Operations and Management Area Working Group M. Boucadair, Ed. Internet-Draft Orange Obsoletes: 9105 (if approved) B. Wu Intended status: Standards Track G. Zheng Expires: 22 June 2025 M. Wang Huawei Technologies 19 December 2024 A YANG Data Model for Terminal Access Controller Access-Control System Plus (TACACS+) draft-ietf-opsawg-secure-tacacs-yang-04 Abstract This document defines a Terminal Access Controller Access-Control System Plus (TACACS+) client YANG module that augments the System Management data model, defined in RFC 7317, to allow devices to make use of TACACS+ servers for centralized Authentication, Authorization, and Accounting (AAA). Specifically, this document defines a YANG module for TACACS+ over TLS 1.3. This document obsoletes RFC 9105. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 22 June 2025. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. Boucadair, et al. Expires 22 June 2025 [Page 1] Internet-Draft YANG for TACACS+ over TLS December 2024 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Changes Since RFC 9105 . . . . . . . . . . . . . . . . . 3 1.2. Editorial Note (To be removed by RFC Editor) . . . . . . 3 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 4 2.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 3. Design of the TACACS+ Data Model . . . . . . . . . . . . . . 4 4. TACACS+ Client Module . . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 25 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 27 7.1. Normative References . . . . . . . . . . . . . . . . . . 27 7.2. Informative References . . . . . . . . . . . . . . . . . 29 Appendix A. Example TACACS+ Authentication Configuration with Shared Secret . . . . . . . . . . . . . . . . . . . . . . 30 Appendix B. TACACS+TLS Examples . . . . . . . . . . . . . . . . 31 B.1. Example TACACS+ Authentication Configuration with Explicit Certificate Definitions . . . . . . . . . . . . . . . . . 31 B.2. Example TACACS+ Authentication Configuration with Certificate References . . . . . . . . . . . . . . . . . 32 Appendix C. Full Tree . . . . . . . . . . . . . . . . . . . . . 34 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 45 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 1. Introduction The System Management data model [RFC7317] defines separate functionality to support local and Remote Authentication Dial In User Service (RADIUS) authentication: User Authentication Model: Defines a list of user names with associated passwords and a configuration leaf to decide the order in which local or RADIUS authentication is used. RADIUS Client Model: Defines a list of RADIUS servers used by a device for centralized user authentication. Boucadair, et al. Expires 22 June 2025 [Page 2] Internet-Draft YANG for TACACS+ over TLS December 2024 [RFC9105] defines a YANG module ("ietf-system-tacacs-plus") that augments the System Management data model [RFC7317] for the management of Terminal Access Controller Access-Control System Plus (TACACS+) clients as an alternative to RADIUS servers [RFC2865]. Typically, the "ietf-system-tacacs-plus" module is used to configure a TACACS+ client on a device to support deployment scenarios with centralized authentication, authorization, and accounting servers. This document defines a YANG module for managing TACACS+ clients (Section 4), including TACACS+ over TLS 1.3 clients [I-D.ietf-opsawg-tacacs-tls13]. This document obsoletes [RFC9105]. The YANG module in this document conforms to the Network Management Datastore Architecture (NMDA) defined in [RFC8342]. 1.1. Changes Since RFC 9105 The following changes have been made to [RFC9105]: * Add support for TLS [I-D.ietf-opsawg-tacacs-tls13] * Fix a must statement under 'tacacs-plus' * Fix errors in the example provided in Appendix A of [RFC9105] * Add new examples to illustrate the use of TACACS+TLS data nodes Detailed YANG changes are listed in Section 4. 1.2. Editorial Note (To be removed by RFC Editor) Note to the RFC Editor: This section is to be removed prior to publication. This document contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. Please apply the following replacements: * XXXX --> the assigned RFC number for this I-D * SSSS --> the assigned RFC number for [I-D.ietf-opsawg-tacacs-tls13] * TBD --> the assigned port number in Section 7 of [I-D.ietf-opsawg-tacacs-tls13] Boucadair, et al. Expires 22 June 2025 [Page 3] Internet-Draft YANG for TACACS+ over TLS December 2024 * 2024-12-11 --> the actual date of the publication of this document 2. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. The terminology for describing YANG data models is defined in [RFC7950]. The document uses the terms defined in Section 2 of [I-D.ietf-opsawg-tacacs-tls13] and Section 3 of [RFC8907]. 'client' refers to TACACS+ client, while 'server' refers to TACACS+ server. 2.1. Tree Diagrams The tree diagram used in this document follows the notation defined in [RFC8340]. 3. Design of the TACACS+ Data Model This module is used to configure a TACACS+ client on a device to support deployment scenarios with centralized authentication, authorization, and accounting servers. Authentication is used to validate a user's username and password, authorization allows the user to access and execute commands at various privilege levels assigned to the user, and accounting keeps track of the activity of a user who has accessed the device. The "ietf-system-tacacs-plus" module augments the '/sys:system' path defined in the "ietf-system" module with the contents of the 'tacacs- plus' grouping. Therefore, a device can use local, RADIUS, or TACACS+ authentication to validate users who attempt to access the device by several mechanisms, e.g., a command line interface or a web-based user interface. The 'server' list, which is directly under the 'tacacs-plus' container, holds a list of TACACS+ servers and uses 'server-type' to distinguish between Authentication, Authorization, and Accounting (AAA) services. The list of servers is for redundancy. Boucadair, et al. Expires 22 June 2025 [Page 4] Internet-Draft YANG for TACACS+ over TLS December 2024 When there are multiple interfaces connected to a TACACS+ client or server, the source address of outgoing TACACS+ packets could be specified, or the source address could be specified through the interface IP address setting or derived from the outbound interface from the local Forwarding Information Base (FIB). For a TACACS+ server located in a Virtual Private Network (VPN), a VPN Routing and Forwarding (VRF) instance needs to be specified. The 'statistics' container under the 'server' list is a collection of read-only counters for sent and received messages from a configured server. The YANG module for TACACS+ client has the structure shown in Figure 1. augment /sys:system: +--rw tacacs-plus +--rw client-credentials* [id] {credential-reference}? | +--rw id string | +--rw (auth-type)? | +--:(certificate) | | ... | +--:(raw-public-key) {tlsc:client-ident-raw-public-key}? | | ... | +--:(tls13-epsk) {tlsc:client-ident-tls13-epsk}? | ... +--rw server-credentials* [id] {credential-reference}? | +--rw id string | +--rw ca-certs! | | ... | +--rw ee-certs! | | ... | +--rw raw-public-keys! {tlsc:server-auth-raw-public-key}? | | ... | +--rw tls13-epsks? empty | {tlsc:server-auth-tls13-epsk}? +--rw server* [name] +--rw name string +--rw server-type | tacacs-plus-server-type +--rw domain-name? inet:domain-name +--rw sni-enabled? boolean +--rw address inet:host +--rw port? inet:port-number +--rw (security) | +--:(tls) | | +--rw client-identity! | | | +--rw (ref-or-explicit)? Boucadair, et al. Expires 22 June 2025 [Page 5] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | +--:(ref) | | | | +--rw credentials-reference? | | | | sys-tcs-plus:client-credentials-ref | | | | {credential-reference}? | | | +--:(explicit) | | | +--rw (auth-type)? | | | +--:(certificate) | | | | ... | | | +--:(raw-public-key) | | | | {tlsc:client-ident-raw-public-key}? | | | | ... | | | +--:(tls13-epsk) | | | {tlsc:client-ident-tls13-epsk}? | | | ... | | +--rw server-authentication | | | +--rw (ref-or-explicit)? | | | +--:(ref) | | | | +--rw credentials-reference? | | | | sys-tcs-plus:server-credentials-ref | | | | {credential-reference}? | | | +--:(explicit) | | | +--rw ca-certs! | | | | ... | | | +--rw ee-certs! | | | | ... | | | +--rw raw-public-keys! | | | | {tlsc:server-auth-raw-public-key}? | | | | ... | | | +--rw tls13-epsks? empty | | | {tlsc:server-auth-tls13-epsk} | | +--rw hello-params {tlscmn:hello-params}? | | +--rw tls-versions | | | +--rw min? identityref | | | +--rw max? identityref | | +--rw cipher-suites | | +--rw cipher-suite* | | tlscsa:tls-cipher-suite-algorithm | +--:(obfuscation) | +--rw shared-secret? string +--rw (source-type)? | +--:(source-ip) | | +--rw source-ip? inet:ip-address | +--:(source-interface) | +--rw source-interface? if:interface-ref +--rw vrf-instance? | -> /ni:network-instances/network-instance/name +--rw single-connection? boolean +--rw timeout? uint16 Boucadair, et al. Expires 22 June 2025 [Page 6] Internet-Draft YANG for TACACS+ over TLS December 2024 +--ro statistics +--ro discontinuity-time? yang:date-and-time +--ro connection-opens? yang:counter64 +--ro connection-closes? yang:counter64 +--ro connection-aborts? yang:counter64 +--ro connection-failures? yang:counter64 +--ro connection-timeouts? yang:counter64 +--ro messages-sent? yang:counter64 +--ro messages-received? yang:counter64 +--ro errors-received? yang:counter64 +--ro sessions? yang:counter64 +--ro cert-errors? yang:counter64 +--ro rpk-errors? yang:counter64 {tlsc:server-auth-raw-public-key}? Figure 1: Tree Structure Overview Specifically, the module is designed to cover the following key requirements specified in [I-D.ietf-opsawg-tacacs-tls13]: * TLS 1.3 [RFC8446] MUST be used for transport. * Earlier TLS versions TLS MUST NOT be used. * The cipher suites offered or accepted SHOULD be configurable. * Implementations MAY support Raw Public Keys and PSK. * Implementations MUST support the ability to configure the server's domain name, so that it may be included in the TLS Server Name Indication (SNI) extension. The following new data nodes are supported compared to [RFC9105]: 'client-credentials' and 'server-credentials': Defines a set credentials that can be globally provisioned and then referenced under specific servers. 'domain-name': Provides a domain name of the server per Section 3.3 of [I-D.ietf-opsawg-tacacs-tls13]. 'sni-enabled': Controls activation of Server Name Indication (SNI) (Section 3 of [RFC6066]). This parameter can be used only if a domain name is provided. 'client-identity': Specifies the identity credentials that the Boucadair, et al. Expires 22 June 2025 [Page 7] Internet-Draft YANG for TACACS+ over TLS December 2024 client may present when establishing a connection to a server. Client identities can be configured at the top level and then referenced for specific server instances. Alternatively, client identities can be configured explicitely under each server instance. 'server-authentication': Specifies how a client authenticates servers. Server credentials can be configured at the top level and then referenced for specific server instances. Alternatively, client identities can be configured explicitely under each server instance. 'hello-params': Controls TLS versions and cipher suites. 'discontinuity-time': The time on the most recent occasion at which the client suffered a discontinuity. 'cert-errors': Number of connection failures due to certificate issues. 'rpk-errors': Number of raw public key related connection failures. 4. TACACS+ Client Module This YANG module uses types and groupings defined in [RFC6991], [RFC8341], [RFC8343], [RFC8529], [RFC9640], [RFC9641], [RFC9642], and [RFC9645]. The module augments [RFC7317]. The module also cites [RFC6520], [RFC9257], and [RFC9258]. file "ietf-system-tacacs-plus@2024-12-11.yang" module ietf-system-tacacs-plus { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus"; prefix sys-tcs-plus; import ietf-inet-types { prefix inet; reference "RFC 6991: Common YANG Data Types"; } import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Data Types"; } Boucadair, et al. Expires 22 June 2025 [Page 8] Internet-Draft YANG for TACACS+ over TLS December 2024 import ietf-system { prefix sys; reference "RFC 7317: A YANG Data Model for System Management"; } import ietf-netconf-acm { prefix nacm; reference "RFC 8341: Network Configuration Access Control Model"; } import ietf-interfaces { prefix if; reference "RFC 8343: A YANG Data Model for Interface Management"; } import ietf-network-instance { prefix ni; reference "RFC 8529: YANG Data Model for Network Instances"; } 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"; } import ietf-tls-client { prefix tlsc; reference "RFC 9645: YANG Groupings for TLS Clients and TLS Servers"; } organization "IETF OPSAWG (Operations and Management Area Working Group)"; Boucadair, et al. Expires 22 June 2025 [Page 9] Internet-Draft YANG for TACACS+ over TLS December 2024 contact "WG Web: WG List: Editor: Mohamed Boucadair Author: Bo Wu Author: Guangying Zheng "; description "This module provides configuration of TACACS+ clients. 