RFC 9645
YANG Groupings for TLS Clients and TLS Servers
Abstract β¨
okay bestie, so this doc is basically a starter pack π It presents four YANG 1.1 modules: three IETF ones and one IANA one.
The three IETF modules are ietf-tls-common, ietf-tls-client, and ietf-tls-server. The ietf-tls-client and ietf-tls-server modules are the main stars here, handling the configuration and monitoring of TLS clients and servers π
The IANA module is iana-tls-cipher-suite-algs. It defines YANG enumerations that support an algorithm registry that IANA maintains π¦
Status of This Memo π
This is an Internet Standards Track document πΈ
It's a product of the Internet Engineering Task Force (IETF), so it represents the consensus of the IETF community. It went through public review and got approved for publication by the Internet Engineering Steering Group (IESG). If you want more on Internet Standards, check out Section 2 of RFC 7841 β¨
For the current status, any errata, and how to send feedback, go to https://www.rfc-editor.org/info/rfc9645 π
Copyright Notice Β©οΈ
Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) as they stand on the publication date. Please actually read these, because they lay out your rights and restrictions for this document π«Ά
Code Components pulled out of this document must include the Revised BSD License text, as described in Section 4.e of the Trust Legal Provisions. They come without warranty, as the Revised BSD License describes π₯
Table of Contents π§
1. Introduction
1.1. Regarding the Three IETF Modules
1.2. Relation to Other RFCs
1.3. Specification Language
1.4. Adherence to the NMDA
1.5. Conventions
2. The "ietf-tls-common" Module
2.1. Data Model Overview
2.2. Example Usage
2.3. YANG Module
3. The "ietf-tls-client" Module
3.1. Data Model Overview
3.2. Example Usage
3.3. YANG Module
4. The "ietf-tls-server" Module
4.1. Data Model Overview
4.2. Example Usage
4.3. YANG Module
5. Security Considerations
5.1. Considerations for the "iana-tls-cipher-suite-algs" YANG
Module
5.2. Considerations for the "ietf-tls-common" YANG Module
5.3. Considerations for the "ietf-tls-client" YANG Module
5.4. Considerations for the "ietf-tls-server" YANG Module
6. IANA Considerations
6.1. The IETF XML Registry
6.2. The YANG Module Names Registry
6.3. Considerations for the "iana-tls-cipher-suite-algs" YANG
Module
7. References
7.1. Normative References
7.2. Informative References
Appendix A. Script to Generate IANA-Maintained YANG Modules
Acknowledgements
Contributors
Author's AddressTitle Block π
- Stream: Internet Engineering Task Force (IETF) π
- RFC number: 9645
- Title: YANG Groupings for TLS Clients and TLS Servers
- Authors: K. Watsen, Watsen Networks
- Category: Standards Track
- Date: October 2024
- ISSN: 2070-1721
The title block doesn't list any Obsoletes or Updates entries, so nothing is named there as replaced or updated π
1. Introduction β¨
This document presents four YANG 1.1 [RFC7950] modules: three IETF modules and one IANA module π
The three IETF modules are ietf-tls-common (Section 2), ietf-tls-client (Section 3), and ietf-tls-server (Section 4). The ietf-tls-client and ietf-tls-server modules are the primary productions of this work, supporting the configuration and monitoring of TLS clients and servers π
The groupings in this document are expected to be used alongside the groupings in an underlying transport-level module, like the ones defined in [RFC9643]. The transport-level data model lets you configure transport-level values such as a remote address, a remote port, a local address, and a local port π¦
The IANA module is iana-tls-cipher-suite-algs. It defines YANG enumerations that support an IANA-maintained algorithm registry β¨
IANA used the script in Appendix A to generate the iana-tls-cipher-suite-algs YANG module. This document doesn't publish the initial version of the module, because IANA publishes and maintains it πΈ
1.1. Regarding the Three IETF Modules π·
The three IETF modules define features and groupings for modeling "generic" TLS clients and TLS servers. Here, "generic" means "least common denominator," not "complete" π Basic TLS protocol support is covered by these modules, and anything advanced is left to augmentations made by consuming modules.
The YANG groupings are meant for applications that need to configure TLS client and server protocol stacks. For example, they help define the data model for HTTPS [RFC9110] and for clients and servers based on the Network Configuration Protocol (NETCONF) over TLS [RFC7589], in [HTTP-CLIENT-SERVER] and [NETCONF-CLIENT-SERVER] respectively π
The ietf-tls-client and ietf-tls-server YANG modules each define one grouping. That grouping focuses only on TLS-specific configuration and deliberately skips transport-level configuration, like which ports to listen on or connect to. That gives applications room to decide how the underlying TCP connection gets established π§ For example, applications supporting NETCONF Call Home [RFC8071] could use the tls-server-grouping grouping for the TLS parts, while adding data nodes for the TCP-level call-home configuration.
Both TLS 1.2 and TLS 1.3 may be configured. TLS 1.2 [RFC5246] has been obsoleted by TLS 1.3 [RFC8446], but it's still in common use, so its feature statement is marked status deprecated π₯Ή
1.2. Relation to Other RFCs π
This document presents four YANG modules [RFC7950] that are part of a collection of RFCs working together to support the configuration of both the clients and the servers of the NETCONF [RFC6241] and RESTCONF [RFC8040] protocols π
The diagram below shows how the primary YANG groupings in the various RFCs depend on each other. Some documents also define secondary groupings that bring in dependencies the diagram doesn't show. The labels in the diagram are shorthand names for the defining RFCs, and the citation references for those shorthand names come right after it π
Heads up: the arrows point from referencer to referenced. So, for example, the "crypto-types" RFC has no dependencies, whilst the "keystore" RFC depends on the "crypto-types" RFC π
crypto-types
^ ^
/ \
/ \
truststore keystore
^ ^ ^ ^
| +---------+ | |
| | | |
| +------------+ |
tcp-client-server | / | |
^ ^ ssh-client-server | |
| | ^ tls-client-server
| | | ^ ^ http-client-server
| | | | | ^
| | | +-----+ +---------+ |
| | | | | |
| +-----------|--------|--------------+ | |
| | | | | |
+-----------+ | | | | |
| | | | | |
| | | | | |
netconf-client-server restconf-client-server+========================+==========================+
| Label in Diagram | Originating RFC |
+========================+==========================+
| crypto-types | [RFC9640] |
+------------------------+--------------------------+
| truststore | [RFC9641] |
+------------------------+--------------------------+
| keystore | [RFC9642] |
+------------------------+--------------------------+
| tcp-client-server | [RFC9643] |
+------------------------+--------------------------+
| ssh-client-server | [RFC9644] |
+------------------------+--------------------------+
| tls-client-server | RFC 9645 |
+------------------------+--------------------------+
| http-client-server | [HTTP-CLIENT-SERVER] |
+------------------------+--------------------------+
| netconf-client-server | [NETCONF-CLIENT-SERVER] |
+------------------------+--------------------------+
| restconf-client-server | [RESTCONF-CLIENT-SERVER] |
+------------------------+--------------------------+
Table 1: Labels in Diagram to RFC Mapping1.3. Specification Language π
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 π«Ά
1.4. Adherence to the NMDA ποΈ
This document complies with the Network Management Datastore Architecture (NMDA) [RFC8342]. For instance, as described in [RFC9641] and [RFC9642], trust anchors and keys installed during manufacturing are expected to appear in <operational> (Section 5.3 of [RFC8342]) and in <system> [SYSTEM-CONFIG] if implemented β¨
1.5. Conventions π
Various examples in this document use BASE64VALUE= as a placeholder for binary data that has been base64 encoded (per Section 9.8 of [RFC7950]). The placeholder is there because real base64-encoded structures are often many lines long, which would be super distracting in the middle of an example π
Various examples in this document use the XML [W3C.REC-xml-20081126] encoding. Other encodings, such as JSON [RFC8259], could be used instead πΈ
Various examples in this document contain long lines that may be folded, as described in [RFC8792] π¦
2. The "ietf-tls-common" Module β¨
okay bestie, this section is all about the TLS common model π¦ which is the stuff that TLS clients AND TLS servers both need. the main character here is the "hello-params-grouping" grouping π because it lets you configure the list of TLS algorithms a client or server is allowed to use. the lists are ordered, so if the client permits more than one algorithm, the one that's first in its list AND also permitted by the server is the one that gets used for the TLS transport layer connection π₯. you can also restrict which algorithms are allowed, which is lowkey essential for TLS clients and servers that can do that and need to line up with local security policies π«Ά. this model supports both TLS 1.2 [RFC5246] and TLS 1.3 [RFC8446] π
so, to support both TLS 1.2 and TLS 1.3, the cipher suites part of the "hello-params-grouping" grouping should include these three parameters for configuring its permitted TLS algorithms: TLS Cipher Suites, TLS SignatureScheme, and TLS Supported Groups π
2.1. Data Model Overview
this part gives you the overview of the "ietf-tls-common" module in terms of its features, identities, and groupings π§
2.1.1. Features
the diagram below lists every single "feature" statement defined in the "ietf-tls-common" module π
Features:
+-- tls12
+-- tls13
+-- hello-params
+-- asymmetric-key-pair-generation
+-- supported-algorithmsngl the diagram above uses syntax that's similar to [RFC8340] but it isn't actually defined there, so don't go looking for it π
for what each feature does, check the YANG module, it has the descriptions π
2.1.2. Identities
this diagram shows the relationship between the "identity" statements defined in the "ietf-tls-common" module π¦
Identities:
+-- tls-version-base
+-- tls12
+-- tls13same deal as before: the diagram uses syntax that's similar to but not defined in [RFC8340] π
Comments:
- the diagram shows there are two base identities πΈ
- one base identity is used to specify TLS versions. this base identity is "abstract" in the object-oriented programming sense, because it defines a "class" of things rather than one specific thing π
- these base identities are "abstract" in the object-oriented programming sense too, because they only define a "class" of things rather than a specific thing π
2.1.3. Groupings
the "ietf-tls-common" module defines this one "grouping" statement:
- hello-params-grouping
we'll get into it in the next subsection π
2.1.3.1. The "hello-params-grouping" Grouping
this tree diagram [RFC8340] shows the "hello-params-grouping" grouping π³
grouping hello-params-grouping:
+-- tls-versions
| +-- min? identityref
| +-- max? identityref
+-- cipher-suites
+-- cipher-suite* tlscsa:tls-cipher-suite-algorithmComments:
- this grouping is used by both the "tls-client-grouping" and the "tls-server-grouping" groupings, which are defined in Sections 3.1.2.1 and 4.1.2.1, respectively π
- this grouping lets client and server configurations specify the TLS versions and cipher suites that get used when TLS sessions are being established β¨
- the "cipher-suites" list is "ordered-by user" π«Ά
2.1.4. Protocol-Accessible Nodes
this tree diagram [RFC8340] lists every protocol-accessible node defined in the "ietf-tls-common" module, without expanding the "grouping" statements π¦
module: ietf-tls-common
+--ro supported-algorithms {algorithm-discovery}?
