draft-ietf-teep-protocol-00.txt   draft-ietf-teep-protocol-01.txt 
TEEP H. Tschofenig TEEP H. Tschofenig
Internet-Draft Arm Ltd. Internet-Draft Arm Ltd.
Intended status: Standards Track M. Pei Intended status: Standards Track M. Pei
Expires: June 9, 2020 Broadcom Expires: September 10, 2020 Broadcom
D. Wheeler D. Wheeler
Intel Intel
D. Thaler D. Thaler
Microsoft Microsoft
December 7, 2019 March 9, 2020
Trusted Execution Environment Provisioning (TEEP) Protocol Trusted Execution Environment Provisioning (TEEP) Protocol
draft-ietf-teep-protocol-00 draft-ietf-teep-protocol-01
Abstract Abstract
This document specifies a protocol that installs, updates, and This document specifies a protocol that installs, updates, and
deletes Trusted Applications (TAs) in a device with a Trusted deletes Trusted Applications (TAs) in a device with a Trusted
Execution Environment (TEE). This specification defines an Execution Environment (TEE). This specification defines an
interoperable protocol for managing the lifecycle of TAs. interoperable protocol for managing the lifecycle of TAs.
The protocol name is pronounced teepee. This conjures an image of a The protocol name is pronounced teepee. This conjures an image of a
wedge-shaped protective covering for one's belongings, which sort of wedge-shaped protective covering for one's belongings, which sort of
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 9, 2020. This Internet-Draft will expire on September 10, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Message Overview . . . . . . . . . . . . . . . . . . . . . . 3 3. Message Overview . . . . . . . . . . . . . . . . . . . . . . 3
4. Detailed Messages Specification . . . . . . . . . . . . . . . 5 4. Detailed Messages Specification . . . . . . . . . . . . . . . 5
4.1. QueryRequest . . . . . . . . . . . . . . . . . . . . . . 5 4.1. QueryRequest . . . . . . . . . . . . . . . . . . . . . . 5
4.2. QueryResponse . . . . . . . . . . . . . . . . . . . . . . 7 4.2. QueryResponse . . . . . . . . . . . . . . . . . . . . . . 7
4.3. TrustedAppInstall . . . . . . . . . . . . . . . . . . . . 9 4.3. TrustedAppInstall . . . . . . . . . . . . . . . . . . . . 7
4.4. TrustedAppDelete . . . . . . . . . . . . . . . . . . . . 9 4.4. TrustedAppDelete . . . . . . . . . . . . . . . . . . . . 8
4.5. Success . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.5. Success . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.6. Error . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.6. Error . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Ciphersuites . . . . . . . . . . . . . . . . . . . . . . . . 12 5. Ciphersuites . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Security Consideration . . . . . . . . . . . . . . . . . . . 13 6. Security Consideration . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7.1. Media Type Registration . . . . . . . . . . . . . . . . . 14 7.1. Media Type Registration . . . . . . . . . . . . . . . . . 13
7.2. Error Code Registry . . . . . . . . . . . . . . . . . . . 16 7.2. Error Code Registry . . . . . . . . . . . . . . . . . . . 14
7.3. Ciphersuite Registry . . . . . . . . . . . . . . . . . . 17 7.3. Ciphersuite Registry . . . . . . . . . . . . . . . . . . 15
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . 17 8.1. Normative References . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . 18 8.2. Informative References . . . . . . . . . . . . . . . . . 16
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 19 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 16
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 19 Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
The Trusted Execution Environment (TEE) concept has been designed to The Trusted Execution Environment (TEE) concept has been designed to
separate a regular operating system, also referred as a Rich separate a regular operating system, also referred as a Rich
Execution Environment (REE), from security-sensitive applications. Execution Environment (REE), from security-sensitive applications.
In an TEE ecosystem, different device vendors may use different In an TEE ecosystem, device vendors may use different operating
operating systems in the REE and may use different types of TEEs. systems in the REE and may use different types of TEEs. When
When application providers or device administrators use Trusted application providers or device administrators use Trusted
Application Managers (TAMs) to install, update, and delete Trusted Application Managers (TAMs) to install, update, and delete Trusted
Applications (TAs) on a wide range of devices with potentially Applications (TAs) on a wide range of devices with potentially
different TEEs then an interoperability need arises. different TEEs then an interoperability need arises.
This document specifies the protocol for communicating between a TAM This document specifies the protocol for communicating between a TAM
and a TEEP Agent, involving a TEEP Broker. and a TEEP Agent, involving a TEEP Broker.
