SUIT B. Moran
Internet-Draft H. Tschofenig
Intended status: Standards Track Arm Limited
Expires: January 14, 2021 H. Birkholz
Fraunhofer SIT
K. Zandberg
Inria
July 13, 2020
A Concise Binary Object Representation (CBOR)-based Serialization Format
for the Software Updates for Internet of Things (SUIT) Manifest
draft-ietf-suit-manifest-09
Abstract
This specification describes the format of a manifest. A manifest is
a bundle of metadata about the firmware for an IoT device, where to
find the firmware, the devices to which it applies, and cryptographic
information protecting the manifest. Firmware updates and secure
boot both tend to use sequences of common operations, so the manifest
encodes those sequences of operations, rather than declaring the
metadata. The manifest also serves as a building block for secure
boot.
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
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 14, 2021.
Copyright Notice
Copyright (c) 2020 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 6
3. How to use this Document . . . . . . . . . . . . . . . . . . 8
4. Background . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. IoT Firmware Update Constraints . . . . . . . . . . . . . 9
4.2. SUIT Workflow Model . . . . . . . . . . . . . . . . . . . 10
5. Metadata Structure Overview . . . . . . . . . . . . . . . . . 11
5.1. Envelope . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2. Delegation Chains . . . . . . . . . . . . . . . . . . . . 12
5.3. Authentication Block . . . . . . . . . . . . . . . . . . 13
5.4. Manifest . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4.1. Critical Metadata . . . . . . . . . . . . . . . . . . 13
5.4.2. Common . . . . . . . . . . . . . . . . . . . . . . . 13
5.4.3. Command Sequences . . . . . . . . . . . . . . . . . . 14
5.4.4. Integrity Check Values . . . . . . . . . . . . . . . 14
5.4.5. Human-Readable Text . . . . . . . . . . . . . . . . . 14
5.5. Severable Elements . . . . . . . . . . . . . . . . . . . 15
5.6. Integrated Dependencies and Payloads . . . . . . . . . . 15
6. Interpreter Behavior . . . . . . . . . . . . . . . . . . . . 15
6.1. Interpreter Setup . . . . . . . . . . . . . . . . . . . . 16
6.2. Required Checks . . . . . . . . . . . . . . . . . . . . . 17
6.2.1. Minimizing Signature Verifications . . . . . . . . . 18
6.3. Interpreter Fundamental Properties . . . . . . . . . . . 19
6.4. Abstract Machine Description . . . . . . . . . . . . . . 19
6.5. Special Cases of Component Index and Dependency Index . . 21
6.6. Serialized Processing Interpreter . . . . . . . . . . . . 22
6.7. Parallel Processing Interpreter . . . . . . . . . . . . . 22
6.8. Processing Dependencies . . . . . . . . . . . . . . . . . 23
6.9. Multiple Manifest Processors . . . . . . . . . . . . . . 23
7. Creating Manifests . . . . . . . . . . . . . . . . . . . . . 24
7.1. Compatibility Check Template . . . . . . . . . . . . . . 25
7.2. Secure Boot Template . . . . . . . . . . . . . . . . . . 25
7.3. Firmware Download Template . . . . . . . . . . . . . . . 26
7.4. Install Template . . . . . . . . . . . . . . . . . . . . 26
7.5. Integrated Payload Template . . . . . . . . . . . . . . . 27
7.6. Load from Nonvolatile Storage Template . . . . . . . . . 27
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7.7. Load & Decompress from Nonvolatile Storage Template . . . 27
7.8. Dependency Template . . . . . . . . . . . . . . . . . . . 28
7.8.1. Composite Manifests . . . . . . . . . . . . . . . . . 28
7.9. Encrypted Manifest Template . . . . . . . . . . . . . . . 29
7.10. A/B Image Template . . . . . . . . . . . . . . . . . . . 29
8. Metadata Structure . . . . . . . . . . . . . . . . . . . . . 30
8.1. Encoding Considerations . . . . . . . . . . . . . . . . . 31
8.2. Envelope . . . . . . . . . . . . . . . . . . . . . . . . 31
8.3. Delegation Chains . . . . . . . . . . . . . . . . . . . . 31
8.4. Authenticated Manifests . . . . . . . . . . . . . . . . . 32
8.5. Encrypted Manifests . . . . . . . . . . . . . . . . . . . 32
8.6. Manifest . . . . . . . . . . . . . . . . . . . . . . . . 32
8.6.1. suit-manifest-version . . . . . . . . . . . . . . . . 33
8.6.2. suit-manifest-sequence-number . . . . . . . . . . . . 33
8.6.3. suit-reference-uri . . . . . . . . . . . . . . . . . 33
8.6.4. suit-text . . . . . . . . . . . . . . . . . . . . . . 34
8.7. text-version-required . . . . . . . . . . . . . . . . . . 35
8.7.1. suit-coswid . . . . . . . . . . . . . . . . . . . . . 35
8.7.2. suit-common . . . . . . . . . . . . . . . . . . . . . 36
8.7.3. SUIT_Command_Sequence . . . . . . . . . . . . . . . . 37
8.7.4. Reporting Policy . . . . . . . . . . . . . . . . . . 40
8.7.5. SUIT_Parameters . . . . . . . . . . . . . . . . . . . 41
8.7.6. SUIT_Condition . . . . . . . . . . . . . . . . . . . 51
8.7.7. SUIT_Directive . . . . . . . . . . . . . . . . . . . 55
8.7.8. Integrity Check Values . . . . . . . . . . . . . . . 62
8.8. Severable Elements . . . . . . . . . . . . . . . . . . . 62
9. Access Control Lists . . . . . . . . . . . . . . . . . . . . 63
10. SUIT Digest Container . . . . . . . . . . . . . . . . . . . . 63
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 63
11.1. SUIT Commands . . . . . . . . . . . . . . . . . . . . . 64
11.2. SUIT Parameters . . . . . . . . . . . . . . . . . . . . 65
11.3. SUIT Text Values . . . . . . . . . . . . . . . . . . . . 67
11.4. SUIT Component Text Values . . . . . . . . . . . . . . . 67
11.5. SUIT Algorithm Identifiers . . . . . . . . . . . . . . . 67
11.5.1. SUIT Digest Algorithm Identifiers . . . . . . . . . 67
11.5.2. SUIT Compression Algorithm Identifiers . . . . . . . 68
11.5.3. Unpack Algorithms . . . . . . . . . . . . . . . . . 68
12. Security Considerations . . . . . . . . . . . . . . . . . . . 69
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 69
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 69
14.1. Normative References . . . . . . . . . . . . . . . . . . 69
14.2. Informative References . . . . . . . . . . . . . . . . . 70
14.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 71
A. Full CDDL . . . . . . . . . . . . . . . . . . . . . . . . . . 72
B. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
B.1. Example 0: Secure Boot . . . . . . . . . . . . . . . . . 83
B.2. Example 1: Simultaneous Download and Installation of
Payload . . . . . . . . . . . . . . . . . . . . . . . . . 85
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B.3. Example 2: Simultaneous Download, Installation, Secure
Boot, Severed Fields . . . . . . . . . . . . . . . . . . 88
B.4. Example 3: A/B images . . . . . . . . . . . . . . . . . . 92
B.5. Example 4: Load and Decompress from External Storage . . 96
B.6. Example 5: Two Images . . . . . . . . . . . . . . . . . . 100
C. Design Rational . . . . . . . . . . . . . . . . . . . . . . . 103
C.1. C.1 Design Rationale: Envelope . . . . . . . . . . . . . 104
C.2. C.2 Byte String Wrappers . . . . . . . . . . . . . . . . 105
D. Implementation Conformance Matrix . . . . . . . . . . . . . . 106
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 109
1. Introduction
A firmware update mechanism is an essential security feature for IoT
devices to deal with vulnerabilities. While the transport of
firmware images to the devices themselves is important there are
already various techniques available. Equally important is the
inclusion of metadata about the conveyed firmware image (in the form
of a manifest) and the use of a security wrapper to provide end-to-
end security protection to detect modifications and (optionally) to
make reverse engineering more difficult. End-to-end security allows
the author, who builds the firmware image, to be sure that no other
party (including potential adversaries) can install firmware updates
on IoT devices without adequate privileges. For confidentiality
protected firmware images it is additionally required to encrypt the
firmware image. Starting security protection at the author is a risk
mitigation technique so firmware images and manifests can be stored
on untrusted repositories; it also reduces the scope of a compromise
of any repository or intermediate system to be no worse than a denial
of service.
A manifest is a bundle of metadata about the firmware for an IoT
device, where to find the firmware, the devices to which it applies,
and cryptographic information protecting the manifest.
This specification defines the SUIT manifest format and it is
intended to meet several goals:
- Meet the requirements defined in
[I-D.ietf-suit-information-model].
- Simple to parse on a constrained node
- Simple to process on a constrained node
- Compact encoding
- Comprehensible by an intermediate system
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- Expressive enough to enable advanced use cases on advanced nodes
- Extensible
The SUIT manifest can be used for a variety of purposes throughout
its lifecycle, such as:
- the Firmware Author to reason about releasing a firmware.
- the Network Operator to reason about compatibility of a firmware.
- the Device Operator to reason about the impact of a firmware.
- the Device Operator to manage distribution of firmware to devices.
- the Plant Manager to reason about timing and acceptance of
firmware updates.
- the device to reason about the authority & authenticity of a
firmware prior to installation.
- the device to reason about the applicability of a firmware.
- the device to reason about the installation of a firmware.
- the device to reason about the authenticity & encoding of a
firmware at boot.
Each of these uses happens at a different stage of the manifest
lifecycle, so each has different requirements.
It is assumed that the reader is familiar with the high-level
firmware update architecture [I-D.ietf-suit-architecture] and the
threats, requirements, and user stories in
[I-D.ietf-suit-information-model].
The design of this specification is based on an observation that the
vast majority of operations that a device can perform during an
update or secure boot are composed of a small group of operations:
- Copy some data from one place to another
- Transform some data
- Digest some data and compare to an expected value
- Compare some system parameters to an expected value
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- Run some code
In the SUIT manifest specification, these operations are called
commands. Commands are classed as either conditions or directives.
Conditions have no side-effects, while directives do have side-
effects. Conceptually, a sequence of commands is like a script but
the used language is tailored to software updates and secure boot.
The available commands support simple steps, such as copying a
firmware image from one place to another, checking that a firmware
image is correct, verifying that the specified firmware is the
correct firmware for the device, or unpacking a firmware. By using
these steps in different orders and changing the parameters they use,
a broad range of use cases can be supported. The SUIT manifest uses
this observation to optimize metadata for consumption by constrained
devices.
While the SUIT manifest is informed by and optimized for firmware
update and secure boot use cases, there is nothing in the
[I-D.ietf-suit-information-model] that restricts its use to only
those use cases. Other use cases include the management of trusted
applications in a Trusted Execution Environment (TEE), see
[I-D.ietf-teep-architecture].
2. Conventions and Terminology
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.
The following terminology is used throughout this document:
- SUIT: Software Update for the Internet of Things, also the IETF
working group for this standard.
- Payload: A piece of information to be delivered. Typically
Firmware for the purposes of SUIT.
- Resource: A piece of information that is used to construct a
payload.
- Manifest: A manifest is a bundle of metadata about the firmware
for an IoT device, where to find the firmware, and the devices to
which it applies.
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- Envelope: A container with the manifest, an authentication wrapper
with cryptographic information protecting the manifest,
authorization information, and severed fields.
- Update: One or more manifests that describe one or more payloads.
- Update Authority: The owner of a cryptographic key used to sign
updates, trusted by Recipients.
- Recipient: The system, typically an IoT device, that receives and
processes a manifest.
- Manifest Processor: A component of the Recipient that consumes
Manifests and executes the commands in the Manifest.
- Component: An updatable logical block of the Firmware, Software,
configuration, or data of the Recipient.
- Component Set: A group of interdependent Components that must be
updated simultaneously.
- Command: A Condition or a Directive.
- Condition: A test for a property of the Recipient or its
Components.
- Directive: An action for the Recipient to perform.
- Trusted Execution: A process by which a system ensures that only
trusted code is executed, for example secure boot.
- A/B images: Dividing a Recipient's storage into two or more
bootable images, at different offsets, such that the active image
can write to the inactive image(s).
- Record: The result of a Command and any metadata about it.
- Report: A list of Records.
- Procedure: The process of invoking one or more sequences of
commands.
- Update Procedure: A procedure that updates a Recipient by fetching
dependencies, software images, and installing them.
- Boot Procedure: A procedure that boots a Recipient by verifying
dependencies and images, loading images, and invoking one or more
image.
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- Software: Instructions and data that allow a Recipient to perform
a useful function.
- Firmware: Instructions and data that allow a Recipient to perform
a useful function. Typically, changed infrequently, stored in
nonvolatile memory, and small enough to apply to [RFC7228] Class
0-2 devices.
- Image: Information that a Recipient uses to perform its function,
typically firmware/software, configuration, or resource data such
as text or images. Also, a Payload, once installed is an Image.
- Slot: One of several possible storage locations for a given
Component, typically used in A/B image systems
- Abort: The Manifest Processor immediately halts execution of the
current Procedure. It creates a Record of an error condition.
3. How to use this Document
This specification covers five aspects of firmware update:
- Section 4 describes the device constraints, use cases, and design
principles that informed the structure of the manifest.
- Section 5 gives a general overview of the metadata structure to
inform the following sections
- Section 6 describes what actions a Manifest processor should take.
- Section 7 describes the process of creating a Manifest.
- Section 8 specifies the content of the Envelope and the Manifest.
To implement an updatable device, see Section 6 and Section 8. To
implement a tool that generates updates, see Section 7 and Section 8.
The IANA consideration section, see Section 11, provides instructions
to IANA to create several registries. This section also provides the
CBOR labels for the structures defined in this document.
The complete CDDL description is provided in [full-cddl], examples
are given in [examples] and a design rational is offered in
[design-rationale]. Finally, [implementation-matrix] gives a
summarize of the mandatory-to-implement features of this
specification.
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4. Background
Distributing firmware updates to diverse devices with diverse trust
anchors in a coordinated system presents unique challenges. Devices
have a broad set of constraints, requiring different metadata to make
appropriate decisions. There may be many actors in production IoT
systems, each of whom has some authority. Distributing firmware in
such a multi-party environment presents additional challenges. Each
party requires a different subset of data. Some data may not be
accessible to all parties. Multiple signatures may be required from
parties with different authorities. This topic is covered in more
depth in [I-D.ietf-suit-architecture]. The security aspects are
described in [I-D.ietf-suit-information-model].
4.1. IoT Firmware Update Constraints
The various constraints of IoT devices and the range of use cases
that need to be supported create a broad set of urequirements. For
example, devices with:
- limited processing power and storage may require a simple
representation of metadata.
- bandwidth constraints may require firmware compression or partial
update support.
- bootloader complexity constraints may require simple selection
between two bootable images.
- small internal storage may require external storage support.
- multiple microcontrollers may require coordinated update of all
applications.
- large storage and complex functionality may require parallel
update of many software components.
- extra information may need to be conveyed in the manifest in the
earlier stages of the device lifecycle before those data items are
stripped when the manifest is delivery to a constrained device.
Supporting the requirements introduced by the constraints on IoT
devices requires the flexibility to represent a diverse set of
possible metadata, but also requires that the encoding is kept
simple.
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4.2. SUIT Workflow Model
There are several fundamental assumptions that inform the model of
Update Procedure workflow:
- Compatibility must be checked before any other operation is
performed.
- All dependency manifests should be present before any payload is
fetched.
- In some applications, payloads must be fetched and validated prior
to installation.
There are several fundamental assumptions that inform the model of
the Boot Procedure workflow:
- Compatibility must be checked before any other operation is
performed.
- All dependencies and payloads must be validated prior to loading.
- All loaded images must be validated prior to execution.
Based on these assumptions, the manifest is structured to work with a
pull parser, where each section of the manifest is used in sequence.
The expected workflow for a Recipient installing an update can be
broken down into five steps:
1. Verify the signature of the manifest.
2. Verify the applicability of the manifest.
3. Resolve dependencies.
4. Fetch payload(s).
5. Install payload(s).
When installation is complete, similar information can be used for
validating and running images in a further three steps:
1. Verify image(s).
2. Load image(s).
3. Run image(s).
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If verification and running is implemented in a bootloader, then the
bootloader MUST also verify the signature of the manifest and the
applicability of the manifest in order to implement secure boot
workflows. The bootloader may add its own authentication, e.g. a
MAC, to the manifest in order to prevent further verifications.
When multiple manifests are used for an update, each manifest's steps
occur in a lockstep fashion; all manifests have dependency resolution
performed before any manifest performs a payload fetch, etc.
5. Metadata Structure Overview
This section provides a high level overview of the manifest
structure. The full description of the manifest structure is in
Section 8.6
The manifest is structured from several key components:
1. The Envelope (see Section 5.1) contains Delegation Chains, the
Authentication Block, the Manifest, any Severable Elements, and
any Integrated Payloads or Dependencies.
2. Delegation Chains (see Section 5.2) allow a Recipient to work
from one of its Trust Anchors to an authority of the
Authentication Block.
3. The Authentication Block (see Section 5.3) contains a list of
signatures or MACs of the manifest..
4. The Manifest (see Section 5.4) contains all critical, non-
severable metadata that the Recipient requires. It is further
broken down into:
1. Critical metadata, such as sequence number.
2. Common metadata, including lists of dependencies and affected
components.
3. Command sequences, directing the Recipient how to install and
use the payload(s).
4. Integrity check values for severable fields.
5. Severable fields (see Section 5.5).
6. Integrated dependencies (see Section 5.6).
7. Integrated payloads (see Section 5.6).
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The diagram below illustrates the hierarchy of the Envelope.
+-------------------------+
| Envelope |
+-------------------------+
| Delegation Chains |
| Authentication Block |
| Manifest ------------> +------------------------------+
| Severable Elements | | Manifest |
| Human-Readable Text | +------------------------------+
| COSWID | | Structure Version |
| Integrated Dependencies | | Sequence Number |
| Integrated Payloads | | Reference to Full Manifest |
+-------------------------+ +------ Common Structure |
| +---- Commands |
+-----------------------+ | | | Digests of Envelope Elements |
| Common Structure | <--+ | +------------------------------+
+-----------------------+ |
| Dependencies | +-> +-----------------------+
| Components IDs | | Commands |
| Common Commands ---------------> +-----------------------+
+-----------------------+ | List of ( pairs of ( |
| * command code |
| * argument |
| )) |
+-----------------------+
5.1. Envelope
The SUIT Envelope is a container that encloses Delegation Chains, the
Authentication Block, the Manifest, any Severable Elements, and any
integrated payloads or dependencies. The Envelope is used instead of
conventional cryptographic envelopes, such as COSE_Envelope because
it allows modular processing, severing of elements, and integrated
payloads in a way that would add substantial complexity with existing
solutions. See Appendix C.1 for a description of the reasoning for
this.
See Section 8.2 for more detail.
5.2. Delegation Chains
Delegation Chains allow a Recipient to validate intermediate Update
Authorities against long-term a Trust Anchor. These are lists of
CWTs, where the first in the list is signed by a Trust Anchor.
See Section 8.3 for more detail.
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5.3. Authentication Block
The Authentication Block contains one or more COSE authentication
blocks. These blocks are one of:
- COSE_Sign_Tagged
- COSE_Sign1_Tagged
- COSE_Mac_Tagged
- COSE_Mac0_Tagged
The payload element in each of these COSE elements is a SUIT_Digest
Section 10.
See Section 8.4 for more detail.
5.4. Manifest
The Manifest contains most metadata about one or more images. The
Manifest is divided into Critical Metadata, Common Metadata, Command
Sequences, and Integrity Check Values.
See Section 8.6 for more detail.
5.4.1. Critical Metadata
Some metadata needs to be accessed before the manifest is processed.
This metadata can be used to determine which the newest manifest is
and whether the structure version is supported. It also MAY provide
a URI for obtaining a canonical copy of the manifest and Envelope.
See Section 8.6.1, Section 8.6.2, Section 8.6.3 for more detail.
5.4.2. Common
Some metadata is used repeatedly and in more than one command
sequence. In order to reduce the size of the manifest, this metadata
is collected into the Common section. Common is composed of three
parts: a list of dependencies, a list of components referenced by the
manifest, and a command sequence to execute prior to each other
command sequence. The common command sequence is typically used to
set commonly used values and perform compatibility checks. The
common command sequence MUST NOT have any side-effects outside of
setting parameter values.
See Section 8.7.2, Section 8.7.2.1 for more detail.
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5.4.3. Command Sequences
Command sequences provide the instructions that a Recipient requires
in order to install or use an image. These sequences tell a device
to set parameter values, test system parameters, copy data from one
place to another, transform data, digest data, and run code.
Command sequences are broken up into three groups: Common Command
Sequence (see Section 5.4.2), update commands, and secure boot
commands.
Update Command Sequences are: Dependency Resolution, Payload Fetch,
and Payload Installation. An Update Procedure is the complete set of
each Update Command Sequence, each preceded by the Common Command
Sequence.
Boot Command Sequences are: System Validation, Image Loading, and
Image Invocation. A Boot Procedure is the complete set of each Boot
Command Sequence, each preceded by the Common Command Sequence.
Command Sequences are grouped into these sets to ensure that there is
common coordination between dependencies and dependents on when to
execute each command.
See Section 8.7.3 for more detail.
5.4.4. Integrity Check Values
To enable Section 5.5, there needs to be a mechanism to verify
integrity of any metadata outside the manifest. Integrity Check
Values are used to verify the integrity of metadata that is not
contained in the manifest. This MAY include Severable Command
Sequences, CoSWID, or Text data. Integrated Dependencies and
Integrated Payloads are integrity-checked using Command Sequences, so
they do not have Integrity Check Values present in the Manifest.
See Section 8.7.8 for more detail.
5.4.5. Human-Readable Text
Text is typically a Severable Element (Section 5.5). It contains all
the text that describes the update. Because text is explicitly for
human consumption, it is all grouped together so that it can be
Severed easily. The text section has space both for describing the
manifest as a whole and for describing each individual component.
See Section 8.6.4 for more detail.
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5.5. Severable Elements
Severable Elements are elements of the Envelope (Section 5.1) that
have Integrity Check Values (Section 5.4.4) in the Manifest
(Section 5.4).
Because of this organisation, these elements can be discarded or
"Severed" from the Envelope without changing the signature of the
Manifest. This allows savings based on the size of the Envelope in
several scenarios, for example:
- A management system Severs the Text and CoSWID sections before
sending an Envelope to a constrained Recipient, which saves
Recipient bandwidth.
- A Recipient Severs the Installation section after installing the
Update, which saves storage space.
See Section 8.8 for more detail.
5.6. Integrated Dependencies and Payloads
In some cases, it is beneficial to include a dependency or a payload
in the Envelope of a manifest. For example:
- When an update is delivered via a comparatively unconstrained
medium, such as a removable mass storage device, it may be
beneficial to bundle updates into single files.
- When a manifest requires encryption, it must be referenced as a
dependency, so a trivial manifest may be used to enclose the
encrypted manifest. The encrypted manifest may be contained in
the dependent manifest's envelope.
- When a manifest transports a small payload, such as an encrypted
key, that payload may be placed in the manifest's envelope.
See Section 7.8.1, Section 8.5 for more detail.
6. Interpreter Behavior
This section describes the behavior of the manifest interpreter and
focuses primarily on interpreting commands in the manifest. However,
there are several other important behaviors of the interpreter:
encoding version detection, rollback protection, and authenticity
verification are chief among these.
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6.1. Interpreter Setup
Prior to executing any command sequence, the interpreter or its host
application MUST inspect the manifest version field and fail when it
encounters an unsupported encoding version. Next, the interpreter or
its host application MUST extract the manifest sequence number and
perform a rollback check using this sequence number. The exact logic
of rollback protection may vary by application, but it has the
following properties:
- Whenever the interpreter can choose between several manifests, it
MUST select the latest valid, authentic manifest.
- If the latest valid, authentic manifest fails, it MAY select the
next latest valid, authentic manifest.
Here, valid means that a manifest has a supported encoding version
and it has not been excluded for other reasons. Reasons for
excluding typically involve first executing the manifest and may
include:
- Test failed (e.g. Vendor ID/Class ID).
- Unsupported command encountered.
- Unsupported parameter encountered.
- Unsupported component ID encountered.
- Payload not available.
- Dependency not available.
- Application crashed when executed.
- Watchdog timeout occurred.
- Dependency or Payload verification failed.
- Missing component from a set.
- Required parameter not supplied.
These failure reasons MAY be combined with retry mechanisms prior to
marking a manifest as invalid.
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Following these initial tests, the interpreter clears all parameter
storage. This ensures that the interpreter begins without any leaked
data.
6.2. Required Checks
The RECOMMENDED process is to verify the signature of the manifest
prior to parsing/executing any section of the manifest. This guards
the parser against arbitrary input by unauthenticated third parties,
but it costs extra energy when a Recipient receives an incompatible
manifest.
When validating authenticity of manifests, the interpreter MAY use an
ACL (see Section 9) to determine the extent of the rights conferred
by that authenticity. Where a device supports only one level of
access, it MAY choose to skip signature verification of dependencies,
since they are referenced by digest. Where a device supports more
than one trusted party, it MAY choose to defer the verification of
signatures of dependencies until the list of affected components is
known so that it can skip redundant signature verifications. For
example, a dependency signed by the same author as the dependent does
not require a signature verification. Similarly, if the signer of
the dependent has full rights to the device, according to the ACL,
then no signature verification is necessary on the dependency.
Once a valid, authentic manifest has been selected, the interpreter
MUST examine the component list and verify that its maximum number of
components is not exceeded and that each listed component ID is
supported.
For each listed component, the interpreter MUST provide storage for
the supported parameters. If the interpreter does not have
sufficient temporary storage to process the parameters for all
components, it MAY process components serially for each command
sequence. See Section 6.6 for more details.
The interpreter SHOULD check that the common section contains at
least one vendor ID check and at least one class ID check.
If the manifest contains more than one component, each command
sequence MUST begin with a Set Current Component command.
If a dependency is specified, then the interpreter MUST perform the
following checks:
1. At the beginning of each section in the dependent: all previous
sections of each dependency have been executed.
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2. At the end of each section in the dependent: The corresponding
section in each dependency has been executed.
If the interpreter does not support dependencies and a manifest
specifies a dependency, then the interpreter MUST reject the
manifest.
If a Recipient supports groups of interdependent components (a
Component Set), then it SHOULD require that all Components in the
Component Set are specified by one manifest and its dependencies.
This manifest is called the Root Manifest.
6.2.1. Minimizing Signature Verifications
Signature verification can be energy and time expensive on a
constrained device. MAC verification is typically unaffected by
these concerns. A Recipient MAY choose to parse and execute only the
SUIT_Common section of the manifest prior to signature verification,
if all of the below apply:
- The Authentication Block contains a COSE_Sign_Tagged or
COSE_Sign1_Tagged
- The Recipient can receive many incompatible or inapplicable
manifests, and
- The Recipient has a power budget that makes signature verification
undesirable
The guidelines in Creating Manifests (Section 7) require that the
common section contains the applicability checks, so this section is
sufficient for applicability verification. The parser MUST restrict
acceptable commands to: Conditions, Override Parameters, Set
Parameters, Try-Each, and Run Sequence ONLY. The manifest parser
MUST NOT execute any command with side-effects outside the parser
(for example, Run, Copy, Swap, or Fetch commands) prior to
authentication and any such command MUST Abort. The Common Sequence
MUST be executed again in its entirety after authenticity validation.
When executing Common prior to authenticity validation, the Manifest
Processor MUST evaluate the integrity of the manifest using the
SUIT_Digest present in the authentication block.
Alternatively, a Recipient MAY rely on network infrastructure to
filter inapplicable manifests.
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6.3. Interpreter Fundamental Properties
The interpreter has a small set of design goals:
1. Executing an update MUST either result in an error, or a
verifiably correct system state.
2. Executing a secure boot MUST either result in an error, or a
booted system.
3. Executing the same manifest on multiple Recipients MUST result in
the same system state.
NOTE: when using A/B images, the manifest functions as two (or more)
logical manifests, each of which applies to a system in a particular
starting state. With that provision, design goal 3 holds.
6.4. Abstract Machine Description
The heart of the manifest is the list of commands, which are
processed by an interpreter. This interpreter can be modeled as a
simple abstract machine. This machine consists of several data
storage locations that are modified by commands.
There are two types of commands, namely those that modify state
(directives) and those that perform tests (conditions). Parameters
are used as the inputs to commands. Some directives offer control
flow operations. Directives target a specific component or
dependency. A dependency is another SUIT_Envelope that describes
additional components. Dependencies are identified by digest, but
referenced in commands by Dependency Index, the index into the array
of Dependencies. A component is a unit of code or data that can be
targeted by an update. Components are identified by Component
Identifiers, i.e. arrays of binary strings, but referenced in
commands by Component Index, the index into the array of Component
Identifiers.
Conditions MUST NOT have any side-effects other than informing the
interpreter of success or failure. The Interpreter does not Abort if
the Soft Failure flag is set when a Condition reports failure.
Directives MAY have side-effects in the parameter table, the
interpreter state, or the current component. The Interpreter MUST
Abort if a Directive reports failure regardless of the Soft Failure
flag.
The following table describes the behavior of each command. "params"
represents the parameters for the current component or dependency.
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Most commands operate on either a component or a dependency. Setting
the Component Index clears the Dependency Index. Setting the
Dependency Index clears the Component Index.
+-------------------+-----------------------------------------------+
| Command Name | Semantic of the Operation |
+-------------------+-----------------------------------------------+
| Check Vendor | assert(binary-match(current, |
| Identifier | current.params[vendor-id])) |
| | |
| Check Class | assert(binary-match(current, |
| Identifier | current.params[class-id])) |
| | |
| Verify Image | assert(binary-match(digest(current), |
| | current.params[digest])) |
| | |
| Set Component | current := components[arg] |
| Index | |
| | |
| Override | current.params[k] := v for k,v in arg |
| Parameters | |
| | |
| Set Dependency | current := dependencies[arg] |
| Index | |
| | |
| Set Parameters | current.params[k] := v if not k in params for |
| | k,v in arg |
| | |
| Process | exec(current[common]); exec(current[current- |
| Dependency | segment]) |
| | |
| Run | run(current) |
| | |
| Fetch | store(current, fetch(current.params[uri])) |
| | |
| Use Before | assert(now() < arg) |
| | |
| Check Component | assert(offsetof(current) == arg) |
| Offset | |
| | |
| Check Device | assert(binary-match(current, |
| Identifier | current.params[device-id])) |
| | |
| Check Image Not | assert(not binary-match(digest(current), |
| Match | current.params[digest])) |
| | |
| Check Minimum | assert(battery >= arg) |
| Battery | |
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| | |
| Check Update | assert(isAuthorized()) |
| Authorized | |
| | |
| Check Version | assert(version_check(current, arg)) |
| | |
| Abort | assert(0) |
| | |
| Try Each | break if exec(seq) is not error for-each seq |
| | in arg |
| | |
| Copy | store(current, current.params[src-component]) |
| | |
| Swap | swap(current, current.params[src-component]) |
| | |
| Wait For Event | until event(arg), wait |
| | |
| Run Sequence | exec(arg) |
| | |
| Run with | run(current, arg) |
| Arguments | |
+-------------------+-----------------------------------------------+
6.5. Special Cases of Component Index and Dependency Index
The interpreter MUST support a special case of Component Index if
more than two or more components are supported: setting Component
Index to True is allowed. When a command is invoked and the
Component Index is True, the command MUST be invoked once for each
Component, in the order listed in the array of Component Identifiers.
The interpreter MUST support a special case of Dependency Index when
two or more dependencies are supported. When a command is invoked
and the Dependency Index is True, the command MUST be invoked once
for each Dependency, in the order listed in the array of
Dependencies.
This is represented by the following pseudocode.
if iscomponent(current):
if current is true:
cmd(component) for-each component in components
else:
cmd(current)
else:
if current is true:
cmd(dependency) for-each dependency in dependencies
else:
cmd(current)
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Try Each and Run Sequence are affected in the same way as other
commands: they are invoked once for each possible Component or
Dependency. This means that the sequences that are arguments to Try
Each and Run Sequence are NOT invoked with Component Index = True or
Dependency Index = True. They are only invoked with integer indices.
The interpreter loops over the whole sequence, setting the Component
Index or Dependency Index to each possible index in turn.
6.6. Serialized Processing Interpreter
In highly constrained devices, where storage for parameters is
limited, the manifest processor MAY handle one component at a time,
traversing the manifest tree once for each listed component. In this
mode, the interpreter ignores any commands executed while the
component index is not the current component. This reduces the
overall volatile storage required to process the update so that the
only limit on number of components is the size of the manifest.
However, this approach requires additional processing power.
In order to operate in this mode, the manifest processor loops on
each section for every supported component, simply ignoring commands
when the current component is not selected.
When a serialized Manifest Processor encounters a component or
dependency index of True, it does not ignore any commands. It
applies them to the current component or dependency on each
iteration.
6.7. Parallel Processing Interpreter
Advanced Recipients MAY make use of the Strict Order parameter and
enable parallel processing of some Command Sequences, or it may
reorder some Command Sequences. To perform parallel processing, once
the Strict Order parameter is set to False, the Recipient may fork a
process for each command until the Strict Order parameter is returned
to True or the Command Sequence ends. Then, it joins all forked
processes before continuing processing of commands. To perform out-
of-order processing, a similar approach is used, except the Recipient
consumes all commands after the Strict Order parameter is set to
False, then it sorts these commands into its preferred order, invokes
them all, then continues processing.
Under each of these scenarios the parallel processing must halt:
- Set Parameters.
- Override Parameters.
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- Set Strict Order = True.
- Set Dependency Index.
- Set Component Index.
To perform more useful parallel operations, sequences of commands may
be collected in a suit-directive-run-sequence. Then, each of these
sequences may be run in parallel. Each sequence defaults to Strict
Order = True. To isolate each sequence from each other sequence,
each sequence MUST begin with a Set Component Index directive. The
interpreter MUST track each Set Component Index directive, and cause
an Abort if more than one Set Component Index directive targets the
same Component Index. When Strict Order = False, each suit-
directive-run-sequence MUST begin with a Set Component Index
directive. Any further Set Component Index directives MUST cause an
Abort. This allows the interpreter that forks suit-directive-run-
sequence processes to check that the first element is correct, then
fork a process to handle the remainder of the sequence.
6.8. Processing Dependencies
As described in Section 6.2, each manifest must invoke each of its
dependencies sections from the corresponding section of the
dependent. Any changes made to parameters by the dependency persist
in the dependent.
When a Process Dependency command is encountered, the interpreter
loads the dependency identified by the Current Dependency Index. The
interpreter first executes the common-sequence section of the
identified dependency, then it executes the section of the dependency
that corresponds to the currently executing section of the dependent.
The Manifest Processor MUST also support a Dependency Index of True,
which applies to every dependency, as described in Section 6.5
The interpreter also performs the checks described in Section 6.2 to
ensure that the dependent is processing the dependency correctly.
6.9. Multiple Manifest Processors
When a system has multiple security domains they MAY require
independent verification of authenticity or security policies.
Security domains may be divided by separation technology such as Arm
TrustZone, or Intel SGX. Security domains may also be divided into
separate processors and memory spaces, with a communication interface
between them.
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For example, an application processor may have an attached
communications module that contains a processor. The communications
module may require metadata signed by a specific Trust Authority for
regulatory approval. This may be a different Trust Authority than
the application processor.
When there are two or more security domains, a manifest processor MAY
be required in each. The first manifest processor is the normal
manifest processor as described for the Recipient in Abstract
Machine. The second manifest processor only executes sections when
the first manifest processor requests it. An API interface is
provided from the second manifest processor to the first. This
allows the first manifest processor to request a limited set of
operations from the second. These operations are limited to: setting
parameters, inserting an Envelope, invoking a Manifest Command
Sequence. The second manifest processor declares a prefix to the
first, which tells the first manifest processor when it should
delegate to the second. These rules are enforced by underlying
separation of privilege infrastructure, such as TEEs, or physical
separation.
When the first manifest processor encounters a dependency prefix,
that informs the first manifest processor that it should provide the
second manifest processor with the corresponding dependency Envelope.
This is done when the dependency is fetched. The second manifest
processor immediately verifies any authentication information in the
dependency Envelope. When a parameter is set for any component that
matches the prefix, this parameter setting is passed to the second
manifest processor via an API. As the first manifest processor works
through the Procedure (set of command sequences) it is executing,
each time it sees a Process Dependency command that is associated
with the prefix declared by the second manifest processor, it uses
the API to ask the second manifest processor to invoke that
dependency section instead.
7. Creating Manifests
Manifests are created using tools for constructing COSE structures,
calculating cryptographic values and compiling desired system state
into a sequence of operations required to achieve that state. The
process of constructing COSE structures and the calculation of
cryptographic values is covered in [RFC8152].
Compiling desired system state into a sequence of operations can be
accomplished in many ways. Several templates are provided below to
cover common use-cases. These templates can be combined to produce
more complex behavior.
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The Author MUST ensure that all parameters consumed by a command are
set prior to invoking that command. Where Component Index = True or
Dependency Index = True, this means that the parameters consumed by
each command MUST have been set for each Component or Dependency,
respectively.
NOTE: On systems that support only a single component, Set Current
Component has no effect and can be omitted.
NOTE: *A digest MUST always be set using Override Parameters, since
this prevents a less-privileged dependent from replacing the digest.*
7.1. Compatibility Check Template
The compatibility check ensures that Recipients only install
compatible images. In this template all information is contained in
the common block and the following sequence of operations are used:
- Set Component Index directive (see Section 8.7.7.1)
- Set Parameters directive (see Section 8.7.7.6) for Vendor ID and
Class ID (see Section 8.7.5)
- Check Vendor Identifier condition (see Section 8.7.5.1)
- Check Class Identifier condication (see Section 8.7.5.1)
7.2. Secure Boot Template
This template performs a secure boot operation.
The following operations are placed into the common block:
- Set Component Index directive (see Section 8.7.7.1)
- Override Parameters directive (see Section 8.7.7.7) for Image
Digest and Image Size (see Section 8.7.5)
Then, the run block contains the following operations:
- Set Component Index directive (see Section 8.7.7.1)
- Check Image Match condition (see Section 8.7.6.2)
- Run directive (see Section 8.7.7.13)
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According to Section 6.4, the Run directive applies to the component
referenced by the current Component Index. Hence, the Set Component
Index directive has to be used to target a specific component.
7.3. Firmware Download Template
This template triggers the download of firmware.
The following operations are placed into the common block:
- Set Component Index directive (see Section 8.7.7.1)
- Override Parameters directive (see Section 8.7.7.7) for Image
Digest and Image Size (see Section 8.7.5)
Then, the install block contains the following operations:
- Set Component Index directive (see Section 8.7.7.1)
- Set Parameters directive (see Section 8.7.7.6) for URI (see
Section 8.7.5.12)
- Fetch directive (see Section 8.7.7.8)
- Check Image Match condition (see Section 8.7.6.2)
The Fetch directive needs the URI parameter to be set to determine
where the image is retrieved from. Additionally, the destination of
where the component shall be stored has to be configured. The URI is
configured via the Set Parameters directive while the destination is
configured via the Set Component Index directive.
7.4. Install Template
This template modifies the Firmware Download template and adds an
additional sequence. The Firmware Download operations are moved from
the Payload Install sequence to the Payload Fetch sequence.
Then, the Install sequence contains the following operations:
- Set Component Index directive (see Section 8.7.7.1)
- Set Parameters directive (see Section 8.7.7.6) for Source
Component (see Section 8.7.5.13)
- Copy directive (see Section 8.7.7.10)
- Check Image Match condition (see Section 8.7.6.2)
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7.5. Integrated Payload Template
This template triggers the installation of a payload included in the
manifest envelope. It is identical to Section 7.3 except that it
places an added restriction on the URI passed to the Set Parameters
directive.
An implementor MAY choose to place a payload in the envelope of a
manifest. The payload envelope key MAY be a positive or negative
integer. The payload envelope key MUST NOT be a value between 0 and
24 and it MUST NOT be used by any other envelope element in the
manifest. The payload MUST be serialized in a bstr element.
The URI for a payload enclosed in this way MUST be expressed as a
fragment-only reference, as defined in [RFC3986], Section 4.4. The
fragment identifier is the stringified envelope key of the payload.
For example, an envelope that contains a payload a key 42 would use a
URI "#42", key -73 would use a URI "#-73".
7.6. Load from Nonvolatile Storage Template
This directive loads an firmware image from external storage.
The following operations are placed into the load block:
- Set Component Index directive (see Section 8.7.7.1)
- Set Parameters directive (see Section 8.7.7.6) for Component Index
(see Section 8.7.5)
- Copy directive (see Section 8.7.7.10)
As outlined in Section 6.4, the Copy directive needs a source and a
destination to be configured. The source is configured via Component
Index (with the Set Parameters directive) and the destination is
configured via the Set Component Index directive.
7.7. Load & Decompress from Nonvolatile Storage Template
The following operations are placed into the load block:
- Set Component Index directive (see Section 8.7.7.1)
- Set Parameters directive (see Section 8.7.7.6) for Source
Component Index and Compression Info (see Section 8.7.5)
- Copy directive (see Section 8.7.7.10)
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This template is similar to Section 7.6 but additionally performs
decompression. Hence, the only difference is in setting the
Compression Info parameter.
7.8. Dependency Template
The following operations are placed into the dependency resolution
block:
- Set Dependency Index directive (see Section 8.7.7.2)
- Set Parameters directive (see Section 8.7.7.6) for URI (see
Section 8.7.5)
- Fetch directive (see Section 8.7.7.8)
- Check Image Match condition (see Section 8.7.6.2)
- Process Dependency directive (see Section 8.7.7.5)
Then, the validate block contains the following operations:
- Set Dependency Index directive (see Section 8.7.7.2)
- Check Image Match condition (see Section 8.7.6.2)
- Process Dependency directive (see Section 8.7.7.5)
NOTE: Any changes made to parameters in a dependency persist in the
dependent.
7.8.1. Composite Manifests
An implementor MAY choose to place a dependency's envelope in the
envelope of its dependent. The dependent envelope key for the
dependency envelope MUST NOT be a value between 0 and 24 and it MUST
NOT be used by any other envelope element in the dependent manifest.
The URI for a dependency enclosed in this way MUST be expressed as a
fragment-only reference, as defined in [RFC3986], Section 4.4. The
fragment identifier is the stringified envelope key of the
dependency. For example, an envelope that contains a dependency at
key 42 would use a URI "#42", key -73 would use a URI "#-73".
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7.9. Encrypted Manifest Template
To use an encrypted manifest, create a plaintext dependent, and add
the encrypted manifest as a dependency. The dependent can include
very little information.
The following operations are placed into the dependency resolution
block:
- Set Dependency Index directive (see Section 8.7.7.2)
- Set Parameters directive (see Section 8.7.7.6) for
o URI (see Section 8.7.5)
o Encryption Info (see Section 8.7.5)
- Fetch directive (see Section 8.7.7.8)
- Check Image Match condition (see Section 8.7.6.2)
- Process Dependency directive (see Section 8.7.7.5)
Then, the validate block contains the following operations:
- Set Dependency Index directive (see Section 8.7.7.2)
- Check Image Match condition (see Section 8.7.6.2)
- Process Dependency directive (see Section 8.7.7.5)
A plaintext manifest and its encrypted dependency may also form a
composite manifest (Section 7.8.1).
7.10. A/B Image Template
The following operations are placed in the common block:
- Set Component Index directive (see Section 8.7.7.1)
- Try Each
o First Sequence:
* Override Parameters directive (see Section 8.7.7.7,
Section 8.7.5) for Offset A
* Check Offset Condition (see Section 8.7.6.5)
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* Override Parameters directive (see Section 8.7.7.7) for
Image Digest A and Image Size A (see Section 8.7.5)
o Second Sequence:
* Override Parameters directive (see Section 8.7.7.7,
Section 8.7.5) for Offset B
* Check Offset Condition (see Section 8.7.6.5)
* Override Parameters directive (see Section 8.7.7.7) for
Image Digest B and Image Size B (see Section 8.7.5)
The following operations are placed in the fetch block or install
block
- Set Component Index directive (see Section 8.7.7.1)
- Try Each
o First Sequence:
* Override Parameters directive (see Section 8.7.7.7,
Section 8.7.5) for Offset A
* Check Offset Condition (see Section 8.7.6.5)
* Set Parameters directive (see Section 8.7.7.7) for URI A
(see Section 8.7.5)
o Second Sequence:
* Override Parameters directive (see Section 8.7.7.7,
Section 8.7.5) for Offset B
* Check Offset Condition (see Section 8.7.6.5)
* Set Parameters directive (see Section 8.7.7.7) for URI B
(see Section 8.7.5)
- Fetch
8. Metadata Structure
The metadata for SUIT updates is composed of several primary
constituent parts: the Envelope, Delegation Chains, Authentication
Information, Manifest, and Severable Elements.
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For a diagram of the metadata structure, see Section 5.
8.1. Encoding Considerations
The map indices in the envelope encoding are reset to 1 for each map
within the structure. This is to keep the indices as small as
possible. The goal is to keep the index objects to single bytes
(CBOR positive integers 1-23).
Wherever enumerations are used, they are started at 1. This allows
detection of several common software errors that are caused by
uninitialised variables. Positive numbers in enumerations are
reserved for IANA registration. Negative numbers are used to
identify application-specific implementations.
All elements of the envelope must be wrapped in a bstr to minimize
the complexity of the code that evaluates the cryptographic integrity
of the element and to ensure correct serialization for integrity and
authenticity checks.
8.2. Envelope
The Envelope contains each of the other primary constituent parts of
the SUIT metadata. It allows for modular processing of the manifest
by ordering components in the expected order of processing.
The Envelope is encoded as a CBOR Map. Each element of the Envelope
is enclosed in a bstr, which allows computation of a message digest
against known bounds.
8.3. Delegation Chains
The suit-delegation field MAY carry one or more CBOR Web Tokens
(CWTs) [RFC8392], with [RFC8747] cnf claims. They can be used to
perform enhanced authorization decisions. The CWTs are arranged into
a list of lists. Each list starts with CWT authorized by a Trust
Anchor, and finishes with a key used to authenticate the Manifest
(see Section 8.4). This allows an Update Authority to delegate from
a long term Trust Anchor, down through intermediaries, to a delegate
without any out-of-band updates Trust Anchors.
A Recipient MAY choose to cache intermediaries and/or delegates. If
an Update Distributor knows that a targeted Recipient has cached some
intermediaries or delegates, it MAY choose to strip any cached
intermediaries or delegates from the Delegation Chains in order to
reduce bandwidth and energy.
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8.4. Authenticated Manifests
The suit-authentication-wrapper contains a list of one or more
cryptographic authentication wrappers for the Manifest. These are
implemented as COSE_Mac_Tagged or COSE_Sign_Tagged blocks. Each of
these blocks contains a SUIT_Digest of the Manifest. This enables
modular processing of the manifest. The COSE_Mac_Tagged and
COSE_Sign_Tagged blocks are described in RFC 8152 [RFC8152]. The
suit-authentication-wrapper MUST come before any element in the
SUIT_Envelope, except for the OPTIONAL suit-delegation, regardless of
canonical encoding of CBOR. All validators MUST reject any
SUIT_Envelope that begins with any element other than a suit-
authentication-wrapper or suit-delegation.
A SUIT_Envelope that has not had authentication information added
MUST still contain the suit-authentication-wrapper element, but the
content MUST be an empty list.
8.5. Encrypted Manifests
To use an encrypted manifest, it must be a dependency of a plaintext
manifest. This allows fine-grained control of what information is
accessible to intermediate systems for the purposes of management,
while still preserving the confidentiality of the manifest contents.
This also means that a Recipient can process an encrypted manifest in
the same way as an encrypted payload, allowing code reuse.
A template for using an encrypted manifest is covered in Encrypted
Manifest Template (Section 7.9).
8.6. Manifest
The manifest contains:
- a version number (see Section 8.6.1)
- a sequence number (see Section 8.6.2)
- a reference URI (see Section 8.6.3)
- a common structure with information that is shared between command
sequences (see Section 8.7.2)
- one or more lists of commands that the Recipient should perform
(see Section 8.7.3)
- a reference to the full manifest (see Section 8.6.3)
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- human-readable text describing the manifest found in the
SUIT_Envelope (see Section 8.6.4)
- a Concise Software Identifier found in the SUIT_Envelope (see
Section 8.7.1)
The CoSWID, Text section, or any Command Sequence of the Update
Procedure (Dependency Resolution, Image Fetch, Image Installation)
can be either a CBOR structure or a SUIT_Digest. In each of these
cases, the SUIT_Digest provides for a severable field. Severable
fields are RECOMMENDED to implement. In particular, the human-
readable text SHOULD be severable, since most useful text elements
occupy more space than a SUIT_Digest, but are not needed by the
Recipient. Because SUIT_Digest is a CBOR Array and each severable
element is a CBOR bstr, it is straight-forward for a Recipient to
determine whether an element has been severed. The key used for a
severable element is the same in the SUIT_Manifest and in the
SUIT_Envelope so that a Recipient can easily identify the correct
data in the envelope. See Section 8.7.8 for more detail.
8.6.1. suit-manifest-version
The suit-manifest-version indicates the version of serialization used
to encode the manifest. Version 1 is the version described in this
document. suit-manifest-version is REQUIRED to implement.
8.6.2. suit-manifest-sequence-number
The suit-manifest-sequence-number is a monotonically increasing anti-
rollback counter. It also helps Recipients to determine which in a
set of manifests is the "root" manifest in a given update. Each
manifest MUST have a sequence number higher than each of its
dependencies. Each Recipient MUST reject any manifest that has a
sequence number lower than its current sequence number. It MAY be
convenient to use a UTC timestamp in seconds as the sequence number.
suit-manifest-sequence-number is REQUIRED to implement.
8.6.3. suit-reference-uri
suit-reference-uri is a text string that encodes a URI where a full
version of this manifest can be found. This is convenient for
allowing management systems to show the severed elements of a
manifest when this URI is reported by a Recipient after installation.
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8.6.4. suit-text
suit-text SHOULD be a severable element. suit-text is a map of pairs.
It MAY contain two different types of pair:
- integer => text mappings
- SUIT_Component_Identifier => map mappings
Each SUIT_Component_Identifier => map entry contains a map of integer
=> text values. All SUIT_Component_Identifiers present in suit-text
MUST also be present in suit-common (Section 8.7.2) or the suit-
common of a dependency.
suit-text contains all the human-readable information that describes
any and all parts of the manifest, its payload(s) and its
resource(s). The text section is typically severable, allowing
manifests to be distributed without the text, since end-nodes do not
require text. The meaning of each field is described below.
Each section MAY be present. If present, each section MUST be as
described. Negative integer IDs are reserved for application-
specific text values.
The following table describes the text fields available in suit-text:
+--------------------------------+----------------------------------+
| CDDL Structure | Description |
+--------------------------------+----------------------------------+
| suit-text-manifest-description | Free text description of the |
| | manifest |
| | |
| suit-text-update-description | Free text description of the |
| | update |
| | |
| suit-text-manifest-json-source | The JSON-formatted document that |
| | was used to create the manifest |
| | |
| suit-text-manifest-yaml-source | The yaml-formatted document that |
| | was used to create the manifest |
+--------------------------------+----------------------------------+
The following table describes the text fields available in each map
identified by a SUIT_Component_Identifier.
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+---------------------------------+---------------------------------+
| CDDL Structure | Description |
+---------------------------------+---------------------------------+
| suit-text-vendor-name | Free text vendor name |
| | |
| suit-text-model-name | Free text model name |
| | |
| suit-text-vendor-domain | The domain used to create the |
| | vendor-id condition |
| | |
| suit-text-model-info | The information used to create |
| | the class-id condition |
| | |
| suit-text-component-description | Free text description of each |
| | component in the manifest |
| | |
| suit-text-component-version | A text version number |
| | |
| suit-text-version-required | A text expression of the |
| | required version number |
+---------------------------------+---------------------------------+
suit-text is OPTIONAL to implement.
8.7. text-version-required
suit-text-version-required is used to represent a version-based
dependency on suit-parameter-version as described in Section 8.7.5.17
and Section 8.7.6.8. To describe a version dependency, a Manifest
Author should populate the suit-text map with a
SUIT_Component_Identifier key for the dependency component, and place
in the corresponding map a suit-text-version-required key with a text
expression that is representative of the version constraints placed
on the dependency.
For example, to express a dependency on a component "['x', 'y']",
where the version should be any v1.x later than v1.2.5, but not v2.0
or above, the author would add the following structure to the suit-
text element. Note that this text is in cbor-diag notation.
" [h'78',h'79'] : { 7 : ">=1.2.5,<2" } "
8.7.1. suit-coswid
suit-coswid contains a Concise Software Identifier. This element
SHOULD be made severable so that it can be discarded by the Recipient
or an intermediary if it is not required by the Recipient.
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suit-coswid is OPTIONAL to implement.
8.7.2. suit-common
suit-common encodes all the information that is shared between each
of the command sequences, including: suit-dependencies, suit-
components, and suit-common-sequence. suit-common is REQUIRED to
implement.
suit-dependencies is a list of Section 8.7.2.1 blocks that specify
manifests that must be present before the current manifest can be
processed. suit-dependencies is OPTIONAL to implement.
suit-components is a list of SUIT_Component_Identifier
(Section 8.7.2.2) blocks that specify the component identifiers that
will be affected by the content of the current manifest. suit-
components is REQUIRED to implement; at least one manifest in a
dependency tree MUST contain a suit-components block.
suit-common-sequence is a SUIT_Command_Sequence to execute prior to
executing any other command sequence. Typical actions in suit-
common-sequence include setting expected Recipient identity and image
digests when they are conditional (see Section 8.7.7.4 and
Section 7.10 for more information on conditional sequences). suit-
common-sequence is RECOMMENDED to implement. It is REQUIRED if the
optimizations described in Section 6.2.1 will be used. Whenever a
parameter or try-each is required by more than one Command Sequence,
suit-common-sequence results in a smaller encoding.
8.7.2.1. Dependencies
SUIT_Dependency specifies a manifest that describes a dependency of
the current manifest. The Manifest is identified, however the
Recipient should expect an Envelope when it acquires the dependency.
This is because the Manifest is the one invariant element of the
Envelope, where other elements may change by countersigning, adding
authentication blocks, or severing elements.
The suit-dependency-digest specifies the dependency manifest uniquely
by identifying a particular Manifest structure. This is identical to
the digest that would be present as the payload of any suit-
authentication-block in the dependency's Envelope. The digest is
calculated over the Manifest structure instead of the COSE
Sig_structure or Mac_structure. This is necessary to ensure that
removing a signature from a manifest does not break dependencies due
to missing signature elements. This is also necessary to support the
trusted intermediary use case, where an intermediary re-signs the
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Manifest, removing the original signature, potentially with a
different algorithm, or trading COSE_Sign for COSE_Mac.
The suit-dependency-prefix element contains a
SUIT_Component_Identifier (see Section 8.7.2.2). This specifies the
scope at which the dependency operates. This allows the dependency
to be forwarded on to a component that is capable of parsing its own
manifests. It also allows one manifest to be deployed to multiple
dependent Recipients without those Recipients needing consistent
component hierarchy. This element is OPTIONAL.
A dependency prefix can be used with a component identifier. This
allows complex systems to understand where dependencies need to be
applied. The dependency prefix can be used in one of two ways. The
first simply prepends the prefix to all Component Identifiers in the
dependency.
A dependency prefix can also be used to indicate when a dependency
manifest needs to be processed by a secondary manifest processor, as
described in Section 6.9.
8.7.2.2. SUIT_Component_Identifier
A component is a unit of code or data that can be targeted by an
update. To facilitate composite devices, components are identified
by a list of CBOR byte strings, which allows construction of
hierarchical component structures. A dependency MAY declare a prefix
to the components defined in the dependency manifest. Components are
identified by Component Identifiers, i.e. arrays of binary strings,
but referenced in commands
A Component Identifier can be trivial, such as the simple array
[h'00']. It can also represent a filesystem path by encoding each
segment of the path as an element in the list. For example, the path
"/usr/bin/env" would encode to ['usr','bin','env'].
This hierarchical construction allows a component identifier to
identify any part of a complex, multi-component system.
8.7.3. SUIT_Command_Sequence
A SUIT_Command_Sequence defines a series of actions that the
Recipient MUST take to accomplish a particular goal. These goals are
defined in the manifest and include:
1. Dependency Resolution: suit-dependency-resolution is a
SUIT_Command_Sequence to execute in order to perform dependency
resolution. Typical actions include configuring URIs of
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dependency manifests, fetching dependency manifests, and
validating dependency manifests' contents. suit-dependency-
resolution is REQUIRED to implement and to use when suit-
dependencies is present.
2. Payload Fetch: suit-payload-fetch is a SUIT_Command_Sequence to
execute in order to obtain a payload. Some manifests may include
these actions in the suit-install section instead if they operate
in a streaming installation mode. This is particularly relevant
for constrained devices without any temporary storage for staging
the update. suit-payload-fetch is OPTIONAL to implement.
3. Payload Installation: suit-install is a SUIT_Command_Sequence to
execute in order to install a payload. Typical actions include
verifying a payload stored in temporary storage, copying a staged
payload from temporary storage, and unpacking a payload. suit-
install is OPTIONAL to implement.
4. Image Validation: suit-validate is a SUIT_Command_Sequence to
execute in order to validate that the result of applying the
update is correct. Typical actions involve image validation and
manifest validation. suit-validate is REQUIRED to implement. If
the manifest contains dependencies, one process-dependency
invocation per dependency or one process-dependency invocation
targeting all dependencies SHOULD be present in validate.
5. Image Loading: suit-load is a SUIT_Command_Sequence to execute in
order to prepare a payload for execution. Typical actions
include copying an image from permanent storage into RAM,
optionally including actions such as decryption or decompression.
suit-load is OPTIONAL to implement.
6. Run or Boot: suit-run is a SUIT_Command_Sequence to execute in
order to run an image. suit-run typically contains a single
instruction: either the "run" directive for the bootable manifest
or the "process dependencies" directive for any dependents of the
bootable manifest. suit-run is OPTIONAL to implement. Only one
manifest in an update may contain the "run" directive.
Goals 1,2,3 form the Update Procedure. Goals 4,5,6 form the Boot
Procedure.
Each Command Sequence follows exactly the same structure to ensure
that the parser is as simple as possible.
Lists of commands are constructed from two kinds of element:
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1. Conditions that MUST be true-any failure is treated as a failure
of the update/load/boot
2. Directives that MUST be executed.
Each condition is a command code identifier, followed by a
SUIT_Reporting_Policy (Section 8.7.4).
Each directive is composed of:
1. A command code identifier
2. An argument block or a reporting policy
Argument blocks are consumed only by flow-control directives:
- Set Component/Dependency Index
- Set/Override Parameters
- Try Each
- Run Sequence
Reporting policies provide a hint to the manifest processor of
whether or not to add the success or failure of a command to any
report that it generates.
Many conditions and directives apply to a given component, and these
generally grouped together. Therefore, a special command to set the
current component index is provided with a matching command to set
the current dependency index. This index is a numeric index into the
component ID tables defined at the beginning of the document. For
the purpose of setting the index, the two component ID tables are
considered to be concatenated together.
To facilitate optional conditions, a special directive,
Section 8.7.7.4, is provided. It runs several new lists of
conditions/directives, one after another, that are contained as an
argument to the directive. By default, it assumes that a failure of
a condition should not indicate a failure of the update/boot, but a
parameter is provided to override this behavior. See
Section 8.7.5.22.
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8.7.4. Reporting Policy
To facilitate construction of Reports that describe the success, or
failure of a given Procedure, each command is given a Reporting
Policy. This is an integer bitfield that follows the command and
indicates what the Recipient should do with the Record of executing
the command. The options are summarized in the table below.
+-----------------------------+-------------------------------------+
| Policy | Description |
+-----------------------------+-------------------------------------+
| suit-send-record-on-success | Record when the command succeeds |
| | |
| suit-send-record-on-failure | Record when the command fails |
| | |
| suit-send-sysinfo-success | Add system information when the |
| | command succeeds |
| | |
| suit-send-sysinfo-failure | Add system information when the |
| | command fails |
+-----------------------------+-------------------------------------+
Any or all of these policies may be enabled at once.
If the component index is set to True when a command is executed with
a non-zero reporting policy, then the Reporting Engine MUST receive
one Record for each Component, in the order expressed in the
Components list. If the dependency index is set to True when a
command is executed with a non-zero reporting policy, then the
Reporting Engine MUST receive one Record for each Dependency, in the
order expressed in the Dependencies list.
SUIT does NOT REQUIRE a particular format of Records or Reports.
SUIT only defines hints to the Reporting engine for which Records it
should aggregate into the Report.
For example, a system using DICE certificates MAY use instances of
suit-send-sysinfo-success to construct its certificates.
An OPTIONAL Record format, SUIT_Record is defined in [full-cddl]. It
is encoded as a map, with the following elements.
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+---------------------------------+---------------------------------+
| Element | Description |
+---------------------------------+---------------------------------+
| suit-record-success | The boolean or integer success |
| | or failure code of the command. |
| | |
| suit-record-component-id | The current component when the |
| | record was generated. |
| | |
| suit-record-dependency-id | The current dependency digest |
| | when the record was generated. |
| | |
| suit-record-command-sequence-id | The label of the Command |
| | Sequence that was executing |
| | when the record was generated. |
| | |
| suit-record-command-id | The label of the command that |
| | was in progress when the record |
| | was generated. |
| | |
| suit-record-params | The set of parameters that was |
| | consumed by the current |
| | command. |
| | |
| suit-record-actual | The value against which a suit- |
| | condition compared a parameter. |
+---------------------------------+---------------------------------+
In Secure Boot operations, the Reporting engine MAY aggregate the
Records produced in a Procedure into the evidence used for an
attestation report.
8.7.5. SUIT_Parameters
Many conditions and directives require additional information. That
information is contained within parameters that can be set in a
consistent way. This allows reduction of manifest size and
replacement of parameters from one manifest to the next.
Most parameters are scoped to a specific component. This means that
setting a parameter for one component has no effect on the parameters
of any other component. The only exceptions to this are two Manifest
Processor parameters: Strict Order and Soft Failure.
The defined manifest parameters are described below.
+----------------+----------------------------------+---------------+
| Name | CDDL Structure | Reference |
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+----------------+----------------------------------+---------------+
| Vendor ID | suit-parameter-vendor-identifier | Section 8.7.5 |
| | | .2 |
| | | |
| Class ID | suit-parameter-class-identifier | Section 8.7.5 |
| | | .3 |
| | | |
| Image Digest | suit-parameter-image-digest | Section 8.7.5 |
| | | .5 |
| | | |
| Image Size | suit-parameter-image-size | Section 8.7.5 |
| | | .6 |
| | | |
| Use Before | suit-parameter-use-before | Section 8.7.5 |
| | | .7 |
| | | |
| Component | suit-parameter-component-offset | Section 8.7.5 |
| Offset | | .8 |
| | | |
| Encryption | suit-parameter-encryption-info | Section 8.7.5 |
| Info | | .9 |
| | | |
| Compression | suit-parameter-compression-info | Section 8.7.5 |
| Info | | .10 |
| | | |
| Unpack Info | suit-parameter-unpack-info | Section 8.7.5 |
| | | .11 |
| | | |
| URI | suit-parameter-uri | Section 8.7.5 |
| | | .12 |
| | | |
| Source | suit-parameter-source-component | Section 8.7.5 |
| Component | | .13 |
| | | |
| Run Args | suit-parameter-run-args | Section 8.7.5 |
| | | .14 |
| | | |
| Device ID | suit-parameter-device-identifier | Section 8.7.5 |
| | | .4 |
| | | |
| Minimum | suit-parameter-minimum-battery | Section 8.7.5 |
| Battery | | .15 |
| | | |
| Update | suit-parameter-update-priority | Section 8.7.5 |
| Priority | | .16 |
| | | |
| Version | suit-parameter-version | Section 8.7.5 |
| | | .17 |
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| | | |
| Wait Info | suit-parameter-wait-info | Section 8.7.5 |
| | | .18 |
| | | |
| URI List | suit-parameter-uri-list | Section 8.7.5 |
| | | .19 |
| | | |
| Fetch | suit-parameter-fetch-arguments | Section 8.7.5 |
| Arguments | | .20 |
| | | |
| Strict Order | suit-parameter-strict-order | Section 8.7.5 |
| | | .21 |
| | | |
| Soft Failure | suit-parameter-soft-failure | Section 8.7.5 |
| | | .22 |
| | | |
| Custom | suit-parameter-custom | Section 8.7.5 |
| | | .23 |
+----------------+----------------------------------+---------------+
CBOR-encoded object parameters are still wrapped in a bstr. This is
because it allows a parser that is aggregating parameters to
reference the object with a single pointer and traverse it without
understanding the contents. This is important for modularization and
division of responsibility within a pull parser. The same
consideration does not apply to Directives because those elements are
invoked with their arguments immediately
8.7.5.1. Constructing Identifiers
Several conditions use identifiers to determine whether a manifest
matches a given Recipient or not. These identifiers are defined to
be RFC 4122 [RFC4122] UUIDs. These UUIDs are not human-readable and
are therefore used for machine-based processing only.
A Recipient MAY match any number of UUIDs for vendor or class
identifier. This may be relevant to physical or software modules.
For example, a Recipient that has an OS and one or more applications
might list one Vendor ID for the OS and one or more additional Vendor
IDs for the applications. This Recipient might also have a Class ID
that must be matched for the OS and one or more Class IDs for the
applications.
Identifiers are used for compatibility checks. They MUST NOT be used
as assertions of identity. They are evaluated by identifier
conditions (Section 8.7.6.1).
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A more complete example: Imagine a device has the following physical
components: 1. A host MCU 2. A WiFi module
This same device has three software modules: 1. An operating system
2. A WiFi module interface driver 3. An application
Suppose that the WiFi module's firmware has a proprietary update
mechanism and doesn't support manifest processing. This device can
report four class IDs:
1. Hardware model/revision
2. OS
3. WiFi module model/revision
4. Application
This allows the OS, WiFi module, and application to be updated
independently. To combat possible incompatibilities, the OS class ID
can be changed each time the OS has a change to its API.
This approach allows a vendor to target, for example, all devices
with a particular WiFi module with an update, which is a very
powerful mechanism, particularly when used for security updates.
UUIDs MUST be created according to RFC 4122 [RFC4122]. UUIDs SHOULD
use versions 3, 4, or 5, as described in RFC4122. Versions 1 and 2
do not provide a tangible benefit over version 4 for this
application.
The RECOMMENDED method to create a vendor ID is: Vendor ID =
UUID5(DNS_PREFIX, vendor domain name)
The RECOMMENDED method to create a class ID is: Class ID =
UUID5(Vendor ID, Class-Specific-Information)
Class-specific information is composed of a variety of data, for
example:
- Model number.
- Hardware revision.
- Bootloader version (for immutable bootloaders).
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8.7.5.2. suit-parameter-vendor-identifier
A RFC 4122 UUID representing the vendor of the device or component.
The UUID is encoded as a 16 byte bstr, containing the raw bytes of
the UUID. It MUST be constructed as described in Section 8.7.5.1
8.7.5.3. suit-parameter-class-identifier
A RFC 4122 UUID representing the class of the device or component.
The UUID is encoded as a 16 byte bstr, containing the raw bytes of
the UUID. It MUST be constructed as described in Section 8.7.5.1
8.7.5.4. suit-parameter-device-identifier
A RFC 4122 UUID representing the specific device or component. The
UUID is encoded as a 16 byte bstr, containing the raw bytes of the
UUID. It MUST be constructed as described in Section 8.7.5.1
8.7.5.5. suit-parameter-image-digest
A fingerprint computed over the component itself, encoded in the
Section 10 structure. The SUIT_Digest is wrapped in a bstr, as
required in Section 8.7.5.
8.7.5.6. suit-parameter-image-size
The size of the firmware image in bytes. This size is encoded as a
positive integer.
8.7.5.7. suit-parameter-use-before
An expiry date for the use of the manifest encoded as a POSIX
timestamp; a positive integer. Implementations that use this
parameter MUST use a 64-bit internal representation of the integer.
8.7.5.8. suit-parameter-component-offset
This parameter sets the offset in a component. Some components
support multiple possible Slots (offsets into a storage area). This
parameter describes the intended Slot to use, identified by its
offset into the component's storage area. This offset MUST be
encoded as a positive integer.
8.7.5.9. suit-parameter-encryption-info
Encryption Info defines the mechanism that Fetch or Copy should use
to decrypt the data they transfer. SUIT_Parameter_Encryption_Info is
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encoded as a COSE_Encrypt_Tagged or a COSE_Encrypt0_Tagged, wrapped
in a bstr.
8.7.5.10. suit-parameter-compression-info
Compression Info defines any information that is required for a
Recipient to perform decompression operations. Typically, this
includes the algorithm identifier. This document defines the use of
ZLIB [RFC1950], Brotli [RFC7932], and ZSTD
[I-D.kucherawy-rfc8478bis].
Additional compression formats can be registered through the IANA-
maintained registry.
8.7.5.11. suit-parameter-unpack-info
SUIT_Unpack_Info defines the information required for a Recipient to
interpret a packed format. This document defines the use of the
following binary encodings: Intel HEX [HEX], Motorola S-record
[SREC], Executable and Linkable Format (ELF) [ELF], and Common Object
File Format (COFF) [COFF].
Additional packing formats can be registered through the IANA-
maintained registry.
8.7.5.12. suit-parameter-uri
A URI from which to fetch a resource.
8.7.5.13. suit-parameter-source-component
This parameter sets the source component to be used with either
Section 8.7.7.10 or with Section 8.7.7.14. The current Component, as
set by suit-directive-set-component-index defines the destination,
and suit-parameter-source-component defines the source.
8.7.5.14. suit-parameter-run-args
This parameter contains an encoded set of arguments for
Section 8.7.7.11. The arguments MUST be provided as an
implementation-defined bstr.
8.7.5.15. suit-parameter-minimum-battery
This parameter sets the minimum battery level in mWh. This parameter
is encoded as a positive integer. Used with Section 8.7.6.6.
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8.7.5.16. suit-parameter-update-priority
This parameter sets the priority of the update. This parameter is
encoded as an integer. It is used along with suit-condition-update-
authorized [1] to ask an application for permission to initiate an
update. This does not constitute a privilege inversion because an
explicit request for authorization has been provided by the Update
Authority in the form of the suit-condition-update-authorized
command.
Applications MAY define their own meanings for the update priority.
For example, critical reliability & vulnerability fixes MAY be given
negative numbers, while bug fixes MAY be given small positive
numbers, and feature additions MAY be given larger positive numbers,
which allows an application to make an informed decision about
whether and when to allow an update to proceed.
8.7.5.17. suit-parameter-version
Indicates allowable versions for the specified component. Allowable
versions can be specified, either with a list or with range matching.
This parameter is compared with version asserted by the current
component when Section 8.7.6.8 is invoked. The current component may
assert the current version in many ways, including storage in a
parameter storage database, in a metadata object, or in a known
location within the component itself.
The component version can be compared as:
- Greater.
- Greater or Equal.
- Equal.
- Lesser or Equal.
- Lesser.
Versions are encoded as a CBOR list of integers. Comparisons are
done on each integer in sequence. Comparison stops after all
integers in the list defined by the manifest have been consumed OR
after a non-equal match has occurred. For example, if the manifest
defines a comparison, "Equal [1]", then this will match all version
sequences starting with 1. If a manifest defines both "Greater or
Equal [1,0]" and "Lesser [1,10]", then it will match versions 1.0.x
up to, but not including 1.10.
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While the exact encoding of versions is application-defined, semantic
versions map conveniently. For example,
- 1.2.3 = [1,2,3].
- 1.2-rc3 = [1,2,-1,3].
- 1.2-beta = [1,2,-2].
- 1.2-alpha = [1,2,-3].
- 1.2-alpha4 = [1,2,-3,4].
suit-condition-version is OPTIONAL to implement.
Versions SHOULD be provided as follows:
1. The first integer represents the major number. This indicates
breaking changes to the component.
2. The second integer represents the minor number. This is
typically reserved for new features or large, non-breaking
changes.
3. The third integer is the patch version. This is typically
reserved for bug fixes.
4. The fourth integer is the build number.
Where Alpha (-3), Beta (-2), and Release Candidate (-1) are used,
they are inserted as a negative number between Minor and Patch
numbers. This allows these releases to compare correctly with final
releases. For example, Version 2.0, RC1 should be lower than Version
2.0.0 and higher than any Version 1.x. By encoding RC as -1, this
works correctly: [2,0,-1,1] compares as lower than [2,0,0].
Similarly, beta (-2) is lower than RC and alpha (-3) is lower than
RC.
8.7.5.18. suit-parameter-wait-info
suit-directive-wait Section 8.7.7.12 directs the manifest processor
to pause until a specified event occurs. The suit-parameter-wait-
info encodes the parameters needed for the directive.
The exact implementation of the pause is implementation-defined. For
example, this could be done by blocking on a semaphore, registering
an event handler and suspending the manifest processor, polling for a
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notification, or aborting the update entirely, then restarting when a
notification is received.
suit-parameter-wait-info is encoded as a map of wait events. When
ALL wait events are satisfied, the Manifest Processor continues. The
wait events currently defined are described in the following table.
+--------------------------------------+----------+-----------------+
| Name | Encoding | Description |
+--------------------------------------+----------+-----------------+
| suit-wait-event-authorization | int | Same as Section |
| | | 8.7.5.16 |
| | | |
| suit-wait-event-power | int | Wait until |
| | | power state |
| | | |
| suit-wait-event-network | int | Wait until |
| | | network state |
| | | |
| suit-wait-event-other-device-version | See | Wait for other |
| | below | device to match |
| | | version |
| | | |
| suit-wait-event-time | uint | Wait until time |
| | | (POSIX |
| | | timestamp) |
| | | |
| suit-wait-event-time-of-day | uint | Wait until |
| | | seconds since |
| | | 00:00:00 |
| | | |
| suit-wait-event-day-of-week | uint | Wait until days |
| | | since Sunday |
+--------------------------------------+----------+-----------------+
suit-wait-event-other-device-version reuses the encoding of suit-
parameter-version-match. It is encoded as a sequence that contains
an implementation-defined bstr identifier for the other device, and a
list of one or more SUIT_Parameter_Version_Match.
8.7.5.19. suit-parameter-uri-list
Indicates a list of URIs from which to fetch a resource. The URI
list is encoded as a list of tstr, in priority order. The Recipient
should attempt to fetch the resource from each URI in turn, ruling
out each, in order, if the resource is inaccessible or it is
otherwise undesirable to fetch from that URI. suit-parameter-uri-list
is consumed by Section 8.7.7.9.
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8.7.5.20. suit-parameter-fetch-arguments
An implementation-defined set of arguments to Section 8.7.7.8.
Arguments are encoded in a bstr.
8.7.5.21. suit-parameter-strict-order
The Strict Order Parameter allows a manifest to govern when
directives can be executed out-of-order. This allows for systems
that have a sensitivity to order of updates to choose the order in
which they are executed. It also allows for more advanced systems to
parallelize their handling of updates. Strict Order defaults to
True. It MAY be set to False when the order of operations does not
matter. When arriving at the end of a command sequence, ALL commands
MUST have completed, regardless of the state of
SUIT_Parameter_Strict_Order. If SUIT_Parameter_Strict_Order is
returned to True, ALL preceding commands MUST complete before the
next command is executed.
See Section 6.7 for behavioral description of Strict Order.
8.7.5.22. suit-parameter-soft-failure
When executing a command sequence inside Section 8.7.7.4 or
Section 8.7.7.13 and a condition failure occurs, the manifest
processor aborts the sequence. For suit-directive-try-each, if Soft
Failure is True, the next sequence in Try Each is invoked, otherwise
suit-directive-try-each fails with the condition failure code. In
suit-directive-run-sequence, if Soft Failure is True the suit-
directive-run-sequence simply halts with no side-effects and the
Manifest Processor continues with the following command, otherwise,
the suit-directive-run-sequence fails with the condition failure
code.
suit-parameter-soft-failure is scoped to the enclosing
SUIT_Command_Sequence. Its value is discarded when
SUIT_Command_Sequence terminates. It MUST NOT be set outside of
suit-directive-try-each or suit-directive-run-sequence.
When suit-directive-try-each is invoked, Soft Failure defaults to
True. An Update Author may choose to set Soft Failure to False if
they require a failed condition in a sequence to force an Abort.
When suit-directive-run-sequence is invoked, Soft Failure defaults to
False. An Update Author may choose to make failures soft within a
suit-directive-run-sequence.
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8.7.5.23. suit-parameter-custom
This parameter is an extension point for any proprietary, application
specific conditions and directives.
8.7.6. SUIT_Condition
Conditions are used to define mandatory properties of a system in
order for an update to be applied. They can be pre-conditions or
post-conditions of any directive or series of directives, depending
on where they are placed in the list. All Conditions specify a
Reporting Policy as described Section 8.7.4. Conditions include:
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+----------------+----------------------------------+---------------+
| Name | CDDL Structure | Reference |
+----------------+----------------------------------+---------------+
| Vendor | suit-condition-vendor-identifier | Section 8.7.6 |
| Identifier | | .1 |
| | | |
| Class | suit-condition-class-identifier | Section 8.7.6 |
| Identifier | | .1 |
| | | |
| Device | suit-condition-device-identifier | Section 8.7.6 |
| Identifier | | .1 |
| | | |
| Image Match | suit-condition-image-match | Section 8.7.6 |
| | | .2 |
| | | |
| Image Not | suit-condition-image-not-match | Section 8.7.6 |
| Match | | .3 |
| | | |
| Use Before | suit-condition-use-before | Section 8.7.6 |
| | | .4 |
| | | |
| Component | suit-condition-component-offset | Section 8.7.6 |
| Offset | | .5 |
| | | |
| Minimum | suit-condition-minimum-battery | Section 8.7.6 |
| Battery | | .6 |
| | | |
| Update | suit-condition-update-authorized | Section 8.7.6 |
| Authorized | | .7 |
| | | |
| Version | suit-condition-version | Section 8.7.6 |
| | | .8 |
| | | |
| Custom | SUIT_Condition_Custom | Section 8.7.6 |
| Condition | | .9 |
+----------------+----------------------------------+---------------+
The abstract description of these conditions is defined in
Section 6.4.
Conditions compare parameters against properties of the system.
These properties may be asserted in many different ways, including:
calculation on-demand, volatile definition in memory, static
definition within the manifest processor, storage in known location
within an image, storage within a key storage system, storage in One-
Time-Programmable memory, inclusion in mask ROM, or inclusion as a
register in hardware. Some of these assertion methods are global in
scope, such as a hardware register, some are scoped to an individual
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component, such as storage at a known location in an image, and some
assertion methods can be either global or component-scope, based on
implementation.
Each condition MUST report a result code on completion. If a
condition reports failure, then the current sequence of commands MUST
terminate. A subsequent command or command sequence MAY continue
executing if Section 8.7.5.22 is set. If a condition requires
additional information, this MUST be specified in one or more
parameters before the condition is executed. If a Recipient attempts
to process a condition that expects additional information and that
information has not been set, it MUST report a failure. If a
Recipient encounters an unknown condition, it MUST report a failure.
Condition labels in the positive number range are reserved for IANA
registration while those in the negative range are custom conditions
reserved for proprietary use. See Section 11 for more details.
8.7.6.1. suit-condition-vendor-identifier, suit-condition-class-
identifier, and suit-condition-device-identifier
There are three identifier-based conditions: suit-condition-vendor-
identifier, suit-condition-class-identifier, and suit-condition-
device-identifier. Each of these conditions match a RFC 4122
[RFC4122] UUID that MUST have already been set as a parameter. The
installing Recipient MUST match the specified UUID in order to
consider the manifest valid. These identifiers are scoped by
component in the manifest. The Recipient MAY treat them as scoped by
component or as global identifiers.
The Recipient uses the ID parameter that has already been set using
the Set Parameters directive. If no ID has been set, this condition
fails. suit-condition-class-identifier and suit-condition-vendor-
identifier are REQUIRED to implement. suit-condition-device-
identifier is OPTIONAL to implement.
Each identifier condition compares the corresponding identifier
parameter to a parameter asserted to the Manifest Processor by the
Recipient. Identifiers MUST be known to the Manifest Processor in
order to evaluate compatibility.
Globally-scoped identifiers MUST match, regardless of current
component index. Component-scoped identifiers match only when the
current component index resolves to the component associated with the
component-scoped identifier.
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8.7.6.2. suit-condition-image-match
Verify that the current component matches the Section 8.7.5.5 for the
current component. The digest is verified against the digest
specified in the Component's parameters list. If no digest is
specified, the condition fails. suit-condition-image-match is
REQUIRED to implement.
8.7.6.3. suit-condition-image-not-match
Verify that the current component does not match the Section 8.7.5.5.
If no digest is specified, the condition fails. suit-condition-image-
not-match is OPTIONAL to implement.
8.7.6.4. suit-condition-use-before
Verify that the current time is BEFORE the specified time. suit-
condition-use-before is used to specify the last time at which an
update should be installed. The recipient evaluates the current time
against the suit-parameter-use-before parameter (Section 8.7.5.7),
which must have already been set as a parameter, encoded as a POSIX
timestamp, that is seconds after 1970-01-01 00:00:00. Timestamp
conditions MUST be evaluated in 64 bits, regardless of encoded CBOR
size. suit-condition-use-before is OPTIONAL to implement.
8.7.6.5. suit-condition-component-offset
Verify that the offset of the current component matches the offset
set in Section 8.7.5.8. This condition allows a manifest to select
between several images to match a target offset.
8.7.6.6. suit-condition-minimum-battery
suit-condition-minimum-battery provides a mechanism to test a
Recipient's battery level before installing an update. This
condition is primarily for use in primary-cell applications, where
the battery is only ever discharged. For batteries that are charged,
suit-directive-wait is more appropriate, since it defines a "wait"
until the battery level is sufficient to install the update. suit-
condition-minimum-battery is specified in mWh. suit-condition-
minimum-battery is OPTIONAL to implement. suit-condition-minimum-
battery consumes Section 8.7.5.15.
8.7.6.7. suit-condition-update-authorized
Request Authorization from the application and fail if not
authorized. This can allow a user to decline an update.
Section 8.7.5.16 provides an integer priority level that the
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application can use to determine whether or not to authorize the
update. Priorities are application defined. suit-condition-update-
authorized is OPTIONAL to implement.
8.7.6.8. suit-condition-version
suit-condition-version allows comparing versions of firmware.
Verifying image digests is preferred to version checks because
digests are more precise. suit-condition-version examines a
component's version against the version info specified in
Section 8.7.5.17
8.7.6.9. SUIT_Condition_Custom
SUIT_Condition_Custom describes any proprietary, application specific
condition. This is encoded as a negative integer, chosen by the
firmware developer. If additional information must be provided to
the condition, it should be encoded in a custom parameter (a nint) as
described in Section 8.7.5. SUIT_Condition_Custom is OPTIONAL to
implement.
8.7.7. SUIT_Directive
Directives are used to define the behavior of the recipient.
Directives include:
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+---------------+-------------------------------------+-------------+
| Name | CDDL Structure | Reference |
+---------------+-------------------------------------+-------------+
| Set Component | suit-directive-set-component-index | Section 8.7 |
| Index | | .7.1 |
| | | |
| Set | suit-directive-set-dependency-index | Section 8.7 |
| Dependency | | .7.2 |
| Index | | |
| | | |
| Abort | suit-directive-abort | Section 8.7 |
| | | .7.3 |
| | | |
| Try Each | suit-directive-try-each | Section 8.7 |
| | | .7.4 |
| | | |
| Process | suit-directive-process-dependency | Section 8.7 |
| Dependency | | .7.5 |
| | | |
| Set | suit-directive-set-parameters | Section 8.7 |
| Parameters | | .7.6 |
| | | |
| Override | suit-directive-override-parameters | Section 8.7 |
| Parameters | | .7.7 |
| | | |
| Fetch | suit-directive-fetch | Section 8.7 |
| | | .7.8 |
| | | |
| Copy | suit-directive-copy | Section 8.7 |
| | | .7.10 |
| | | |
| Run | suit-directive-run | Section 8.7 |
| | | .7.11 |
| | | |
| Wait For | suit-directive-wait | Section 8.7 |
| Event | | .7.12 |
| | | |
| Run Sequence | suit-directive-run-sequence | Section 8.7 |
| | | .7.13 |
| | | |
| Swap | suit-directive-swap | Section 8.7 |
| | | .7.14 |
| | | |
| Fetch URI | suit-directive-fetch-uri-list | Section 8.7 |
| list | | .7.9 |
+---------------+-------------------------------------+-------------+
The abstract description of these commands is defined in Section 6.4.
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When a Recipient executes a Directive, it MUST report a result code.
If the Directive reports failure, then the current Command Sequence
MUST terminate.
8.7.7.1. suit-directive-set-component-index
Set Component Index defines the component to which successive
directives and conditions will apply. The supplied argument MUST be
either a boolean or an unsigned integer index into suit-components.
If the following commands apply to ALL components, then the boolean
value "True" is used instead of an index. If the following commands
apply to NO components, then the boolean value "False" is used. When
suit-directive-set-dependency-index is used, suit-directive-set-
component-index = False is implied. When suit-directive-set-
component-index is used, suit-directive-set-dependency-index = False
is implied.
If component index is set to True when a command is invoked, then the
command applies to all components, in the order they appear in suit-
common-components. When the Manifest Processor invokes a command
while the component index is set to True, it must execute the command
once for each possible component index, ensuring that the command
receives the parameters corresponding to that component index.
8.7.7.2. suit-directive-set-dependency-index
Set Dependency Index defines the manifest to which successive
directives and conditions will apply. The supplied argument MUST be
either a boolean or an unsigned integer index into the dependencies.
If the following directives apply to ALL dependencies, then the
boolean value "True" is used instead of an index. If the following
directives apply to NO dependencies, then the boolean value "False"
is used. When suit-directive-set-component-index is used, suit-
directive-set-dependency-index = False is implied. When suit-
directive-set-dependency-index is used, suit-directive-set-component-
index = False is implied.
If dependency index is set to True when a command is invoked, then
the command applies to all dependencies, in the order they appear in
suit-common-components. When the Manifest Processor invokes a
command while the dependency index is set to True, it must execute
the command once for each possible dependency index, ensuring that
the command receives the parameters corresponding to that dependency
index.
Typical operations that require suit-directive-set-dependency-index
include setting a source URI or Encryption Information, invoking
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"Fetch," or invoking "Process Dependency" for an individual
dependency.
8.7.7.3. suit-directive-abort
Unconditionally fail. This operation is typically used in
conjunction with suit-directive-try-each.
8.7.7.4. suit-directive-try-each
This command runs several SUIT_Command_Sequence, one after another,
in a strict order. Use this command to implement a "try/catch-try/
catch" sequence. Manifest processors MAY implement this command.
Section 8.7.5.22 is initialized to True at the beginning of each
sequence. If one sequence aborts due to a condition failure, the
next is started. If no sequence completes without condition failure,
then suit-directive-try-each returns an error. If a particular
application calls for all sequences to fail and still continue, then
an empty sequence (nil) can be added to the Try Each Argument.
The argument to suit-directive-try-each is a list of
SUIT_Command_Sequence. suit-directive-try-each does not specify a
reporting policy.
8.7.7.5. suit-directive-process-dependency
Execute the commands in the common section of the current dependency,
followed by the commands in the equivalent section of the current
dependency. For example, if the current section is "fetch payload,"
this will execute "common" in the current dependency, then "fetch
payload" in the current dependency. Once this is complete, the
command following suit-directive-process-dependency will be
processed.
If the current dependency is False, this directive has no effect. If
the current dependency is True, then this directive applies to all
dependencies. If the current section is "common," this directive
MUST have no effect.
When SUIT_Process_Dependency completes, it forwards the last status
code that occurred in the dependency.
8.7.7.6. suit-directive-set-parameters
suit-directive-set-parameters allows the manifest to configure
behavior of future directives by changing parameters that are read by
those directives. When dependencies are used, suit-directive-set-
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parameters also allows a manifest to modify the behavior of its
dependencies.
Available parameters are defined in Section 8.7.5.
If a parameter is already set, suit-directive-set-parameters will
skip setting the parameter to its argument. This provides the core
of the override mechanism, allowing dependent manifests to change the
behavior of a manifest.
suit-directive-set-parameters does not specify a reporting policy.
8.7.7.7. suit-directive-override-parameters
suit-directive-override-parameters replaces any listed parameters
that are already set with the values that are provided in its
argument. This allows a manifest to prevent replacement of critical
parameters.
Available parameters are defined in Section 8.7.5.
suit-directive-override-parameters does not specify a reporting
policy.
8.7.7.8. suit-directive-fetch
suit-directive-fetch instructs the manifest processor to obtain one
or more manifests or payloads, as specified by the manifest index and
component index, respectively.
suit-directive-fetch can target one or more manifests and one or more
payloads. suit-directive-fetch retrieves each component and each
manifest listed in component-index and dependency-index,
respectively. If component-index or dependency-index is True,
instead of an integer, then all current manifest components/manifests
are fetched. The current manifest's dependent-components are not
automatically fetched. In order to pre-fetch these, they MUST be
specified in a component-index integer.
suit-directive-fetch typically takes no arguments unless one is
needed to modify fetch behavior. If an argument is needed, it must
be wrapped in a bstr and set in suit-parameter-fetch-arguments.
suit-directive-fetch reads the URI parameter to find the source of
the fetch it performs.
The behavior of suit-directive-fetch can be modified by setting one
or more of SUIT_Parameter_Encryption_Info,
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SUIT_Parameter_Compression_Info, SUIT_Parameter_Unpack_Info. These
three parameters each activate and configure a processing step that
can be applied to the data that is transferred during suit-directive-
fetch.
8.7.7.9. suit-directive-fetch-uri-list
suit-directive-fetch-uri-list uses the same semantics as
Section 8.7.7.8, however it iterates over the URI List
(Section 8.7.5.19) to select a URI to fetch from.
8.7.7.10. suit-directive-copy
suit-directive-copy instructs the manifest processor to obtain one or
more payloads, as specified by the component index. suit-directive-
copy retrieves each component listed in component-index,
respectively. If component-index is True, instead of an integer,
then all current manifest components are copied. The current
manifest's dependent-components are not automatically copied. In
order to copy these, they MUST be specified in a component-index
integer.
The behavior of suit-directive-copy can be modified by setting one or
more of SUIT_Parameter_Encryption_Info,
SUIT_Parameter_Compression_Info, SUIT_Parameter_Unpack_Info. These
three parameters each activate and configure a processing step that
can be applied to the data that is transferred during suit-directive-
copy.
suit-directive-copy reads its source from Section 8.7.5.13.
8.7.7.11. suit-directive-run
suit-directive-run directs the manifest processor to transfer
execution to the current Component Index. When this is invoked, the
manifest processor MAY be unloaded and execution continues in the
Component Index. Arguments are provided to suit-directive-run
through suit-parameter-run-arguments (Section 8.7.5.14) and are
forwarded to the executable code located in Component Index in an
application-specific way. For example, this could form the Linux
Kernel Command Line if booting a Linux device.
If the executable code at Component Index is constructed in such a
way that it does not unload the manifest processor, then the manifest
processor may resume execution after the executable completes. This
allows the manifest processor to invoke suitable helpers and to
verify them with image conditions.
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8.7.7.12. suit-directive-wait
suit-directive-wait directs the manifest processor to pause until a
specified event occurs. Some possible events include:
1. Authorization
2. External Power
3. Network availability
4. Other Device Firmware Version
5. Time
6. Time of Day
7. Day of Week
8.7.7.13. suit-directive-run-sequence
To enable conditional commands, and to allow several strictly ordered
sequences to be executed out-of-order, suit-directive-run-sequence
allows the manifest processor to execute its argument as a
SUIT_Command_Sequence. The argument must be wrapped in a bstr.
When a sequence is executed, any failure of a condition causes
immediate termination of the sequence.
When suit-directive-run-sequence completes, it forwards the last
status code that occurred in the sequence. If the Soft Failure
parameter is true, then suit-directive-run-sequence only fails when a
directive in the argument sequence fails.
Section 8.7.5.22 defaults to False when suit-directive-run-sequence
begins. Its value is discarded when suit-directive-run-sequence
terminates.
8.7.7.14. suit-directive-swap
suit-directive-swap instructs the manifest processor to move the
source to the destination and the destination to the source
simultaneously. Swap has nearly identical semantics to suit-
directive-copy except that suit-directive-swap replaces the source
with the current contents of the destination in an application-
defined way. If SUIT_Parameter_Compression_Info or
SUIT_Parameter_Encryption_Info are present, they MUST be handled in a
symmetric way, so that the source is decompressed into the
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destination and the destination is compressed into the source. The
source is decrypted into the destination and the destination is
encrypted into the source. suit-directive-swap is OPTIONAL to
implement.
8.7.8. Integrity Check Values
When the CoSWID, Text section, or any Command Sequence of the Update
Procedure is made severable, it is moved to the Envelope and replaced
with a SUIT_Digest. The SUIT_Digest is computed over the entire bstr
enclosing the Manifest element that has been moved to the Envelope.
Each element that is made severable from the Manifest is placed in
the Envelope with an identical key, so that it matches the key of the
corresponding Integrity Check Value.
Each Integrity Check Value covers the corresponding Envelope Element
as described in Section 8.8.
8.8. Severable Elements
Because the manifest can be used by different actors at different
times, some parts of the manifest can be removed or "Severed" without
affecting later stages of the lifecycle. Severing of information is
achieved by separating that information from the signed container so
that removing it does not affect the signature. This means that
ensuring integrity of severable parts of the manifest is a
requirement for the signed portion of the manifest. Severing some
parts makes it possible to discard parts of the manifest that are no
longer necessary. This is important because it allows the storage
used by the manifest to be greatly reduced. For example, no text
size limits are needed if text is removed from the manifest prior to
delivery to a constrained device.
Elements are made severable by removing them from the manifest,
encoding them in a bstr, and placing a SUIT_Digest of the bstr in the
manifest so that they can still be authenticated. The SUIT_Digest
typically consumes 4 bytes more than the size of the raw digest,
therefore elements smaller than (Digest Bits)/8 + 4 SHOULD NOT be
severable. Elements larger than (Digest Bits)/8 + 4 MAY be
severable, while elements that are much larger than (Digest Bits)/8 +
4 SHOULD be severable.
Because of this, all command sequences in the manifest are encoded in
a bstr so that there is a single code path needed for all command
sequences.
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9. Access Control Lists
To manage permissions in the manifest, there are three models that
can be used.
First, the simplest model requires that all manifests are
authenticated by a single trusted key. This mode has the advantage
that only a root manifest needs to be authenticated, since all of its
dependencies have digests included in the root manifest.
This simplest model can be extended by adding key delegation without
much increase in complexity.
A second model requires an ACL to be presented to the Recipient,
authenticated by a trusted party or stored on the Recipient. This
ACL grants access rights for specific component IDs or component ID
prefixes to the listed identities or identity groups. Any identity
may verify an image digest, but fetching into or fetching from a
component ID requires approval from the ACL.
A third model allows a Recipient to provide even more fine-grained
controls: The ACL lists the component ID or component ID prefix that
an identity may use, and also lists the commands that the identity
may use in combination with that component ID.
10. SUIT Digest Container
RFC 8152 [RFC8152] provides containers for signature, MAC, and
encryption, but no basic digest container. The container needed for
a digest requires a type identifier and a container for the raw
digest data. Some forms of digest may require additional parameters.
These can be added following the digest.
The SUIT digest is a CBOR List containing two elements: a suit-
digest-algorithm-id and a bstr containing the bytes of the digest.
11. IANA Considerations
IANA is requested to:
- allocate a CBOR tag for the SUIT Envelope and another for the SUIT
Manifest.
- allocate a media type for suit: application/suit-envelope
- setup several registries as described below
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IANA is requested to setup a registry for SUIT manifests. Several
registries defined in the subsections below need to be created.
For each registry, values 0-23 are Standards Action, 24-255 are IETF
Review, 256-65535 are Expert Review, and 65536 or greater are First
Come First Served.
Negative values -23 to 0 are Experimental Use, -24 and lower are
Private Use.
11.1. SUIT Commands
+-------+----------------------+
| Label | Name |
+-------+----------------------+
| 1 | Vendor Identifier |
| | |
| 2 | Class Identifier |
| | |
| 3 | Image Match |
| | |
| 4 | Use Before |
| | |
| 5 | Component Offset |
| | |
| 12 | Set Component Index |
| | |
| 13 | Set Dependency Index |
| | |
| 14 | Abort |
| | |
| 15 | Try Each |
| | |
| 16 | Reserved |
| | |
| 17 | Reserved |
| | |
| 18 | Process Dependency |
| | |
| 19 | Set Parameters |
| | |
| 20 | Override Parameters |
| | |
| 21 | Fetch |
| | |
| 22 | Copy |
| | |
| 23 | Run |
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| | |
| 24 | Device Identifier |
| | |
| 25 | Image Not Match |
| | |
| 26 | Minimum Battery |
| | |
| 27 | Update Authorized |
| | |
| 28 | Version |
| | |
| 29 | Wait For Event |
| | |
| 30 | Fetch URI List |
| | |
| 31 | Swap |
| | |
| 32 | Run Sequence |
| | |
| nint | Custom Condition |
+-------+----------------------+
11.2. SUIT Parameters
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+-------+------------------+
| Label | Name |
+-------+------------------+
| 1 | Vendor ID |
| | |
| 2 | Class ID |
| | |
| 3 | Image Digest |
| | |
| 4 | Use Before |
| | |
| 5 | Component Offset |
| | |
| 12 | Strict Order |
| | |
| 13 | Soft Failure |
| | |
| 14 | Image Size |
| | |
| 18 | Encryption Info |
| | |
| 19 | Compression Info |
| | |
| 20 | Unpack Info |
| | |
| 21 | URI |
| | |
| 22 | Source Component |
| | |
| 23 | Run Args |
| | |
| 24 | Device ID |
| | |
| 26 | Minimum Battery |
| | |
| 27 | Update Priority |
| | |
| 28 | Version |
| | |
| 29 | Wait Info |
| | |
| 30 | URI List |
| | |
| 31 | Component Index |
| | |
| nint | Custom |
+-------+------------------+
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11.3. SUIT Text Values
+-------+----------------------+
| Label | Name |
+-------+----------------------+
| 1 | Manifest Description |
| | |
| 2 | Update Description |
| | |
| 3 | Manifest JSON Source |
| | |
| 4 | Manifest YAML Source |
| | |
| nint | Custom |
+-------+----------------------+
11.4. SUIT Component Text Values
+-------+----------------------------+
| Label | Name |
+-------+----------------------------+
| 1 | Vendor Name |
| | |
| 2 | Model Name |
| | |
| 3 | Vendor Domain |
| | |
| 4 | Model Info |
| | |
| 5 | Component Description |
| | |
| 6 | Component Version |
| | |
| 7 | Component Version Required |
| | |
| nint | Custom |
+-------+----------------------------+
11.5. SUIT Algorithm Identifiers
11.5.1. SUIT Digest Algorithm Identifiers
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+-------+----------+
| Label | Name |
+-------+----------+
| 1 | SHA224 |
| | |
| 2 | SHA256 |
| | |
| 3 | SHA384 |
| | |
| 4 | SHA512 |
| | |
| 5 | SHA3-224 |
| | |
| 6 | SHA3-256 |
| | |
| 7 | SHA3-384 |
| | |
| 8 | SHA3-512 |
+-------+----------+
11.5.2. SUIT Compression Algorithm Identifiers
+-------+--------+
| Label | Name |
+-------+--------+
| 1 | zlib |
| | |
| 2 | Brotli |
| | |
| 3 | zstd |
+-------+--------+
11.5.3. Unpack Algorithms
+-------+------+
| Label | Name |
+-------+------+
| 1 | HEX |
| | |
| 2 | ELF |
| | |
| 3 | COFF |
| | |
| 4 | SREC |
+-------+------+
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12. Security Considerations
This document is about a manifest format describing and protecting
firmware images and as such it is part of a larger solution for
offering a standardized way of delivering firmware updates to IoT
devices. A detailed security treatment can be found in the
architecture [I-D.ietf-suit-architecture] and in the information
model [I-D.ietf-suit-information-model] documents.
13. Acknowledgements
We would like to thank the following persons for their support in
designing this mechanism:
- Milosch Meriac
- Geraint Luff
- Dan Ros
- John-Paul Stanford
- Hugo Vincent
- Carsten Bormann
- Oeyvind Roenningstad
- Frank Audun Kvamtroe
- Krzysztof Chruściński
- Andrzej Puzdrowski
- Michael Richardson
- David Brown
- Emmanuel Baccelli
14. References
14.1. 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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[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.
[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
RFC 8152, DOI 10.17487/RFC8152, July 2017,
<https://www.rfc-editor.org/info/rfc8152>.
[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>.
14.2. Informative References
[COFF] Wikipedia, ., "Common Object File Format (COFF)", 2020,
<https://en.wikipedia.org/wiki/COFF>.
[ELF] Wikipedia, ., "Executable and Linkable Format (ELF)",
2020, <https://en.wikipedia.org/wiki/
Executable_and_Linkable_Format>.
[HEX] Wikipedia, ., "Intel HEX", 2020,
<https://en.wikipedia.org/wiki/Intel_HEX>.
[I-D.ietf-suit-architecture]
Moran, B., Tschofenig, H., Brown, D., and M. Meriac, "A
Firmware Update Architecture for Internet of Things",
draft-ietf-suit-architecture-11 (work in progress), May
2020.
[I-D.ietf-suit-information-model]
Moran, B., Tschofenig, H., and H. Birkholz, "An
Information Model for Firmware Updates in IoT Devices",
draft-ietf-suit-information-model-07 (work in progress),
June 2020.
[I-D.ietf-teep-architecture]
Pei, M., Tschofenig, H., Thaler, D., and D. Wheeler,
"Trusted Execution Environment Provisioning (TEEP)
Architecture", draft-ietf-teep-architecture-11 (work in
progress), July 2020.
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[I-D.kucherawy-rfc8478bis]
Collet, Y. and M. Kucherawy, "Zstandard Compression and
the application/zstd Media Type", draft-kucherawy-
rfc8478bis-05 (work in progress), April 2020.
[RFC1950] Deutsch, P. and J-L. Gailly, "ZLIB Compressed Data Format
Specification version 3.3", RFC 1950,
DOI 10.17487/RFC1950, May 1996,
<https://www.rfc-editor.org/info/rfc1950>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC7932] Alakuijala, J. and Z. Szabadka, "Brotli Compressed Data
Format", RFC 7932, DOI 10.17487/RFC7932, July 2016,
<https://www.rfc-editor.org/info/rfc7932>.
[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,
May 2018, <https://www.rfc-editor.org/info/rfc8392>.
[RFC8747] Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.
Tschofenig, "Proof-of-Possession Key Semantics for CBOR
Web Tokens (CWTs)", RFC 8747, DOI 10.17487/RFC8747, March
2020, <https://www.rfc-editor.org/info/rfc8747>.
[SREC] Wikipedia, ., "SREC (file format)", 2020,
<https://en.wikipedia.org/wiki/SREC_(file_format)>.
14.3. URIs
[1] suit-condition-update-authorized
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A. Full CDDL
In order to create a valid SUIT Manifest document the structure of
the corresponding CBOR message MUST adhere to the following CDDL data
definition.
SUIT_Envelope = {
? suit-delegation => bstr .cbor SUIT_Delegation,
? suit-authentication-wrapper => bstr .cbor SUIT_Authentication,
suit-manifest => bstr .cbor SUIT_Manifest,
SUIT_Severable_Manifest_Members,
* $$SUIT_Envelope_Extensions,
(int => bstr)
}
SUIT_Delegation = [ + [ + bstr .cbor CWT ] ]
CWT = SUIT_Authentication_Block
SUIT_Authentication = [ + bstr .cbor SUIT_Authentication_Block ]
SUIT_Authentication_Block /= COSE_Mac_Tagged
SUIT_Authentication_Block /= COSE_Sign_Tagged
SUIT_Authentication_Block /= COSE_Mac0_Tagged
SUIT_Authentication_Block /= COSE_Sign1_Tagged
SUIT_Severable_Manifest_Members = (
? suit-dependency-resolution => bstr .cbor SUIT_Command_Sequence,
? suit-payload-fetch => bstr .cbor SUIT_Command_Sequence,
? suit-install => bstr .cbor SUIT_Command_Sequence,
? suit-text => bstr .cbor SUIT_Text_Map,
? suit-coswid => bstr .cbor concise-software-identity,
* $$SUIT_severable-members-extensions,
)
COSE_Mac_Tagged = any
COSE_Sign_Tagged = any
COSE_Mac0_Tagged = any
COSE_Sign1_Tagged = any
COSE_Encrypt_Tagged = any
COSE_Encrypt0_Tagged = any
SUIT_Digest = [
suit-digest-algorithm-id : suit-digest-algorithm-ids,
suit-digest-bytes : bstr,
* $$SUIT_Digest-extensions
]
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; Named Information Hash Algorithm Identifiers
suit-digest-algorithm-ids /= algorithm-id-sha224
suit-digest-algorithm-ids /= algorithm-id-sha256
suit-digest-algorithm-ids /= algorithm-id-sha384
suit-digest-algorithm-ids /= algorithm-id-sha512
suit-digest-algorithm-ids /= algorithm-id-sha3-224
suit-digest-algorithm-ids /= algorithm-id-sha3-256
suit-digest-algorithm-ids /= algorithm-id-sha3-384
suit-digest-algorithm-ids /= algorithm-id-sha3-512
algorithm-id-sha224 = 1
algorithm-id-sha256 = 2
algorithm-id-sha384 = 3
algorithm-id-sha512 = 4
algorithm-id-sha3-224 = 5
algorithm-id-sha3-256 = 6
algorithm-id-sha3-384 = 7
algorithm-id-sha3-512 = 8
SUIT_Manifest = {
suit-manifest-version => 1,
suit-manifest-sequence-number => uint,
suit-common => bstr .cbor SUIT_Common,
? suit-reference-uri => tstr,
SUIT_Severable_Members,
SUIT_Severable_Members_Digests,
SUIT_Unseverable_Members,
* $$SUIT_Manifest_Extensions,
}
SUIT_Unseverable_Members = (
? suit-validate => bstr .cbor SUIT_Command_Sequence,
? suit-load => bstr .cbor SUIT_Command_Sequence,
? suit-run => bstr .cbor SUIT_Command_Sequence,
* $$unserverble-manifest-member-extensions,
)
SUIT_Severable_Members_Digests = (
? suit-dependency-resolution-digest => SUIT_Digest,
? suit-payload-fetch-digest => SUIT_Digest,
? suit-install-digest => SUIT_Digest,
? suit-text-digest => SUIT_Digest,
? suit-coswid-digest => SUIT_Digest,
* $$severable-manifest-members-digests-extensions
)
SUIT_Common = {
? suit-dependencies => SUIT_Dependencies,
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? suit-components => SUIT_Components,
? suit-common-sequence => bstr .cbor SUIT_Common_Sequence,
* $$SUIT_Common-extensions,
}
SUIT_Dependencies = [ + SUIT_Dependency ]
SUIT_Components = [ + SUIT_Component_Identifier ]
concise-software-identity = any
SUIT_Dependency = {
suit-dependency-digest => SUIT_Digest,
? suit-dependency-prefix => SUIT_Component_Identifier,
* $$SUIT_Dependency-extensions,
}
SUIT_Component_Identifier = [* bstr]
SUIT_Component_Reference = {
suit-component-identifier => SUIT_Component_Identifier,
suit-component-dependency-index => uint
}
SUIT_Common_Sequence = [
+ ( SUIT_Condition // SUIT_Common_Commands )
]
SUIT_Common_Commands //= (suit-directive-set-component-index, uint/bool)
SUIT_Common_Commands //= (suit-directive-set-dependency-index, uint/bool)
SUIT_Common_Commands //= (suit-directive-run-sequence,
bstr .cbor SUIT_Command_Sequence)
SUIT_Common_Commands //= (suit-directive-try-each,
SUIT_Directive_Try_Each_Argument)
SUIT_Common_Commands //= (suit-directive-set-parameters,
{+ SUIT_Parameters})
SUIT_Common_Commands //= (suit-directive-override-parameters,
{+ SUIT_Parameters})
SUIT_Command_Sequence = [ + (
SUIT_Condition // SUIT_Directive // SUIT_Command_Custom
) ]
SUIT_Command_Custom = (suit-command-custom, bstr/tstr/int/nil)
SUIT_Condition //= (suit-condition-vendor-identifier, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-class-identifier, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-device-identifier, SUIT_Reporting_Policy)
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SUIT_Condition //= (suit-condition-image-match, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-image-not-match, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-use-before, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-minimum-battery, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-update-authorized, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-version, SUIT_Reporting_Policy)
SUIT_Condition //= (suit-condition-component-offset, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-set-component-index, uint/bool)
SUIT_Directive //= (suit-directive-set-dependency-index, uint/bool)
SUIT_Directive //= (suit-directive-run-sequence,
bstr .cbor SUIT_Command_Sequence)
SUIT_Directive //= (suit-directive-try-each,
SUIT_Directive_Try_Each_Argument)
SUIT_Directive //= (suit-directive-process-dependency, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-set-parameters,
{+ SUIT_Parameters})
SUIT_Directive //= (suit-directive-override-parameters,
{+ SUIT_Parameters})
SUIT_Directive //= (suit-directive-fetch, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-copy, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-swap, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-run, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-wait, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-abort, SUIT_Reporting_Policy)
SUIT_Directive //= (suit-directive-fetch-uri-list, SUIT_Reporting_Policy)
SUIT_Directive_Try_Each_Argument = [
+ bstr .cbor SUIT_Command_Sequence,
nil / bstr .cbor SUIT_Command_Sequence
]
SUIT_Reporting_Policy = uint .bits suit-reporting-bits
suit-reporting-bits = &(
suit-send-record-success : 0,
suit-send-record-failure : 1,
suit-send-sysinfo-success : 2,
suit-send-sysinfo-failure : 3
)
SUIT_Command_ID /= suit-command-custom
SUIT_Command_ID /= suit-condition-vendor-identifier
SUIT_Command_ID /= suit-condition-class-identifier
SUIT_Command_ID /= suit-condition-image-match
SUIT_Command_ID /= suit-condition-use-before
SUIT_Command_ID /= suit-condition-component-offset
SUIT_Command_ID /= suit-condition-device-identifier
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SUIT_Command_ID /= suit-condition-image-not-match
SUIT_Command_ID /= suit-condition-minimum-battery
SUIT_Command_ID /= suit-condition-update-authorized
SUIT_Command_ID /= suit-condition-version
SUIT_Command_ID /= suit-directive-set-component-index
SUIT_Command_ID /= suit-directive-set-dependency-index
SUIT_Command_ID /= suit-directive-abort
SUIT_Command_ID /= suit-directive-try-each
;SUIT_Command_ID /= suit-directive-do-each
;SUIT_Command_ID /= suit-directive-map-filter
SUIT_Command_ID /= suit-directive-process-dependency
SUIT_Command_ID /= suit-directive-set-parameters
SUIT_Command_ID /= suit-directive-override-parameters
SUIT_Command_ID /= suit-directive-fetch
SUIT_Command_ID /= suit-directive-copy
SUIT_Command_ID /= suit-directive-run
SUIT_Command_ID /= suit-directive-wait
SUIT_Command_ID /= suit-directive-run-sequence
SUIT_Command_ID /= suit-directive-swap
SUIT_Command_ID /= suit-directive-fetch-uri-list
suit-record = {
suit-record-success => bool/int,
? suit-record-component-id => SUIT_Component_ID,
? suit-record-dependency-id => SUIT_Digest,
? suit-record-command-sequence-id => (
suit-common-sequence /
suit-dependency-resolution /
suit-payload-fetch /
suit-install /
suit-validate /
suit-load /
suit-run /
* $$suit-command-sequence-list-extensions
),
? suit-record-interpeter-offset => uint,
? suit-record-command-id => SUIT_Command_ID,
? suit-record-params => SUIT_Parameters,
? suit-record-actual => SUIT_Parameters,
* $$suit-record-extensions
}
SUIT_Wait_Event = { + SUIT_Wait_Events }
SUIT_Wait_Events //= (suit-wait-event-authorization => int)
SUIT_Wait_Events //= (suit-wait-event-power => int)
SUIT_Wait_Events //= (suit-wait-event-network => int)
SUIT_Wait_Events //= (suit-wait-event-other-device-version
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=> SUIT_Wait_Event_Argument_Other_Device_Version)
SUIT_Wait_Events //= (suit-wait-event-time => uint); Timestamp
SUIT_Wait_Events //= (suit-wait-event-time-of-day
=> uint); Time of Day (seconds since 00:00:00)
SUIT_Wait_Events //= (suit-wait-event-day-of-week
=> uint); Days since Sunday
SUIT_Wait_Event_Argument_Other_Device_Version = [
other-device: bstr,
other-device-version: [ + SUIT_Parameter_Version_Match ]
]
SUIT_Parameters //= (suit-parameter-vendor-identifier => RFC4122_UUID)
SUIT_Parameters //= (suit-parameter-class-identifier => RFC4122_UUID)
SUIT_Parameters //= (suit-parameter-image-digest
=> bstr .cbor SUIT_Digest)
SUIT_Parameters //= (suit-parameter-image-size => uint)
SUIT_Parameters //= (suit-parameter-use-before => uint)
SUIT_Parameters //= (suit-parameter-component-offset => uint)
SUIT_Parameters //= (suit-parameter-encryption-info
=> bstr .cbor SUIT_Encryption_Info)
SUIT_Parameters //= (suit-parameter-compression-info
=> bstr .cbor SUIT_Compression_Info)
SUIT_Parameters //= (suit-parameter-unpack-info
=> bstr .cbor SUIT_Unpack_Info)
SUIT_Parameters //= (suit-parameter-uri => tstr)
SUIT_Parameters //= (suit-parameter-source-component => uint)
SUIT_Parameters //= (suit-parameter-run-args => bstr)
SUIT_Parameters //= (suit-parameter-device-identifier => RFC4122_UUID)
SUIT_Parameters //= (suit-parameter-minimum-battery => uint)
SUIT_Parameters //= (suit-parameter-update-priority => uint)
SUIT_Parameters //= (suit-parameter-version =>
SUIT_Parameter_Version_Match)
SUIT_Parameters //= (suit-parameter-wait-info =>
bstr .cbor SUIT_Wait_Event)
SUIT_Parameters //= (suit-parameter-custom => int/bool/tstr/bstr)
SUIT_Parameters //= (suit-parameter-strict-order => bool)
SUIT_Parameters //= (suit-parameter-soft-failure => bool)
SUIT_Parameters //= (suit-parameter-uri-list =>
bstr .cbor SUIT_URI_List)
RFC4122_UUID = bstr .size 16
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SUIT_Parameter_Version_Match = [
suit-condition-version-comparison-type:
SUIT_Condition_Version_Comparison_Types,
suit-condition-version-comparison-value:
SUIT_Condition_Version_Comparison_Value
]
SUIT_Condition_Version_Comparison_Types /=
suit-condition-version-comparison-greater
SUIT_Condition_Version_Comparison_Types /=
suit-condition-version-comparison-greater-equal
SUIT_Condition_Version_Comparison_Types /=
suit-condition-version-comparison-equal
SUIT_Condition_Version_Comparison_Types /=
suit-condition-version-comparison-lesser-equal
SUIT_Condition_Version_Comparison_Types /=
suit-condition-version-comparison-lesser
suit-condition-version-comparison-greater = 1
suit-condition-version-comparison-greater-equal = 2
suit-condition-version-comparison-equal = 3
suit-condition-version-comparison-lesser-equal = 4
suit-condition-version-comparison-lesser = 5
SUIT_Condition_Version_Comparison_Value = [+int]
SUIT_Encryption_Info = COSE_Encrypt_Tagged/COSE_Encrypt0_Tagged
SUIT_Compression_Info = {
suit-compression-algorithm => SUIT_Compression_Algorithms,
* $$SUIT_Compression_Info-extensions,
}
SUIT_Compression_Algorithms /= SUIT_Compression_Algorithm_zlib
SUIT_Compression_Algorithms /= SUIT_Compression_Algorithm_brotli
SUIT_Compression_Algorithms /= SUIT_Compression_Algorithm_zstd
SUIT_Compression_Algorithm_zlib = 1
SUIT_Compression_Algorithm_brotli = 2
SUIT_Compression_Algorithm_zstd = 3
SUIT_Unpack_Info = {
suit-unpack-algorithm => SUIT_Unpack_Algorithms,
* $$SUIT_Unpack_Info-extensions,
}
SUIT_Unpack_Algorithms /= SUIT_Unpack_Algorithm_Hex
SUIT_Unpack_Algorithms /= SUIT_Unpack_Algorithm_Elf
SUIT_Unpack_Algorithms /= SUIT_Unpack_Algorithm_Coff
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SUIT_Unpack_Algorithms /= SUIT_Unpack_Algorithm_Srec
SUIT_Unpack_Algorithm_Hex = 1
SUIT_Unpack_Algorithm_Elf = 2
SUIT_Unpack_Algorithm_Coff = 3
SUIT_Unpack_Algorithm_Srec = 4
SUIT_URI_List = [+ tstr ]
SUIT_Text_Map = {
? suit-text-components =>
[
+ {
1 => SUIT_Component_Identifier
SUIT_Text_Component_Keys
}
],
SUIT_Text_Keys
}
SUIT_Text_Component_Keys = (
? suit-text-vendor-name => tstr,
? suit-text-model-name => tstr,
? suit-text-vendor-domain => tstr,
? suit-text-model-info => tstr,
? suit-text-component-description => tstr,
? suit-text-component-version => tstr,
? suit-text-version-required => tstr,
* $$suit-text-component-key-extensions
)
SUIT_Text_Keys = (
? suit-text-manifest-description => tstr,
? suit-text-update-description => tstr,
? suit-text-manifest-json-source => tstr,
? suit-text-manifest-yaml-source => tstr,
* $$suit-text-key-extensions
)
suit-delegation = 1
suit-authentication-wrapper = 2
suit-manifest = 3
suit-manifest-version = 1
suit-manifest-sequence-number = 2
suit-common = 3
suit-reference-uri = 4
suit-dependency-resolution = 7
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suit-payload-fetch = 8
suit-install = 9
suit-validate = 10
suit-load = 11
suit-run = 12
suit-text = 13
suit-coswid = 14
suit-dependencies = 1
suit-components = 2
suit-dependency-components = 3
suit-common-sequence = 4
suit-dependency-digest = 1
suit-dependency-prefix = 2
suit-component-identifier = 1
suit-component-dependency-index = 2
suit-command-custom = nint
suit-condition-vendor-identifier = 1
suit-condition-class-identifier = 2
suit-condition-image-match = 3
suit-condition-use-before = 4
suit-condition-component-offset = 5
suit-condition-device-identifier = 24
suit-condition-image-not-match = 25
suit-condition-minimum-battery = 26
suit-condition-update-authorized = 27
suit-condition-version = 28
suit-directive-set-component-index = 12
suit-directive-set-dependency-index = 13
suit-directive-abort = 14
suit-directive-try-each = 15
;suit-directive-do-each = 16 ; TBD
;suit-directive-map-filter = 17 ; TBD
suit-directive-process-dependency = 18
suit-directive-set-parameters = 19
suit-directive-override-parameters = 20
suit-directive-fetch = 21
suit-directive-copy = 22
suit-directive-run = 23
suit-directive-wait = 29
suit-directive-fetch-uri-list = 30
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suit-directive-swap = 31
suit-directive-run-sequence = 32
suit-wait-event-authorization = 1
suit-wait-event-power = 2
suit-wait-event-network = 3
suit-wait-event-other-device-version = 4
suit-wait-event-time = 5
suit-wait-event-time-of-day = 6
suit-wait-event-day-of-week = 7
suit-parameter-vendor-identifier = 1
suit-parameter-class-identifier = 2
suit-parameter-image-digest = 3
suit-parameter-use-before = 4
suit-parameter-component-offset = 5
suit-parameter-strict-order = 12
suit-parameter-soft-failure = 13
suit-parameter-image-size = 14
suit-parameter-encryption-info = 18
suit-parameter-compression-info = 19
suit-parameter-unpack-info = 20
suit-parameter-uri = 21
suit-parameter-source-component = 22
suit-parameter-run-args = 23
suit-parameter-device-identifier = 24
suit-parameter-minimum-battery = 26
suit-parameter-update-priority = 27
suit-parameter-version = 28
suit-parameter-wait-info = 29
suit-parameter-uri-list = 30
suit-parameter-custom = nint
suit-compression-algorithm = 1
suit-compression-parameters = 2
suit-unpack-algorithm = 1
suit-unpack-parameters = 2
suit-text-manifest-description = 1
suit-text-update-description = 2
suit-text-manifest-json-source = 3
suit-text-manifest-yaml-source = 4
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suit-text-vendor-name = 1
suit-text-model-name = 2
suit-text-vendor-domain = 3
suit-text-model-info = 4
suit-text-component-description = 5
suit-text-component-version = 6
suit-text-version-required = 7
B. Examples
The following examples demonstrate a small subset of the
functionality of the manifest. However, despite this, even a simple
manifest processor can execute most of these manifests.
The examples are signed using the following ECDSA secp256r1 key:
-----BEGIN PRIVATE KEY-----
MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgApZYjZCUGLM50VBC
CjYStX+09jGmnyJPrpDLTz/hiXOhRANCAASEloEarguqq9JhVxie7NomvqqL8Rtv
P+bitWWchdvArTsfKktsCYExwKNtrNHXi9OB3N+wnAUtszmR23M4tKiW
-----END PRIVATE KEY-----
The corresponding public key can be used to verify these examples:
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEhJaBGq4LqqvSYVcYnuzaJr6qi/Eb
bz/m4rVlnIXbwK07HypLbAmBMcCjbazR14vTgdzfsJwFLbM5kdtzOLSolg==
-----END PUBLIC KEY-----
Each example uses SHA256 as the digest function.
Note that reporting policies are declared for each non-flow-control
command in these examples. The reporting policies used in the
examples are described in the following tables.
+-----------------------------+----------+
| Policy | Label |
+-----------------------------+----------+
| suit-send-record-on-success | Rec-Pass |
| | |
| suit-send-record-on-failure | Rec-Fail |
| | |
| suit-send-sysinfo-success | Sys-Pass |
| | |
| suit-send-sysinfo-failure | Sys-Fail |
+-----------------------------+----------+
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+----------------------------+--------+---------+---------+---------+
| Command | Sys- | Sys- | Rec- | Rec- |
| | Fail | Pass | Fail | Pass |
+----------------------------+--------+---------+---------+---------+
| suit-condition-vendor- | 1 | 1 | 1 | 1 |
| identifier | | | | |
| | | | | |
| suit-condition-class- | 1 | 1 | 1 | 1 |
| identifier | | | | |
| | | | | |
| suit-condition-image-match | 1 | 1 | 1 | 1 |
| | | | | |
| suit-condition-component- | 0 | 1 | 0 | 1 |
| offset | | | | |
| | | | | |
| suit-directive-fetch | 0 | 0 | 1 | 0 |
| | | | | |
| suit-directive-copy | 0 | 0 | 1 | 0 |
| | | | | |
| suit-directive-run | 0 | 0 | 1 | 0 |
+----------------------------+--------+---------+---------+---------+
B.1. Example 0: Secure Boot
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Secure Boot (Section 7.2)
It also serves as the minimum example.
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840356
3303937656636346266336262396234393465373165316632343138656566386434363
6636339303266363339613835356563396166336539656464623939584093347ceebc1
209a2d660bfbbe78e461079f1952c614e1ae8f734ff0ea438110d056c1a0cce6b0599d
b54e6704847de49efe60e9a7b821215d83368a2c8c7c088' / [
h'd28443a10126a05844820258403563303937656636346266336262396234
3934653731653166323431386565663864343636636339303266363339613835356563
396166336539656464623939584093347ceebc1209a2d660bfbbe78e461079f1952c61
4e1ae8f734ff0ea438110d056c1a0cce6b0599db54e6704847de49efe60e9a7b821215
d83368a2c8c7c088' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
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/ payload / h'8202584035633039376566363462663362623962
3439346537316531663234313865656638643436366363393032663633396138353565
63396166336539656464623939' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'3563303937656636346266336262396
2343934653731653166323431386565663864343636636339303266363339613835356
563396166336539656464623939'
] /,
/ signature / h'93347ceebc1209a2d660bfbbe78e461079f195
2c614e1ae8f734ff0ea438110d056c1a0cce6b0599db54e6704847de49efe60e9a7b82
1215d83368a2c8c7c088'
]) /
] /,
/ manifest / 3:h'a50101020003585fa202818141000458568614a40150fa6b4
a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab450358248
202582000112233445566778899aabbccddeeff0123456789abcdeffedcba987654321
00e1987d0010f020f0a4382030f0c43821702' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:0,
/ common / 3:h'a202818141000458568614a40150fa6b4a53d5ad5fdfbe9
de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45035824820258200011223
3445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f0
20f' / {
/ components / 2:[
[h'00']
],
/ common-sequence / 4:h'8614a40150fa6b4a53d5ad5fdfbe9de663
e4d41ffe02501492af1425695e48bf429b2d51f2ab4503582482025820001122334455
66778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f020f'
/ [
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
/ image-digest / 3:h'8202582000112233445566778899a
abbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
} ,
/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15
] /,
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} /,
/ validate / 10:h'82030f' / [
/ condition-image-match / 3,15
] /,
/ run / 12:h'821702' / [
/ directive-run / 23,2
] /,
} /,
}
Total size of Envelope without COSE authentication object: 117
Envelope:
a1035871a50101020003585fa202818141000458568614a40150fa6b4a53
d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
0358248202582000112233445566778899aabbccddeeff0123456789abcd
effedcba98765432100e1987d0010f020f0a4382030f0c43821702
Total size of Envelope with COSE authentication object: 266
Envelope with COSE authentication object:
a202589281588fd28443a10126a058448202584035633039376566363462
663362623962343934653731653166323431386565663864343636636339
303266363339613835356563396166336539656464623939584093347cee
bc1209a2d660bfbbe78e461079f1952c614e1ae8f734ff0ea438110d056c
1a0cce6b0599db54e6704847de49efe60e9a7b821215d83368a2c8c7c088
035871a50101020003585fa202818141000458568614a40150fa6b4a53d5
ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab4503
58248202582000112233445566778899aabbccddeeff0123456789abcdef
fedcba98765432100e1987d0010f020f0a4382030f0c43821702
B.2. Example 1: Simultaneous Download and Installation of Payload
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Firmware Download (Section 7.3)
Simultaneous download and installation of payload. No secure boot is
present in this example to demonstrate a download-only manifest.
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840393
8376565633835666139396664333164333332333831623938313066393062303563326
530643466323834613666343231313230376564303066666637353058404931df82e15
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3bf1e3af5a59800216d8a47c33a37839e7d63d9f526fd369aa8359daae18f7619c9591
23e7f7f928ee92a9893afedd35d06a936d6ed3d5843bf2a' / [
h'd28443a10126a05844820258403938376565633835666139396664333164
3333323338316239383130663930623035633265306434663238346136663432313132
30376564303066666637353058404931df82e153bf1e3af5a59800216d8a47c33a3783
9e7d63d9f526fd369aa8359daae18f7619c959123e7f7f928ee92a9893afedd35d06a9
36d6ed3d5843bf2a' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
/ payload / h'8202584039383765656338356661393966643331
6433333233383162393831306639306230356332653064346632383461366634323131
32303765643030666666373530' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'3938376565633835666139396664333
1643333323338316239383130663930623035633265306434663238346136663432313
132303765643030666666373530'
] /,
/ signature / h'4931df82e153bf1e3af5a59800216d8a47c33a
37839e7d63d9f526fd369aa8359daae18f7619c959123e7f7f928ee92a9893afedd35d
06a936d6ed3d5843bf2a'
]) /
] /,
/ manifest / 3:h'a50101020103585fa202818141000458568614a40150fa6b4
a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab450358248
202582000112233445566778899aabbccddeeff0123456789abcdeffedcba987654321
00e1987d0010f020f0958258613a115781b687474703a2f2f6578616d706c652e636f6
d2f66696c652e62696e1502030f0a4382030f' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:1,
/ common / 3:h'a202818141000458568614a40150fa6b4a53d5ad5fdfbe9
de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45035824820258200011223
3445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f0
20f' / {
/ components / 2:[
[h'00']
],
/ common-sequence / 4:h'8614a40150fa6b4a53d5ad5fdfbe9de663
e4d41ffe02501492af1425695e48bf429b2d51f2ab4503582482025820001122334455
66778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f020f'
/ [
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
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2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
/ image-digest / 3:h'8202582000112233445566778899a
abbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
} ,
/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15
] /,
} /,
/ install / 9:h'8613a115781b687474703a2f2f6578616d706c652e636f
6d2f66696c652e62696e1502030f' / [
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file.bin',
} ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15
] /,
/ validate / 10:h'82030f' / [
/ condition-image-match / 3,15
] /,
} /,
}
Total size of Envelope without COSE authentication object: 152
Envelope:
a1035894a50101020103585fa202818141000458568614a40150fa6b4a53
d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
0358248202582000112233445566778899aabbccddeeff0123456789abcd
effedcba98765432100e1987d0010f020f0958258613a115781b68747470
3a2f2f6578616d706c652e636f6d2f66696c652e62696e1502030f0a4382
030f
Total size of Envelope with COSE authentication object: 301
Envelope with COSE authentication object:
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a202589281588fd28443a10126a058448202584039383765656338356661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B.3. Example 2: Simultaneous Download, Installation, Secure Boot,
Severed Fields
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Secure Boot (Section 7.2)
- Firmware Download (Section 7.3)
This example also demonstrates severable elements (Section 5.5), and
text (Section 8.6.4).
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840373
5363835353739613833626162643731656338656632326661343961633837336637386
13730386134336136373465373832616433306236353938643137615840faca70796c3
19ce6dae69690a64ced3ab91b9bb7f3e9a5004122d629d2816216a870448424ce4410d
658b80215185e32d8ec6feb15c7275d64437c36418463e4' / [
h'd28443a10126a05844820258403735363835353739613833626162643731
6563386566323266613439616338373366373861373038613433613637346537383261
6433306236353938643137615840faca70796c319ce6dae69690a64ced3ab91b9bb7f3
e9a5004122d629d2816216a870448424ce4410d658b80215185e32d8ec6feb15c7275d
64437c36418463e4' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
/ payload / h'8202584037353638353537396138336261626437
3165633865663232666134396163383733663738613730386134336136373465373832
61643330623635393864313761' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'3735363835353739613833626162643
7316563386566323266613439616338373366373861373038613433613637346537383
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261643330623635393864313761'
] /,
/ signature / h'faca70796c319ce6dae69690a64ced3ab91b9b
b7f3e9a5004122d629d2816216a870448424ce4410d658b80215185e32d8ec6feb15c7
275d64437c36418463e4'
]) /
] /,
/ manifest / 3:h'a70101020203585fa202818141000458568614a40150fa6b4
a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab450358248
202582000112233445566778899aabbccddeeff0123456789abcdeffedcba987654321
00e1987d0010f020f09820258203ee96dc79641970ae46b929ccf0b72ba9536dd84602
0dbdc9f949d84ea0e18d20a4382030f0c438217020d8202582023f48b2e2838650f43c
144234aee18401ffe3cce4733b23881c3a8ae2d2b66e8' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:2,
/ common / 3:h'a202818141000458568614a40150fa6b4a53d5ad5fdfbe9
de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45035824820258200011223
3445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f0
20f' / {
/ components / 2:[
[h'00']
],
/ common-sequence / 4:h'8614a40150fa6b4a53d5ad5fdfbe9de663
e4d41ffe02501492af1425695e48bf429b2d51f2ab4503582482025820001122334455
66778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f020f'
/ [
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
/ image-digest / 3:h'8202582000112233445566778899a
abbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
} ,
/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15
] /,
} /,
/ install / 9:[
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
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h'3ee96dc79641970ae46b929ccf0b72ba9536dd846020dbdc9f949d84ea0e18d2'
],
/ validate / 10:h'82030f' / [
/ condition-image-match / 3,15
] /,
/ run / 12:h'821702' / [
/ directive-run / 23,2
] /,
/ text / 13:[
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'23f48b2e2838650f43c144234aee18401ffe3cce4733b23881c3a8ae2d2b66e8'
],
} /,
/ install / 9:h'8613a1157832687474703a2f2f6578616d706c652e636f6d2f
766572792f6c6f6e672f706174682f746f2f66696c652f66696c652e62696e1502030f
' / [
/ directive-set-parameters / 19,{
/ uri /
21:'http://example.com/very/long/path/to/file/file.bin',
} ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15
] /,
/ text / 13:h'a1814100a2036761726d2e636f6d0578525468697320636f6d70
6f6e656e7420697320612064656d6f6e7374726174696f6e2e20546865206469676573
7420697320612073616d706c65207061747465726e2c206e6f742061207265616c206f
6e652e' / {
[h'00']:{
/ vendor-domain / 3:'arm.com',
/ component-description / 5:'This component is a
demonstration. The digest is a sample pattern, not a real one.',
}
} /,
}
Total size of the Envelope without COSE authentication object or
Severable Elements: 191
Envelope:
a10358bba70101020203585fa202818141000458568614a40150fa6b4a53
d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
0358248202582000112233445566778899aabbccddeeff0123456789abcd
effedcba98765432100e1987d0010f020f09820258203ee96dc79641970a
e46b929ccf0b72ba9536dd846020dbdc9f949d84ea0e18d20a4382030f0c
438217020d8202582023f48b2e2838650f43c144234aee18401ffe3cce47
33b23881c3a8ae2d2b66e8
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Total size of the Envelope with COSE authentication object but
without Severable Elements: 340
Envelope: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Total size of Envelope with COSE authentication object: 923
Envelope with COSE authentication object:
Moran, et al. Expires January 14, 2021 [Page 91]
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a402589281588fd28443a10126a058448202584037353638353537396138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B.4. Example 3: A/B images
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Secure Boot (Section 7.2)
- Firmware Download (Section 7.3)
- A/B Image Template (Section 7.10)
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840616
5306331656136383963393830306138343335353066333837393662366664626435326
1306337386265356432363031316438653738346461343364343763584010222ddbce4
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e82a85f6ec7b72db34d7c5be8d2e822e4b2d099a4cf1d08aa2174c56c2e93bf20c785b
ca298900208d92d352faf86e6cddc902a726bbc443c21ff' / [
h'd28443a10126a05844820258406165306331656136383963393830306138
3433353530663338373936623666646264353261306337386265356432363031316438
653738346461343364343763584010222ddbce4e82a85f6ec7b72db34d7c5be8d2e822
e4b2d099a4cf1d08aa2174c56c2e93bf20c785bca298900208d92d352faf86e6cddc90
2a726bbc443c21ff' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
/ payload / h'8202584061653063316561363839633938303061
3834333535306633383739366236666462643532613063373862653564323630313164
38653738346461343364343763' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'6165306331656136383963393830306
1383433353530663338373936623666646264353261306337386265356432363031316
438653738346461343364343763'
] /,
/ signature / h'10222ddbce4e82a85f6ec7b72db34d7c5be8d2
e822e4b2d099a4cf1d08aa2174c56c2e93bf20c785bca298900208d92d352faf86e6cd
dc902a726bbc443c21ff'
]) /
] /,
/ manifest / 3:h'a5010102030358aaa202818141000458a18814a20150fa6b4
a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab450f82583
68614a105198400050514a20358248202582000112233445566778899aabbccddeeff0
123456789abcdeffedcba98765432100e1987d0583a8614a1051a00084400050514a20
35824820258200123456789abcdeffedcba987654321000112233445566778899aabbc
cddeeff0e1a00012c22010f020f095861860f82582a8613a105198400050513a115781
c687474703a2f2f6578616d706c652e636f6d2f66696c65312e62696e582c8613a1051
a00084400050513a115781c687474703a2f2f6578616d706c652e636f6d2f66696c653
22e62696e1502030f0a4382030f' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:3,
/ common / 3:h'a202818141000458a18814a20150fa6b4a53d5ad5fdfbe9
de663e4d41ffe02501492af1425695e48bf429b2d51f2ab450f8258368614a10519840
0050514a20358248202582000112233445566778899aabbccddeeff0123456789abcde
ffedcba98765432100e1987d0583a8614a1051a00084400050514a2035824820258200
123456789abcdeffedcba987654321000112233445566778899aabbccddeeff0e1a000
12c22010f020f' / {
/ components / 2:[
[h'00']
],
/ common-sequence / 4:h'8814a20150fa6b4a53d5ad5fdfbe9de663
e4d41ffe02501492af1425695e48bf429b2d51f2ab450f8258368614a1051984000505
14a20358248202582000112233445566778899aabbccddeeff0123456789abcdeffedc
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ba98765432100e1987d0583a8614a1051a00084400050514a203582482025820012345
6789abcdeffedcba987654321000112233445566778899aabbccddeeff0e1a00012c22
010f020f' / [
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
} ,
/ directive-try-each / 15,[
h'8614a105198400050514a203582482025820001122334455
66778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0' / [
/ directive-override-parameters / 20,{
/ offset / 5:33792,
} ,
/ condition-component-offset / 5,5 ,
/ directive-override-parameters / 20,{
/ image-digest / 3:h'820258200011223344556
6778899aabbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
}
] / ,
h'8614a1051a00084400050514a20358248202582001234567
89abcdeffedcba987654321000112233445566778899aabbccddeeff0e1a00012c22'
/ [
/ directive-override-parameters / 20,{
/ offset / 5:541696,
} ,
/ condition-component-offset / 5,5 ,
/ directive-override-parameters / 20,{
/ image-digest / 3:h'820258200123456789abc
deffedcba987654321000112233445566778899aabbccddeeff' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
] /,
/ image-size / 14:76834,
}
] /
] ,
/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15
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] /,
} /,
/ install / 9:h'860f82582a8613a105198400050513a115781c68747470
3a2f2f6578616d706c652e636f6d2f66696c65312e62696e582c8613a1051a00084400
050513a115781c687474703a2f2f6578616d706c652e636f6d2f66696c65322e62696e
1502030f' / [
/ directive-try-each / 15,[
h'8613a105198400050513a115781c687474703a2f2f6578616d70
6c652e636f6d2f66696c65312e62696e' / [
/ directive-set-parameters / 19,{
/ offset / 5:33792,
} ,
/ condition-component-offset / 5,5 ,
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file1.bin',
}
] / ,
h'8613a1051a00084400050513a115781c687474703a2f2f657861
6d706c652e636f6d2f66696c65322e62696e' / [
/ directive-set-parameters / 19,{
/ offset / 5:541696,
} ,
/ condition-component-offset / 5,5 ,
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file2.bin',
}
] /
] ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15
] /,
/ validate / 10:h'82030f' / [
/ condition-image-match / 3,15
] /,
} /,
}
Total size of Envelope without COSE authentication object: 288
Envelope:
Moran, et al. Expires January 14, 2021 [Page 95]
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a10359011ba5010102030358aaa202818141000458a18814a20150fa6b4a
53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab
450f8258368614a105198400050514a20358248202582000112233445566
778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d058
3a8614a1051a00084400050514a2035824820258200123456789abcdeffe
dcba987654321000112233445566778899aabbccddeeff0e1a00012c2201
0f020f095861860f82582a8613a105198400050513a115781c687474703a
2f2f6578616d706c652e636f6d2f66696c65312e62696e582c8613a1051a
00084400050513a115781c687474703a2f2f6578616d706c652e636f6d2f
66696c65322e62696e1502030f0a4382030f
Total size of Envelope with COSE authentication object: 437
Envelope with COSE authentication object: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B.5. Example 4: Load and Decompress from External Storage
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Secure Boot (Section 7.2)
- Firmware Download (Section 7.3)
- Install (Section 7.4)
- Load & Decompress (Section 7.7)
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840346
2346337633863306664613736633963393539316139646231363039313865326233633
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93661353862306135653439383466643465386639333539613932385840d7063361f65
3d57e63691e1bd9c856058c773b94e488bff58d599c45277788e90eb92fbef666f584e
8d35b3b20ceef50a69b94dcff12beee92e426a06ea31320' / [
h'd28443a10126a05844820258403462346337633863306664613736633963
3935393161396462313630393138653262336339366135386230613565343938346664
3465386639333539613932385840d7063361f653d57e63691e1bd9c856058c773b94e4
88bff58d599c45277788e90eb92fbef666f584e8d35b3b20ceef50a69b94dcff12beee
92e426a06ea31320' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
/ payload / h'8202584034623463376338633066646137366339
6339353931613964623136303931386532623363393661353862306135653439383466
64346538663933353961393238' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'3462346337633863306664613736633
9633935393161396462313630393138653262336339366135386230613565343938346
664346538663933353961393238'
] /,
/ signature / h'd7063361f653d57e63691e1bd9c856058c773b
94e488bff58d599c45277788e90eb92fbef666f584e8d35b3b20ceef50a69b94dcff12
beee92e426a06ea31320'
]) /
] /,
/ manifest / 3:h'a801010204035867a20283814100814102814101045858880
c0014a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2
d51f2ab450358248202582000112233445566778899aabbccddeeff0123456789abcde
ffedcba98765432100e1987d0010f020f085827880c0113a115781b687474703a2f2f6
578616d706c652e636f6d2f66696c652e62696e1502030f094b880c0013a1160116020
30f0a45840c00030f0b583a880c0213a4035824820258200123456789abcdeffedcba9
87654321000112233445566778899aabbccddeeff0e1a00012c22130116001602030f0
c45840c021702' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:4,
/ common / 3:h'a20283814100814102814101045858880c0014a40150fa6
b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab4503582
48202582000112233445566778899aabbccddeeff0123456789abcdeffedcba9876543
2100e1987d0010f020f' / {
/ components / 2:[
[h'00'] ,
[h'02'] ,
[h'01']
],
/ common-sequence / 4:h'880c0014a40150fa6b4a53d5ad5fdfbe9d
e663e4d41ffe02501492af1425695e48bf429b2d51f2ab450358248202582000112233
445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f02
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0f' / [
/ directive-set-component-index / 12,0 ,
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
/ image-digest / 3:h'8202582000112233445566778899a
abbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
} ,
/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15
] /,
} /,
/ payload-fetch / 8:h'880c0113a115781b687474703a2f2f6578616d70
6c652e636f6d2f66696c652e62696e1502030f' / [
/ directive-set-component-index / 12,1 ,
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file.bin',
} ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15
] /,
/ install / 9:h'880c0013a116011602030f' / [
/ directive-set-component-index / 12,0 ,
/ directive-set-parameters / 19,{
/ source-component / 22:1 / [h'02'] /,
} ,
/ directive-copy / 22,2 ,
/ condition-image-match / 3,15
] /,
/ validate / 10:h'840c00030f' / [
/ directive-set-component-index / 12,0 ,
/ condition-image-match / 3,15
] /,
/ load / 11:h'880c0213a4035824820258200123456789abcdeffedcba98
7654321000112233445566778899aabbccddeeff0e1a00012c22130116001602030f'
/ [
/ directive-set-component-index / 12,2 ,
/ directive-set-parameters / 19,{
/ image-digest / 3:h'820258200123456789abcdeffedcba987
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654321000112233445566778899aabbccddeeff' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
] /,
/ image-size / 14:76834,
/ source-component / 22:0 / [h'00'] /,
/ compression-info / 19:1 / "gzip" /,
} ,
/ directive-copy / 22,2 ,
/ condition-image-match / 3,15
] /,
/ run / 12:h'840c021702' / [
/ directive-set-component-index / 12,2 ,
/ directive-run / 23,2
] /,
} /,
}
Total size of Envelope without COSE authentication object: 245
Envelope: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Total size of Envelope with COSE authentication object: 394
Envelope with COSE authentication object:
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a202589281588fd28443a10126a058448202584034623463376338633066
646137366339633935393161396462313630393138653262336339366135
3862306135653439383466643465386639333539613932385840d7063361
f653d57e63691e1bd9c856058c773b94e488bff58d599c45277788e90eb9
2fbef666f584e8d35b3b20ceef50a69b94dcff12beee92e426a06ea31320
0358f1a801010204035867a20283814100814102814101045858880c0014
a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf
429b2d51f2ab450358248202582000112233445566778899aabbccddeeff
0123456789abcdeffedcba98765432100e1987d0010f020f085827880c01
13a115781b687474703a2f2f6578616d706c652e636f6d2f66696c652e62
696e1502030f094b880c0013a116011602030f0a45840c00030f0b583a88
0c0213a4035824820258200123456789abcdeffedcba9876543210001122
33445566778899aabbccddeeff0e1a00012c22130116001602030f0c4584
0c021702
B.6. Example 5: Two Images
This example covers the following templates:
- Compatibility Check (Section 7.1)
- Secure Boot (Section 7.2)
- Firmware Download (Section 7.3)
Furthermore, it shows using these templates with two images.
{
/ authentication-wrapper / 2:h'81588fd28443a10126a0584482025840323
1306231323835306332333930393164386538326330653965393130363632623638616
33834323435386136343138653333663637303165643538333432635840b5b8cb30c2b
bb646c4d32426d72768668d6d6af54c26ac46c4020ca37ada47b9468340b4d0b2ddd15
db824a7e6b0bc233e753940dfb7131fa145ddc456da3cf6' / [
h'd28443a10126a05844820258403231306231323835306332333930393164
3865383263306539653931303636326236386163383432343538613634313865333366
3637303165643538333432635840b5b8cb30c2bbb646c4d32426d72768668d6d6af54c
26ac46c4020ca37ada47b9468340b4d0b2ddd15db824a7e6b0bc233e753940dfb7131f
a145ddc456da3cf6' / 18([
/ protected / h'a10126' / {
/ alg / 1:-7 / "ES256" /,
} /,
/ unprotected / {
},
/ payload / h'8202584032313062313238353063323339303931
6438653832633065396539313036363262363861633834323435386136343138653333
66363730316564353833343263' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes / h'3231306231323835306332333930393
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1643865383263306539653931303636326236386163383432343538613634313865333
366363730316564353833343263'
] /,
/ signature / h'b5b8cb30c2bbb646c4d32426d72768668d6d6a
f54c26ac46c4020ca37ada47b9468340b4d0b2ddd15db824a7e6b0bc233e753940dfb7
131fa145ddc456da3cf6'
]) /
] /,
/ manifest / 3:h'a601010205035895a202828141008141010458898c0c0014a
40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2a
b450358248202582000112233445566778899aabbccddeeff0123456789abcdeffedcb
a98765432100e1987d0010f020f0c0114a2035824820258200123456789abcdeffedcb
a987654321000112233445566778899aabbccddeeff0e1a00012c2209584f900c0013a
115781c687474703a2f2f6578616d706c652e636f6d2f66696c65312e62696e1502030
f0c0113a115781c687474703a2f2f6578616d706c652e636f6d2f66696c65322e62696
e1502030f0a49880c00030f0c01030f0c47860c0017021702' / {
/ manifest-version / 1:1,
/ manifest-sequence-number / 2:5,
/ common / 3:h'a202828141008141010458898c0c0014a40150fa6b4a53d
5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab4503582482025
82000112233445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1
987d0010f020f0c0114a2035824820258200123456789abcdeffedcba9876543210001
12233445566778899aabbccddeeff0e1a00012c22' / {
/ components / 2:[
[h'00'] ,
[h'01']
],
/ common-sequence / 4:h'8c0c0014a40150fa6b4a53d5ad5fdfbe9d
e663e4d41ffe02501492af1425695e48bf429b2d51f2ab450358248202582000112233
445566778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f02
0f0c0114a2035824820258200123456789abcdeffedcba987654321000112233445566
778899aabbccddeeff0e1a00012c22' / [
/ directive-set-component-index / 12,0 ,
/ directive-override-parameters / 20,{
/ vendor-id /
1:h'"fa6b4a53d5ad5fdfbe9de663e4d41ffe"' / fa6b4a53-d5ad-5fdf-
be9d-e663e4d41ffe /,
/ class-id /
2:h'"1492af1425695e48bf429b2d51f2ab45"' /
1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
/ image-digest / 3:h'8202582000112233445566778899a
abbccddeeff0123456789abcdeffedcba9876543210' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
] /,
/ image-size / 14:34768,
} ,
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/ condition-vendor-identifier / 1,15 ,
/ condition-class-identifier / 2,15 ,
/ directive-set-component-index / 12,1 ,
/ directive-override-parameters / 20,{
/ image-digest / 3:h'820258200123456789abcdeffedcb
a987654321000112233445566778899aabbccddeeff' / [
/ algorithm-id / 2 / "sha256" /,
/ digest-bytes /
h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
] /,
/ image-size / 14:76834,
}
] /,
} /,
/ install / 9:h'900c0013a115781c687474703a2f2f6578616d706c652e
636f6d2f66696c65312e62696e1502030f0c0113a115781c687474703a2f2f6578616d
706c652e636f6d2f66696c65322e62696e1502030f' / [
/ directive-set-component-index / 12,0 ,
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file1.bin',
} ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15 ,
/ directive-set-component-index / 12,1 ,
/ directive-set-parameters / 19,{
/ uri / 21:'http://example.com/file2.bin',
} ,
/ directive-fetch / 21,2 ,
/ condition-image-match / 3,15
] /,
/ validate / 10:h'880c00030f0c01030f' / [
/ directive-set-component-index / 12,0 ,
/ condition-image-match / 3,15 ,
/ directive-set-component-index / 12,1 ,
/ condition-image-match / 3,15
] /,
/ run / 12:h'860c0017021702' / [
/ directive-set-component-index / 12,0 ,
/ directive-run / 23,2 ,
/ directive-run / 23,2
] /,
} /,
}
Total size of Envelope without COSE authentication object: 264
Envelope:
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a103590103a601010205035895a202828141008141010458898c0c0014a4
0150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf42
9b2d51f2ab450358248202582000112233445566778899aabbccddeeff01
23456789abcdeffedcba98765432100e1987d0010f020f0c0114a2035824
820258200123456789abcdeffedcba987654321000112233445566778899
aabbccddeeff0e1a00012c2209584f900c0013a115781c687474703a2f2f
6578616d706c652e636f6d2f66696c65312e62696e1502030f0c0113a115
781c687474703a2f2f6578616d706c652e636f6d2f66696c65322e62696e
1502030f0a49880c00030f0c01030f0c47860c0017021702
Total size of Envelope with COSE authentication object: 413
Envelope with COSE authentication object: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C. Design Rational
In order to provide flexible behavior to constrained devices, while
still allowing more powerful devices to use their full capabilities,
the SUIT manifest encodes the required behavior of a Recipient
device. Behavior is encoded as a specialized byte code, contained in
a CBOR list. This promotes a flat encoding, which simplifies the
parser. The information encoded by this byte code closely matches
the operations that a device will perform, which promotes ease of
processing. The core operations used by most update and trusted
execution operations are represented in the byte code. The byte code
can be extended by registering new operations.
The specialized byte code approach gives benefits equivalent to those
provided by a scripting language or conventional byte code, with two
substantial differences. First, the language is extremely high
level, consisting of only the operations that a device may perform
during update and trusted execution of a firmware image. Second, the
language specifies linear behavior, without reverse branches.
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Conditional processing is supported, and parallel and out-of-order
processing may be performed by sufficiently capable devices.
By structuring the data in this way, the manifest processor becomes a
very simple engine that uses a pull parser to interpret the manifest.
This pull parser invokes a series of command handlers that evaluate a
Condition or execute a Directive. Most data is structured in a
highly regular pattern, which simplifies the parser.
The results of this allow a Recipient to implement a very small
parser for constrained applications. If needed, such a parser also
allows the Recipient to perform complex updates with reduced
overhead. Conditional execution of commands allows a simple device
to perform important decisions at validation-time.
Dependency handling is vastly simplified as well. Dependencies
function like subroutines of the language. When a manifest has a
dependency, it can invoke that dependency's commands and modify their
behavior by setting parameters. Because some parameters come with
security implications, the dependencies also have a mechanism to
reject modifications to parameters on a fine-grained level.
Developing a robust permissions system works in this model too. The
Recipient can use a simple ACL that is a table of Identities and
Component Identifier permissions to ensure that operations on
components fail unless they are permitted by the ACL. This table can
be further refined with individual parameters and commands.
Capability reporting is similarly simplified. A Recipient can report
the Commands, Parameters, Algorithms, and Component Identifiers that
it supports. This is sufficiently precise for a manifest author to
create a manifest that the Recipient can accept.
The simplicity of design in the Recipient due to all of these
benefits allows even a highly constrained platform to use advanced
update capabilities.
C.1. C.1 Design Rationale: Envelope
The Envelope is used instead of a COSE structure for several reasons:
1. This enables the use of Severable Elements (Section 8.8)
2. This enables modular processing of manifests, particularly with
large signatures.
3. This enables multiple authentication schemes.
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4. This allows integrity verification by a dependent to be
unaffected by adding or removing authentication structures.
Modular processing is important because it allows a Manifest
Processor to iterate forward over an Envelope, processing Delegation
Chains and Authentication Blocks, retaining only intermediate values,
without any need to seek forward and backwards in a stream until it
gets to the Manifest itself. This allows the use of large, Post-
Quantum signatures without requiring retention of the signature
itself, or seeking forward and back.
Four authentication objects are supported by the Envelope:
- COSE_Sign_Tagged
- COSE_Sign1_Tagged
- COSE_Mac_Tagged
- COSE_Mac0_Tagged
The SUIT Envelope allows an Update Authority or intermediary to mix
and match any number of different authentication blocks it wants
without any concern for modifying the integrity of another
authentication block. This also allows the addition or removal of an
authentication blocks without changing the integrity check of the
Manifest, which is important for dependency handling. See
Section 6.2
C.2. C.2 Byte String Wrappers
Byte string wrappers are used in several places in the suit manifest.
The primary reason for wrappers it to limit the parser extent when
invoked at different times, with a possible loss of context.
The elements of the suit envelope are wrapped both to set the extents
used by the parser and to simplify integrity checks by clearly
defining the length of each element.
The common block is re-parsed in order to find components identifiers
from their indices, to find dependency prefixes and digests from
their identifiers, and to find the common sequence. The common
sequence is wrapped so that it matches other sequences, simplifying
the code path.
A severed SUIT command sequence will appear in the envelope, so it
must be wrapped as with all envelope elements. For consistency,
command sequences are also wrapped in the manifest. This also allows
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the parser to discern the difference between a command sequence and a
SUIT_Digest.
Parameters that are structured types (arrays and maps) are also
wrapped in a bstr. This is so that parser extents can be set
correctly using only a reference to the beginning of the parameter.
This enables a parser to store a simple list of references to
parameters that can be retrieved when needed.
D. Implementation Conformance Matrix
This section summarizes the functionality a minimal implementation
needs to offer to claim conformance to this specification, in the
absence of an application profile standard specifying otherwise.
The subsequent table shows the conditions.
+-------------------+-----------------+----------------+
| Name | Reference | Implementation |
+-------------------+-----------------+----------------+
| Vendor Identifier | Section 8.7.5.1 | REQUIRED |
| | | |
| Class Identifier | Section 8.7.5.1 | REQUIRED |
| | | |
| Device Identifier | Section 8.7.5.1 | OPTIONAL |
| | | |
| Image Match | Section 8.7.6.2 | REQUIRED |
| | | |
| Image Not Match | Section 8.7.6.3 | OPTIONAL |
| | | |
| Use Before | Section 8.7.6.4 | OPTIONAL |
| | | |
| Component Offset | Section 8.7.6.5 | OPTIONAL |
| | | |
| Minimum Battery | Section 8.7.6.6 | OPTIONAL |
| | | |
| Update Authorized | Section 8.7.6.7 | OPTIONAL |
| | | |
| Version | Section 8.7.6.8 | OPTIONAL |
| | | |
| Custom Condition | Section 8.7.6.9 | OPTIONAL |
+-------------------+-----------------+----------------+
The subsequent table shows the directives.
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+-------------------+----------------+------------------------------+
| Name | Reference | Implementation |
+-------------------+----------------+------------------------------+
| Set Component | Section 8.7.7. | REQUIRED if more than one |
| Index | 1 | component |
| | | |
| Set Dependency | Section 8.7.7. | REQUIRED if dependencies |
| Index | 2 | used |
| | | |
| Abort | Section 8.7.7. | OPTIONAL |
| | 3 | |
| | | |
| Try Each | Section 8.7.7. | OPTIONAL |
| | 4 | |
| | | |
| Process | Section 8.7.7. | OPTIONAL |
| Dependency | 5 | |
| | | |
| Set Parameters | Section 8.7.7. | OPTIONAL |
| | 6 | |
| | | |
| Override | Section 8.7.7. | REQUIRED |
| Parameters | 7 | |
| | | |
| Fetch | Section 8.7.7. | REQUIRED for Updater |
| | 8 | |
| | | |
| Copy | Section 8.7.7. | OPTIONAL |
| | 10 | |
| | | |
| Run | Section 8.7.7. | REQUIRED for Bootloader |
| | 11 | |
| | | |
| Wait For Event | Section 8.7.7. | OPTIONAL |
| | 12 | |
| | | |
| Run Sequence | Section 8.7.7. | OPTIONAL |
| | 13 | |
| | | |
| Swap | Section 8.7.7. | OPTIONAL |
| | 14 | |
| | | |
| Fetch URI List | Section 8.7.7. | OPTIONAL |
| | 9 | |
+-------------------+----------------+------------------------------+
The subsequent table shows the parameters.
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+------------------+------------------+----------------------+
| Name | Reference | Implementation |
+------------------+------------------+----------------------+
| Vendor ID | Section 8.7.5.2 | REQUIRED |
| | | |
| Class ID | Section 8.7.5.3 | REQUIRED |
| | | |
| Image Digest | Section 8.7.5.5 | REQUIRED |
| | | |
| Image Size | Section 8.7.5.6 | REQUIRED |
| | | |
| Use Before | Section 8.7.5.7 | RECOMMENDED |
| | | |
| Component Offset | Section 8.7.5.8 | OPTIONAL |
| | | |
| Encryption Info | Section 8.7.5.9 | RECOMMENDED |
| | | |
| Compression Info | Section 8.7.5.10 | RECOMMENDED |
| | | |
| Unpack Info | Section 8.7.5.11 | RECOMMENDED |
| | | |
| URI | Section 8.7.5.12 | REQUIRED for Updater |
| | | |
| Source Component | Section 8.7.5.13 | OPTIONAL |
| | | |
| Run Args | Section 8.7.5.14 | OPTIONAL |
| | | |
| Device ID | Section 8.7.5.4 | OPTIONAL |
| | | |
| Minimum Battery | Section 8.7.5.15 | OPTIONAL |
| | | |
| Update Priority | Section 8.7.5.16 | OPTIONAL |
| | | |
| Version Match | Section 8.7.5.17 | OPTIONAL |
| | | |
| Wait Info | Section 8.7.5.18 | OPTIONAL |
| | | |
| URI List | Section 8.7.5.19 | OPTIONAL |
| | | |
| Strict Order | Section 8.7.5.21 | OPTIONAL |
| | | |
| Soft Failure | Section 8.7.5.22 | OPTIONAL |
| | | |
| Custom | Section 8.7.5.23 | OPTIONAL |
+------------------+------------------+----------------------+
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Authors' Addresses
Brendan Moran
Arm Limited
EMail: Brendan.Moran@arm.com
Hannes Tschofenig
Arm Limited
EMail: hannes.tschofenig@arm.com
Henk Birkholz
Fraunhofer SIT
EMail: henk.birkholz@sit.fraunhofer.de
Koen Zandberg
Inria
EMail: koen.zandberg@inria.fr
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