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 XXXX; see the RFC itself for full legal notices."; revision 2024-12-11 { description "This revision adds TLS support. Specifically, this revision adds: - a new feature 'credential-reference' - a new container 'client-credentials' - a new container 'server-credentials' - a new leaf 'domain-name' - a new leaf 'sni-enabled' - TLS as a new security choice - a new leaf 'discontinuity-time' under 'statistics' - a new leaf 'cert-errors' under 'statistics' - a new leaf 'rpk-errors' under 'statistics' Also, this revision: - updates the reference of 'tacacs-plus' identity to also cite RFC SSSS Boucadair, et al. Expires 22 June 2025 [Page 10] Internet-Draft YANG for TACACS+ over TLS December 2024 - fixes a must statement under 'tacacs-plus' by adding a missing prefix - updates the description of the 'name' under 'server' list to better reflect the intended use and clarifies the difference with the new domain-name - removes the default statement for the 'port' under 'server' list because a distinct default port number is used for TACACS+TLS - updates the 'port' leaf under 'server' list to enumerate the various TACACS+ default port numbers - updates the description of timeout to remove redundant text with the default statement"; reference "RFC XXXX: A YANG Data Model for Terminal Access Controller Access-Control System Plus (TACACS+)"; } revision 2021-08-05 { description "Initial revision."; reference "RFC 9105: A YANG Data Model for Terminal Access Controller Access-Control System Plus (TACACS+)"; } feature credential-reference { description "Indicates whether service credentials references are supported."; } identity tacacs-plus { base sys:authentication-method; description "Indicates AAA operation using TACACS+."; reference "RFC SSSS: Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3 RFC 8907: The TACACS+ Protocol"; } typedef tacacs-plus-server-type { type bits { bit authentication { description "Indicates that the TACACS+ server is providing authentication services."; } Boucadair, et al. Expires 22 June 2025 [Page 11] Internet-Draft YANG for TACACS+ over TLS December 2024 bit authorization { description "Indicates that the TACACS+ server is providing authorization services."; } bit accounting { description "Indicates that the TACACS+ server is providing accounting services."; } } description "The type can be set to authentication, authorization, accounting, or any combination of the three types."; } typedef client-credentials-ref { type leafref { path "/sys:system/sys-tcs-plus:tacacs-plus" + "/sys-tcs-plus:client-credentials/sys-tcs-plus:id"; } description "Defines a type to reference client credentials."; } typedef server-credentials-ref { type leafref { path "/sys:system/sys-tcs-plus:tacacs-plus" + "/sys-tcs-plus:server-credentials/sys-tcs-plus:id"; } description "Defines a type to reference server credentials."; } grouping statistics { description "Grouping for TACACS+ statistics attributes, including TLS specifics."; container statistics { config false; description "A collection of server-related statistics objects."; leaf discontinuity-time { type yang:date-and-time; description "The time on the most recent occasion at which the TACACS+ client suffered a discontinuity."; } Boucadair, et al. Expires 22 June 2025 [Page 12] Internet-Draft YANG for TACACS+ over TLS December 2024 leaf connection-opens { type yang:counter64; description "Number of new connection requests sent to the server, e.g., socket open."; } leaf connection-closes { type yang:counter64; description "Number of connection close requests sent to the server, e.g., socket close."; } leaf connection-aborts { type yang:counter64; description "Number of aborted connections to the server. These do not include connections that are closed gracefully."; } leaf connection-failures { type yang:counter64; description "Number of connection failures to the server."; } leaf connection-timeouts { type yang:counter64; description "Number of connection timeouts to the server."; } leaf messages-sent { type yang:counter64; description "Number of messages sent to the server."; } leaf messages-received { type yang:counter64; description "Number of messages received from the server."; } leaf errors-received { type yang:counter64; description "Number of error messages received from the server."; } leaf sessions { type yang:counter64; description "Number of TACACS+ sessions completed with the server. If the Single Connection Mode was not enabled, the number Boucadair, et al. Expires 22 June 2025 [Page 13] Internet-Draft YANG for TACACS+ over TLS December 2024 of sessions is the same as the number of 'connection-closes'. If the Single Connection Mode was enabled, a single TCP connection may contain multiple TACACS+ sessions."; } leaf cert-errors { type yang:counter64; description "Number of connection failures due to certificate issues."; } leaf rpk-errors { if-feature "tlsc:server-auth-raw-public-key"; type yang:counter64; description "Number of RPK-related connection failures."; } } } grouping certificate { description "Specifies a certificate that can be used for client identity."; 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")'; } } } grouping raw-private-key { description "Specifies raw private key (RPK) that can be used for client identity."; 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' Boucadair, et al. Expires 22 June 2025 [Page 14] Internet-Draft YANG for TACACS+ over TLS December 2024 + '(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")'; } } } grouping 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). When Pre-Shared Keys (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."; reference "RFC 8446: The Transport Layer Security (TLS) Protocol Version 1.3, Section 4.2.11 RFC 9257: Guidance for External Pre-Shared Key (PSK) Usage in TLS, Section 6 RFC 9258: Importing External Pre-Shared Keys (PSKs) for TLS 1.3, Section 5.1"; uses ks:inline-or-keystore-symmetric-key-grouping; leaf external-identity { type string; mandatory true; description "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, Section 4.2.11 RFC 9257: Guidance for External Pre-Shared Key (PSK) Usage in TLS, Section 4.1"; } leaf hash { type tlscmn:epsk-supported-hash; default "sha-256"; description "For externally established PSKs, the Hash algorithm must be set when the PSK is established or default to SHA-256 if no such algorithm is defined."; Boucadair, et al. Expires 22 June 2025 [Page 15] Internet-Draft YANG for TACACS+ over TLS December 2024 reference "RFC 8446: The Transport Layer Security (TLS) Protocol Version 1.3, Section 4.2.11"; } leaf context { type string; description "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."; reference "RFC 9258: Importing External Pre-Shared Keys (PSKs) for TLS 1.3, Section 5.1 "; } leaf target-protocol { type uint16; description "Specifies the protocol for which a PSK is imported for use."; reference "RFC 9258: Importing External Pre-Shared Keys (PSKs) for TLS 1.3, Section 3 "; } leaf target-kdf { type uint16; description "The KDF for which a PSK is imported for use."; reference "RFC 9258: Importing External Pre-Shared Keys (PSKs) for TLS 1.3, Section 3"; } } grouping client-identity { description "Identity credentials that a TLS client may present when establishing a connection to a TLS server. When configured, and requested by the TLS server when establishing a TLS session, these credentials are passed in the Certificate message."; reference "RFC 8446: The Transport Layer Security (TLS) Protocol Version 1.3, Section 