| RFC 9645 | Groupings for TLS Clients and Servers | October 2024 |
| Watsen | Standards Track | [Page] |
This document presents four YANG 1.1 modules -- three IETF modules and one supporting IANA module.¶
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 primary productions of this work, supporting the configuration and monitoring of TLS clients and servers.¶
The IANA module is "iana-tls-cipher-suite-algs". This module defines YANG enumerations that provide support for an IANA-maintained algorithm registry.¶
This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9645.¶
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) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
This document presents four YANG 1.1 [RFC7950] modules -- three IETF modules and one IANA module.¶
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.¶
The groupings defined in this document are expected to be used in conjunction with the groupings defined in an underlying transport-level module, such as the groupings defined in [RFC9643]. The transport-level data model enables the configuration of transport-level values such as a remote address, a remote port, a local address, and a local port.¶
The IANA module is "iana-tls-cipher-suite-algs". This module defines YANG enumerations that provide support for an IANA-maintained algorithm registry.¶
IANA used the script in Appendix A to generate the "iana-tls-cipher-suite-algs" YANG module. This document does not publish the initial version of the module; it is published and maintained by IANA.¶
The three IETF modules define features and groupings to model "generic" TLS clients and TLS servers, where "generic" should be interpreted as "least common denominator" rather than "complete." Basic TLS protocol support is afforded by these modules, leaving configuration of advance features to augmentations made by consuming modules.¶
It is intended that the YANG groupings will be used by applications needing to configure TLS client and server protocol stacks. For instance, these groupings are used to help define the data model for HTTPS [RFC9110] and clients and servers based on the Network Configuration Protocol (NETCONF) over TLS [RFC7589] in [HTTP-CLIENT-SERVER] and [NETCONF-CLIENT-SERVER], respectively.¶
The "ietf-tls-client" and "ietf-tls-server" YANG modules each define one grouping, which is focused on just TLS-specific configuration, and specifically avoid any transport-level configuration, such as what ports to listen on or connect to. This affords applications the opportunity to define their own strategy for how the underlying TCP connection is established. For instance, applications supporting NETCONF Call Home [RFC8071] could use the "tls-server-grouping" grouping for the TLS parts it provides, 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] is obsoleted by TLS 1.3 [RFC8446] but is still in common use, and hence its "feature" statement is marked "status deprecated".¶
This document presents four YANG modules [RFC7950] that are part of a collection of RFCs that work together to ultimately support the configuration of both the clients and servers of the NETCONF [RFC6241] and RESTCONF [RFC8040] protocols.¶
The dependency relationship between the primary YANG groupings defined in the various RFCs is presented in the diagram below. In some cases, a document may define secondary groupings that introduce dependencies not illustrated in the diagram. The labels in the diagram are shorthand names for the defining RFCs. The citation references for the shorthand names are provided below the diagram.¶
Please note that the arrows in the diagram point from referencer to referenced. For example, the "crypto-types" RFC does not have any dependencies, whilst the "keystore" RFC depends on the "crypto-types" RFC.¶
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] |
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.¶
This document is compliant 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 <system> [SYSTEM-CONFIG] if implemented.¶
Various examples in this document use "BASE64VALUE=" as a placeholder value for binary data that has been base64 encoded (per Section 9.8 of [RFC7950]). This placeholder value is used because real base64-encoded structures are often many lines long and hence distracting to the example being presented.¶
Various examples in this document use the XML [W3C.REC-xml-20081126] encoding. Other encodings, such as JSON [RFC8259], could alternatively be used.¶
Various examples in this document contain long lines that may be folded, as described in [RFC8792].¶
The TLS common model presented in this section contains features and groupings common to both TLS clients and TLS servers. The "hello-params-grouping" grouping can be used to configure the list of TLS algorithms permitted by the TLS client or TLS server. The lists of algorithms are ordered such that, if multiple algorithms are permitted by the client, the algorithm that appears first in its list and that is also permitted by the server is used for the TLS transport layer connection. The ability to restrict the algorithms allowed is provided in this grouping for TLS clients and TLS servers that are capable of doing so and that may serve to make TLS clients and TLS servers compliant with local security policies. This model supports both TLS 1.2 [RFC5246] and TLS 1.3 [RFC8446].¶