+--ro supported-algorithm* tlscsa:tls-cipher-suite-algorithm
rpcs:
+---x generate-asymmetric-key-pair
{asymmetric-key-pair-generation}?
+---w input
| +---w algorithm
| | tlscsa:tls-cipher-suite-algorithm
| +---w num-bits? uint16
| +---w private-key-encoding
| +---w (private-key-encoding)
| +--:(cleartext) {ct:cleartext-private-keys}?
| | +---w cleartext? empty
| +--:(encrypted) {ct:encrypted-private-keys}?
| | +---w encrypted
| | +---w ks:encrypted-by-grouping
| +--:(hidden) {ct:hidden-private-keys}?
| +---w hidden? empty
+--ro output
+--ro (key-or-hidden)?
+--:(key)
| +---u ct:asymmetric-key-pair-grouping
+--:(hidden)
+--ro location?
instance-identifierComments:
- protocol-accessible nodes are the nodes you can reach when the module is "implemented", as described in Section 5.6.5 of [RFC7950] π
- the protocol-accessible nodes for the "ietf-tls-common" module are limited to two things: the "supported-algorithms" container, which is constrained by the "algorithm-discovery" feature, and the "generate-asymmetric-key-pair" RPC, which is constrained by the "asymmetric-key-pair-generation" feature π
- the "encrypted-by-grouping" grouping is discussed in Section 2.1.3.1 of [RFC9642] π
- the "asymmetric-key-pair-grouping" grouping is discussed in Section 2.1.4.6 of [RFC9640] π
2.2. Example Usage
this example shows the "hello-params-grouping" grouping filled in with some actual data πΈ
<!-- The outermost element below doesn't exist in the data model. -->
<!-- It simulates if the "grouping" were a "container" instead. -->
<hello-params
xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-common"
xmlns:tlscmn="urn:ietf:params:xml:ns:yang:ietf-tls-common">
<tls-versions>
<min>tlscmn:tls12</min>
<max>tlscmn:tls13</max>
</tls-versions>
<cipher-suites>
<cipher-suite>TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA</cipher-suite>
<cipher-suite>TLS_DHE_RSA_WITH_AES_128_CBC_SHA256</cipher-suite>
<cipher-suite>TLS_RSA_WITH_3DES_EDE_CBC_SHA</cipher-suite>
</cipher-suites>
</hello-params>next up is an example of operational state data showing the TLS algorithms the server supports π
=============== NOTE: '\' line wrapping per RFC 8792 ================<supported-algorithms
xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-common">
<supported-algorithm>TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA</support\
ed-algorithm>
<supported-algorithm>TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384</supp\
orted-algorithm>
<supported-algorithm>TLS_DHE_RSA_WITH_AES_128_CBC_SHA256</supporte\
d-algorithm>
<supported-algorithm>TLS_RSA_WITH_3DES_EDE_CBC_SHA</supported-algo\
rithm>
<supported-algorithm>TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384</suppor\
ted-algorithm>
<supported-algorithm>TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256</su\
pported-algorithm>
<supported-algorithm>TLS_ECCPWD_WITH_AES_256_GCM_SHA384</supported\
-algorithm>
<supported-algorithm>TLS_PSK_WITH_AES_256_CCM</supported-algorithm>
<supported-algorithm>TLS_PSK_WITH_AES_256_CCM_8</supported-algorit\
hm>
<supported-algorithm>TLS_DHE_PSK_WITH_CAMELLIA_256_CBC_SHA384</sup\
ported-algorithm>
<supported-algorithm>TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384</support\
ed-algorithm>
<supported-algorithm>TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA</supported\
-algorithm>
<supported-algorithm>TLS_DH_DSS_WITH_AES_128_GCM_SHA256</supported\
-algorithm>
</supported-algorithms>last but not least, an example of the "generate-asymmetric-key-pair" RPC in action π§
REQUEST
=============== NOTE: '\' line wrapping per RFC 8792 ================<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<generate-asymmetric-key-pair
xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-common">
<algorithm>TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256</algorithm>
<num-bits>521</num-bits>
<private-key-encoding>
<encrypted>
<asymmetric-key-ref>hidden-asymmetric-key</asymmetric-key-re\
f>
</encrypted>
</private-key-encoding>
</generate-asymmetric-key-pair>
</rpc>RESPONSE
=============== NOTE: '\' line wrapping per RFC 8792 ================<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
xmlns:tlscmn="urn:ietf:params:xml:ns:yang:ietf-tls-common">
<tlscmn:public-key-format>ct:subject-public-key-info-format</tlscm\
n:public-key-format>
<tlscmn:public-key>BASE64VALUE=</tlscmn:public-key>
<tlscmn:private-key-format>ct:ec-private-key-format</tlscmn:privat\
e-key-format>
<tlscmn:cleartext-private-key>BASE64VALUE=</tlscmn:cleartext-priva\
te-key>
</rpc-reply>2.3. YANG Module π
okay so the whole module lives in one file, and I'm obsessed with how neatly it's packed π It has normative references to [RFC5288], [RFC5289], [RFC8422], [RFC9640], [RFC9642], [FIPS180-4], and [FIPS186-5]. It has informative references to [RFC5246] and [RFC8446].
file "ietf-tls-common@2024-10-10.yang"
module ietf-tls-common {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-tls-common";
prefix tlscmn;
import iana-tls-cipher-suite-algs {
prefix tlscsa;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC 9640: YANG Data Types and Groupings for Cryptography";
}
import ietf-keystore {
prefix ks;
reference
"RFC 9642: A YANG Data Model for a Keystore";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG List: NETCONF WG list <mailto:netconf@ietf.org>
WG Web: https://datatracker.ietf.org/wg/netconf
Author: Kent Watsen <mailto:kent+ietf@watsen.net>
Author: Jeff Hartley <mailto:intensifysecurity@gmail.com>
Author: Gary Wu <mailto:garywu@cisco.com>";
description
"This module defines common features and groupings for
Transport Layer Security (TLS).
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.
Copyright (c) 2024 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9645
(https://www.rfc-editor.org/info/rfc9645); see the RFC
itself for full legal notices.";
revision 2024-10-10 {
description
"Initial version.";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
// Features
feature tls12 {
description
"TLS Protocol Version 1.2 is supported. TLS 1.2 is obsolete,
and thus it is NOT RECOMMENDED to enable this feature.";
reference
"RFC 5246: The Transport Layer Security (TLS) Protocol
Version 1.2";
}
feature tls13 {
description
"TLS Protocol Version 1.3 is supported.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3";
}
feature hello-params {
description
"TLS hello message parameters are configurable.";
}
feature algorithm-discovery {
description
"Indicates that the server implements the
'supported-algorithms' container.";
}
feature asymmetric-key-pair-generation {
description
"Indicates that the server implements the
'generate-asymmetric-key-pair' RPC.";
}
// Identities
identity tls-version-base {
description
"Base identity used to identify TLS protocol versions.";
}
identity tls12 {
if-feature "tls12";
base tls-version-base;
description
"TLS Protocol Version 1.2.";
reference
"RFC 5246: The Transport Layer Security (TLS) Protocol
Version 1.2";
}
identity tls13 {
if-feature "tls13";
base tls-version-base;
description
"TLS Protocol Version 1.3.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3";
}
// Typedefs
typedef epsk-supported-hash {
type enumeration {
enum sha-256 {
description
"The SHA-256 hash.";
}
enum sha-384 {
description
"The SHA-384 hash.";
}
}
description
"As per Section 4.2.11 of RFC 8446, the hash algorithm
supported by an instance of an External Pre-Shared
Key (EPSK).";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3";
}
// Groupings
grouping hello-params-grouping {
description
"A reusable grouping for TLS hello message parameters.";
reference
"RFC 5246: The Transport Layer Security (TLS) Protocol
Version 1.2
RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3";
container tls-versions {
description
"Parameters limiting which TLS versions, amongst
those enabled by 'features', are presented during
the TLS handshake.";
leaf min {
type identityref {
base tls-version-base;
}
description
"If not specified, then there is no configured
minimum version.";
}
leaf max {
type identityref {
base tls-version-base;
}
description
"If not specified, then there is no configured
maximum version.";
}
}
container cipher-suites {
description
"Parameters regarding cipher suites.";
leaf-list cipher-suite {
type tlscsa:tls-cipher-suite-algorithm;
ordered-by user;
description
"Acceptable cipher suites in order of descending
preference. The configured host key algorithms should
be compatible with the algorithm used by the configured
private key. Please see Section 5 of RFC 9645 for
valid combinations.
If this leaf-list is not configured (has zero elements),
the acceptable cipher suites are implementation-
defined.";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
}
} // hello-params-grouping
// Protocol-accessible Nodes
container supported-algorithms {
if-feature "algorithm-discovery";
config false;
description
"A container for a list of cipher suite algorithms supported
by the server.";
leaf-list supported-algorithm {
type tlscsa:tls-cipher-suite-algorithm;
description
"A cipher suite algorithm supported by the server.";
}
}
rpc generate-asymmetric-key-pair {
if-feature "asymmetric-key-pair-generation";
description
"Requests the device to generate an 'asymmetric-key-pair'
key using the specified key algorithm.";
input {
leaf algorithm {
type tlscsa:tls-cipher-suite-algorithm;
mandatory true;
description
"The cipher suite algorithm that the generated key
works with. Implementations derive the public key
algorithm from the cipher suite algorithm. For
example, cipher suite
'tls-rsa-with-aes-256-cbc-sha256' maps to the RSA
public key.";
}
leaf num-bits {
type uint16;
description
"Specifies the number of bits to create in the key.
For RSA keys, the minimum size is 1024 bits, and
the default is 3072 bits. Generally, 3072 bits is
considered sufficient. DSA keys must be exactly
1024 bits as specified by FIPS 186-2. For
elliptical keys, the 'num-bits' value determines
the key length of the curve (e.g., 256, 384, or 521),
where valid values supported by the server are
conveyed via an unspecified mechanism. For some
public algorithms, the keys have a fixed length, and
thus the 'num-bits' value is not specified.";
}
container private-key-encoding {
description
"Indicates how the private key is to be encoded.";
choice private-key-encoding {
mandatory true;
description
"A choice amongst optional private key handling.";
case cleartext {
if-feature "ct:cleartext-private-keys";
leaf cleartext {
type empty;
description
"Indicates that the private key is to be returned
as a cleartext value.";
}
}
case encrypted {
if-feature "ct:encrypted-private-keys";
container encrypted {
description
"Indicates that the key is to be encrypted using
the specified symmetric or asymmetric key.";
uses ks:encrypted-by-grouping;
}
}
case hidden {
if-feature "ct:hidden-private-keys";
leaf hidden {
type empty;
description
"Indicates that the private key is to be hidden.
