module ietf-ssh-common {

    yang-version 1.1;

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-ssh-common";

    prefix sshcmn;

    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";


    }
    import iana-ssh-encryption-algs {
      prefix sshea;
      reference
        "RFC 9644: YANG Groupings for SSH Clients and SSH Servers";


    }
    import iana-ssh-key-exchange-algs {
      prefix sshkea;
      reference
        "RFC 9644: YANG Groupings for SSH Clients and SSH Servers";


    }
    import iana-ssh-mac-algs {
      prefix sshma;
      reference
        "RFC 9644: YANG Groupings for SSH Clients and SSH Servers";


    }
    import iana-ssh-public-key-algs {
      prefix sshpka;
      reference
        "RFC 9644: YANG Groupings for SSH Clients and SSH Servers";


    }

    organization
      "IETF NETCONF (Network Configuration) Working Group";

    contact
      "WG Web:   https://datatracker.ietf.org/wg/netconf
WG List:  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 common features and groupings for
Secure Shell (SSH).

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 9644
(https://www.rfc-editor.org/info/rfc9644); see the RFC
itself for full legal notices.";

    revision "2024-10-10" {
      description "Initial version.";
      reference
        "RFC 9644: YANG Groupings for SSH Clients and SSH Servers";

    }


    feature ssh-x509-certs {
      description
        "X.509v3 certificates are supported for SSH.";
      reference
        "RFC 6187: X.509v3 Certificates for Secure Shell
        	  Authentication";

    }

    feature transport-params {
      description
        "SSH transport layer parameters are configurable.";
    }

    feature asymmetric-key-pair-generation {
      description
        "Indicates that the server implements the
'generate-asymmetric-key-pair' RPC.";
    }

    feature algorithm-discovery {
      description
        "Indicates that the server implements the
'supported-algorithms' container.";
    }

    typedef ssh-public-key-algorithm {
      type union {
        type sshpka:ssh-public-key-algorithm;
        type string {
          length "1..64";
          pattern '.*@.*';
        }
      }
      description
        "A type that enables the public key algorithm to be
either an IANA-maintained public key algorithm in
the 'iana-ssh-public-key-algs' YANG module (RFC 9644)
or a locally defined algorithm, per Section 4.6.1
of RFC 4250.";
      reference
        "RFC 4250: The Secure Shell (SSH) Protocol Assigned Numbers
         RFC 9644: YANG Groupings for SSH Clients and SSH Servers";

    }

    typedef ssh-key-exchange-algorithm {
      type union {
        type sshkea:ssh-key-exchange-algorithm;
        type string {
          length "1..64";
          pattern '.*@.*';
        }
      }
      description
        "A type that enables the key exchange algorithm to be
either an IANA-maintained key exchange algorithm in
the 'iana-ssh-key-exchange-algs' YANG module (RFC 9644)
or a locally defined algorithm, per Section 4.6.1
of RFC 4250.";
      reference
        "RFC 4250: The Secure Shell (SSH) Protocol Assigned Numbers
         RFC 9644: YANG Groupings for SSH Clients and SSH Servers";

    }

    typedef ssh-encryption-algorithm {
      type union {
        type sshea:ssh-encryption-algorithm;
        type string {
          length "1..64";
          pattern '.*@.*';
        }
      }
      description
        "A type that enables the encryption algorithm to be
either an IANA-maintained encryption algorithm in
the 'iana-ssh-encryption-algs' YANG module (RFC 9644)
or a locally defined algorithm, per Section 4.6.1
of RFC 4250.";
      reference
        "RFC 4250: The Secure Shell (SSH) Protocol Assigned Numbers
         RFC 9644: YANG Groupings for SSH Clients and SSH Servers";

    }

    typedef ssh-mac-algorithm {
      type union {
        type sshma:ssh-mac-algorithm;
        type string {
          length "1..64";
          pattern '.*@.*';
        }
      }
      description
        "A type that enables the message authentication code (MAC)
algorithm to be either an IANA-maintained MAC algorithm
in the 'iana-ssh-mac-algs' YANG module (RFC 9644)
or a locally defined algorithm, per Section 4.6.1
of RFC 4250.";
      reference
        "RFC 4250: The Secure Shell (SSH) Protocol Assigned Numbers
         RFC 9644: YANG Groupings for SSH Clients and SSH Servers";

    }

    container supported-algorithms {
      if-feature algorithm-discovery;
      config false;
      description
        "Identifies all of the supported algorithms.";
      container public-key-algorithms {
        description
          "A container for a list of public key algorithms
supported by the server.";
        leaf-list supported-algorithm {
          type ssh-public-key-algorithm;
          description
            "A public key algorithm supported by the server.";
        }
      }  // container public-key-algorithms

      container encryption-algorithms {
        description
          "A container for a list of encryption algorithms
supported by the server.";
        leaf-list supported-algorithm {
          type ssh-encryption-algorithm;
          description
            "An encryption algorithm supported by the server.";
        }
      }  // container encryption-algorithms

      container key-exchange-algorithms {
        config false;
        description
          "A container for a list of key exchange algorithms
supported by the server.";
        leaf-list supported-algorithm {
          type ssh-key-exchange-algorithm;
          description
            "A key exchange algorithm supported by the server.";
        }
      }  // container key-exchange-algorithms

      container mac-algorithms {
        config false;
        description
          "A container for a list of MAC algorithms
supported by the server.";
        leaf-list supported-algorithm {
          type ssh-mac-algorithm;
          description
            "A MAC algorithm supported by the server.";
        }
      }  // container mac-algorithms
    }  // container supported-algorithms

    rpc generate-asymmetric-key-pair {
      if-feature asymmetric-key-pair-generation;
      description
        "Requests the device to generate a public key using
the specified key algorithm.";
      input {
        leaf algorithm {
          type ssh-public-key-algorithm;
          mandatory true;
          description
            "The algorithm to be used when generating the key.";
        }

        leaf num-bits {
          type uint16;
          description
            "Specifies the number of bits in the key to create.
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 186-5.  For Elliptic Curve
Digital Signature Algorithm (ECDSA) keys, the
'num-bits' value determines the key length by selecting
from one of three elliptic curve sizes: 256, 384, or
521 bits.  Attempting to use bit lengths other than
these three values for ECDSA keys will fail.  ECDSA-SK,
Ed25519, and Ed25519-SK keys have a fixed length, and
thus, the 'num-bits' value is not specified.";
          reference
            "FIPS 186-5: Digital Signature Standard (DSS)";

        }

        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 cleartext

            case encrypted {
              if-feature ct:encrypted-private-keys;
              container encrypted {
                description
                  "Indicates that the private key is to be encrypted
using the specified symmetric or asymmetric key.";
                choice encrypted-by {
                  nacm:default-deny-write;
                  mandatory true;
                  description
                    "A choice amongst other symmetric or asymmetric keys.";
                  case central-symmetric-key-ref {
                    if-feature central-keystore-supported;
                    if-feature symmetric-keys;
                    leaf symmetric-key-ref {
                      type ks:central-symmetric-key-ref;
                      description
                        "Identifies the symmetric key used to encrypt the
associated key.";
                    }
                  }  // case central-symmetric-key-ref

                  case central-asymmetric-key-ref {
                    if-feature central-keystore-supported;
                    if-feature asymmetric-keys;
                    leaf asymmetric-key-ref {
                      type ks:central-asymmetric-key-ref;
                      description
                        "Identifies the asymmetric key whose public key
encrypted the associated key.";
                    }
                  }  // case central-asymmetric-key-ref
                }  // choice encrypted-by
              }  // container encrypted
            }  // case encrypted

            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 the 'Support for Built-in Keys'
section in RFC 9642 for information about hidden
keys.

It is expected that the server will instantiate
the hidden key in the same location where built-in
keys are located.  Rather than returning the key,
just the key's location is returned in the output.";
              }
            }  // case hidden
          }  // choice private-key-encoding
        }  // container private-key-encoding
      }

      output {
        choice key-or-hidden {
          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).";
          case key {
            leaf public-key-format {
              nacm:default-deny-write;
              type identityref {
                base public-key-format;
              }
              mandatory true;
              description
                "Identifies the public key's format.  Implementations SHOULD
ensure that the incoming public key value is encoded in the
specified format.";
            }

            leaf public-key {
              nacm:default-deny-write;
              type binary;
              mandatory true;
              description
                "The binary value of the public key.  The interpretation
of the value is defined by the 'public-key-format' field.";
            }

            leaf private-key-format {
              nacm:default-deny-write;
              type identityref {
                base private-key-format;
              }
              description
                "Identifies the private key's format.  Implementations SHOULD
ensure that the incoming private key value is encoded in the
specified format.

For encrypted keys, the value is the decrypted key's
format (i.e., the 'encrypted-value-format' conveys the
encrypted key's format).";
            }

            choice private-key-type {
              nacm:default-deny-write;
              mandatory true;
              description
                "Choice between key types.";
              case cleartext-private-key {
                if-feature cleartext-private-keys;
                leaf cleartext-private-key {
                  nacm:default-deny-all;
                  type binary;
                  must
                    "../private-key-format";
                  description
                    "The value of the binary key.  The key's value is
interpreted by the 'private-key-format' field.";
                }
              }  // case cleartext-private-key

              case hidden-private-key {
                if-feature hidden-private-keys;
                leaf hidden-private-key {
                  type empty;
                  must
                    "not(../private-key-format)";
                  description
                    "A hidden key.  It is of type 'empty' as its value is
inaccessible via management interfaces.  Though hidden
to users, such keys are not hidden to the server and
may be referenced by configuration to indicate which
key a server should use for a cryptographic operation.
How such keys are created is outside the scope of this
module.";
                }
              }  // case hidden-private-key

              case encrypted-private-key {
                if-feature encrypted-private-keys;
                container encrypted-private-key {
                  must
                    "../private-key-format";
                  description
                    "A container for the encrypted asymmetric private key
value.  The interpretation of the 'encrypted-value'
node is via the 'private-key-format' node";
                  container encrypted-by {
                    nacm:default-deny-write;
                    description
                      "An empty container enabling a reference to the key that
encrypted the value to be augmented in.  The referenced
key MUST be a symmetric key or an asymmetric key.

A symmetric key MUST be referenced via a leaf node called
'symmetric-key-ref'.  An asymmetric key MUST be referenced
via a leaf node called 'asymmetric-key-ref'.

The leaf nodes MUST be direct descendants in the data tree
and MAY be direct descendants in the schema tree (e.g.,
'choice'/'case' statements are allowed but not a
container).";
                  }  // container encrypted-by

                  leaf encrypted-value-format {
                    type identityref {
                      base encrypted-value-format;
                    }
                    mandatory true;
                    description
                      "Identifies the format of the 'encrypted-value' leaf.

If 'encrypted-by' points to a symmetric key, then an
identity based on 'symmetrically-encrypted-value-format'
MUST be set (e.g., 'cms-encrypted-data-format').

If 'encrypted-by' points to an asymmetric key, then an
identity based on 'asymmetrically-encrypted-value-format'
MUST be set (e.g., 'cms-enveloped-data-format').";
                  }

                  leaf encrypted-value {
                    nacm:default-deny-write;
                    type binary;
                    must "../encrypted-by";
                    mandatory true;
                    description
                      "The value, encrypted using the referenced symmetric
or asymmetric key.  The value MUST be encoded using
the format associated with the 'encrypted-value-format'
leaf.";
                  }
                }  // container encrypted-private-key
              }  // case encrypted-private-key
            }  // choice private-key-type
          }  // case key
          leaf location {
            type instance-identifier;
            description
              "The location to where a hidden key was created.";
          }
        }  // choice key-or-hidden
      }
    }  // rpc generate-asymmetric-key-pair
  }  // module ietf-ssh-common