Thus, in order to support both TLS 1.2 and TLS 1.3, the cipher suites part of the "hello-params-grouping" grouping should include the following three parameters for configuring its permitted TLS algorithms: TLS Cipher Suites, TLS SignatureScheme, and TLS Supported Groups.¶
This section provides an overview of the "ietf-tls-common" module in terms of its features, identities, and groupings.¶
The following diagram lists all the "feature" statements defined in the "ietf-tls-common" module:¶
Features: +-- tls12 +-- tls13 +-- hello-params +-- asymmetric-key-pair-generation +-- supported-algorithms¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
Please refer to the YANG module for a description of each feature.¶
The following diagram illustrates the relationship amongst the "identity" statements defined in the "ietf-tls-common" module:¶
Identities:
+-- tls-version-base
+-- tls12
+-- tls13
¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
Comments:¶
The "ietf-tls-common" module defines the following "grouping" statement:¶
This grouping is presented in the following subsection.¶
The following tree diagram [RFC8340] illustrates the "hello-params-grouping" grouping:¶
grouping hello-params-grouping:
+-- tls-versions
| +-- min? identityref
| +-- max? identityref
+-- cipher-suites
+-- cipher-suite* tlscsa:tls-cipher-suite-algorithm
¶
Comments:¶
The following tree diagram [RFC8340] lists all the protocol-accessible nodes defined in the "ietf-tls-common" module, without expanding the "grouping" statements:¶
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-identifier
¶
Comments:¶
The following example illustrates the "hello-params-grouping" grouping when populated with some data.¶
<!-- 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>
¶
The following example illustrates operational state data indicating the TLS algorithms supported by the server.¶
=============== 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>¶
The following example illustrates the "generate-asymmetric-key-pair" RPC.¶
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>¶
This YANG module has normative references to [RFC5288], [RFC5289], [RFC8422], [RFC9640], [RFC9642], [FIPS180-4], and [FIPS186-5].¶
This YANG module has informative references to [RFC5246] and [RFC8446].¶
<CODE BEGINS> file "ietf-tls-common@2024-03-16.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 2024-03-16 {
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
}
<CODE ENDS>¶
This section defines a YANG 1.1 [RFC7950] module called "ietf-tls-client". A high-level overview of the module is provided in Section 3.1. Examples illustrating the module's use are provided in Section 3.2 ("Example Usage"). The YANG module itself is defined in Section 3.3.¶
This section provides an overview of the "ietf-tls-client" module in terms of its features and groupings.¶
The following diagram lists all the "feature" statements defined in the "ietf-tls-client" module:¶
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-psk¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
Please refer to the YANG module for a description of each feature.¶
The "ietf-tls-client" module defines the following "grouping" statement:¶
This grouping is presented in the following subsection.¶
The following tree diagram [RFC8340] illustrates the "tls-client-grouping" grouping:¶
=============== 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? uint8
¶
Comments:¶
For the referenced grouping statement(s):¶
The "ietf-tls-client" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes. Thus, this module does not itself define any protocol-accessible nodes when implemented.¶
This section presents two examples showing the "tls-client-grouping" grouping populated with some data. These examples are effectively the same except the first configures the client identity using a local key while the second uses a key configured in a keystore. Both examples are consistent with the examples presented in Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642].¶
The following configuration example uses inline-definitions for the client identity and server authentication:¶
=============== 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>
¶
The following configuration example uses central-keystore-references for the client identity and central-truststore-references for server authentication from the keystore:¶
=============== 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>
¶
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].¶
<CODE BEGINS> file "ietf-tls-client@2024-03-16.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 2024-03-16 {
description
"Initial version";
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
// Features
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>¶
This section defines a YANG 1.1 module called "ietf-tls-server". A high-level overview of the module is provided in Section 4.1. Examples illustrating the module's use are provided in Section 4.2 ("Example Usage"). The YANG module itself is defined in Section 4.3.¶
This section provides an overview of the "ietf-tls-server" module in terms of its features and groupings.¶