Unlike the 'cleartext' and 'encrypt' options, the
key returned is a placeholder for an internally
stored key. See Section 3 of RFC 9642 ('Support
for Built-In Keys') for information about hidden
keys.";
}
}
}
}
}
output {
choice key-or-hidden {
case key {
uses ct:asymmetric-key-pair-grouping;
}
case hidden {
leaf location {
type instance-identifier;
description
"The location to where a hidden key was created.";
}
}
description
"The output can be either a key (for cleartext and
encrypted keys) or the location to where the key
was created (for hidden keys).";
}
}
} // end generate-asymmetric-key-pair
}3. The "ietf-tls-client" Module β¨
okay bestie, this section defines a YANG 1.1 [RFC7950] module called "ietf-tls-client" π§ There's a high-level overview in Section 3.1, examples of how to use it in Section 3.2 ("Example Usage"), and the actual module itself is in Section 3.3.
3.1. Data Model Overview π
this part gives you the overview of the "ietf-tls-client" module, covering its features and groupings. literally the cheat sheet π
3.1.1. Features π¦
here's the diagram listing every single "feature" statement in the "ietf-tls-client" module, no cap:
Features:
+-- tls-client-keepalives
+-- client-ident-x509-cert
+-- client-ident-raw-public-key
+-- client-ident-psk
+-- server-auth-x509-cert
+-- server-auth-raw-public-key
+-- server-auth-pskthe diagram uses syntax that is similar to but not defined in [RFC8340], so it's giving "close but not quite" vibes π for what each feature actually does, check the YANG module, it has a description for every one π
3.1.2. Groupings πΈ
the "ietf-tls-client" module defines the following "grouping" statement:
tls-client-grouping
this grouping is presented in the following subsection π«Ά
3.1.2.1. The "tls-client-grouping" Grouping β¨
okay so this is the big one, bestie π
the tls-client-grouping grouping, and this tree diagram [RFC8340] shows you the whole vibe at once πΈ
=============== NOTE: '\' line wrapping per RFC 8792 ================
grouping tls-client-grouping:
+-- client-identity!
| +-- (auth-type)
| +--:(certificate) {client-ident-x509-cert}?
| | +-- certificate
| | +---u ks:inline-or-keystore-end-entity-cert-with-key\
-grouping
| +--:(raw-public-key) {client-ident-raw-public-key}?
| | +-- raw-private-key
| | +---u ks:inline-or-keystore-asymmetric-key-grouping
| +--:(tls12-psk) {client-ident-tls12-psk}?
| | +-- tls12-psk
| | +---u ks:inline-or-keystore-symmetric-key-grouping
| | +-- id?
| | string
| +--:(tls13-epsk) {client-ident-tls13-epsk}?
| +-- tls13-epsk
| +---u ks:inline-or-keystore-symmetric-key-grouping
| +-- external-identity
| | string
| +-- hash?
| | tlscmn:epsk-supported-hash
| +-- context?
| | string
| +-- target-protocol?
| | uint16
| +-- target-kdf?
| uint16
+-- server-authentication
| +-- ca-certs! {server-auth-x509-cert}?
| | +---u ts:inline-or-truststore-certs-grouping
| +-- ee-certs! {server-auth-x509-cert}?
| | +---u ts:inline-or-truststore-certs-grouping
| +-- raw-public-keys! {server-auth-raw-public-key}?
| | +---u ts:inline-or-truststore-public-keys-grouping
| +-- tls12-psks? empty {server-auth-tls12-psk}?
| +-- tls13-epsks? empty {server-auth-tls13-epsk}?
+-- hello-params {tlscmn:hello-params}?
| +---u tlscmn:hello-params-grouping
+-- keepalives {tls-client-keepalives}?
+-- peer-allowed-to-send? empty
+-- test-peer-aliveness!
+-- max-wait? uint16
+-- max-attempts? uint8Comments, bestie π:
- The
client-identitynode is optional, bc client authentication MAY occur at a higher protocol layer π«Ά It configures identity credentials, and each one is switched on by afeaturestatement from Section 3.1.1. - The
server-authenticationnode sets up the trust anchors for authenticating the TLS server π Every option is gated by its ownfeaturestatement, so no cap, it's very picky about what's on. - The
hello-paramsnode has to be enabled by a feature π It configures the parameters for the TLS sessions that get set up with this configuration. - The
keepalivesnode also needs a feature to be on β¨ It configures apresencecontainer so you can check whether the TLS server is still alive. That aliveness test happens at the TLS protocol layer, so it's giving low-level π§ - For the referenced grouping statements, here's where to look:
- The
inline-or-keystore-end-entity-cert-with-key-groupinggrouping is discussed in Section 2.1.3.6 of [RFC9642]. - The
inline-or-keystore-asymmetric-key-groupinggrouping is discussed in Section 2.1.3.4 of [RFC9642]. - The
inline-or-keystore-symmetric-key-groupinggrouping is discussed in Section 2.1.3.3 of [RFC9642]. - The
inline-or-truststore-certs-groupinggrouping is discussed in Section 2.1.3.3 of [RFC9641]. - The
inline-or-truststore-public-keys-groupinggrouping is discussed in Section 2.1.3.4 of [RFC9641]. - The
hello-params-groupinggrouping is discussed in Section 2.1.3.1 in this document π
- The
3.1.3. Protocol-Accessible Nodes π¦
okay, so the ietf-tls-client module only defines grouping statements. Other modules use those groupings to create protocol-accessible nodes π§ That means this module doesn't create any protocol-accessible nodes by itself when it's implemented. Main character energy, but make it a supporting role π
3.2. Example Usage π
this section has two examples of the tls-client-grouping grouping filled in with some data π
They're basically the same, except the first one sets up the client identity with a local key, and the second one uses a key that lives in a keystore π Both are consistent with the examples in Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642] π«Ά
Here's the first example, which uses inline definitions for the client identity and server authentication β¨
=============== NOTE: '\' line wrapping per RFC 8792 ================
<!-- The outermost element below doesn't exist in the data model. -->
<!-- It simulates if the "grouping" were a "container" instead. -->
<tls-client
xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-client"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<!-- how this client will authenticate itself to the server -->
<client-identity>
<certificate>
<inline-definition>
<private-key-format>ct:rsa-private-key-format</priva\
te-key-format>
<cleartext-private-key>BASE64VALUE=</cleartext-priva\
te-key>
<cert-data>BASE64VALUE=</cert-data>
</inline-definition>
</certificate>
</client-identity>
<!-- which certificates will this client trust -->
<server-authentication>
<ca-certs>
<inline-definition>
<certificate>
<name>Server Cert Issuer #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>Server Cert Issuer #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</inline-definition>
</ca-certs>
<ee-certs>
<inline-definition>
<certificate>
<name>My Application #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>My Application #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</inline-definition>
</ee-certs>
<raw-public-keys>
<inline-definition>
<public-key>
<name>corp-fw1</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
<public-key>
<name>corp-fw2</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
</inline-definition>
</raw-public-keys>
<tls12-psks/>
<tls13-epsks/>
</server-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-client>And the second example uses central-keystore-references for the client identity and central-truststore-references for server authentication, pulled from the keystore ποΈβ¨
=============== NOTE: '\' line wrapping per RFC 8792 ================
<!-- The outermost element below doesn't exist in the data model. -->
<!-- It simulates if the "grouping" were a "container" instead. -->
<tls-client xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-client">
<!-- how this client will authenticate itself to the server -->
<client-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</client-identity>
<!-- which certificates will this client trust -->
<server-authentication>
<ca-certs>
<central-truststore-reference>trusted-server-ca-certs</c\
entral-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-server-ee-certs</c\
entral-truststore-reference>
</ee-certs>
<raw-public-keys>
<central-truststore-reference>Raw Public Keys for TLS Se\
rvers</central-truststore-reference>
</raw-public-keys>
<tls12-psks/>
<tls13-epsks/>
</server-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-client>3.3. YANG Module π
this YANG module has normative references to [RFC4279], [RFC5280], [RFC6520], [RFC7250], [RFC9640], [RFC9641], and [RFC9642], and informative references to [RFC5056], [RFC5246], [RFC8446], [RFC9258], and [RFC9257] π
<CODE BEGINS> file "ietf-tls-client@2024-10-10.yang"
module ietf-tls-client {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-tls-client";
prefix tlsc;
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC 9640: YANG Data Types and Groupings for Cryptography";
}
import ietf-truststore {
prefix ts;
reference
"RFC 9641: A YANG Data Model for a Truststore";
}
import ietf-keystore {
prefix ks;
reference
"RFC 9642: A YANG Data Model for a Keystore";
}
import ietf-tls-common {
prefix tlscmn;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG List: NETCONF WG list <mailto:netconf@ietf.org>
WG Web: https://datatracker.ietf.org/wg/netconf
Author: Kent Watsen <mailto:kent+ietf@watsen.net>
Author: Jeff Hartley <mailto:intensifysecurity@gmail.com>";
description
"This module defines reusable groupings for TLS clients that
can be used as a basis for specific TLS client instances.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.
Copyright (c) 2024 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9645
(https://www.rfc-editor.org/info/rfc9645); see the RFC
itself for full legal notices.";
revision 2024-10-10 {
description
"Initial version";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
// Featuresokay bestie, the external PSK rules are where it gets very specific πβ¨
feature tls-client-keepalives {
description
"Per-socket TLS keepalive parameters are configurable for
TLS clients on the server implementing this feature.";
}
feature client-ident-x509-cert {
description
"Indicates that the client supports identifying itself
using X.509 certificates.";
reference
"RFC 5280:
Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile";
}
feature client-ident-raw-public-key {
description
"Indicates that the client supports identifying itself
using raw public keys.";
reference
"RFC 7250:
Using Raw Public Keys in Transport Layer Security (TLS)
and Datagram Transport Layer Security (DTLS)";
}
feature client-ident-tls12-psk {
if-feature "tlscmn:tls12";
description
"Indicates that the client supports identifying itself
using TLS 1.2 PSKs (pre-shared or pairwise symmetric keys).";
reference
"RFC 4279:
Pre-Shared Key Ciphersuites for Transport Layer Security
(TLS)";
}
feature client-ident-tls13-epsk {
if-feature "tlscmn:tls13";
description
"Indicates that the client supports identifying itself
using TLS 1.3 External PSKs (pre-shared keys).";
reference
"RFC 8446:
The Transport Layer Security (TLS) Protocol Version 1.3";
}
feature server-auth-x509-cert {
description
"Indicates that the client supports authenticating servers
using X.509 certificates.";
reference
"RFC 5280:
Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile";
}
feature server-auth-raw-public-key {
description
"Indicates that the client supports authenticating servers
using raw public keys.";
reference
"RFC 7250:
Using Raw Public Keys in Transport Layer Security (TLS)
and Datagram Transport Layer Security (DTLS)";
}
feature server-auth-tls12-psk {
description
"Indicates that the client supports authenticating servers
using PSKs (pre-shared or pairwise symmetric keys).";
reference
"RFC 4279:
Pre-Shared Key Ciphersuites for Transport Layer Security
(TLS)";
}
feature server-auth-tls13-epsk {
description
"Indicates that the client supports authenticating servers
using TLS 1.3 External PSKs (pre-shared keys).";
reference
"RFC 8446:
The Transport Layer Security (TLS) Protocol Version 1.3";
}
// Groupings
grouping tls-client-grouping {
description
"A reusable grouping for configuring a TLS client without
any consideration for how an underlying TCP session is
established.