The Trusted Execution Environment Provisioning (TEEP) architecture The Trusted Execution Environment Provisioning (TEEP) architecture
document [I-D.ietf-teep-architecture] has set to provide a design document [I-D.ietf-teep-architecture] has set to provide a design
guidance for such an interoperable protocol and introduces the guidance for such an interoperable protocol and introduces the
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
This specification re-uses the terminology defined in This specification re-uses the terminology defined in
[I-D.ietf-teep-architecture]. [I-D.ietf-teep-architecture].
3. Message Overview 3. Message Overview
The TEEP protocol consists of a couple of messages exchanged between The TEEP protocol consists of a couple of messages exchanged between
a TAM and a TEEP Agent via a TEEP Broker. The messages are encoded a TAM and a TEEP Agent via a TEEP Broker. The messages are encoded
either in JSON or CBOR and designed to provide end-to-end security. in CBOR and designed to provide end-to-end security. TEEP protocol
TEEP protocol messages are signed and/or encrypted by the endpoints, messages are signed by the endpoints, i.e., the TAM and the TEEP
i.e., the TAM and the TEEP Agent, but trusted applications may as Agent, but trusted applications may as well be encrypted and signed
well be encrypted and signed by the service provider. The TEEP by the service provider. The TEEP protocol not only re-use CBOR but
protocol not only re-use JSON and CBOR but also the respective also the respective security wrapper, namely COSE [RFC8152].
security wrappers, namely JOSE (JWS [RFC7515] and JWE [RFC7516], to Furthermore, for attestation the Entity Attestation Token (EAT)
be more specific) and COSE [RFC8152]. Furthermore, for attestation [I-D.ietf-rats-eat] and for software updates the SUIT manifest format
the Entity Attestation Token (EAT) [I-D.ietf-rats-eat] and for [I-D.ietf-suit-manifest] are re-used.
software updates the SUIT manifest format [I-D.ietf-suit-manifest]
are re-used.
This specification defines six messages. This specification defines six messages.
A TAM queries a device's current state with a QueryRequest message. A TAM queries a device's current state with a QueryRequest message.
A TEEP Agent will, after authenticating and authorizing the request, A TEEP Agent will, after authenticating and authorizing the request,
report attestation information, list all TAs, and provide information report attestation information, list all TAs, and provide information
about supported algorithms and extensions in a QueryResponse message. about supported algorithms and extensions in a QueryResponse message.
An error message is returned if the request could not be processed. An error message is returned if the request could not be processed.
A TAM will process the QueryResponse message and determine whether A TAM will process the QueryResponse message and determine whether
subsequent message exchanges to install, update, or delete trusted subsequent message exchanges to install, update, or delete trusted
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TrustedAppDelete ----> TrustedAppDelete ---->
Success Success
<---- or <---- or
Error Error
4. Detailed Messages Specification 4. Detailed Messages Specification
For a CBOR-based encoding the following security wrapper is used The CBOR-encoded messages are protected by COSE, as described in CDDL
(described in CDDL format [I-D.ietf-cbor-cddl]). format [I-D.ietf-cbor-cddl] below.
Outer_Wrapper = { Outer_Wrapper = {
msg-authenc-wrapper => bstr .cbor msg-authenc-wrapper => bstr .cbor
Msg_AuthEnc_Wrapper / nil, Msg_AuthEnc_Wrapper / nil,
teep-message => (QueryRequest / teep-message => (QueryRequest /
QueryResponse / QueryResponse /
TrustedAppInstall / TrustedAppInstall /
TrustedAppDelete / TrustedAppDelete /
Error / Error /
Success ), Success ),
} }
msg-authenc-wrapper = 1 msg-authenc-wrapper = 1
teep-message = 2 teep-message = 2
Msg_AuthEnc_Wrapper = [ * (COSE_Mac_Tagged / Msg_AuthEnc_Wrapper = [ * (COSE_Mac_Tagged /
COSE_Sign_Tagged / COSE_Sign_Tagged /
COSE_Mac0_Tagged / COSE_Mac0_Tagged /
COSE_Sign1_Tagged)] COSE_Sign1_Tagged)]
A future version of this specification will also describe the
security wrapper for JSON (in CDDL format).