4.4.2"; nacm:default-deny-write; choice auth-type { default "certificate"; //mandatory true; description Boucadair, et al. Expires 22 June 2025 [Page 16] Internet-Draft YANG for TACACS+ over TLS December 2024 "A choice amongst authentication types."; case certificate { container certificate { description "Specifies the client identity using a certificate."; uses certificate; } } case raw-public-key { if-feature "tlsc:client-ident-raw-public-key"; container raw-private-key { description "Specifies the client identity using RPK."; uses raw-private-key; } } case tls13-epsk { if-feature "tlsc:client-ident-tls13-epsk"; container tls13-epsk { description "An EPSK is established or provisioned out-of-band."; uses tls13-epsk; } } } } grouping client-identity-with-ref { description "Identity credentials that the TLS client may present when establishing a connection to a TLS server. When configured, and requested by the TLS server when establishing a TLS session, these credentials are passed in the Certificate message."; choice ref-or-explicit { description "A choice between a reference or explicit configuration."; case ref { description "Provides a reference to a client identity."; leaf credentials-reference { if-feature "credential-reference"; type sys-tcs-plus:client-credentials-ref; description "Specifies the client credentials reference."; } } case explicit { Boucadair, et al. Expires 22 June 2025 [Page 17] Internet-Draft YANG for TACACS+ over TLS December 2024 description "Explicit configuration of the client identity."; uses client-identity; } } } grouping server-authentication { description "Specifies how a TLS client can authenticate TLS servers. Any combination of credentials is additive and unordered."; nacm:default-deny-write; container ca-certs { 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 { 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., end entity certificates) used by a 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 "tlsc: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 Boucadair, et al. Expires 22 June 2025 [Page 18] Internet-Draft YANG for TACACS+ over TLS December 2024 configured."; description "A set of raw public keys used by a 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 tls13-epsks { if-feature "tlsc:server-auth-tls13-epsk"; type empty; description "Indicates that a TLS client can authenticate TLS servers using configured EPSKs."; } } grouping server-authentication-with-ref { description "Specifies how a TLS client can authenticate TLS servers."; choice ref-or-explicit { description "A choice between a reference of explicit configuration."; case ref { description "Provides a reference to server credentials."; leaf credentials-reference { if-feature "credential-reference"; type sys-tcs-plus:server-credentials-ref; description "Specifies the server credentials reference."; } } case explicit { Boucadair, et al. Expires 22 June 2025 [Page 19] Internet-Draft YANG for TACACS+ over TLS December 2024 description "Explicit configuration of a server credentials."; uses server-authentication; } } } grouping hello-params { description "Configurable parameters for the TLS Hello message."; reference "RFC SSSS: Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3, Section 5.1"; nacm:default-deny-write; uses tlscmn:hello-params-grouping { refine "tls-versions/min" { must "not(derived-from-or-self(current(), " + "'tlscmn:tls12'))" { error-message "TLS 1.2 is not supported as min TLS version"; } } refine "tls-versions/max" { must "not(derived-from-or-self(current(), " + "'tlscmn:tls12'))" { error-message "TLS 1.2 is not supported as max TLS version"; } } } } grouping tls-client { description "A grouping for configuring a TLS client without any consideration for how an underlying TCP session is established."; container client-identity { presence "Indicates that a TLS-level client identity has been configured. This statement is present so the mandatory descendant do not imply that this node must be configured."; description "Identity credentials that a TLS client may present when establishing a connection to a TLS server."; uses client-identity-with-ref; } Boucadair, et al. Expires 22 June 2025 [Page 20] Internet-Draft YANG for TACACS+ over TLS December 2024 container server-authentication { must 'credentials-reference or ca-certs or ee-certs or ' + 'raw-public-keys or tls13-epsks'; description "Specifies how a TLS client can authenticate TLS servers."; uses server-authentication-with-ref; } container hello-params { if-feature "tlscmn:hello-params"; description "Configurable parameters for the TLS Hello message."; uses hello-params; } } grouping tacacs-plus { description "Grouping for TACACS+ attributes."; container tacacs-plus { must "not(derived-from-or-self(../sys:authentication" + "/sys:user-authentication-order, " + "'sys-tcs-plus:tacacs-plus'))" + " or bit-is-set(server/server-type,'authentication')" { error-message "When 'tacacs-plus' is used as a system authentication method, a TACACS+ authentication server must be configured."; description "When 'tacacs-plus' is used as an authentication method, a TACACS+ server must be configured."; } description "Container for TACACS+ configurations and operations."; list client-credentials { if-feature "credential-reference"; key "id"; description "Identity credentials that a TLS client may present when establishing a connection to a TLS server. A list of client credentials that can be referenced when configuring server instances."; nacm:default-deny-write; leaf id { type string; description "An identifier that uniquely identifies a client identity within the device configuration."; } Boucadair, et al. Expires 22 June 2025 [Page 21] Internet-Draft YANG for TACACS+ over TLS December 2024 uses client-identity; } list server-credentials { if-feature "credential-reference"; key "id"; description "Identity credentials that a TLS client may present when establishing a connection to a TLS server."; nacm:default-deny-write; leaf id { type string; description "An identifier that uniquely identify server credentials within the device configuration."; } uses server-authentication; } list server { key "name"; ordered-by user; description "List of TACACS+ servers used by the device."; leaf name { type string; description "A name that is used to uniquely identify a TACACS+ server within the device configuration. This name is not to be confused with the domain-name."; } leaf server-type { type tacacs-plus-server-type; mandatory true; description "Server type: authentication/authorization/accounting and various combinations."; } leaf domain-name { type inet:domain-name; description "Provides a domain name of the TACACS+ server."; reference "RFC SSSS: Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3, Section 3.4.2"; } leaf sni-enabled { type boolean; must '../domain-name' { Boucadair, et al. Expires 22 June 2025 [Page 22] Internet-Draft YANG