Note that this grouping uses fairly typical descendant
node names such that a stack of 'uses' statements will
have name conflicts. It is intended that the consuming
data model will resolve the issue (e.g., by wrapping
the 'uses' statement in a container called
'tls-client-parameters'). This model purposely does
not do this itself so as to provide maximum flexibility
to consuming models.";
container client-identity {
nacm:default-deny-write;
presence "Indicates that a TLS-level client identity has been
configured. This statement is present so the
mandatory descendant nodes do not imply that this
node must be configured.";
description
"Identity credentials the TLS client MAY present when
establishing a connection to a TLS server. If not
configured, then client authentication is presumed to
occur in a protocol layer above TLS. When configured,
and requested by the TLS server when establishing a
TLS session, these credentials are passed in the
Certificate message defined in Section 7.4.2 of
RFC 5246 and Section 4.4.2 of RFC 8446.";
reference
"RFC 5246: The Transport Layer Security (TLS)
Protocol Version 1.2
RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3
RFC 9642: A YANG Data Model for a Keystore";
choice auth-type {
mandatory true;
description
"A choice amongst authentication types, of which one must
be enabled (via its associated 'feature') and selected.";
case certificate {
if-feature "client-ident-x509-cert";
container certificate {
description
"Specifies the client identity using a certificate.";
uses "ks:inline-or-keystore-end-entity-cert-with-key-"
+ "grouping" {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format, "ct:subject-public-key-'
+ 'info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference/asymmetric-key" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-'
+ 'key-format, "ct:subject-public-key-info-'
+ 'format")';
}
}
}
}
case raw-public-key {
if-feature "client-ident-raw-public-key";
container raw-private-key {
description
"Specifies the client identity using a raw
private key.";
uses ks:inline-or-keystore-asymmetric-key-grouping {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format, "ct:subject-public-key-'
+ 'info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-'
+ 'key-format, "ct:subject-public-key-info-'
+ 'format")';
}
}
}
}
case tls12-psk {
if-feature "client-ident-tls12-psk";
container tls12-psk {
description
"Specifies the client identity using a PSK (pre-shared
or pairwise symmetric key).";
uses ks:inline-or-keystore-symmetric-key-grouping;
leaf id {
type string;
description
"The key 'psk_identity' value used in the TLS
'ClientKeyExchange' message.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for
Transport Layer Security (TLS)";
}
}
}
case tls13-epsk {
if-feature "client-ident-tls13-epsk";
container tls13-epsk {
description
"An External Pre-Shared Key (EPSK) is established
or provisioned out of band, i.e., not from a TLS
connection. An EPSK is a tuple of (Base Key,
External Identity, Hash). EPSKs MUST NOT be
imported for (D)TLS 1.2 or prior versions. When
PSKs are provisioned out of band, the PSK identity
and the Key Derivation Function (KDF) hash algorithm
to be used with the PSK MUST also be provisioned.
The structure of this container is designed to satisfy
the requirements in Section 4.2.11 of RFC 8446, the
recommendations from Section 6 of RFC 9257, and the
EPSK input fields detailed in Section 5.1 of RFC 9258.
The base-key is based upon
'ks:inline-or-keystore-symmetric-key-grouping' in
order to provide users with flexible and secure
storage options.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3
RFC 9257: Guidance for External Pre-Shared Key
(PSK) Usage in TLS
RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
uses ks:inline-or-keystore-symmetric-key-grouping;
leaf external-identity {
type string;
mandatory true;
description
"As per Section 4.2.11 of RFC 8446 and Section 4.1
of RFC 9257, a sequence of bytes used to identify
an EPSK. A label for a pre-shared key established
externally.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3
RFC 9257: Guidance for External Pre-Shared Key
(PSK) Usage in TLS";
}
leaf hash {
type tlscmn:epsk-supported-hash;
default "sha-256";
description
"As per Section 4.2.11 of RFC 8446, for EPSKs,
the hash algorithm MUST be set when the PSK is
established; otherwise, default to SHA-256 if
no such algorithm is defined. The server MUST
ensure that it selects a compatible PSK (if any)
and cipher suite. Each PSK MUST only be used
with a single hash function.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3";
}
leaf context {
type string;
description
"As per Section 5.1 of RFC 9258, context MUST
include the context used to determine the EPSK,
if any exists. For example, context may include
information about peer roles or identities
to mitigate Selfie-style reflection attacks.
Since the EPSK is a key derived from an external
protocol or a sequence of protocols, context MUST
include a channel binding for the deriving
protocols (see RFC 5056). The details of this
binding are protocol specific and out of scope
for this document.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
leaf target-protocol {
type uint16;
description
"As per Section 3 of RFC 9258, the protocol
for which a PSK is imported for use.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
leaf target-kdf {
type uint16;
description
"As per Section 3 of RFC 9258, the Key Derivation
Function (KDF) for which a PSK is imported for
use.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
}
}
}
} // container client-identity
container server-authentication {
nacm:default-deny-write;
must "ca-certs or ee-certs or raw-public-keys or tls12-psks
or tls13-epsks";
description
"Specifies how the TLS client can authenticate TLS servers.
Any combination of credentials is additive and unordered.
Note that no configuration is required for authentication
based on PSK (pre-shared or pairwise symmetric key) as
the key is necessarily the same as configured in the
'../client-identity' node.";
container ca-certs {
if-feature "server-auth-x509-cert";
presence "Indicates that Certification Authority (CA)
certificates have been configured. This
statement is present so the mandatory
descendant nodes do not imply that this
node must be configured.";
description
"A set of CA certificates used by the TLS client to
authenticate TLS server certificates. A server
certificate is authenticated if it has a valid chain of
trust to a configured CA certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container ee-certs {
if-feature "server-auth-x509-cert";
presence "Indicates that End-Entity (EE) certificates have
been configured. This statement is present so
the mandatory descendant nodes do not imply
that this node must be configured.";
description
"A set of server certificates (i.e., EE certificates) used
by the TLS client to authenticate certificates presented
by TLS servers. A server certificate is authenticated if
it is an exact match to a configured server certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container raw-public-keys {
if-feature "server-auth-raw-public-key";
presence "Indicates that raw public keys have been
configured. This statement is present so
the mandatory descendant nodes do not imply
that this node must be configured.";
description
"A set of raw public keys used by the TLS client to
authenticate raw public keys presented by the TLS
server. A raw public key is authenticated if it
is an exact match to a configured raw public key.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-public-keys-grouping {
refine "inline-or-truststore/inline/inline-definition/"
+ "public-key" {
must 'derived-from-or-self(public-key-format,'
+ ' "ct:subject-public-key-info-format")';
}
refine "inline-or-truststore/central-truststore/"
+ "central-truststore-reference" {
must 'not(deref(.)/../ts:public-key/ts:public-key-'
+ 'format[not(derived-from-or-self(., "ct:subject-'
+ 'public-key-info-format"))])';
}
}
}
leaf tls12-psks {
if-feature "server-auth-tls12-psk";
type empty;
description
"Indicates that the TLS client can authenticate TLS servers
using configured PSKs (pre-shared or pairwise symmetric
keys).
No configuration is required since the PSK value is the
same as the PSK value configured in the 'client-identity'
node.";
}
leaf tls13-epsks {
if-feature "server-auth-tls13-epsk";
type empty;
description
"Indicates that the TLS client can authenticate TLS servers
using configured External PSKs (pre-shared keys).
No configuration is required since the PSK value is the
same as the PSK value configured in the 'client-identity'
node.";
}
} // container server-authentication
container hello-params {
nacm:default-deny-write;
if-feature "tlscmn:hello-params";
uses tlscmn:hello-params-grouping;
description
"Configurable parameters for the TLS hello message.";
} // container hello-params
container keepalives {
nacm:default-deny-write;
if-feature "tls-client-keepalives";
description
"Configures the keepalive policy for the TLS client.";
leaf peer-allowed-to-send {
type empty;
description
"Indicates that the remote TLS server is allowed to send
HeartbeatRequest messages, as defined by RFC 6520,
to this TLS client.";
reference
"RFC 6520: Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS) Heartbeat Extension";
}
container test-peer-aliveness {
presence "Indicates that the TLS client proactively tests the
aliveness of the remote TLS server.";
description
"Configures the keepalive policy to proactively test
the aliveness of the TLS server. An unresponsive
TLS server is dropped after approximately max-wait
* max-attempts seconds. The TLS client MUST send
HeartbeatRequest messages, as defined in RFC 6520.";
reference
"RFC 6520: Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS) Heartbeat Extension";
leaf max-wait {
type uint16 {
range "1..max";
}
units "seconds";
default "30";
description
"Sets the amount of time in seconds, after which a
TLS-level message will be sent to test the
aliveness of the TLS server if no data has been
received from the TLS server.";
}
leaf max-attempts {
type uint8;
default "3";
description
"Sets the maximum number of sequential keepalive
messages that can fail to obtain a response from
the TLS server before assuming the TLS server is
no longer alive.";
}
}
}
} // grouping tls-client-grouping
}
<CODE ENDS>4. The "ietf-tls-server" Module β¨
okay bestie, now we're on the server side π§ This section defines a YANG 1.1 module called "ietf-tls-server". The high-level overview is in Section 4.1, examples of how it gets used (the "Example Usage" bit) are in Section 4.2, and the YANG module itself is defined in Section 4.3.
