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module ietf-ssh-server {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ssh-server";
prefix sshs;
import ietf-ssh-common {
prefix sshcmn;
revision-date 2019-07-02;
reference
"RFC XXXX: YANG Groupings for SSH Clients and SSH Servers";
}
import ietf-keystore {
prefix ks;
reference
"RFC ZZZZ: A YANG Data Model for a Keystore";
}
import iana-crypt-hash {
prefix ianach;
reference
"RFC 7317: A YANG Data Model for System Management";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://datatracker.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Author: Kent Watsen <mailto:kent+ietf@watsen.net>
Author: Gary Wu <mailto:garywu@cisco.com>";
description
"This module defines reusable groupings for SSH servers that
can be used as a basis for specific SSH server instances.
Copyright (c) 2019 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 Simplified
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
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices.;
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.";
revision 2019-07-02 {
description
"Initial version";
reference
"RFC XXXX: YANG Groupings for SSH Clients and SSH Servers";
}
feature ssh-server-transport-params-config {
description
"SSH transport layer parameters are configurable on an SSH
server.";
}
feature ssh-server-keepalives {
description
"Per socket SSH keepalive parameters are configurable for
SSH servers on the server implementing this feature.";
}
feature local-client-auth-supported {
description
"Indicates that the SSH server supports local configuration
of client credentials.";
}
feature external-client-auth-supported {
description
"Indicates that the SSH server supports external configuration
of client credentials.";
}
grouping ssh-server-grouping {
description
"A reusable grouping for configuring a SSH server without
any consideration for how underlying TCP sessions are
established.
Note that this grouping uses fairly typical descendent
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
'ssh-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
"The list of host-keys the SSH server will present when
establishing a SSH connection.";
list host-key {
key "name";
min-elements 1;
ordered-by user;
description
"An ordered list of host keys the SSH server will use to
construct its ordered list of algorithms, when sending
its SSH_MSG_KEXINIT message, as defined in Section 7.1
of RFC 4253.";
reference
"RFC 4253: The Secure Shell (SSH) Transport Layer
Protocol";
leaf name {
type string;
description
"An arbitrary name for this host-key";
}
choice host-key-type {
mandatory true;
description
"The type of host key being specified";
container public-key {
description
"A locally-defined or referenced asymmetric key pair
to be used for the SSH server's host key.";
reference
"RFC ZZZZ: YANG Data Model for a Centralized
Keystore Mechanism";
uses ks:local-or-keystore-asymmetric-key-grouping;
}
container certificate {
if-feature "sshcmn:ssh-x509-certs";
description
"A locally-defined or referenced end-entity
certificate to be used for the SSH server's
host key.";
reference
"RFC ZZZZ: YANG Data Model for a Centralized
Keystore Mechanism";
uses ks:local-or-keystore-end-entity-cert-with-key-grouping;
}
}
}
}
container client-authentication {
nacm:default-deny-write;
description
"Specifies if SSH client authentication is required or
optional, and specifies if the SSH client authentication
credentials are configured locally or externally.";
container supported-authentication-methods {
description
"Indicates which authentication methods the server
supports.";
leaf publickey {
type empty;
description
"Indicates that the 'publickey' method is supported.
Note that RFC 6187 X.509v3 Certificates for SSH uses
the 'publickey' method name.";
reference
"RFC 4252: The Secure Shell (SSH) Authentication
Protocol.
RFC 6187: X.509v3 Certificates for Secure Shell
Authentication.";
}
leaf passsword {
type empty;
description
"Indicates that the 'password' method is supported.";
reference
"RFC 4252: The Secure Shell (SSH) Authentication
Protocol.";
}
leaf hostbased {
type empty;
description
"Indicates that the 'hostbased' method is supported.";
reference
"RFC 4252: The Secure Shell (SSH) Authentication
Protocol.";
}
leaf none {
type empty;
description
"Indicates that the 'none' method is supported.";
reference
"RFC 4252: The Secure Shell (SSH) Authentication
Protocol.";
}
leaf-list other {
type string;
description
"Indicates a supported method name not defined by
RFC 4253.";
reference
"RFC 4252: The Secure Shell (SSH) Authentication
Protocol.";
}
}
choice local-or-external {
description
"Indicates if the client credentials are configured
locally or externally.";
case local {
if-feature "local-client-auth-supported";
description
"Client credentials are configured locally.";
container users {
description
"A list of locally configured users.";
list user {
key "name";
description
"The list of local users configured on this device.";
leaf name {
type string;
description
"The user name string identifying this entry.";
}
leaf password {
type ianach:crypt-hash;
description
"The password for this entry.";
}
list authorized-key {
key "name";
description
"A list of public SSH keys for this user. These
keys are allowed for SSH authentication, as
described in RFC 4253.";
reference
"RFC 4253: The Secure Shell (SSH) Transport Layer
Protocol";
leaf name {
type string;
description
"An arbitrary name for the SSH key.";
}
leaf algorithm {
type string;
mandatory true;
description
"The public key algorithm name for this SSH key.
Valid values are the values in the IANA 'Secure
Shell (SSH) Protocol Parameters' registry,
Public Key Algorithm Names.";
reference
"IANA 'Secure Shell (SSH) Protocol Parameters'
registry, Public Key Algorithm Names";
}
leaf key-data {
type binary;
mandatory true;
description
"The binary public key data for this SSH key, as
specified by RFC 4253, Section 6.6, i.e.:
string certificate or public key format
identifier
byte[n] key/certificate data.";
reference
"RFC 4253: The Secure Shell (SSH) Transport Layer
Protocol";
}
}
}
}
}
case external {
if-feature "external-client-auth-supported";
description
"Client credentials are configured externally, such
as via RADIUS, RFC 7317, or another mechanism.";
leaf client-auth-defined-elsewhere {
type empty;
description
"Indicates that client credentials are configured
elsewhere.";
}
}
}
}
container transport-params {
nacm:default-deny-write;
if-feature "ssh-server-transport-params-config";
description
"Configurable parameters of the SSH transport layer.";
uses sshcmn:transport-params-grouping;
}
container keepalives {
nacm:default-deny-write;
if-feature "ssh-server-keepalives";
presence "Indicates that keepalives are enabled.";
description
"Configures the keep-alive policy, to proactively test
the aliveness of the SSL client. An unresponsive SSL
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
if no data has been received from the SSL client,
a SSL-level message will be sent to test the
aliveness of the SSL client.";
}
leaf max-attempts {
type uint8;
default "3";
description
"Sets the maximum number of sequential keep-alive
messages that can fail to obtain a response from
the SSL client before assuming the SSL client is
no longer alive.";
}
}
}
}
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