The following diagram lists all the "feature" statements defined in the "ietf-tls-server" module:¶
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-psk¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
Please refer to the YANG module for a description of each feature.¶
The "ietf-tls-server" module defines the following "grouping" statement:¶
This grouping is presented in the following subsection.¶
The following tree diagram [RFC8340] illustrates the "tls-server-grouping" grouping:¶
=============== 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? uint8
¶
Comments:¶
For the referenced grouping statement(s):¶
The "ietf-tls-server" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes. Thus, this module does not itself define any protocol-accessible nodes when implemented.¶
This section presents two examples showing the "tls-server-grouping" grouping populated with some data. These examples are effectively the same except the first configures the server identity using a local key while the second uses a key configured in a keystore. Both examples are consistent with the examples presented in Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642].¶
The following configuration example uses inline-definitions for the server identity and client authentication:¶
=============== 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-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>
¶
The following configuration example uses central-keystore-references for the server identity and central-truststore-references for client authentication from the keystore:¶
=============== 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-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>
¶
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].¶
<CODE BEGINS> file "ietf-tls-server@2024-03-16.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.
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 2024-03-16 {
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.
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
}
<CODE ENDS>¶
The three IETF YANG modules in this document define groupings and will not be deployed as standalone modules. Their security implications may be context dependent based on their use in other modules. The designers of modules that import these grouping must conduct their own analysis of the security considerations.¶
This section is modeled after the template defined in Section 3.7.1 of [RFC8407].¶
The "iana-tls-cipher-suite-algs" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have mandatory-to-implement secure transport layers (e.g., Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication.¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular users to a preconfigured subset of all available protocol operations and content.¶
This YANG module defines YANG enumerations, for a public IANA-maintained registry.¶
YANG enumerations are not security-sensitive, as they are statically defined in the publicly accessible YANG module. IANA MAY deprecate and/or obsolete enumerations over time as needed to address security issues found in the algorithms.¶
This module does not define any writable nodes, RPCs, actions, or notifications, and thus the security considerations for such are not provided here.¶
This section is modeled after the template defined in Section 3.7.1 of [RFC8407].¶
The "ietf-tls-common" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have mandatory-to-implement secure transport layers (e.g., Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication.¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular users to a preconfigured subset of all available protocol operations and content.¶
Please be aware that this YANG module uses groupings from other YANG modules that define nodes that may be considered sensitive or vulnerable in network environments. Please review the Security Considerations for dependent YANG modules for information as to which nodes may be considered sensitive or vulnerable in network environments.¶
None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module.¶
None of the writable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in this module.¶
This module defines the "generate-asymmetric-key-pair" RPC that may, if the "ct:cleartext-private-keys" feature is enabled and the client requests it, return the private clear in cleartext form. It is NOT RECOMMENDED for private keys to pass the server's security perimeter.¶
This module does not define any actions or notifications, and thus the security considerations for such are not provided here.¶
This section is modeled after the template defined in Section 3.7.1 of [RFC8407].¶
The "ietf-tls-client" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have mandatory-to-implement secure transport layers (e.g., Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication.¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular users to a preconfigured subset of all available protocol operations and content.¶
Please be aware that this YANG module uses groupings from other YANG modules that define nodes that may be considered sensitive or vulnerable in network environments. Please review the Security Considerations for dependent YANG modules for information as to which nodes may be considered sensitive or vulnerable in network environments.¶