4.1. Data Model Overview
this section gives you the overview of the "ietf-tls-server" module π we're looking at its features and groupings, so you can see the whole vibe before we dig into the details πΈ
4.1.1. Features β¨
okay so here's the full list of every "feature" statement in the "ietf-tls-server" module π the diagram below shows them all at once:
Features:
+-- tls-server-keepalives
+-- server-ident-x509-cert
+-- server-ident-raw-public-key
+-- server-ident-psk
+-- client-auth-supported
+-- client-auth-x509-cert
+-- client-auth-raw-public-key
+-- client-auth-pskthe diagram uses syntax that's similar to [RFC8340] but isn't actually defined there, so don't go looking for it in there π
for what each feature does, check out the YANG module itself, it has the descriptions π
4.1.2. Groupings π§
the "ietf-tls-server" module defines just one "grouping" statement:
- tls-server-grouping
and we'll get into it in the next subsection π
4.1.2.1. The "tls-server-grouping" Grouping πΈ
here's the tree diagram [RFC8340] for the "tls-server-grouping" grouping, it's giving full structure π
=============== NOTE: '\' line wrapping per RFC 8792 ================
grouping tls-server-grouping:
+-- server-identity
| +-- (auth-type)
| +--:(certificate) {server-ident-x509-cert}?
| | +-- certificate
| | +---u ks:inline-or-keystore-end-entity-cert-with-key\
-grouping
| +--:(raw-private-key) {server-ident-raw-public-key}?
| | +-- raw-private-key
| | +---u ks:inline-or-keystore-asymmetric-key-grouping
| +--:(tls12-psk) {server-ident-tls12-psk}?
| | +-- tls12-psk
| | +---u ks:inline-or-keystore-symmetric-key-grouping
| | +-- id-hint?
| | string
| +--:(tls13-epsk) {server-ident-tls13-epsk}?
| +-- tls13-epsk
| +---u ks:inline-or-keystore-symmetric-key-grouping
| +-- external-identity
| | string
| +-- hash?
| | tlscmn:epsk-supported-hash
| +-- context?
| | string
| +-- target-protocol?
| | uint16
| +-- target-kdf?
| uint16
+-- client-authentication! {client-auth-supported}?
| +-- ca-certs! {client-auth-x509-cert}?
| | +---u ts:inline-or-truststore-certs-grouping
| +-- ee-certs! {client-auth-x509-cert}?
| | +---u ts:inline-or-truststore-certs-grouping
| +-- raw-public-keys! {client-auth-raw-public-key}?
| | +---u ts:inline-or-truststore-public-keys-grouping
| +-- tls12-psks? empty {client-auth-tls12-psk}?
| +-- tls13-epsks? empty {client-auth-tls13-epsk}?
+-- hello-params {tlscmn:hello-params}?
| +---u tlscmn:hello-params-grouping
+-- keepalives {tls-server-keepalives}?
+-- peer-allowed-to-send? empty
+-- test-peer-aliveness!
+-- max-wait? uint16
+-- max-attempts? uint8here's the tea on each part β
- the "server-identity" node is where the server's identity credentials live πͺͺ and each one gets switched on by a "feature".
- the "client-authentication" node is optional π«Ά (client authentication MAY occur at a higher protocol layer). it sets up the trust anchors used to authenticate the TLS client, and each option is enabled by its own "feature" statement.
- the "hello-params" node must be enabled by a feature. it configures the parameters for the TLS sessions set up by this configuration.
- the "keepalives" node must be enabled by a feature. it has a flag that lets the TLS client test whether the TLS server is still alive π, plus a "presence" container so the TLS client's own aliveness can be tested. these aliveness-tests happen at the TLS protocol layer.
- for the grouping statements being referenced:
- the "inline-or-keystore-end-entity-cert-with-key-grouping" grouping is discussed in Section 2.1.3.6 of [RFC9642].
- the "inline-or-keystore-asymmetric-key-grouping" grouping is discussed in Section 2.1.3.4 of [RFC9642].
- the "inline-or-keystore-symmetric-key-grouping" grouping is discussed in Section 2.1.3.3 of [RFC9642].
- the "inline-or-truststore-public-keys-grouping" grouping is discussed in Section 2.1.3.4 of [RFC9641].
- the "inline-or-truststore-certs-grouping" grouping is discussed in Section 2.1.3.3 of [RFC9641].
- the "hello-params-grouping" grouping is discussed in Section 2.1.3.1 in this document.
4.1.3. Protocol-Accessible Nodes π¦
the "ietf-tls-server" module only defines "grouping" statements. other modules pick those up and use them to make protocol-accessible nodes. so when you implement this module, it doesn't create any protocol-accessible nodes by itself. no cap, it's just the blueprint π
4.2. Example Usage π
this section has two examples of the "tls-server-grouping" grouping filled in with some data. they're basically the same, except the first sets up the server identity with a local key and the second uses a key from a keystore π both match the examples in Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642] too, so everything lines up β¨
first up, the one with inline-definitions for the server identity and client authentication:
<!-- The outermost element below doesn't exist in the data model. -->
<!-- It simulates if the "grouping" were a "container" instead. -->
<tls-server
xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-server"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<!-- how this server will authenticate itself to the client -->
<server-identity>
<certificate>
<inline-definition>
<private-key-format>ct:rsa-private-key-format</private\
-key-format>
<cleartext-private-key>BASE64VALUE=</cleartext-private\
-key>
<cert-data>BASE64VALUE=</cert-data>
</inline-definition>
</certificate>
</server-identity>
<!-- which certificates will this server trust -->
<client-authentication>
<ca-certs>
<inline-definition>
<certificate>
<name>Identity Cert Issuer #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>Identity Cert Issuer #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</inline-definition>
</ca-certs>
<ee-certs>
<inline-definition>
<certificate>
<name>Application #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>Application #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</inline-definition>
</ee-certs>
<raw-public-keys>
<inline-definition>
<public-key>
<name>User A</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
<public-key>
<name>User B</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
</inline-definition>
</raw-public-keys>
<tls12-psks/>
<tls13-epsks/>
</client-authentication>
<keepalives>
<peer-allowed-to-send/>
</keepalives>
</tls-server>next, the one that uses central-keystore-references for the server identity and central-truststore-references for client authentication from the keystore ποΈ
<!-- The outermost element below doesn't exist in the data model. -->
<!-- It simulates if the "grouping" were a "container" instead. -->
<tls-server xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-server">
<!-- how this server will authenticate itself to the client -->
<server-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</server-identity>
<!-- which certificates will this server trust -->
<client-authentication>
<ca-certs>
<central-truststore-reference>trusted-client-ca-certs</c\
entral-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-client-ee-certs</c\
entral-truststore-reference>
</ee-certs>
<raw-public-keys>
<central-truststore-reference>Raw Public Keys for TLS Cl\
ients</central-truststore-reference>
</raw-public-keys>
<tls12-psks/>
<tls13-epsks/>
</client-authentication>
<keepalives>
<peer-allowed-to-send/>
</keepalives>
</tls-server>4.3. YANG Module π
this YANG module has normative references to [RFC4279], [RFC5280], [RFC6520], [RFC7250], [RFC9640], [RFC9641], and [RFC9642], and informative references to [RFC5056], [RFC5246], [RFC8446], [RFC9258], and [RFC9257] π
<CODE BEGINS> file "ietf-tls-server@2024-10-10.yang"
module ietf-tls-server {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-tls-server";
prefix tlss;
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC 9640: YANG Data Types and Groupings for Cryptography";
}
import ietf-truststore {
prefix ts;
reference
"RFC 9641: A YANG Data Model for a Truststore";
}
import ietf-keystore {
prefix ks;
reference
"RFC 9642: A YANG Data Model for a Keystore";
}
import ietf-tls-common {
prefix tlscmn;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG List: NETCONF WG list <mailto:netconf@ietf.org>
WG Web: https://datatracker.ietf.org/wg/netconf
Author: Kent Watsen <mailto:kent+ietf@watsen.net>
Author: Jeff Hartley <mailto:intensifysecurity@gmail.com>";
description
"This module defines reusable groupings for TLS servers that
can be used as a basis for specific TLS server instances.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.
Copyright (c) 2024 IETF Trust and the persons identified
as authors of the code. All rights reserved.okay so the license bit is up next, and it's giving legal-but-make-it-fashion π Here's the rest of the module header, verbatim:
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9645
(https://www.rfc-editor.org/info/rfc9645); see the RFC
itself for full legal notices.";
revision 2024-10-10 {
description
"Initial version.";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
// Features
feature tls-server-keepalives {
description
"Per-socket TLS keepalive parameters are configurable for
TLS servers on the server implementing this feature.";
}
feature server-ident-x509-cert {
description
"Indicates that the server supports identifying itself
using X.509 certificates.";
reference
"RFC 5280:
Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile";
}
feature server-ident-raw-public-key {
description
"Indicates that the server supports identifying itself
using raw public keys.";
reference
"RFC 7250:
Using Raw Public Keys in Transport Layer Security (TLS)
and Datagram Transport Layer Security (DTLS)";
}
feature server-ident-tls12-psk {
if-feature "tlscmn:tls12";
description
"Indicates that the server supports identifying itself
using TLS 1.2 PSKs (pre-shared or pairwise symmetric keys).";
reference
"RFC 4279:
Pre-Shared Key Ciphersuites for Transport Layer Security
(TLS)";
}
feature server-ident-tls13-epsk {
if-feature "tlscmn:tls13";
description
"Indicates that the server supports identifying itself
using TLS 1.3 External PSKs (pre-shared keys).";
reference
"RFC 8446:
The Transport Layer Security (TLS) Protocol Version 1.3";
}
feature client-auth-supported {
description
"Indicates that the configuration for how to authenticate
clients can be configured herein. TLS-level client
authentication may not be needed when client authentication
is expected to occur only at another protocol layer.";
}
feature client-auth-x509-cert {
description
"Indicates that the server supports authenticating clients
using X.509 certificates.";
reference
"RFC 5280:
Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile";
}
feature client-auth-raw-public-key {
description
"Indicates that the server supports authenticating clients
using raw public keys.";
reference
"RFC 7250:
Using Raw Public Keys in Transport Layer Security (TLS)
and Datagram Transport Layer Security (DTLS)";
}
feature client-auth-tls12-psk {
description
"Indicates that the server supports authenticating clients
using PSKs (pre-shared or pairwise symmetric keys).";
reference
"RFC 4279:
Pre-Shared Key Ciphersuites for Transport Layer Security
(TLS)";
}
feature client-auth-tls13-epsk {
description
"Indicates that the server supports authenticating clients
using TLS 1.3 External PSKs (pre-shared keys).";
reference
"RFC 8446:
The Transport Layer Security (TLS) Protocol Version 1.3";
}
// Groupings
grouping tls-server-grouping {
description
"A reusable grouping for configuring a TLS server without
any consideration for how underlying TCP sessions are
established.