for TACACS+ over TLS December 2024 error-message "A domain name must be provided to make use of Server Name Indication (SNI)."; } description "Enables the use of SNI, when set to true. Disables the use of SNI, when set to false."; reference "RFC 6066: Transport Layer Security (TLS) Extensions: Extension Definitions, Section 3 RFC SSSS: Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3, Section 3.4.2"; } leaf address { type inet:host; mandatory true; description "The IP address of the TACACS+ server."; } leaf port { type inet:port-number; //default "49"; description "The port number of TACACS+ server port number. Default port number for legacy TACACS+ is 49, while it is TBD for TACACS+TLS."; } choice security { mandatory true; description "Security mechanism between TACACS+ client and server."; case tls { description "TLS is used to secure TACACS+ exchanges."; reference "RFC SSSS: Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3"; uses tls-client; } case obfuscation { leaf shared-secret { type string { length "1..max"; } description "The shared secret, which is known to both the TACACS+ client and server. TACACS+ server Boucadair, et al. Expires 22 June 2025 [Page 23] Internet-Draft YANG for TACACS+ over TLS December 2024 administrators SHOULD configure a shared secret with a minimum length of 16 characters. It is highly recommended that this shared secret is at least 32 characters long and sufficiently complex with a mix of different character types, i.e., upper case, lower case, numeric, and punctuation. Note that this security mechanism is best described as 'obfuscation' and not 'encryption' as it does not provide any meaningful integrity, privacy, or replay protection."; reference "RFC 8907: The TACACS+ Protocol"; nacm:default-deny-all; } } } choice source-type { description "The source address type for outbound TACACS+ packets."; case source-ip { leaf source-ip { type inet:ip-address; description "Specifies the source IP address for TACACS+ outbound packets."; } } case source-interface { leaf source-interface { type if:interface-ref; description "Specifies the interface from which the IP address is derived for use as the source for outbound TACACS+ packets."; } } } leaf vrf-instance { type leafref { path "/ni:network-instances/ni:network-instance/ni:name"; } description "Specifies the VPN Routing and Forwarding (VRF) instance to use to communicate with the TACACS+ server."; reference "RFC 8529: YANG Data Model for Network Instances"; } leaf single-connection { Boucadair, et al. Expires 22 June 2025 [Page 24] Internet-Draft YANG for TACACS+ over TLS December 2024 type boolean; default "false"; description "Indicates whether the Single Connection Mode is enabled for the server."; } leaf timeout { type uint16 { range "1..max"; } units "seconds"; default "5"; description "The number of seconds that the device will wait for a response from each TACACS+ server before trying with a different server."; } uses statistics; } } } augment "/sys:system" { description "Augments the system model with the tacacs-plus data nodes."; uses tacacs-plus; } } 5. Security Considerations This section is modeled after the template described in Section 3.7 of [I-D.ietf-netmod-rfc8407bis]. The "ietf-ac-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 to use a secure transport layer (e.g., SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and have to use mutual authentication. The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. Boucadair, et al. Expires 22 June 2025 [Page 25] Internet-Draft YANG for TACACS+ over TLS December 2024 There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., "config true", which is the default). All writable data nodes are likely to be reasonably sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) and delete operations to these data nodes without proper protection or authentication can have a negative effect on network operations. The following subtrees and data nodes have particular sensitivities/vulnerabilities: 'server': This list contains the data nodes used to control the TACACS+ servers used by the device. Unauthorized access to this list could enable an attacker to assume complete control over the device by pointing to a compromised TACACS+ server, or to modify the counters to hide attacks against the device. 'shared-secret': This leaf controls the key known to both the TACACS+ client and server. Unauthorized access to this leaf could make the device vulnerable to attacks; therefore, it has been restricted using the "default-deny-all" access control defined in [RFC8341]. When setting, it is highly recommended that the leaf is at least 32 characters long and sufficiently complex with a mix of different character types, i.e., upper case, lower case, numeric, and punctuation. 'client-identity' and 'server-authentication': 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. This YANG module uses groupings from other YANG modules that define nodes that may be considered sensitive or vulnerable in network environments. Refer to Section 5.3 of [RFC9642] and Section 5.3 of [RFC9645] for information as to which nodes may be considered sensitive or vulnerable in network environments. 6. IANA Considerations IANA is requested to update the following URI in the "ns" subregistry within the "IETF XML Registry" [RFC3688]: URI: urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. IANA is requested to register the following YANG module in the "YANG Module Names" registry [RFC6020] within the "YANG Parameters" registry group: Boucadair, et al. Expires 22 June 2025 [Page 26] Internet-Draft YANG for TACACS+ over TLS December 2024 Name: ietf-system-tacacs-plus Namespace: urn:ietf:params:xml:ns:yang:ietf-system-tacacs-plus Prefix: sys-tcs-plus Maintained by IANA? N Reference: RFC XXXX 7. References 7.1. Normative References [I-D.ietf-opsawg-tacacs-tls13] Dahm, T., Heasley, J., dcmgash@cisco.com, and A. Ota, "Terminal Access Controller Access-Control System Plus (TACACS+) over TLS 1.3", Work in Progress, Internet-Draft, draft-ietf-opsawg-tacacs-tls13-16, 12 December 2024, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS) Extensions: Extension Definitions", RFC 6066, DOI 10.17487/RFC6066, January 2011, . [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, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . Boucadair, et al. Expires 22 June 2025 [Page 27] Internet-Draft YANG for TACACS+ over TLS December 2024 [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for System Management", RFC 7317, DOI 10.17487/RFC7317, August 2014, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [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, . [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC8529] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X. Liu, "YANG Data Model for Network Instances", RFC 8529, DOI 10.17487/RFC8529, March 2019, . [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, . [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, . [RFC9640] Watsen, K., "YANG Data Types and Groupings for Cryptography", RFC 9640, DOI 10.17487/RFC9640, October 2024, . Boucadair, et al. Expires 22 June 2025 [Page 28] Internet-Draft YANG for TACACS+ over TLS December 2024 [RFC9641] Watsen, K., "A YANG Data Model for a Truststore", RFC 9641, DOI 10.17487/RFC9641, October 2024, . [RFC9642] Watsen, K., "A YANG Data Model for a Keystore", RFC 9642, DOI 10.17487/RFC9642, October 2024, . [RFC9645] Watsen, K., "YANG Groupings for TLS Clients and TLS Servers", RFC 9645, DOI 10.17487/RFC9645, October 2024, . 