None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module.¶
All the writable data nodes defined by this module may be considered sensitive or vulnerable in some network environments. For instance, any modification to a key or reference to a key may dramatically alter the implemented security policy. For this reason, the NACM extension "default-deny-write" has been set for all data nodes defined in this module.¶
This module does not define any RPCs, actions, or notifications, and thus the security considerations for such are not provided here.¶
This section is modeled after the template defined in Section 3.7.1 of [RFC8407].¶
The "ietf-tls-server" YANG module defines a data model that is designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have mandatory-to-implement secure transport layers (e.g., Secure Shell (SSH) [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-implement mutual authentication.¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular users to a preconfigured subset of all available protocol operations and content.¶
Please be aware that this YANG module uses groupings from other YANG modules that define nodes that may be considered sensitive or vulnerable in network environments. Please review the Security Considerations for dependent YANG modules for information as to which nodes may be considered sensitive or vulnerable in network environments.¶
None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module.¶
Please be aware that this module uses the "key" and "private-key" nodes from the "ietf-crypto-types" module [RFC9640], where said nodes have the NACM extension "default-deny-all" set, thus preventing unrestricted read access to the cleartext key values.¶
All the writable data nodes defined by this module may be considered sensitive or vulnerable in some network environments. For instance, any modification to a key or reference to a key may dramatically alter the implemented security policy. For this reason, the NACM extension "default-deny-write" has been set for all data nodes defined in this module.¶
This module does not define any RPCs, actions, or notifications, and thus the security considerations for such are not provided here.¶
IANA has registered the following four URIs in the "ns" registry of the "IETF XML Registry" [RFC3688].¶
IANA has registered the following four YANG modules in the "YANG Module Names" registry [RFC6020].¶
This section follows the template defined in Section 4.30.3.1 of [RFC8407BIS].¶
IANA used the script in Appendix A to generate the IANA-maintained "iana-tls-cipher-suite-algs" YANG module. The YANG module is available from the "YANG Parameters" registry [IANA-YANG-PARAMETERS].¶
IANA has added the following note to the registry:¶
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 substatements thereof, should be defined as follows:¶
Unassigned or reserved values are not present in the module.¶
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 the update occurred and must have a "reference" substatement that points to the document defining the registry update that resulted in this change. For instance:¶
revision 2024-02-02 {
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].¶
When this registry is modified, the YANG module "iana-tls-cipher-suite-algs" [IANA-YANG-PARAMETERS] must be updated as defined in RFC 9645.¶
This section is not normative.¶
The Python <https://www.python.org> script contained in this section was used to create the initial IANA-maintained "iana-tls-cipher-suite-algs" YANG module maintained at [IANA-YANG-PARAMETERS].¶
Run the script using the command 'python gen-yang-modules.py' to produce the YANG module file in the current directory.¶
Be aware that the script does not attempt to copy the "revision" statements from the previous/current YANG module. Copying the revision statements must be done manually.¶
<CODE BEGINS>
=============== 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",
"hypenated_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["hypenated_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))], PREAMBL\
\E_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_"), "Unrecogni\
\zed 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 Authentic\
\ated 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["D\
\escription"]}\' algorithm.";'
description = textwrap.fill(description, width=69, subse\
\quent_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, subsequen\
\t_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["hypenated_name"] + "-al\
\gs.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()
<CODE ENDS>¶
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, Balázs Kovács, Benoit Claise, Bert Wijnen, David Lamparter, Dhruv Dhody, Éric Vyncke, Gary Wu, Henk Birkholz, Jeff Hartley, Jürgen Schönwälder, Ladislav Lhotka, Liang Xia, Martin Björklund, Martin Thomson, Mehmet Ersue, Michal Vaško, Murray Kucherawy, Paul Wouters, Phil Shafer, Qin Wu, Radek Krejci, Rob Wilton, Roman Danyliw, Russ Housley, Sean Turner, Thomas Martin, and Tom Petch.¶
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.¶