Note that this grouping uses fairly typical descendant
node names such that a stack of 'uses' statements will
have name conflicts. It is intended that the consuming
data model will resolve the issue (e.g., by wrapping
the 'uses' statement in a container called
'tls-server-parameters'). This model purposely does
not do this itself so as to provide maximum flexibility
to consuming models.";
container server-identity {
nacm:default-deny-write;
description
"A locally defined or referenced End-Entity (EE) certificate,
including any configured intermediate certificates, that
the TLS server will present when establishing a TLS
connection in its Certificate message, as defined in
Section 7.4.2 of RFC 5246 and Section 4.4.2 of RFC 8446.";
reference
"RFC 5246: The Transport Layer Security (TLS) Protocol
Version 1.2
RFC 8446: The Transport Layer Security (TLS) Protocol
Version 1.3
RFC 9642: A YANG Data Model for a Keystore";
choice auth-type {
mandatory true;
description
"A choice amongst authentication types, of which one must
be enabled (via its associated 'feature') and selected.";
case certificate {
if-feature "server-ident-x509-cert";
container certificate {
description
"Specifies the server identity using a certificate.";
uses "ks:inline-or-keystore-end-entity-cert-with-key-"
+ "grouping" {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format,'
+ ' "ct:subject-public-'
+ 'key-info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference/asymmetric-key" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-key'
+ '-format, "ct:subject-public-key-info-format")';
}
}
}
}
case raw-private-key {
if-feature "server-ident-raw-public-key";
container raw-private-key {
description
"Specifies the server identity using a raw
private key.";
uses ks:inline-or-keystore-asymmetric-key-grouping {
refine "inline-or-keystore/inline/inline-definition" {
must 'not(public-key-format) or derived-from-or-self'
+ '(public-key-format,'
+ ' "ct:subject-public-'
+ 'key-info-format")';
}
refine "inline-or-keystore/central-keystore/"
+ "central-keystore-reference" {
must 'not(deref(.)/../ks:public-key-format) or '
+ 'derived-from-or-self(deref(.)/../ks:public-key'
+ '-format, "ct:subject-public-key-info-format")';
}
}
}
}
case tls12-psk {
if-feature "server-ident-tls12-psk";
container tls12-psk {
description
"Specifies the server identity using a PSK (pre-shared
or pairwise symmetric key).";
uses ks:inline-or-keystore-symmetric-key-grouping;
leaf id-hint {
type string;
description
"The key 'psk_identity_hint' value used in the TLS
'ServerKeyExchange' message.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for
Transport Layer Security (TLS)";
}
}
}
case tls13-epsk {
if-feature "server-ident-tls13-epsk";
container tls13-epsk {
description
"An External Pre-Shared Key (EPSK) is established
or provisioned out of band, i.e., not from a TLS
connection. An EPSK is a tuple of (Base Key,
External Identity, Hash). EPSKs MUST NOT be
imported for (D)TLS 1.2 or prior versions.
When PSKs are provisioned out of band, the PSK
identity and the KDF hash algorithm to be used
with the PSK MUST also be provisioned.Okay, that's where this part stops, bestie π¦ The tls13-epsk description is still open, so the next part picks up right after with the PSK MUST also be provisioned. πΈ β¨
The structure of this container is designed to
satisfy the requirements in Section 4.2.11 of
RFC 8446, the recommendations from Section 6 of
RFC 9257, and the EPSK input fields detailed in
Section 5.1 of RFC 9258. The base-key is based
upon 'ks:inline-or-keystore-symmetric-key-grouping'
in order to provide users with flexible and
secure storage options.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3
RFC 9257: Guidance for External Pre-Shared Key
(PSK) Usage in TLS
RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
uses ks:inline-or-keystore-symmetric-key-grouping;
leaf external-identity {
type string;
mandatory true;
description
"As per Section 4.2.11 of RFC 8446 and Section 4.1
of RFC 9257, a sequence of bytes used to identify
an EPSK. A label for a pre-shared key established
externally.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3
RFC 9257: Guidance for External Pre-Shared Key
(PSK) Usage in TLS";
}
leaf hash {
type tlscmn:epsk-supported-hash;
default "sha-256";
description
"As per Section 4.2.11 of RFC 8446, for EPSKs,
the hash algorithm MUST be set when the PSK is
established; otherwise, default to SHA-256 if
no such algorithm is defined. The server MUST
ensure that it selects a compatible PSK (if any)
and cipher suite. Each PSK MUST only be used
with a single hash function.";
reference
"RFC 8446: The Transport Layer Security (TLS)
Protocol Version 1.3";
}
leaf context {
type string;
description
"As per Section 5.1 of RFC 9258, context MUST
include the context used to determine the EPSK,
if any exists. For example, context may include
information about peer roles or identities
to mitigate Selfie-style reflection attacks.
Since the EPSK is a key derived from an external
protocol or sequence of protocols, context MUST
include a channel binding for the deriving
protocols (see RFC 5056). The details of this
binding are protocol specific and out of scope
for this document.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
leaf target-protocol {
type uint16;
description
"As per Section 3.1 of RFC 9258, the protocol
for which a PSK is imported for use.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
leaf target-kdf {
type uint16;
description
"As per Section 3 of RFC 9258, the KDF for
which a PSK is imported for use.";
reference
"RFC 9258: Importing External Pre-Shared Keys
(PSKs) for TLS 1.3";
}
}
}
}
} // container server-identity
container client-authentication {
if-feature "client-auth-supported";
nacm:default-deny-write;
must "ca-certs or ee-certs or raw-public-keys or tls12-psks
or tls13-epsks";
presence "Indicates that client authentication is supported
(i.e., that the server will request clients send
certificates). If not configured, the TLS server
SHOULD NOT request that TLS clients provide
authentication credentials.";
description
"Specifies how the TLS server can authenticate TLS clients.
Any combination of credentials is additive and unordered.
Note that no configuration is required for authentication
based on PSK (pre-shared or pairwise symmetric key) as the
the key is necessarily the same as configured in the
'../server-identity' node.";
container ca-certs {
if-feature "client-auth-x509-cert";
presence "Indicates that Certification Authority (CA)
certificates have been configured. This
statement is present so the mandatory
descendant nodes do not imply that this node
must be configured.";
description
"A set of CA certificates used by the TLS server to
authenticate TLS client certificates. A client
certificate is authenticated if it has a valid chain
of trust to a configured CA certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container ee-certs {
if-feature "client-auth-x509-cert";
presence "Indicates that EE certificates have been
configured. This statement is present so the
mandatory descendant nodes do not imply that
this node must be configured.";
description
"A set of client certificates (i.e., EE certificates)
used by the TLS server to authenticate
certificates presented by TLS clients. A client
certificate is authenticated if it is an exact
match to a configured client certificate.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-certs-grouping;
}
container raw-public-keys {
if-feature "client-auth-raw-public-key";
presence "Indicates that raw public keys have been
configured. This statement is present so
the mandatory descendant nodes do not imply
that this node must be configured.";
description
"A set of raw public keys used by the TLS server to
authenticate raw public keys presented by the TLS
client. A raw public key is authenticated if it
is an exact match to a configured raw public key.";
reference
"RFC 9641: A YANG Data Model for a Truststore";
uses ts:inline-or-truststore-public-keys-grouping {
refine "inline-or-truststore/inline/inline-definition/"
+ "public-key" {
must 'derived-from-or-self(public-key-format,'
+ ' "ct:subject-public-key-info-format")';
}
refine "inline-or-truststore/central-truststore/"
+ "central-truststore-reference" {
must 'not(deref(.)/../ts:public-key/ts:public-key-'
+ 'format[not(derived-from-or-self(., "ct:subject-'
+ 'public-key-info-format"))])';
}
}
}
leaf tls12-psks {
if-feature "client-auth-tls12-psk";
type empty;
description
"Indicates that the TLS server can authenticate TLS clients
using configured PSKs (pre-shared or pairwise symmetric
keys).
No configuration is required since the PSK value is the
same as PSK value configured in the 'server-identity'
node.";
}
leaf tls13-epsks {
if-feature "client-auth-tls13-epsk";
type empty;
description
"Indicates that the TLS 1.3 server can authenticate TLS
clients using configured External PSKs (pre-shared keys).
No configuration is required since the PSK value is the
same as PSK value configured in the 'server-identity'
node.";
}
} // container client-authentication
container hello-params {
nacm:default-deny-write;
if-feature "tlscmn:hello-params";
uses tlscmn:hello-params-grouping;
description
"Configurable parameters for the TLS hello message.";
} // container hello-params
container keepalives {
nacm:default-deny-write;
if-feature "tls-server-keepalives";
description
"Configures the keepalive policy for the TLS server.";
leaf peer-allowed-to-send {
type empty;
description
"Indicates that the remote TLS client is allowed to send
HeartbeatRequest messages, as defined by RFC 6520,
to this TLS server.";
reference
"RFC 6520: Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS) Heartbeat Extension";
}
container test-peer-aliveness {
presence "Indicates that the TLS server proactively tests the
aliveness of the remote TLS client.";
description
"Configures the keepalive policy to proactively test
the aliveness of the TLS client. An unresponsive
TLS client is dropped after approximately max-wait
* max-attempts seconds.";
leaf max-wait {
type uint16 {
range "1..max";
}
units "seconds";
default "30";
description
"Sets the amount of time in seconds, after which a
TLS-level message will be sent to test the
aliveness of the TLS client if no data has been
received from the TLS client.";
}
leaf max-attempts {
type uint8;
default "3";
description
"Sets the maximum number of sequential keepalive
messages that can fail to obtain a response from
the TLS client before assuming the TLS client is
no longer alive.";
}
}
} // container keepalives
} // grouping tls-server-grouping
}5. Security Considerations π
okay bestie, this is the part where we get serious for a sec π¨ The three IETF YANG modules in this document only define groupings, so they're not going to be deployed as standalone modules π ββοΈ Their security implications can change depending on how other modules use them, so the security story is context dependent π
So if you're the one designing a module that imports these groupings, you need to do your own security analysis π«Ά Don't just assume the groupings are safe on their own, because the full picture only shows up once they're plugged into your module ππ₯
5.1. Considerations for the "iana-tls-cipher-suite-algs" YANG Module
Okay bestie, this one follows the template from Section 3.7.1 of [RFC8407] πβ¨
The "iana-tls-cipher-suite-algs" YANG module is a data model you access through YANG-based management protocols like NETCONF [RFC6241] and RESTCONF [RFC8040] π¦ Those protocols come with secure transport layers you have to implement (Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mutual authentication, which is non-negotiable π
The Network Configuration Access Control Model (NACM) [RFC8341] lets you restrict particular users to a preset subset of protocol operations and content. Very controlling, very iconic π
This module defines YANG enumerations for a public, IANA-maintained registry π Enumerations aren't security-sensitive, since they're statically defined in a publicly accessible YANG module πΈ IANA MAY deprecate and/or obsolete enumerations over time when that's needed to fix security issues in the algorithms π₯
This module doesn't define any writable nodes, RPCs, actions, or notifications, so the security considerations for those aren't covered here π«Ά
5.2. Considerations for the "ietf-tls-common" YANG Module