4.1. QueryRequest 4.1. QueryRequest
suite = int suite = int
version = int version = int
data_items = ( data_item = int
attestation: 1,
trusted_apps: 2,
extensions: 3,
suit_commands: 4
)
QueryRequest = ( QueryRequest = {
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
REQUEST : [+data_items], REQUEST : [+data_item],
? CIPHER_SUITE : [+suite], ? CIPHER_SUITE : [+suite],
? NONCE : bstr, ? NONCE : bstr,
? VERSION : [+version], ? VERSION : [+version],
? OCSP_DATA : bstr, ? OCSP_DATA : bstr,
* $$extensions * $$extensions
) }
A QueryRequest message is signed by the TAM and has the following A QueryRequest message is signed by the TAM and has the following
fields: fields:
TYPE TYPE = 1 corresponds to a QueryRequest message sent from the TYPE TYPE = 1 corresponds to a QueryRequest message sent from the
TAM to the TEEP Agent. TAM to the TEEP Agent.
TOKEN The value in the TOKEN field is used to match requests to TOKEN The value in the TOKEN field is used to match requests to
responses. responses.
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VERSION The VERSION field lists the version(s) supported by the TAM. VERSION The VERSION field lists the version(s) supported by the TAM.
For this version of the specification this field can be omitted. For this version of the specification this field can be omitted.
OCSP_DATA The OCSP_DATA field contains a list of OCSP stapling data OCSP_DATA The OCSP_DATA field contains a list of OCSP stapling data
respectively for the TAM certificate and each of the CA respectively for the TAM certificate and each of the CA
certificates up to the root certificate. The TAM provides OCSP certificates up to the root certificate. The TAM provides OCSP
data so that the TEEP Agent can validate the status of the TAM data so that the TEEP Agent can validate the status of the TAM
certificate chain without making its own external OCSP service certificate chain without making its own external OCSP service
call. OCSP data MUST be conveyed as a DER-encoded OCSP response call. OCSP data MUST be conveyed as a DER-encoded OCSP response
(using the ASN.1 type OCSPResponse defined in [RFC2560]). The use (using the ASN.1 type OCSPResponse defined in [RFC2560]). The use
of OCSP is optional to implement for both the TAM and the TEEP of OCSP is optional to implement for bo th the TAM and the TEEP
Agent. A TAM can query the TEEP Agent for the support of this Agent. A TAM can query the TEEP Agent for the support of this
functionality via the capability discovery exchange, as described functionality via the capability discovery exchange, as described
above. above.
4.2. QueryResponse 4.2. QueryResponse
ta_id = (
Vendor_ID = bstr,
Class_ID = bstr,
Device_ID = bstr,
* $$extensions
)
ext_info = int ext_info = int
QueryResponse = ( QueryResponse = {
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
? SELECTED_CIPHER_SUITE : suite, ? SELECTED_CIPHER_SUITE : suite,
? SELECTED_VERSION : version, ? SELECTED_VERSION : version,
? EAT : bstr, ? EAT : bstr,
? TA_LIST : [+ta_id], ? TA_LIST : [+bstr],
? EXT_LIST : [+ext_info], ? EXT_LIST : [+ext_info],
* $$extensions * $$extensions
) }
The QueryResponse message is signed and encrypted by the TEEP Agent The QueryResponse message is signed and encrypted by the TEEP Agent
and returned to the TAM. It has the following fields: and returned to the TAM. It has the following fields:
TYPE TYPE = 2 corresponds to a QueryResponse message sent from the TYPE TYPE = 2 corresponds to a QueryResponse message sent from the
TEEP Agent to the TAM. TEEP Agent to the TAM.
TOKEN The value in the TOKEN field is used to match requests to TOKEN The value in the TOKEN field is used to match requests to
responses. The value MUST correspond to the value received with responses. The value MUST correspond to the value received with
the QueryRequest. the QueryRequest.
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selected ciphersuite. Details about the ciphersuite encoding can selected ciphersuite. Details about the ciphersuite encoding can
be found in Section 5. be found in Section 5.
SELECTED_VERSION The SELECTED_VERSION field indicates the protocol SELECTED_VERSION The SELECTED_VERSION field indicates the protocol
version selected by the TEEP Agent. version selected by the TEEP Agent.
EAT The EAT field contains an Entity Attestation Token following the EAT The EAT field contains an Entity Attestation Token following the
encoding defined in [I-D.ietf-rats-eat]. encoding defined in [I-D.ietf-rats-eat].
TA_LIST The TA_LIST field enumerates the trusted applications TA_LIST The TA_LIST field enumerates the trusted applications
installed on the device in form of ta_ids, i.e., a vendor id/class installed on the device in form of TA ID strings.
id/device id triple.
EXT_LIST The EXT_LIST field lists the supported extensions. This EXT_LIST The EXT_LIST field lists the supported extensions. This
document does not define any extensions. document does not define any extensions.
