do not
apply or do not offer the desired results, such as proving that a
certain traffic flow takes a pre-defined path, SLA verification for
the data traffic, detailed statistics on traffic distribution paths
in networks that distribute traffic across multiple paths, or
scenarios in which probe traffic is potentially handled differently
from regular data traffic by the network devices.
IOAM MUST be deployed in an IOAM-Domain. An IOAM-Domain is a set of
nodes that use IOAM. An IOAM-Domain is bounded by its perimeter or
edge. It is expected that all nodes in an IOAM-Domain are managed by
the same administrative entity, that has means to select, monitor,
and control the access to all the networking devices. As such, IOAM-
Data-Fields are carried in clear within packets and there are no
protections against any node or middlebox tampering with the data.
IOAM-Data-Fields collected in an untrusted or semi-trusted
environment require integrity protection to support critical
operational decisions. Please refer to [RFC9197] for more details on
IOAM-Domains.
The following considerations and requirements are to be taken into
account in addition to addressing the problem of detectability of any
integrity breach of the IOAM-Data-Fields collected:
1. IOAM data is processed by the data plane, hence viability of any
method to prove integrity of the IOAM-Data-Fields must be
feasible at data plane processing/forwarding rates (IOAM might be
applied to all traffic a router forwards).
2. IOAM data is carried within packets. Additional space required
to prove integrity of the IOAM-Data-Fields needs to be optimal,
i.e. should not exceed the Maximum Transmission Unit (MTU) or
have adverse effect on packet processing.
3. Protection against replay of old IOAM data should be possible.
Without replay protection, a rogue node can present the old IOAM
data, masking any ongoing network issues/activity and making the
IOAM-Data-Fields collection useless.
This document defines a method to protect the integrity of IOAM-Data-
Fields, using the IOAM Option-Types specified in [RFC9197] and
[RFC9326] as an example. The method will similarly apply to future
IOAM Option-Types.
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2. Conventions
2.1. 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.
2.2. Abbreviations
Abbreviations used in this document:
OAM: Operations, Administration, and Maintenance
IOAM: In-situ OAM
POT: Proof of Transit
E2E: Edge to Edge
DEX: Direct Exporting
3. Threat Analysis
This section presents a threat analysis of integrity-related threats
in the context of IOAM. The threats that are discussed are assumed
to be independent of the lower layer protocols; it is assumed that
threats at other layers are handled by security mechanisms that are
deployed at these layers.
This document is focused on integrity protection for IOAM-Data-
Fields. Thus the threat analysis includes threats that are related
to or result from compromising the integrity of IOAM-Data-Fields.
Other security aspects such as confidentiality are not within the
scope of this document.
Throughout the analysis there is a distinction between on-path and
off-path attackers. As discussed in [RFC9055], on-path attackers are
located in a position that allows interception and modification of
in-flight protocol packets, whereas off-path attackers can only
attack by generating protocol packets.
The analysis also includes the impact of each of the threats.
Generally speaking, the impact of a successful attack on an OAM
protocol [RFC7276] is a false illusion of nonexistent failures or
preventing the detection of actual ones; in both cases, the attack
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may result in denial of service (DoS). Furthermore, creating the
false illusion of a nonexistent issue may trigger unnecessary
processing in some of the IOAM nodes along the path, and may cause
more IOAM-related data to be exported to the management plane than is
conventionally necessary. Beyond these general impacts, threat-
specific impacts are discussed in each of the subsections below.
3.1. Modification: IOAM-Data-Fields
Threat
An on-path attacker can modify the IOAM-Data-Fields of in-transit
packets. The modification can either be applied to all packets or
selectively applied to a subset of the en route packets.
Maliciously modified IOAM-Data-Fields can for example mislead
network diagnostics, result in incorrect network performance
metrics, or could misguide network optimization efforts.
Impact
By systematically modifying the IOAM-Data-Fields of some or all of
the in-transit packets, an attacker can create a false picture of
the paths in the network, the existence of faulty nodes and their
location, and the network performance.
3.2. Modification: IOAM Option-Type Headers
Threat
An on-path attacker can modify the header in IOAM Option-Types in
order to change or disrupt the behavior of nodes processing IOAM-
Data-Fields along the path.
Impact
Changing the header of IOAM Option-Types may have several
implications. An attacker can maliciously increase the processing
overhead in nodes that process IOAM-Data-Fields and increase the
on-the-wire overhead of IOAM-Data-Fields, for example by modifying
the IOAM-Trace-Type field in the IOAM Trace Option-Type header.
An attacker can also prevent some of the nodes that process IOAM-
Data-Fields from incorporating IOAM-Data-Fields, by modifying the
RemainingLen field in the IOAM Trace Option-Type header. Another
possibility for the attacker is to change the context of IOAM-
Data-Fields by modifying the Namespace-ID field in IOAM Option-
Type headers, which makes the integrity protection of IOAM-Data-
Fields completely useless.
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3.3. Injection: IOAM-Data-Fields
Threat
An attacker can inject packets with IOAM Option-Types and IOAM-
Data-Fields. This threat is applicable to both on-path and off-
path attackers.
Impact
This attack and its impacts are similar to Section 3.1.
3.4. Injection: IOAM Option-Type Headers
Threat
An attacker can inject packets with IOAM Option-Type headers, thus
manipulating other nodes that process IOAM-Data-Fields in the
network. This threat is applicable to both on-path and off-path
attackers.
Impact
This attack and its impacts are similar to Section 3.2.
3.5. Replay
Threat
An attacker can replay packets with IOAM-Data-Fields.
Specifically, an attacker may replay a previously transmitted IOAM
Option-Type with a new data packet, therefore attaching old IOAM-
Data-Fields to a fresh user packet. This threat is applicable to
both on-path and off-path attackers.
Impact
By replaying old IOAM-Data-Fields, an attacker can create a false
picture of the network status. The attacker could simulate a
nonexistent failure, or incur non-required processing load on
nodes that process these IOAM-Data-Fields.
3.6. Management and Exporting
Threat
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Attacks that compromise the integrity of IOAM-Data-Fields can be
applied at the management plane, e.g., by manipulating network
management packets. Furthermore, the integrity of IOAM-Data-
Fields that are exported to a receiving entity can also be
compromised. Management plane attacks are not within the scope of
this document; the network management protocol is expected to
include inherent security capabilities. The integrity of exported
data is also not within the scope of this document. It is
expected that the specification of the export format will discuss
the relevant security aspects.
Impact
Malicious manipulation of the management protocol can cause nodes
that process IOAM-Data-Fields to malfunction, to be overloaded, or
to incorporate unnecessary IOAM-Data-Fields into user packets.
The impact of compromising the integrity of exported IOAM-Data-
Fields is similar to the impacts of previous threats that were
described in this section.
3.7. Delay
Threat
An on-path attacker may delay some or all of the in-transit
packets that include IOAM-Data-Fields in order to create the false
illusion of congestion. Delay attacks are well known in the
context of deterministic networks [RFC9055] and synchronization
[RFC7384], and may be somewhat mitigated in these environments by
using redundant paths in a way that is resilient to an attack
along one of the paths. This approach does not address the threat
in the context of IOAM, as it does not meet the requirement to
measure a specific path or to detect a problem along the path. It
is noted that this threat is not within the scope of the threats
that are mitigated in this document.
Impact
Since IOAM can be applied to a fraction of the traffic, an
attacker can detect and delay only the packets that include IOAM-
Data-Fields, thus preventing the authenticity of delay and load
measurements.
3.8. Threat Summary
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+-------------------------------------------+--------+------------+
| Threat |In scope|Out of scope|
+-------------------------------------------+--------+------------+
|Modification: IOAM-Data-Fields | + | |
+-------------------------------------------+--------+------------+
|Modification: IOAM Option-Type Headers | + | |
+-------------------------------------------+--------+------------+
|Injection: IOAM-Data-Fields | + | |
+-------------------------------------------+--------+------------+
|Injection: IOAM Option-Type Headers | + | |
+-------------------------------------------+--------+------------+
|Replay | + | |
+-------------------------------------------+--------+------------+
|Management and Exporting | | + |
+-------------------------------------------+--------+------------+
|Delay | | + |
+-------------------------------------------+--------+------------+
Figure 1: Threat Analysis Summary
4. Integrity Protected Option-Types
This section defines new IOAM Option-Types. Their purpose is to
carry IOAM-Data-Fields with integrity protection. Each of the IOAM
Option-Types defined in [RFC9197] and [RFC9326] is extended as
follows:
64 IOAM Pre-allocated Trace Integrity Protected Option-Type:
corresponds to the IOAM Pre-allocated Trace Option-Type
([RFC9197]) with integrity protection.
65 IOAM Incremental Trace Integrity Protected Option-Type:
corresponds to the IOAM Incremental Trace Option-Type ([RFC9197])
with integrity protection.
66 IOAM POT Integrity Protected Option-Type: corresponds to the IOAM
POT Option-Type ([RFC9197]) with integrity protection.
67 IOAM E2E Integrity Protected Option-Type: corresponds to the IOAM
E2E Option-Type ([RFC9197]) with integrity protection.
68 IOAM DEX Integrity Protected Option-Type: corresponds to the IOAM
DEX Option-Type ([RFC9326]) with integrity protection.
The IOAM Integrity Protection Header follows the IOAM Option-Type
header when the IOAM Option-Type is an Integrity Protected Option-
Type. It is defined as follows:
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0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Signature-suite| Nonce length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Nonce ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: IOAM Integrity Protection Header
Signature-suite: 8-bit unsigned integer. This field defines the
algorithm pair used to compute the digest and the signature over
the IOAM-Data-Fields, as defined in Section 6.2.
Nonce length: 8-bit unsigned integer. This field specifies the
length of the Nonce in octets.
Reserved: 16-bit Reserved field. MUST be set to zero upon
transmission and ignored upon receipt.
Nonce: Variable length field with length specified in Nonce length.
Signature: Digital signature value generated by the algorithm pair
specified by Signature-suite. The Signature length depends on the
Signature-suite value.
4.1. Integrity Protected Trace Option-Types
Both the IOAM Pre-allocated Trace Option-Type header and the IOAM
Incremental Trace Option-Type header, as defined in [RFC9197], are
followed by the Integrity Protection header when the IOAM Option-Type
is respectively set to the IOAM Pre-allocated Trace Integrity
Protected Option-Type or the IOAM Incremental Trace Integrity
Protected Option-Type:
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0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace-ID | NodeLen | Flags | RemainingLen|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IOAM-Trace-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Signature-suite| Nonce length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Nonce ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1.1. Header fields for integrity protection
The following IOAM Pre-allocated or Incremental Option-Type header
fields are involved in the integrity protection of IOAM-Data-Fields:
1. Namespace-ID
2. NodeLen
3. Flags: only bits 1 (Loopback) and 2 (Active)
4. IOAM-Trace-Type
4.2. Integrity Protected POT Option-Type
The IOAM POT Option-Type header, as defined in [RFC9197], is followed
by the Integrity Protection header when the IOAM Option-Type is set
to the IOAM POT Integrity Protected Option-Type:
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0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace-ID | IOAM-POT-Type | IOAM-POT-Flags|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Signature-suite| Nonce length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Nonce ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2.1. Header fields for integrity protection
The following IOAM POT Option-Type header fields are involved in the
integrity protection of IOAM-Data-Fields:
1. Namespace-ID
2. IOAM-POT-Type
4.3. Integrity Protected E2E Option-Type
The IOAM E2E Option-Type header, as defined in [RFC9197], is followed
by the Integrity Protection header when the IOAM Option-Type is set
to the IOAM E2E Integrity Protected Option-Type:
0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace-ID | IOAM-E2E-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Signature-suite| Nonce length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Nonce ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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4.3.1. Header fields for integrity protection
The following IOAM E2E Option-Type header fields are involved in the
integrity protection of IOAM-Data-Fields:
1. Namespace-ID
2. IOAM-E2E-Type
4.4. Integrity Protected DEX Option-Type
The IOAM DEX Option-Type header, as defined in [RFC9326], is followed
by the Integrity Protection header when the IOAM Option-Type is set
to the IOAM DEX Integrity Protected Option-Type:
0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace-ID | Flags |Extension-Flags|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IOAM-Trace-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow ID (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Signature-suite| Nonce length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Nonce ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Signature ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.4.1. Header fields for integrity protection
The following IOAM DEX Option-Type header fields are involved in the
integrity protection of IOAM-Data-Fields:
1. Namespace-ID
2. Extension-Flags: only bits 0 (Flow ID) and 1 (Sequence Number)
3. IOAM-Trace-Type
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The optional fields (i.e., Flow ID and Sequence Number) are treated
as optional IOAM-Data-Fields, not header fields.
5. Integrity Protection Method
This section defines a method that uses a symmetric key based
signature algorithm for integrity protection of IOAM-Data-Fields. In
case of performance concerns, the method can be applied to a subset
of the traffic by using sampling of data.
The symmetric key based signature algorithm MUST use SHA-256 ([SHS])
as the Digest Algorithm, and MUST use Advanced Encryption Standard
([AES]) with a key length of 256 bits and the Galois/Counter Mode
([NIST.800-38D]) as the Signature Algorithm (AES-256-GCM). The
corresponding Signature Suite Identifier is 1, as defined in
Section 6.2. As a consequence, the signature consumes 32 octets.
The Integrity Protection Method is defined by the following steps:
1. The encapsulating node creates a nonce and stores it in the Nonce
field of the IOAM Integrity Protection Header (the Nonce length
field is set accordingly). The Signature-suite field is set to
1. The signature is generated over the hash of header fields
(see Section 4.1.1, Section 4.2.1, Section 4.3.1, or
Section 4.4.1, for the exact list of header fields to include in
the signature, depending on the IOAM Integrity Protected Option-
Type) and IOAM-Data-Fields it has inserted, i.e.,
sign(hash(Header-Fields || IOAM-Data-Fields)), with the Nonce
field provided as the nonce. IOAM-Data-Fields supposed to be
modified by other IOAM nodes on the path MUST be excluded from
the signature (e.g., the POT Cumulative field). The signature is
stored in the Signature field of the IOAM Integrity Protection
Header.
2. A transit node generates a signature over the hash of IOAM-Data-
Fields it has inserted, i.e., sign(hash(IOAM-Data-Fields)), with
the Signature field provided as the nonce. IOAM-Data-Fields
modified in-place by the transit node MUST be excluded from the
signature (e.g., the POT Cumulative field). The signature is
stored in the Signature field of the IOAM Integrity Protection
Header.
* If the transit node does not insert IOAM-Data-Fields (e.g., it
only modifies IOAM-Data-Fields in-place, or does nothing),
then the transit node MUST NOT generate a signature and MUST
NOT update the Signature field.
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3. In the context of the Integrity Protection Method, a node that
performs the validation of the integrity protection is referred
to as a "Validator". The role of a Validator is to recompute the
signature by iteratively following the previous steps of the
method, in the same order and up to itself, using the respective
symmetric keys. The recomputed signature is then compared to the
Signature field. As a result, the Validator can detect if the
IOAM-Data-Fields integrity is intact or was altered. The
validation is trivial in some cases (e.g., with POT Type-0, E2E
or DEX Option-Types), where only the encapsulating node generates
a signature, as specified above by this method. For other cases
where transit nodes also generate a signature (e.g., with Trace
Option-Types), node-ids MUST be included in IOAM-Data-Fields.
Details on how the mapping between node-ids and keys is
implemented on a Validator are outside the scope of this
document.
* Each node that takes actions triggered by fields in the IOAM
Integrity Protected Option-Type header MUST act as a
Validator. Otherwise, an attacker could modify the IOAM
header along the path and change the actions a node performs.
Examples:
- For an Integrity Protected Trace Option-Type (Pre-allocated
or Incremental), each transit node MUST act as a Validator,
if either the IOAM Loopback or Active mode is used.
- For an Integrity Protected DEX Option-Type, each transit
node MUST act as a Validator.
* The decapsulating node MUST act as a Validator. The
decapsulating node MUST NOT generate a signature based on
IOAM-Data-Fields it has inserted, if any, and therefore MUST
NOT update the Signature field.
The method assumes that symmetric keys have been distributed to the
respective nodes as well as the Validator(s). The details of the
mechanisms used for key distribution are outside the scope of this
document.
6. IANA Considerations
6.1. IOAM Option-Types
IANA is requested to define the following new code points in the
"IOAM Option-Type" registry:
64 IOAM Pre-allocated Trace Integrity Protected Option-Type (see
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Section 4)
65 IOAM Incremental Trace Integrity Protected Option-Type (see
Section 4)
66 IOAM POT Integrity Protected Option-Type (see Section 4)
67 IOAM E2E Integrity Protected Option-Type (see Section 4)
68 IOAM DEX Integrity Protected Option-Type (see Section 4)
A document defining a new IOAM Integrity Protected Option-Type MUST
define the IOAM Option-Type header fields involved in the integrity
protection of IOAM-Data-Fields, as done in Section 4.1.1,
Section 4.2.1, Section 4.3.1, and Section 4.4.1 of this document.
6.2. IOAM Integrity Protection Signature Suite
IANA is requested to define a new registry named "IOAM Integrity
Protection Signature Suite", inside the "In Situ OAM (IOAM)" registry
group.
The new registry defines 256 code points to identify the digest and
signature algorithms used in the Signature-suite field, as explained
in Section 4. The following code points are defined in this
document:
Signature
Suite Digest Signature Specification
Identifier Algorithm Algorithm Pointer
+-----------+------------+-------------+----------------+
| 0x00 | Reserved | Reserved | This document |
+-----------+------------+-------------+----------------+
| 0x01 | SHA-256 | AES-256-GCM | This document |
+-----------+------------+-------------+----------------+
| 0x02 | | | |
| ... | Unassigned | Unassigned | |
| 0xFE | | | |
+-----------+------------+-------------+----------------+
| 0xFF | Reserved | Reserved | This document |
+-----------+------------+-------------+----------------+
Figure 3: IOAM Integrity Protection Signature Suite
Code points 2-254 are available for assignment via the "IETF Review"
process, as per [RFC8126].
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New registration requests MUST use the following template: the value
of the requested code point, the associated digest algorithm name and
signature algorithm name, and a reference to the document that
defines the requested code point.
7. Security Considerations
Please refer to Section 3 for a threat analysis of integrity-related
threats in the context of IOAM.
The Integrity Protection Method defined in this document (see
Section 5) leverages symmetric keys. The symmetric keys need to be
exchanged in a secure way between the nodes involved with integrity
protection of IOAM-Data-Fields. The details of the key exchange are
outside the scope of this document.
The Integrity Protection Method defined in this document requires
additional per-packet processing by each node that uses it.
Inappropriate use of the Integrity Protection Method might overload
nodes and cause them to stop functioning properly. Operators
deploying IOAM with the Integrity Protection Method MUST ensure that
such overload situations are avoided. This could for example be
achieved by applying IOAM only to a subset of the entire traffic.
The Nonce makes a signature chain unique but does not necessarily
prevent replay attacks. To enable replay protection, the
encapsulating node and the Validator(s) MUST agree on a common
methodology to keep the Nonce valid only for a specific period of
time, which is outside the scope of this document.
8. Acknowledgements
The authors would like to thank Santhosh N, Rakesh Kandula, Saiprasad
Muchala, Al Morton, Greg Mirsky, Benjamin Kaduk, Mehmet Beyaz, and
Martin Duke for their comments and advice.
9. References
9.1. 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>.
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Internet-Draft IOAM-Data-Fields Integrity October 2023
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[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>.
9.2. Informative References
[AES] National Institute of Standards and Technology, "Advanced
Encryption Standard (AES)", FIPS PUB 197, 2001,
<http://csrc.nist.gov/publications/fips/fips197/fips-
197.pdf>.
[NIST.800-38D]
National Institute of Standards and Technology,
"Recommendation for Block Cipher Modes of Operation:
Galois/Counter Mode (GCM) and GMAC", NIST Special
Publication 800-38D, 2001,
<http://csrc.nist.gov/publications/nistpubs/800-38D/SP-
800-38D.pdf>.
[RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
Weingarten, "An Overview of Operations, Administration,
and Maintenance (OAM) Tools", RFC 7276,
DOI 10.17487/RFC7276, June 2014,
<https://www.rfc-editor.org/info/rfc7276>.
[RFC7384] Mizrahi, T., "Security Requirements of Time Protocols in
Packet Switched Networks", RFC 7384, DOI 10.17487/RFC7384,
October 2014, <https://www.rfc-editor.org/info/rfc7384>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker,
"Deterministic Networking (DetNet) Security
Considerations", RFC 9055, DOI 10.17487/RFC9055, June
2021, <https://www.rfc-editor.org/info/rfc9055>.
[RFC9197] Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
Ed., "Data Fields for In Situ Operations, Administration,
and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
May 2022, <https://www.rfc-editor.org/info/rfc9197>.
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[RFC9326] Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
Mizrahi, "In Situ Operations, Administration, and
Maintenance (IOAM) Direct Exporting", RFC 9326,
DOI 10.17487/RFC9326, November 2022,
<https://www.rfc-editor.org/info/rfc9326>.
[SHS] National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", NIST FIPS Publication 180-4, DOI
10.6028/NIST.FIPS.180-4, 2015,
<http://nvlpubs.nist.gov/nistpubs/FIPS/
NIST.FIPS.180-4.pdf>.
Authors' Addresses
Frank Brockners
Cisco Systems, Inc.
Hansaallee 249, 3rd Floor
40549 DUESSELDORF
Germany
Email: fbrockne@cisco.com
Shwetha Bhandari
Thoughtspot
3rd Floor, Indiqube Orion, 24th Main Rd, Garden Layout, HSR Layout
Bangalore, KARNATAKA 560 102
India
Email: shwetha.bhandari@thoughtspot.com
Tal Mizrahi
Huawei
8-2 Matam
Haifa 3190501
Israel
Email: tal.mizrahi.phd@gmail.com
Justin Iurman
Universite de Liege
10, Allee de la decouverte (B28)
4000 Sart-Tilman
Belgium
Email: justin.iurman@uliege.be
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