This section is also modeled after the template in Section 3.7.1 of [RFC8407] β¨
The "ietf-tls-common" YANG module is another data model you access through YANG-based management protocols like NETCONF [RFC6241] and RESTCONF [RFC8040] π The same mandatory-to-implement secure transports apply (Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]), along with mandatory-to-implement mutual authentication π
NACM [RFC8341] again gives you the tools to restrict particular users to a preconfigured subset of all available protocol operations and content π§
Heads up: this module uses groupings from other YANG modules, and those define nodes that might be sensitive or vulnerable in network environments π Check the Security Considerations for the dependent YANG modules to see which nodes those are β¨
None of the readable data nodes in this module are considered sensitive or vulnerable in network environments π The NACM default-deny-all extension hasn't been set on any data nodes in this module π
None of the writable data nodes in this module are considered sensitive or vulnerable in network environments either π The NACM default-deny-write extension hasn't been set on any data nodes in this module π«Ά
This module defines the generate-asymmetric-key-pair RPC. If the ct:cleartext-private-keys feature is enabled and the client requests it, that RPC can return the private key in cleartext form π It is NOT RECOMMENDED for private keys to pass the server's security perimeter π¨
This module doesn't define any actions or notifications, so the security considerations for those aren't provided here π¦
5.3. Considerations for the "ietf-tls-client" YANG Module
This section follows the Section 3.7.1 template from [RFC8407] too πΈ
The "ietf-tls-client" YANG module is a data model you access through YANG-based management protocols like NETCONF [RFC6241] and RESTCONF [RFC8040] π Same deal: mandatory-to-implement secure transports (Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication π
NACM [RFC8341] restricts particular users to a preconfigured subset of protocol operations and content π§
This module uses groupings from other YANG modules that define nodes which may be sensitive or vulnerable in network environments, so review the Security Considerations for those dependent modules π
None of the readable data nodes in this module are considered sensitive or vulnerable in network environments β¨ The NACM default-deny-all extension hasn't been set on any data nodes in this module π
Okay, now this part is serious π All the writable data nodes defined by this module may be considered sensitive or vulnerable in some network environments. Any change to a key, or to a reference to a key, could seriously alter the implemented security policy π So the NACM extension default-deny-write has been set on all data nodes in this module π
This module doesn't define any RPCs, actions, or notifications, so the security considerations for those aren't provided here π«Ά
5.4. Considerations for the "ietf-tls-server" YANG Module
This section follows the Section 3.7.1 template from [RFC8407] as well π
The "ietf-tls-server" YANG module is a data model you access through YANG-based management protocols like NETCONF [RFC6241] and RESTCONF [RFC8040] π¦ It has the same mandatory-to-implement secure transports (Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication π
NACM [RFC8341] lets you restrict particular users to a preconfigured subset of protocol operations and content π
This module uses groupings from other YANG modules that define nodes which may be sensitive or vulnerable in network environments. Please check the Security Considerations for the dependent YANG modules to see which nodes those are π
None of the readable data nodes in this module are considered sensitive or vulnerable in network environments π The NACM default-deny-all extension hasn't been set on any data nodes in this module π
Please be aware that this module uses the "key" and "private-key" nodes from the "ietf-crypto-types" module [RFC9640]. Those nodes have the NACM extension default-deny-all set, which prevents unrestricted read access to the cleartext key values π
All the writable data nodes defined by this module may be considered sensitive or vulnerable in some network environments. Any change to a key, or to a reference to a key, could dramatically alter the implemented security policy π± That's why the NACM extension default-deny-write has been set on all data nodes in this module π‘οΈ
This module doesn't define any RPCs, actions, or notifications, so the security considerations for those aren't provided here π«Ά
6. IANA Considerations β¨
6.1. The IETF XML Registry
IANA has registered the following four URIs in the "ns" registry of the "IETF XML Registry" [RFC3688] π§
URI: urn:ietf:params:xml:ns:yang:iana-tls-cipher-suite-algs
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-tls-common
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-tls-client
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-tls-server
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.6.2. The YANG Module Names Registry
IANA has registered the following four YANG modules in the "YANG Module Names" registry [RFC6020] π
name: iana-tls-cipher-suite-algs
Maintained by IANA: Y
namespace: urn:ietf:params:xml:ns:yang:iana-tls-cipher-suite-algs
prefix: tlscsa
reference: RFC 9645
name: ietf-tls-common
Maintained by IANA: N
namespace: urn:ietf:params:xml:ns:yang:ietf-tls-common
prefix: tlscmn
reference: RFC 9645
name: ietf-tls-client
Maintained by IANA: N
namespace: urn:ietf:params:xml:ns:yang:ietf-tls-client
prefix: tlsc
reference: RFC 9645
name: ietf-tls-server
Maintained by IANA: N
namespace: urn:ietf:params:xml:ns:yang:ietf-tls-server
prefix: tlss
reference: RFC 96456.3. Considerations for the "iana-tls-cipher-suite-algs" YANG Module
This section follows the template in Section 4.30.3.1 of [RFC8407BIS] π
IANA used the script in Appendix A to generate the IANA-maintained "iana-tls-cipher-suite-algs" YANG module π You can grab it from the "YANG Parameters" registry [IANA-YANG-PARAMETERS] π
IANA has added the following note to the registry π
| New values must not be directly added to the "iana-tls-cipher-
| suite-algs" YANG module. They must instead be added to the "TLS
| Cipher Suites" registry in the "Transport Layer Security (TLS)
| Parameters" registry group [IANA-CIPHER-ALGS].When a value is added to the "TLS Cipher Suites" registry, a new "enum" statement must be added to the "iana-tls-cipher-suite-algs" YANG module. The "enum" statement, and its substatements, should be defined like this π§
enum
Replicates a name from the registry.
value
Contains the decimal value of the IANA-assigned value.
status
Include only if a registration has been deprecated or obsoleted.
An IANA "Recommended" value "N" maps to YANG status "deprecated".
Since the registry is unable to express a logical "MUST NOT"
recommendation, there is no mapping to YANG status "obsolete",
which is unfortunate given the moving of single-DES and
International Data Encryption Algorithm (IDEA) TLS cipher suites
to Historic [RFC8996].
description
Contains "Enumeration for the 'TLS_FOO' algorithm", where
"TLS_FOO" is a placeholder for the algorithm's name (e.g.,
"TLS_PSK_WITH_AES_256_CBC_SHA").
reference
Replicates the reference(s) from the registry with the title of
the document(s) added.Unassigned or reserved values are not present in the module π ββοΈ
When the "iana-tls-cipher-suite-algs" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements. The "revision" must have a "description" statement explaining why the update occurred, and it must have a "reference" substatement that points to the document defining the registry update that caused the change. For instance π
revision 2024-10-10 {
description
"This update reflects the update made to the underlying
'Foo Bar' registry per RFC XXXX.";
reference
"RFC XXXX: Extend the Foo Bar Registry
to Support Something Important";
}IANA has added the following note to the "TLS Cipher Suites" registry under the "Transport Layer Security (TLS) Parameters" registry group [IANA-CIPHER-ALGS] π
| When this registry is modified, the YANG module "iana-tls-cipher-
| suite-algs" [IANA-YANG-PARAMETERS] must be updated as defined in
| RFC 9645.7. References
7.1. Normative References β¨
okay so here are the normative references, aka the docs this spec leans on the hardest π
[FIPS180-4] National Institute of Standards and Technology (NIST), "Secure Hash Standard (SHS)", FIPS PUB 180-4, DOI 10.6028/NIST.FIPS.180-4, August 2015, https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf.
[FIPS186-5] National Institute of Standards and Technology (NIST), "Digital Signature Standard (DSS)", FIPS 186-5, DOI 10.6028/NIST.FIPS.186-5, February 2023, https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5.pdf.
[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. πΈ
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006, https://www.rfc-editor.org/info/rfc4252. π
[RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key Ciphersuites for Transport Layer Security (TLS)", RFC 4279, DOI 10.17487/RFC4279, December 2005, https://www.rfc-editor.org/info/rfc4279. ποΈ
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, https://www.rfc-editor.org/info/rfc5280.
[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois Counter Mode (GCM) Cipher Suites for TLS", RFC 5288, DOI 10.17487/RFC5288, August 2008, https://www.rfc-editor.org/info/rfc5288.
[RFC5289] Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA-256/384 and AES Galois Counter Mode (GCM)", RFC 5289, DOI 10.17487/RFC5289, August 2008, https://www.rfc-editor.org/info/rfc5289.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, https://www.rfc-editor.org/info/rfc6020.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, https://www.rfc-editor.org/info/rfc6241.
[RFC6520] Seggelmann, R., Tuexen, M., and M. Williams, "Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) Heartbeat Extension", RFC 6520, DOI 10.17487/RFC6520, February 2012, https://www.rfc-editor.org/info/rfc6520. π
[RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J., Weiler, S., and T. Kivinen, "Using Raw Public Keys in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, June 2014, https://www.rfc-editor.org/info/rfc7250.
[RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication", RFC 7589, DOI 10.17487/RFC7589, June 2015, https://www.rfc-editor.org/info/rfc7589.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, https://www.rfc-editor.org/info/rfc7950.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, https://www.rfc-editor.org/info/rfc8040.
[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. π
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, https://www.rfc-editor.org/info/rfc8341.
[RFC8422] Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier", RFC 8422, DOI 10.17487/RFC8422, August 2018, https://www.rfc-editor.org/info/rfc8422.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, https://www.rfc-editor.org/info/rfc8446. π
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, https://www.rfc-editor.org/info/rfc9000. β‘
[RFC9640] Watsen, K., "YANG Data Types and Groupings for Cryptography", RFC 9640, DOI 10.17487/RFC9640, October 2024, https://www.rfc-editor.org/info/rfc9640.
[RFC9641] Watsen, K., "A YANG Data Model for a Truststore", RFC 9641, DOI 10.17487/RFC9641, October 2024, https://www.rfc-editor.org/info/rfc9641.
[RFC9642] Watsen, K., "A YANG Data Model for a Keystore", RFC 9642, DOI 10.17487/RFC9642, October 2024, https://www.rfc-editor.org/info/rfc9642.
7.2. Informative References π¦
and these are the informative ones, the extra reading that rounds out the picture π§
[HTTP-CLIENT-SERVER] Watsen, K., "YANG Groupings for HTTP Clients and HTTP Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-http-client-server-23, 15 August 2024, https://datatracker.ietf.org/doc/html/draft-ietf-netconf-http-client-server-23.
[IANA-CIPHER-ALGS] IANA, "TLS Cipher Suites", https://www.iana.org/assignments/tls-parameters/.
[IANA-YANG-PARAMETERS] IANA, "YANG Parameters", https://www.iana.org/assignments/yang-parameters.
[NETCONF-CLIENT-SERVER] Watsen, K., "NETCONF Client and Server Models", Work in Progress, Internet-Draft, draft-ietf-netconf-netconf-client-server-37, 14 August 2024, https://datatracker.ietf.org/doc/html/draft-ietf-netconf-netconf-client-server-37.