4.3. TrustedAppInstall 4.3. TrustedAppInstall
TrustedAppInstall = {
TrustedAppInstall = (
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
? MANIFEST_LIST : [+ SUIT_Outer_Wrapper], ? MANIFEST_LIST : [+ SUIT_Outer_Wrapper],
* $$extensions * $$extensions
) }
The TrustedAppInstall message is MACed and encrypted by the TAM and The TrustedAppInstall message is MACed and encrypted by the TAM and
has the following fields: has the following fields:
TYPE TYPE = 3 corresponds to a TrustedAppInstall message sent from TYPE TYPE = 3 corresponds to a TrustedAppInstall message sent from
the TAM to the TEEP Agent. In case of successful processing, an the TAM to the TEEP Agent. In case of successful processing, an
Success message is returned by the TEEP Agent. In case of an Success message is returned by the TEEP Agent. In case of an
error, an Error message is returned. Note that the error, an Error message is returned. Note that the
TrustedAppInstall message is used for initial TA installation but TrustedAppInstall message is used for initial TA installation but
also for TA updates. also for TA updates.
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cryptographic information protecting the manifest. The manifest cryptographic information protecting the manifest. The manifest
may also convey personalization data. TA binaries and may also convey personalization data. TA binaries and
personalization data is typically signed and encrypted by the SP. personalization data is typically signed and encrypted by the SP.
Other combinations are, however, possible as well. For example, Other combinations are, however, possible as well. For example,
it is also possible for the TAM to sign and encrypt the it is also possible for the TAM to sign and encrypt the
personalization data and to let the SP sign and/or encrypt the TA personalization data and to let the SP sign and/or encrypt the TA
binary. binary.
4.4. TrustedAppDelete 4.4. TrustedAppDelete
TrustedAppDelete = ( TrustedAppDelete = {
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
? TA_LIST : [+ta_id], ? TA_LIST : [+bstr],
* $$extensions * $$extensions
) }
The TrustedAppDelete message is MACed and encrypted by the TAM and The TrustedAppDelete message is MACed and encrypted by the TAM and
has the following fields: has the following fields:
TYPE TYPE = 4 corresponds to a TrustedAppDelete message sent from TYPE TYPE = 4 corresponds to a TrustedAppDelete message sent from
the TAM to the TEEP Agent. In case of successful processing, an the TAM to the TEEP Agent. In case of successful processing, an
Success message is returned by the TEEP Agent. In case of an Success message is returned by the TEEP Agent. In case of an
error, an Error message is returned. error, an Error message is returned.
TOKEN The value in the TOKEN field is used to match requests to TOKEN The value in the TOKEN field is used to match requests to
responses. responses.
TA_LIST The TA_LIST field enumerates the TAs to be deleted. TA_LIST The TA_LIST field enumerates the TAs to be deleted.
4.5. Success 4.5. Success
Success = ( Success = {
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
? MSG : tstr, ? MSG : tstr,
* $$extensions * $$extensions
) }
The Success message is MACed and encrypted by the TEEP Agent and has The Success message is MACed and encrypted by the TEEP Agent and has
the following fields: the following fields:
TYPE TYPE = 5 corresponds to a Error message sent from the TEEP TYPE TYPE = 5 corresponds to a Error message sent from the TEEP
Agent to the TAM. Agent to the TAM.
TOKEN The value in the TOKEN field is used to match requests to TOKEN The value in the TOKEN field is used to match requests to
responses. responses.
MSG The MSG field contains optional diagnostics information encoded MSG The MSG field contains optional diagnostics information encoded
in UTF-8 [RFC3629] returned by the TEEP Agent. in UTF-8 [RFC3629] returned by the TEEP Agent.
4.6. Error 4.6. Error
Error = ( Error = {
TYPE : int, TYPE : int,
TOKEN : bstr, TOKEN : bstr,
ERR_CODE : int, ERR_CODE : int,
? ERR_MSG : tstr, ? ERR_MSG : tstr,
? CIPHER_SUITE : [+suite], ? CIPHER_SUITE : [+suite],
? VERSION : [+version], ? VERSION : [+version],
* $$extensions * $$extensions
) }
If possible, the Error message is MACed and encrypted by the TEEP If possible, the Error message is MACed and encrypted by the TEEP
Agent. Unprotected Error messages MUST be handled with care by the Agent. Unprotected Error messages MUST be handled with care by the
TAM due to possible downgrading attacks. It has the following TAM due to possible downgrading attacks. It has the following
fields: fields:
TYPE TYPE = 6 corresponds to a Error message sent from the TEEP TYPE TYPE = 6 corresponds to a Error message sent from the TEEP
Agent to the TAM. Agent to the TAM.
TOKEN The value in the TOKEN field is used to match requests to TOKEN The value in the TOKEN field is used to match requests to
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supported by the TEEP Agent. This field is optional but MUST be supported by the TEEP Agent. This field is optional but MUST be
returned with the ERR_UNSUPPORTED_MSG_VERSION error message. returned with the ERR_UNSUPPORTED_MSG_VERSION error message.
CIPHER_SUITE The CIPHER_SUITE field lists the ciphersuite(s) CIPHER_SUITE The CIPHER_SUITE field lists the ciphersuite(s)
supported by the TEEP Agent. This field is optional but MUST be supported by the TEEP Agent. This field is optional but MUST be
returned with the ERR_UNSUPPORTED_CRYPTO_ALG error message. returned with the ERR_UNSUPPORTED_CRYPTO_ALG error message.
This specification defines the following initial error messages. This specification defines the following initial error messages.
Additional error code can be registered with IANA. Additional error code can be registered with IANA.
ERR_ILLEGAL_PARAMETER The TEEP Agent sends this error message when a ERR_ILLEGAL_PARAMETER (1) The TEEP Agent sends this error message
request contains incorrect fields or fields that are inconsistent when a request contains incorrect fields or fields that are
with other fields. inconsistent with other fields.
ERR_UNSUPPORTED_EXTENSION The TEEP Agent sends this error message ERR_UNSUPPORTED_EXTENSION (2) The TEEP Agent sends this error
when it recognizes an unsupported extension or unsupported message when it recognizes an unsupported extension or unsupported
message. message.
ERR_REQUEST_SIGNATURE_FAILED The TEEP Agent sends this error message ERR_REQUEST_SIGNATURE_FAILED (3) The TEEP Agent sends this error
when it fails to verify the signature of the message. message when it fails to verify the signature of the message.
ERR_UNSUPPORTED_MSG_VERSION The TEEP Agent receives a message but ERR_UNSUPPORTED_MSG_VERSION (4) The TEEP Agent receives a message
does not support the indicated version. but does not support the indicated version.
ERR_UNSUPPORTED_CRYPTO_ALG The TEEP Agent receives a request message ERR_UNSUPPORTED_CRYPTO_ALG (5) The TEEP Agent receives a request
encoded with an unsupported cryptographic algorithm. message encoded with an unsupported cryptographic algorithm.
ERR_BAD_CERTIFICATE The TEEP Agent returns this error when ERR_BAD_CERTIFICATE (6) The TEEP Agent returns this error when
processing of a certificate failed. For diagnosis purposes it is processing of a certificate failed. For diagnosis purposes it is
RECOMMMENDED to include information about the failing certificate RECOMMMENDED to include information about the failing certificate
in the error message. in the error message.
ERR_UNSUPPORTED_CERTIFICATE The TEEP Agent returns this error when a ERR_UNSUPPORTED_CERTIFICATE (7) The TEEP Agent returns this error
certificate was of an unsupported type. when a certificate was of an unsupported type.
ERR_CERTIFICATE_REVOKED The TEEP Agent returns this error when a ERR_CERTIFICATE_REVOKED (8) The TEEP Agent returns this error when a
certificate was revoked by its signer. certificate was revoked by its signer.
ERR_CERTIFICATE_EXPIRED The TEEP Agent returns this error when a ERR_CERTIFICATE_EXPIRED (9) The TEEP Agent returns this error when a
certificate has expired or is not currently valid. certificate has expired or is not currently valid.
ERR_INTERNAL_ERROR The TEEP Agent returns this error when a ERR_INTERNAL_ERROR (10) The TEEP Agent returns this error when a
miscellaneous internal error occurred while processing the miscellaneous internal error occurred while processing the
request. request.
ERR_RESOURCE_FULL This error is reported when a device resource ERR_RESOURCE_FULL (11) This error is reported when a device resource
isn't available anymore, such as storage space is full. isn't available anymore, such as storage space is full.
ERR_TA_NOT_FOUND This error will occur when the target TA does not ERR_TA_NOT_FOUND (12) This error will occur when the target TA does
exist. This error may happen when the TAM has stale information not exist. This error may happen when the TAM has stale
and tries to delete a TA that has already been deleted. information and tries to delete a TA that has already been
deleted.
ERR_TA_ALREADY_INSTALLED While installing a TA, a TEE will return ERR_TA_ALREADY_INSTALLED (13) While installing a TA, a TEE will
this error if the TA has already been installed. return this error if the TA has already been installed.
ERR_TA_UNKNOWN_FORMAT The TEEP Agent returns this error when it does ERR_TA_UNKNOWN_FORMAT (14) The TEEP Agent returns this error when it
not recognize the format of the TA binary. does not recognize the format of the TA binary.
ERR_TA_DECRYPTION_FAILED The TEEP Agent returns this error when it ERR_TA_DECRYPTION_FAILED (15) The TEEP Agent returns this error when
fails to decrypt the TA binary. it fails to decrypt the TA binary.
ERR_TA_DECOMPRESSION_FAILED The TEEP Agent returns this error when ERR_TA_DECOMPRESSION_FAILED (16) The TEEP Agent returns this error
it fails to decompress the TA binary. when it fails to decompress the TA binary.
ERR_MANIFEST_PROCESSING_FAILED The TEEP Agent returns this error ERR_MANIFEST_PROCESSING_FAILED (17) The TEEP Agent returns this
when manifest processing failures occur that are less specific error when manifest processing failures occur that are less
than ERR_TA_UNKNOWN_FORMAT, ERR_TA_UNKNOWN_FORMAT, and specific than ERR_TA_UNKNOWN_FORMAT, ERR_TA_UNKNOWN_FORMAT, and
ERR_TA_DECOMPRESSION_FAILED. ERR_TA_DECOMPRESSION_FAILED.
ERR_PD_PROCESSING_FAILED The TEEP Agent returns this error when it ERR_PD_PROCESSING_FAILED (18) The TEEP Agent returns this error when
fails to process the provided personalization data. it fails to process the provided personalization data.
5. Ciphersuites 5. Ciphersuites
A ciphersuite consists of an AEAD algorithm, a HMAC algorithm, and a A ciphersuite consists of an AEAD algorithm, a HMAC algorithm, and a
signature algorithm. Each ciphersuite is identified with an integer signature algorithm. Each ciphersuite is identified with an integer
value, which corresponds to an IANA registered ciphersuite. This value, which corresponds to an IANA registered ciphersuite. This
document specifies two ciphersuites. document specifies two ciphersuites.
Value | Ciphersuite Value | Ciphersuite
------+------------------------------------------------ ------+------------------------------------------------
0 | AES-CCM-16-64-128, HMAC 256/256, X25519, EdDSA 0 | AES-CCM-16-64-128, HMAC 256/256, X25519, EdDSA
1 | AES-CCM-16-64-128, HMAC 256/256, P-256, ES256 1 | AES-CCM-16-64-128, HMAC 256/256, P-256, ES256
6. Security Consideration 6. Security Consideration
This section summarizes the security considerations discussed in this This section summarizes the security considerations discussed in this
specification: specification:
Cryptographic Algorithms This specification relies on the Cryptographic Algorithms TEEP protocol messages exchanged between
cryptographic algorithms provided by the security wrappers JOSE the TAM and the TEEP Agent are protected using COSE. This
and COSE, respectively. A companion document makes algorithm specification relies on the cryptographic algorithms provided by
recommendations but this document is written in an algorithm- COSE. Public key based authentication is used to by the TEEP
agnostic way. TEEP protocol messages exchanged between the TAM Agent to authenticate the TAM and vice versa.
and the TEEP Agent are protected using JWS and JWE (for JSON-
encoded messages) and COSE (for CBOR-encoded messages). Public
key based authentication is used to by the TEEP Agent to
authenticate the TAM and vice versa.
Attestation A TAM may rely on the attestation information provided Attestation A TAM may rely on the attestation information provided
by the TEEP Agent and the Entity Attestation Token is re-used to by the TEEP Agent and the Entity Attestation Token is re-used to
convey this information. To sign the Entity Attestation Token it convey this information. To sign the Entity Attestation Token it
is necessary for the device to possess a public key (usually in is necessary for the device to possess a public key (usually in
the form of a certificate) along with the corresponding private the form of a certificate) along with the corresponding private
key. Depending on the properties of the attestation mechanism it key. Depending on the properties of the attestation mechanism it
is possible to uniquely identify a device based on information in is possible to uniquely identify a device based on information in
the attestation information or in the certificate used to sign the the attestation information or in the certificate used to sign the
attestation token. This uniqueness may raise privacy concerns. attestation token. This uniqueness may raise privacy concerns.
skipping to change at page 13, line 44 skipping to change at page 12, line 40
responsibility of the TAM to relay only verified TAs from responsibility of the TAM to relay only verified TAs from
authorized SPs. Delivery of that TA to the TEEP Agent is then the authorized SPs. Delivery of that TA to the TEEP Agent is then the
responsibility of the TAM and the TEEP Broker, using the security responsibility of the TAM and the TEEP Broker, using the security
mechanisms provided by the TEEP protocol. To protect the TA mechanisms provided by the TEEP protocol. To protect the TA
binary the SUIT manifest is re-used and it offers a varity of binary the SUIT manifest is re-used and it offers a varity of
security features, including digitial signatures and symmetric security features, including digitial signatures and symmetric
encryption. encryption.
Personalization Data An SP or a TAM can supply personalization data Personalization Data An SP or a TAM can supply personalization data
along with a TA. This data is also protected by a SUIT manifest. along with a TA. This data is also protected by a SUIT manifest.
The personalization data may be itself is (or can be) opaque to The personalization data may be opaque to the TAM.
the TAM.
TEEP Broker The TEEP protocol relies on the TEEP Broker to relay TEEP Broker The TEEP protocol relies on the TEEP Broker to relay
messages between the TAM and the TEEP Agent. When the TEEP Broker messages between the TAM and the TEEP Agent. When the TEEP Broker
is compromised it can drop messages, delay the delivery of is compromised it can drop messages, delay the delivery of
messages, and replay messages but it cannot modify those messages. messages, and replay messages but it cannot modify those messages.
(A replay would be, however, detected by the TEEP Agent.) A (A replay would be, however, detected by the TEEP Agent.) A
compromised TEEP Broker could reorder messages in an attempt to compromised TEEP Broker could reorder messages in an attempt to
install an old version of a TA. Information in the manifest install an old version of a TA. Information in the manifest
ensures that the TEEP Agents are protected against such ensures that the TEEP Agents are protected against such
downgrading attacks based on features offered by the manifest downgrading attacks based on features offered by the manifest
skipping to change at page 14, line 43 skipping to change at page 13, line 39
validity of intermediate CA certificates). The integrity and the validity of intermediate CA certificates). The integrity and the
accuracy of the clock within the TEE determines the ability to accuracy of the clock within the TEE determines the ability to
determine an expired or revoked certificate since OCSP stapling determine an expired or revoked certificate since OCSP stapling
includes signature generation time, certificate validity dates are includes signature generation time, certificate validity dates are
compared to the current time. compared to the current time.
7. IANA Considerations 7. IANA Considerations
7.1. Media Type Registration 7.1. Media Type Registration
IANA is requested to assign a media type for application/teep+json.
Type name: application
Subtype name: teep+json
Required parameters: none
Optional parameters: none
Encoding considerations: Same as encoding considerations of
application/json as specified in Section 11 of [RFC7159]
Security considerations: See Security Considerations Section of this
document.
Interoperability considerations: Same as interoperability
considerations of application/json as specified in [RFC7159]
Published specification: This document.
Applications that use this media type: TEEP protocol implementations
Fragment identifier considerations: N/A
Additional information:
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person to contact for further information: teep@ietf.org
Intended usage: COMMON
Restrictions on usage: none
Author: See the "Authors' Addresses" section of this document
Change controller: IETF
IANA is requested to assign a media type for application/teep+cbor. IANA is requested to assign a media type for application/teep+cbor.
Type name: application Type name: application
Subtype name: teep+cbor Subtype name: teep+cbor
Required parameters: none Required parameters: none
Optional parameters: none Optional parameters: none
skipping to change at page 17, line 29 skipping to change at page 15, line 29
IANA is also requested to create a new registry for ciphersuites, as IANA is also requested to create a new registry for ciphersuites, as
defined in Section 5. defined in Section 5.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-rats-eat] [I-D.ietf-rats-eat]
Mandyam, G., Lundblade, L., Ballesteros, M., and J. Mandyam, G., Lundblade, L., Ballesteros, M., and J.
O'Donoghue, "The Entity Attestation Token (EAT)", draft- O'Donoghue, "The Entity Attestation Token (EAT)", draft-
ietf-rats-eat-01 (work in progress), July 2019. ietf-rats-eat-03 (work in progress), February 2020.
[I-D.ietf-suit-manifest] [I-D.ietf-suit-manifest]
Moran, B., Tschofenig, H., and H. Birkholz, "A Concise Moran, B., Tschofenig, H., and H. Birkholz, "A Concise
Binary Object Representation (CBOR)-based Serialization Binary Object Representation (CBOR)-based Serialization
Format for the Software Updates for Internet of Things Format for the Software Updates for Internet of Things
(SUIT) Manifest", draft-ietf-suit-manifest-02 (work in (SUIT) Manifest", draft-ietf-suit-manifest-03 (work in
progress), November 2019. progress), February 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2560] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. [RFC2560] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C.
Adams, "X.509 Internet Public Key Infrastructure Online Adams, "X.509 Internet Public Key Infrastructure Online
Certificate Status Protocol - OCSP", RFC 2560, Certificate Status Protocol - OCSP", RFC 2560,
DOI 10.17487/RFC2560, June 1999, DOI 10.17487/RFC2560, June 1999,
skipping to change at page 18, line 17 skipping to change at page 16, line 17
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
[RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network
Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008, Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008,
<https://www.rfc-editor.org/info/rfc5198>. <https://www.rfc-editor.org/info/rfc5198>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>. October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, DOI 10.17487/RFC7516, May 2015,
<https://www.rfc-editor.org/info/rfc7516>.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/info/rfc7517>.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015,
<https://www.rfc-editor.org/info/rfc7518>.
[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)", [RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
RFC 8152, DOI 10.17487/RFC8152, July 2017, RFC 8152, DOI 10.17487/RFC8152, July 2017,
<https://www.rfc-editor.org/info/rfc8152>. <https://www.rfc-editor.org/info/rfc8152>.
8.2. Informative References 8.2. Informative References
[I-D.ietf-cbor-cddl] [I-D.ietf-cbor-cddl]
Birkholz, H., Vigano, C., and C. Bormann, "Concise data Birkholz, H., Vigano, C., and C. Bormann, "Concise data
definition language (CDDL): a notational convention to definition language (CDDL): a notational convention to
express CBOR and JSON data structures", draft-ietf-cbor- express CBOR and JSON data structures", draft-ietf-cbor-
cddl-08 (work in progress), March 2019. cddl-08 (work in progress), March 2019.
[I-D.ietf-teep-architecture] [I-D.ietf-teep-architecture]
Pei, M., Tschofenig, H., Wheeler, D., Atyeo, A., and D. Pei, M., Tschofenig, H., Thaler, D., and D. Wheeler,
Liu, "Trusted Execution Environment Provisioning (TEEP) "Trusted Execution Environment Provisioning (TEEP)
Architecture", draft-ietf-teep-architecture-04 (work in Architecture", draft-ietf-teep-architecture-07 (work in
progress), December 2019. progress), March 2020.
[I-D.ietf-teep-opentrustprotocol] [I-D.ietf-teep-opentrustprotocol]
Pei, M., Atyeo, A., Cook, N., Yoo, M., and H. Tschofenig, Pei, M., Atyeo, A., Cook, N., Yoo, M., and H. Tschofenig,
"The Open Trust Protocol (OTrP)", draft-ietf-teep- "The Open Trust Protocol (OTrP)", draft-ietf-teep-
opentrustprotocol-03 (work in progress), May 2019. opentrustprotocol-03 (work in progress), May 2019.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
Appendix A. Acknowledgements Appendix A. Acknowledgements
This work is based on the initial version of OTrP This work is based on the initial version of OTrP
[I-D.ietf-teep-opentrustprotocol] and hence credits go to those who [I-D.ietf-teep-opentrustprotocol] and hence credits go to those who
have contributed to it. have contributed to it.
We would like to thank Eve Schooler for the suggestion of the We would like to thank Eve Schooler for the suggestion of the
protocol name. protocol name.
We would like to thank Akira Tsukamoto, Isobe Kohei, Kohei Isobe,
Tsukasa Ooi, and Yuichi Takita for their valuable implementation
feedback.
Appendix B. Contributors Appendix B. Contributors
We would like to thank the following individuals for their We would like to thank the following individuals for their
contributions to an earlier version of this specification. contributions to an initial version of this specification.
- Brian Witten - Brian Witten
Symantec Symantec
brian_witten@symantec.com brian_witten@symantec.com
- Tyler Kim - Tyler Kim
Solacia Solacia
tylerkim@iotrust.kr tylerkim@iotrust.kr
- Nick Cook - Nick Cook
skipping to change at page 20, line 9 skipping to change at page 17, line 34
nicholas.cook@arm.com nicholas.cook@arm.com
- Minho Yoo - Minho Yoo
IoTrust IoTrust
minho.yoo@iotrust.kr minho.yoo@iotrust.kr
Authors' Addresses Authors' Addresses
Hannes Tschofenig Hannes Tschofenig
Arm Ltd. Arm Ltd.
110 Fulbourn Rd Absam, Tirol 6067
Cambridge, CB1 9NJ Austria
Great Britain
Email: hannes.tschofenig@arm.com Email: hannes.tschofenig@arm.com
Mingliang Pei Mingliang Pei
Broadcom Broadcom
350 Ellis St 350 Ellis St
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Email: mingliang.pei@broadcom.com Email: mingliang.pei@broadcom.com
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