7.2. Informative References [I-D.ietf-netmod-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-21, 13 November 2024, . [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, DOI 10.17487/RFC2865, June 2000, . [RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006, . [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, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . Boucadair, et al. Expires 22 June 2025 [Page 29] Internet-Draft YANG for TACACS+ over TLS December 2024 [RFC8907] Dahm, T., Ota, A., Medway Gash, D.C., Carrel, D., and L. Grant, "The Terminal Access Controller Access-Control System Plus (TACACS+) Protocol", RFC 8907, DOI 10.17487/RFC8907, September 2020, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . [RFC9105] Wu, B., Ed., Zheng, G., and M. Wang, Ed., "A YANG Data Model for Terminal Access Controller Access-Control System Plus (TACACS+)", RFC 9105, DOI 10.17487/RFC9105, August 2021, . Appendix A. Example TACACS+ Authentication Configuration with Shared Secret Figure 2 shows an example where a TACACS+ authentication server instance is configured using shared secret for authentication. { "ietf-system:system": { "authentication": { "user-authentication-order": [ "ietf-system-tacacs-plus:tacacs-plus", "ietf-system:local-users" ] }, "ietf-system-tacacs-plus:tacacs-plus": { "server": [ { "name": "tac_plus1", "server-type": "authentication", "address": "192.0.2.2", "shared-secret": "QaEfThUkO198010075460923+h3TbE8n", "source-ip": "192.0.2.12", "timeout": 10 } ] } } } Figure 2: Example with Shared Secret Boucadair, et al. Expires 22 June 2025 [Page 30] Internet-Draft YANG for TACACS+ over TLS December 2024 Appendix B. TACACS+TLS Examples This section provides examples to illustrate the configuration of TACACS+TLS clients. These examples follow the convention used in Section 1.5 of [RFC9645] for binary data that has been base64 encoded. B.1. Example TACACS+ Authentication Configuration with Explicit Certificate Definitions Figure 3 shows a configuration example with 'inline-definition' for the client identity and server authentication. =============== NOTE: '\' line wrapping per RFC 8792 ================ { "ietf-system:system": { "authentication": { "user-authentication-order": [ "ietf-system-tacacs-plus:tacacs-plus", "ietf-system:local-users" ] }, "ietf-system-tacacs-plus:tacacs-plus": { "server": [ { "name": "instance-1", "server-type": "authentication", "domain-name": "tacacs.example.com", "sni-enabled": true, "address": "2001:db8::1", "port": 1234, "client-identity": { "certificate": { "inline-definition": { "public-key-format": "ietf-crypto-types:subject-\ public-key-info-format", "public-key": "BASE64VALUE=", "private-key-format": "ietf-crypto-types:rsa-private\ -key-format", "cleartext-private-key": "BASE64VALUE=", "cert-data": "BASE64VALUE=" } } }, "server-authentication": { "ca-certs": { Boucadair, et al. Expires 22 June 2025 [Page 31] Internet-Draft YANG for TACACS+ over TLS December 2024 "inline-definition": { "certificate": [ { "name": "CA-Certificate-1", "cert-data": "BASE64VALUE=" } ] } } }, "hello-params": { "tls-versions": { "min": "ietf-tls-common:tls13", "max": "ietf-tls-common:tls13" }, "cipher-suites": { "cipher-suite": [ "TLS_AES_128_GCM_SHA256" ] } }, "single-connection": false, "timeout": 10 } ] } } } Figure 3: Example with TACACS+TLS with Inline Certificate Definitions B.2. Example TACACS+ Authentication Configuration with Certificate References Figure 4 shows a configuration example with credential references for multiple service instances: four server instances are configured with all using the same credentials. These instances form a redundancy group for both IPv4 and IPv6. =============== NOTE: '\' line wrapping per RFC 8792 ================ { "ietf-system:system": { "ietf-system-tacacs-plus:tacacs-plus": { "client-credentials": [ { "id": "client-cred-1", "certificate": { Boucadair, et al. Expires 22 June 2025 [Page 32] Internet-Draft YANG for TACACS+ over TLS December 2024 "inline-definition": { "public-key-format": "ietf-crypto-types:subject-public\ -key-info-format", "public-key": "BASE64VALUE=", "private-key-format": "ietf-crypto-types:rsa-private-\ key-format", "cleartext-private-key": "BASE64VALUE=", "cert-data": "BASE64VALUE=" } } } ], "server-credentials": [ { "id": "server-cred-1", "ca-certs": { "inline-definition": { "certificate": [ { "name": "CA-Certificate-1", "cert-data": "BASE64VALUE=" } ] } } } ], "server": [ { "name": "primary-v6", "server-type": "authentication", "domain-name": "tacacs.example.com", "sni-enabled": true, "address": "2001:db8::1", "port": 1234, "client-identity": { "credentials-reference": "client-cred-1" }, "server-authentication": { "credentials-reference": "server-cred-1" } }, { "name": "backup-v6", "server-type": "authentication", "domain-name": "tacacs.example.com", "sni-enabled": true, "address": "2001:db8::2", Boucadair, et al. Expires 22 June 2025 [Page 33] Internet-Draft YANG for TACACS+ over TLS December 2024 "port": 1234, "client-identity": { "credentials-reference": "client-cred-1" }, "server-authentication": { "credentials-reference": "server-cred-1" } }, { "name": "primary-v4", "server-type": "authentication", "domain-name": "tacacs.example.com", "sni-enabled": true, "address": "192.0.2.1", "port": 49, "client-identity": { "credentials-reference": "client-cred-1" }, "server-authentication": { "credentials-reference": "server-cred-1" } }, { "name": "backup-v4", "server-type": "authentication", "domain-name": "tacacs.example.com", "sni-enabled": true, "address": "192.0.2.2", "port": 49, "client-identity": { "credentials-reference": "client-cred-1" }, "server-authentication": { "credentials-reference": "server-cred-1" } } ] } } } Figure 4: Example with TACACS+TLS with References Appendix C. Full Tree The full tree structure is shown below: Boucadair, et al. Expires 22 June 2025 [Page 34] Internet-Draft YANG for TACACS+ over TLS December 2024 =============== NOTE: '\' line wrapping per RFC 8792 ================ module: ietf-system-tacacs-plus augment /sys:system: +--rw tacacs-plus +--rw client-credentials* [id] {credential-reference}? | +--rw id string | +--rw (auth-type)? | +--:(certificate) | | +--rw certificate | | +--rw (inline-or-keystore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw public-key-format? | | | | identityref | | | +--rw public-key? | | | | binary | | | +--rw private-key-format? | | | | identityref | | | +--rw (private-key-type) | | | | +--:(cleartext-private-key) | | | | | {cleartext-private-keys}? | | | | | +--rw cleartext-private-key? | | | | | binary | | | | +--:(hidden-private-key) | | | | | {hidden-private-keys}? | | | | | +--rw hidden-private-key? | | | | | empty | | | | +--:(encrypted-private-key) | | | | {encrypted-private-keys}? | | | | +--rw encrypted-private-key | | | | +--rw encrypted-by | | | | +--rw encrypted-value-format | | | | | identityref | | | | +--rw encrypted-value | | | | binary | | | +--rw cert-data? | | | | end-entity-cert-cms | | | +---n certificate-expiration | | | | {certificate-expiration-\ notification}? | | | | +-- expiration-date | | | | yang:date-and-time | | | +---x generate-csr {csr-generation}? | | | +---w input | | | | +---w csr-format identityref | | | | +---w csr-info csr-info Boucadair, et al. Expires 22 June 2025 [Page 35] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | +--ro output | | | +--ro (csr-type) | | | +--:(p10-csr) | | | +--ro p10-csr? p10-csr | | +--:(central-keystore) | | {central-keystore-supported,\ asymmetric-keys}? | | +--rw central-keystore-reference | | +--rw asymmetric-key? | | | ks:central-asymmetric-key-ref | | | {central-keystore-supported,\ asymmetric-keys}? | | +--rw certificate? leafref | +--:(raw-public-key) {tlsc:client-ident-raw-public-key}? | | +--rw raw-private-key | | +--rw (inline-or-keystore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw public-key-format? | | | | identityref | | | +--rw public-key? | | | | binary | | | +--rw private-key-format? | | | | identityref | | | +--rw (private-key-type) | | | +--:(cleartext-private-key) | | | | {cleartext-private-keys}? | | | | +--rw cleartext-private-key? | | | | binary | | | +--:(hidden-private-key) | | | | {hidden-private-keys}? | | | | +--rw hidden-private-key? | | | | empty | | | +--:(encrypted-private-key) | | | {encrypted-private-keys}? | | | +--rw encrypted-private-key | | | +--rw encrypted-by | | | +--rw encrypted-value-format | | | | identityref | | | +--rw encrypted-value | | | binary | | +--:(central-keystore) | | {central-keystore-supported,\ asymmetric-keys}? | | +--rw central-keystore-reference? | | ks:central-asymmetric-key-ref | +--:(tls13-epsk) {tlsc:client-ident-tls13-epsk}? | +--rw tls13-epsk Boucadair, et al. Expires 22 June 2025 [Page 36] Internet-Draft YANG for TACACS+ over TLS December 2024 | +--rw (inline-or-keystore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw key-format? | | | | identityref | | | +--rw (key-type) | | | +--:(cleartext-symmetric-key) | | | | +--rw cleartext-symmetric-key? | | | | binary | | | | {cleartext-symmetric-keys}? | | | +--:(hidden-symmetric-key) | | | | {hidden-symmetric-keys}? | | | | +--rw hidden-symmetric-key? | | | | empty | | | +--:(encrypted-symmetric-key) | | | {encrypted-symmetric-keys}? | | | +--rw encrypted-symmetric-key | | | +--rw encrypted-by | | | +--rw encrypted-value-format | | | | identityref | | | +--rw encrypted-value | | | binary | | +--:(central-keystore) | | {central-keystore-supported,symmetric\ -keys}? | | +--rw central-keystore-reference? | | ks:central-symmetric-key-ref | +--rw external-identity string | +--rw hash? | | tlscmn:epsk-supported-hash | +--rw context? string | +--rw target-protocol? uint16 | +--rw target-kdf? uint16 +--rw server-credentials* [id] {credential-reference}? | +--rw id string | +--rw ca-certs! | | +--rw (inline-or-truststore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw certificate* [name] | | | +--rw name string | | | +--rw cert-data | | | | trust-anchor-cert-cms | | | +---n certificate-expiration | | | {certificate-expiration-\ notification}? | | | +-- expiration-date yang:date-and-time | | +--:(central-truststore) Boucadair, et al. Expires 22 June 2025 [Page 37] Internet-Draft YANG for TACACS+ over TLS December 2024 | | {central-truststore-supported,certificates}? | | +--rw central-truststore-reference? | | ts:central-certificate-bag-ref | +--rw ee-certs! | | +--rw (inline-or-truststore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw certificate* [name] | | | +--rw name string | | | +--rw cert-data | | | | trust-anchor-cert-cms | | | +---n certificate-expiration | | | {certificate-expiration-\ notification}? | | | +-- expiration-date yang:date-and-time | | +--:(central-truststore) | | {central-truststore-supported,certificates}? | | +--rw central-truststore-reference? | | ts:central-certificate-bag-ref | +--rw raw-public-keys! {tlsc:server-auth-raw-public-key}? | | +--rw (inline-or-truststore) | | +--:(inline) {inline-definitions-supported}? | | | +--rw inline-definition | | | +--rw public-key* [name] | | | +--rw name string | | | +--rw public-key-format identityref | | | +--rw public-key binary | | +--:(central-truststore) | | {central-truststore-supported,public-keys}? | | +--rw central-truststore-reference? | | ts:central-public-key-bag-ref | +--rw tls13-epsks? empty | {tlsc:server-auth-tls13-epsk}? +--rw server* [name] +--rw name string +--rw server-type | tacacs-plus-server-type +--rw domain-name? inet:domain-name +--rw sni-enabled? boolean +--rw address inet:host +--rw port? inet:port-number +--rw (security) | +--:(tls) | | +--rw client-identity! | | | +--rw (ref-or-explicit)? | | | +--:(ref) | | | | +--rw credentials-reference? | | | | sys-tcs-plus:client-credentials-ref Boucadair, et al. Expires 22 June 2025 [Page 38] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | | {credential-reference}? | | | +--:(explicit) | | | +--rw (auth-type)? | | | +--:(certificate) | | | | +--rw certificate | | | | +--rw (inline-or-keystore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw public-key-format? | | | | | | identityref | | | | | +--rw public-key? | | | | | | binary | | | | | +--rw private-key-format? | | | | | | identityref | | | | | +--rw (private-key-type) | | | | | | +--:(cleartext-private\ -key) | | | | | | | {cleartext-\ private-keys}? | | | | | | | +--rw cleartext-\ private-key? | | | | | | | binary | | | | | | +--:(hidden-private-\ key) | | | | | | | {hidden-\ private-keys}? | | | | | | | +--rw hidden-\ private-key? | | | | | | | empty | | | | | | +--:(encrypted-private\ -key) | | | | | | {encrypted-\ private-keys}? | | | | | | +--rw encrypted-\ private-key | | | | | | +--rw encrypted-\ by | | | | | | +--rw encrypted-\ value-format | | | | | | | \ identityref | | | | | | +--rw encrypted-\ value | | | | | | binary | | | | | +--rw cert-data? | | | | | | end-entity-cert-\ Boucadair, et al. Expires 22 June 2025 [Page 39] Internet-Draft YANG for TACACS+ over TLS December 2024 cms | | | | | +---n certificate-\ expiration | | | | | | {certificate-\ expiration-notification}? | | | | | | +-- expiration-date | | | | | | yang:date-and-\ time | | | | | +---x generate-csr | | | | | {csr-generation}? | | | | | +---w input | | | | | | +---w csr-format | | | | | | | identityref | | | | | | +---w csr-info | | | | | | csr-info | | | | | +--ro output | | | | | +--ro (csr-type) | | | | | +--:(p10-csr) | | | | | +--ro p10-csr? | | | | | p10-\ csr | | | | +--:(central-keystore) | | | | {central-keystore-\ supported,asymmetric-keys}? | | | | +--rw central-keystore-\ reference | | | | +--rw asymmetric-key? | | | | | ks:central-\ asymmetric-key-ref | | | | | {central-keystore\ -supported,asymmetric-keys}? | | | | +--rw certificate? | | | | leafref | | | +--:(raw-public-key) | | | | {tlsc:client-ident-raw-public-\ key}? | | | | +--rw raw-private-key | | | | +--rw (inline-or-keystore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw public-key-format? | | | | | | identityref | | | | | +--rw public-key? | | | | | | binary | | | | | +--rw private-key-format? | | | | | | identityref Boucadair, et al. Expires 22 June 2025 [Page 40] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | | | +--rw (private-key-type) | | | | | +--:(cleartext-private\ -key) | | | | | | {cleartext-\ private-keys}? | | | | | | +--rw cleartext-\ private-key? | | | | | | binary | | | | | +--:(hidden-private-\ key) | | | | | | {hidden-\ private-keys}? | | | | | | +--rw hidden-\ private-key? | | | | | | empty | | | | | +--:(encrypted-private\ -key) | | | | | {encrypted-\ private-keys}? | | | | | +--rw encrypted-\ private-key | | | | | +--rw encrypted-\ by | | | | | +--rw encrypted-\ value-format | | | | | | \ identityref | | | | | +--rw encrypted-\ value | | | | | binary | | | | +--:(central-keystore) | | | | {central-keystore-\ supported,asymmetric-keys}? | | | | +--rw central-keystore-\ reference? | | | | ks:central-\ asymmetric-key-ref | | | +--:(tls13-epsk) | | | {tlsc:client-ident-tls13-epsk}? | | | +--rw tls13-epsk | | | +--rw (inline-or-keystore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw key-format? | | | | | | identityref | | | | | +--rw (key-type) Boucadair, et al. Expires 22 June 2025 [Page 41] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | | | +--:(cleartext-\ symmetric-key) | | | | | | +--rw cleartext-\ symmetric-key? | | | | | | binary | | | | | | {cleartext-\ symmetric-keys}? | | | | | +--:(hidden-symmetric-\ key) | | | | | | {hidden-\ symmetric-keys}? | | | | | | +--rw hidden-\ symmetric-key? | | | | | | empty | | | | | +--:(encrypted-\ symmetric-key) | | | | | {encrypted-\ symmetric-keys}? | | | | | +--rw encrypted-\ symmetric-key | | | | | +--rw encrypted-\ by | | | | | +--rw encrypted-\ value-format | | | | | | \ identityref | | | | | +--rw encrypted-\ value | | | | | binary | | | | +--:(central-keystore) | | | | {central-keystore-\ supported,symmetric-keys}? | | | | +--rw central-keystore-\ reference? | | | | ks:central-symmetric\ -key-ref | | | +--rw external-identity | | | | string | | | +--rw hash? | | | | tlscmn:epsk-supported-hash | | | +--rw context? | | | | string | | | +--rw target-protocol? | | | | uint16 | | | +--rw target-kdf? | | | uint16 | | +--rw server-authentication | | | +--rw (ref-or-explicit)? Boucadair, et al. Expires 22 June 2025 [Page 42] Internet-Draft YANG for TACACS+ over TLS December 2024 | | | +--:(ref) | | | | +--rw credentials-reference? | | | | sys-tcs-plus:server-credentials-ref | | | | {credential-reference}? | | | +--:(explicit) | | | +--rw ca-certs! | | | | +--rw (inline-or-truststore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw certificate* [name] | | | | | +--rw name | | | | | | string | | | | | +--rw cert-data | | | | | | trust-anchor-cert-cms | | | | | +---n certificate-expiration | | | | | {certificate-\ expiration-notification}? | | | | | +-- expiration-date | | | | | yang:date-and-time | | | | +--:(central-truststore) | | | | {central-truststore-\ supported,certificates}? | | | | +--rw central-truststore-reference? | | | | ts:central-certificate-bag\ -ref | | | +--rw ee-certs! | | | | +--rw (inline-or-truststore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw certificate* [name] | | | | | +--rw name | | | | | | string | | | | | +--rw cert-data | | | | | | trust-anchor-cert-cms | | | | | +---n certificate-expiration | | | | | {certificate-\ expiration-notification}? | | | | | +-- expiration-date | | | | | yang:date-and-time | | | | +--:(central-truststore) | | | | {central-truststore-\ supported,certificates}? | | | | +--rw central-truststore-reference? | | | | ts:central-certificate-bag\ Boucadair, et al. Expires 22 June 2025 [Page 43] Internet-Draft YANG for TACACS+ over TLS December 2024 -ref | | | +--rw raw-public-keys! | | | | {tlsc:server-auth-raw-public-key}? | | | | +--rw (inline-or-truststore) | | | | +--:(inline) | | | | | {inline-definitions-\ supported}? | | | | | +--rw inline-definition | | | | | +--rw public-key* [name] | | | | | +--rw name | | | | | | string | | | | | +--rw public-key-format | | | | | | identityref | | | | | +--rw public-key | | | | | binary | | | | +--:(central-truststore) | | | | {central-truststore-\ supported,public-keys}? | | | | +--rw central-truststore-reference? | | | | ts:central-public-key-bag-\ ref | | | +--rw tls13-epsks? empty | | | {tlsc:server-auth-tls13-epsk}? | | +--rw hello-params {tlscmn:hello-params}? | | +--rw tls-versions | | | +--rw min? identityref | | | +--rw max? identityref | | +--rw cipher-suites | | +--rw cipher-suite* | | tlscsa:tls-cipher-suite-algorithm | +--:(obfuscation) | +--rw shared-secret? string +--rw (source-type)? | +--:(source-ip) | | +--rw source-ip? inet:ip-address | +--:(source-interface) | +--rw source-interface? if:interface-ref +--rw vrf-instance? | -> /ni:network-instances/network-instance/name +--rw single-connection? boolean +--rw timeout? uint16 +--ro statistics +--ro discontinuity-time? yang:date-and-time +--ro connection-opens? yang:counter64 +--ro connection-closes? yang:counter64 +--ro connection-aborts? yang:counter64 +--ro connection-failures? yang:counter64 +--ro connection-timeouts? yang:counter64 Boucadair, et al. Expires 22 June 2025 [Page 44] Internet-Draft YANG for TACACS+ over TLS December 2024 +--ro messages-sent? yang:counter64 +--ro messages-received? yang:counter64 +--ro errors-received? yang:counter64 +--ro sessions? yang:counter64 +--ro cert-errors? yang:counter64 +--ro rpk-errors? yang:counter64 {tlsc:server-auth-raw-public-key}? Acknowledgments The document leverages data structures defined in [RFC9645]. Thanks to Joe Clarke and Tom Petch for the review and comments. Acknowledgments from RFC 9105: The authors wish to thank Alex Campbell, John Heasley, Ebben Aries, Alan DeKok, Joe Clarke, Tom Petch, Robert Wilton, and many others for their helpful comments and suggestions. Authors' Addresses Mohamed Boucadair (editor) Orange Email: mohamed.boucadair@orange.com Bo Wu Huawei Technologies Email: mlana.wubo@huawei.com Guangying Zheng Huawei Technologies Email: zhengguangying@huawei.com Michael Wang Huawei Technologies Email: wangzitao@huawei.com Boucadair, et al. Expires 22 June 2025 [Page 45]