[RESTCONF-CLIENT-SERVER] Watsen, K., "RESTCONF Client and Server Models", Work in Progress, Internet-Draft, draft-ietf-netconf-restconf-client-server-38, 14 August 2024, https://datatracker.ietf.org/doc/html/draft-ietf-netconf-restconf-client-server-38.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, https://www.rfc-editor.org/info/rfc3688.
[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure Channels", RFC 5056, DOI 10.17487/RFC5056, November 2007, https://www.rfc-editor.org/info/rfc5056.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008, https://www.rfc-editor.org/info/rfc5246.
[RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home", RFC 8071, DOI 10.17487/RFC8071, February 2017, https://www.rfc-editor.org/info/rfc8071. π
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017, https://www.rfc-editor.org/info/rfc8259.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, https://www.rfc-editor.org/info/rfc8340. π³
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, https://www.rfc-editor.org/info/rfc8342.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", BCP 216, RFC 8407, DOI 10.17487/RFC8407, October 2018, https://www.rfc-editor.org/info/rfc8407.
[RFC8407BIS] Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", Work in Progress, Internet-Draft, draft-ietf-netmod-rfc8407bis-17, 27 September 2024, https://datatracker.ietf.org/doc/html/draft-ietf-netmod-rfc8407bis-17.
[RFC8996] Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS 1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021, https://www.rfc-editor.org/info/rfc8996. π«
[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, June 2022, https://www.rfc-editor.org/info/rfc9110.
[RFC9257] Housley, R., Hoyland, J., Sethi, M., and C. A. Wood, "Guidance for External Pre-Shared Key (PSK) Usage in TLS", RFC 9257, DOI 10.17487/RFC9257, July 2022, https://www.rfc-editor.org/info/rfc9257.
[RFC9258] Benjamin, D. and C. A. Wood, "Importing External Pre-Shared Keys (PSKs) for TLS 1.3", RFC 9258, DOI 10.17487/RFC9258, July 2022, https://www.rfc-editor.org/info/rfc9258.
[RFC9643] Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients and TCP Servers", RFC 9643, DOI 10.17487/RFC9643, October 2024, https://www.rfc-editor.org/info/rfc9643.
[RFC9644] Watsen, K., "YANG Groupings for SSH Clients and SSH Servers", RFC 9644, DOI 10.17487/RFC9644, October 2024, https://www.rfc-editor.org/info/rfc9644.
[SYSTEM-CONFIG] Ma, Q., Wu, Q., and C. Feng, "System-defined Configuration", Work in Progress, Internet-Draft, draft-ietf-netmod-system-config-09, 29 September 2024, https://datatracker.ietf.org/doc/html/draft-ietf-netmod-system-config-09. βοΈ
[W3C.REC-xml-20081126] Bray, T., Paoli, J., Sperberg-McQueen, C. M., Maler, E., and F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth Edition)", W3C Recommendation REC-xml-20081126, November 2008, https://www.w3.org/TR/xml/. π₯°
Appendix A. Script to Generate IANA-Maintained YANG Modules πβ¨
This section is not normative. π
okay bestie so this part is basically a little Python script ππ«Ά that was used to make the first IANA-maintained "iana-tls-cipher-suite-algs" YANG module π¦. The module lives over at [IANA-YANG-PARAMETERS] and it's giving "auto-generated but make it iconic" π.
To run it, just type python gen-yang-modules.py in your terminal and it spits out the YANG module file in whatever folder you're currently sitting in ππΈ.
Heads up π: the script does NOT copy the "revision" statements from the previous or current YANG module. So if you need those, you gotta copy them over by hand, no cap π.
Here's the whole script, verbatim, with the line wrapping kept exactly as RFC 8792 wants it π:
=============== NOTE: '\\' line wrapping per RFC 8792 ===============
import re
import csv
import requests
import textwrap
import requests_cache
from io import StringIO
from datetime import datetime
# Metadata for the one YANG module produced by this script
MODULES = [
{
"csv_url": "https://www.iana.org/assignments/tls-parameters/\
\tls-parameters-4.csv",
"spaced_name": "cipher-suite",
"hyphenated_name": "cipher-suite",
"prefix": "tlscsa",
}
]
def create_module_begin(module, f):
# Define template for all four modules
PREAMBLE_TEMPLATE="""
module iana-tls-HNAME-algs {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:iana-tls-HNAME-algs";
prefix PREFIX;
organization
"Internet Assigned Numbers Authority (IANA)";
contact
"Postal: ICANN
12025 Waterfront Drive, Suite 300
Los Angeles, CA 90094-2536
United States of America
Tel: +1 310 301 5800
Email: <iana@iana.org>";
description
"This module defines enumerations for the cipher suite
algorithms defined in the 'TLS Cipher Suites' registry
under the 'Transport Layer Security (TLS) Parameters'
registry group maintained by IANA.
Copyright (c) 2024 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
The initial version of this YANG module is part of RFC 9645
(https://www.rfc-editor.org/info/rfc9645); see the RFC
itself for full legal notices.
All versions of this module are published by IANA
(https://www.iana.org/assignments/yang-parameters).";
revision DATE {
description
"This initial version of the module was created using
the script defined in RFC 9645 to reflect the contents
of the SNAME algorithms registry maintained by IANA.";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
typedef tls-HNAME-algorithm {
type enumeration {
"""
# Replacements
rep = {
"DATE": datetime.today().strftime('%Y-%m-%d'),
"YEAR": datetime.today().strftime('%Y'),
"SNAME": module["spaced_name"],
"HNAME": module["hyphenated_name"],
"PREFIX": module["prefix"]
}
# Do the replacement
rep = dict((re.escape(k), v) for k, v in rep.items())
pattern = re.compile("|".join(rep.keys()))
text = pattern.sub(lambda m: rep[re.escape(m.group(0))], PREAMBLE_TEMPLATE)
# Write preamble into the file
f.write(text)
def create_module_body(module, f):
# Fetch the current CSV file from IANA
r = requests.get(module["csv_url"])
assert r.status_code == 200, "Could not get " + module["csv_url"]
# Parse each CSV line
with StringIO(r.text) as csv_file:
csv_reader = csv.DictReader(csv_file)
for row in csv_reader:
# Skip reserved algs
if row["Description"].startswith("Unassigned"):
continue
# Skip unassigned algs
if row["Description"].startswith("Reserved"):
continue
# Ensure this is the TLS line
assert row["Description"].startswith("TLS_"), "Unrecognized description: '" + row["Description"] + "'"
# Set the 'refs' and 'titles' lists
if row["Reference"] == "":
pass # skip when the Reference field is empty
else:
# There may be more than one ref
refs = row["Reference"][1:-1] # remove the '[' and ']' chars
refs = refs.split("][")
titles = []
for ref in refs:
# Ascertain the ref's title
if ref.startswith("RFC"):
# Fetch the current BIBTEX entry
bibtex_url="https://datatracker.ietf.org/doc/"+ ref.lower() + "/bibtex/"
r = requests.get(bibtex_url)
assert r.status_code == 200, "Could not GET " + bibtex_url
# Append to 'titles' value from the "title" line
for item in r.text.split("\n"):
if "title =" in item:
title = re.sub('.*{{(.*)}}.*', r'\g<1>', item)
if title.startswith("ECDHE\_PSK"):
title = re.sub("ECDHE\\\\_PSK", "ECDHE_PSK", title)
titles.append(re.sub('.*{{(.*)}}.*', r'\g<1>', title))
break
else:
raise Exception("RFC title not found")
# Insert a space: "RFC9645" --> "RFC 9645"
index = refs.index(ref)
refs[index] = "RFC " + ref[3:]
elif ref == "IESG Action 2018-08-16":
# Rewrite the ref value
index = refs.index(ref)
refs[index] = "IESG Action"
# Let title be something descriptive
titles.append("IESG Action 2018-08-16")
elif ref == "draft-irtf-cfrg-aegis-aead-08":
# Manually set the document's title
titles.append("The AEGIS Family of Authenticated Encryption Algorithms")
elif ref:
raise Exception(f'ref "{ref}" not found')
else:
raise Exception(f'ref missing: {row}')
# Write out the enum
f.write(f' enum {row["Description"]} {{\n');
if row["Recommended"] == 'N':
f.write(f' status deprecated;\n')
f.write(f' description\n')
description = f' "Enumeration for the \'{row["Description"]}\' algorithm.";'
description = textwrap.fill(description, width=69, subsequent_indent=" ")
f.write(f'{description}\n')
f.write(' reference\n')
f.write(' "')
if row["Reference"] == "":
f.write('Missing in IANA registry.')
else:
ref_len = len(refs)
for i in range(ref_len):
ref = refs[i]
f.write(f'{ref}:\n')
title = " " + titles[i]
if i == ref_len - 1:
title += '";'
title = textwrap.fill(title, width=69, subsequent_indent=" ")
f.write(f'{title}')
if i != ref_len - 1:
f.write('\n ')
f.write('\n')
f.write(' }\n')
def create_module_end(module, f):
# Close out the enumeration, typedef, and module
f.write(" }\n")
f.write(" description\n")
f.write(f' "An enumeration for TLS {module["spaced_name"]} algorithms.";\n')
f.write(" }\n")
f.write('\n')
f.write('}\n')
def create_module(module):
# Install cache for 8x speedup
requests_cache.install_cache()
# Ascertain the yang module's name
yang_module_name = "iana-tls-" + module["hyphenated_name"] + "-algs.yang"
# Create yang module file
with open(yang_module_name, "w") as f:
create_module_begin(module, f)
create_module_body(module, f)
create_module_end(module, f)
def main():
for module in MODULES:
create_module(module)
if __name__ == "__main__":
main()Acknowledgements π«Άπ·
The authors would like to thank the following for lively discussions on list and in the halls (ordered by first name): Alan Luchuk, Andy Bierman, BalΓ‘zs KovΓ‘cs, Benoit Claise, Bert Wijnen, David Lamparter, Dhruv Dhody, Γric Vyncke, Gary Wu, Henk Birkholz, Jeff Hartley, JΓΌrgen SchΓΆnwΓ€lder, Ladislav Lhotka, Liang Xia, Martin BjΓΆrklund, Martin Thomson, Mehmet Ersue, Michal VaΕ‘ko, Murray Kucherawy, Paul Wouters, Phil Shafer, Qin Wu, Radek Krejci, Rob Wilton, Roman Danyliw, Russ Housley, Sean Turner, Thomas Martin, and Tom Petch. π the group chat was clearly poppin π
Contributors π§
Special acknowledgement goes to Gary Wu who contributed the "ietf-tls-common" module and Tom Petch who carefully ensured that references were set correctly throughout. π literal legends only π
Author's Address π¦
Kent Watsen Watsen Networks Email: kent+ietf@watsen.net π
That's the whole thing, bestie! πβ¨ RFC 9645 is officially a wrap ππ
π¦ where this page comes from
- ietf: rfc9645 2024-10
- π girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms