ldap/server: Initial version of ldapspn helper script

ldapspn supports listing, creating and deleting Kerberos service
principals.

roles/ldap/server/files/ldapspn.py

@@ -0,0 +1,135 @@
+#!/usr/bin/python3
+
+import sys
+import argparse
+from time import time
+from struct import pack
+
+import ldap3
+
+
+def ldap_connect():
+    server = ldap3.Server("ldapi:///var/run/ldapi")
+    conn = ldap3.Connection(
+        server,
+        authentication=ldap3.SASL,
+        sasl_mechanism=ldap3.EXTERNAL,
+        sasl_credentials="",
+        client_strategy=ldap3.SYNC,
+    )
+    conn.bind()
+    conn.search(
+        search_base="",
+        search_filter="(objectClass=*)",
+        search_scope=ldap3.BASE,
+        attributes=["namingContexts"],
+    )
+    basedn = conn.response[0]["attributes"]["namingContexts"][0]
+    return (conn, basedn)
+
+
+def get_last_modified(principal):
+    """ create krbExtraData value with KRB5_TL_MOD_PRINC type """
+    data = pack(
+        "<ccL%dsc" % len(principal),
+        b"\x00",
+        b"\x02",
+        int(time()),
+        bytes(principal, "UTF-8"),
+        b"\x00",
+    )
+    return data
+
+
+def get_kvno():
+    """ return krbExtraData value with KRB_TL_MKVNO type with value 0 """
+    return pack("<cccc", b"\x00", b"\x08", b"\x01", b"\x00")
+
+
+def principal_create(args, conn, basedn):
+    if not args.container:
+        (principal, realm) = args.principal.split("@", 2)
+        (service, hostname) = principal.split("/", 2)
+        conn.search(
+            search_base=basedn,
+            search_filter=f"(&(cn={hostname})(objectClass=device))",
+        )
+        if len(conn.response) != 1:
+            print(
+                "ERROR: Could not get container dn for principal '{args.principal}'",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+        args.container = conn.response[0]["dn"]
+    conn.add(
+        f"krbPrincipalName={args.principal},{args.container}",
+        attributes={
+            "objectClass": [
+                "krbPrincipal",
+                "krbPrincipalAux",
+                "krbTicketPolicyAux",
+            ],
+            "krbPrincipalName": args.principal,
+            "krbExtraData": [get_last_modified("root/admin@FOO.SH"), get_kvno()],
+        },
+    )
+    if conn.result["result"] != 0:
+        print(
+            f"ERROR: Failed to add principal: {conn.result['description']}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+
+def principal_delete(args, conn, basedn):
+    conn.search(
+        search_base=basedn,
+        search_filter=f"(&(krbPrincipalName={args.principal})(objectClass=krbPrincipalAux))",
+        attributes=[],
+    )
+    if len(conn.response) != 1:
+        print(f"ERROR: Could not find principal '{args.principal}'", file=sys.stderr)
+        sys.exit(1)
+    conn.delete(conn.response[0]["dn"])
+    if conn.result["result"] != 0:
+        print(
+            f"ERROR: Failed to delete principal: {conn.result['description']}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+
+def principal_list(args, conn, baesdn):
+    conn.search(
+        search_base=basedn,
+        search_filter="(objectClass=krbPrincipalAux)",
+        attributes=["krbPrincipalName"],
+    )
+    for result in conn.response:
+        for name in result["attributes"]["krbPrincipalName"]:
+            print(name)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers()
+
+    create = subparsers.add_parser("add")
+    create.set_defaults(func=principal_create)
+    create.add_argument("--principal", metavar="PRINCIPAL", type=str, required=True)
+    create.add_argument("--container", metavar="CONTAINER", type=str, required=False)
+
+    delete = subparsers.add_parser("del")
+    delete.set_defaults(func=principal_delete)
+    delete.add_argument("--principal", metavar="PRINCIPAL", type=str, required=True)
+
+    show = subparsers.add_parser("list")
+    show.set_defaults(func=principal_list)
+    parser.set_defaults(func=principal_list)
+
+    args = parser.parse_args()
+    try:
+        (conn, basedn) = ldap_connect()
+        args.func(args, conn, basedn)
+    except KeyboardInterrupt:
+        sys.exit(1)

roles/ldap/server/tasks/main.yml

@@ -61,6 +61,14 @@
         hour: 0
         minute: 10
         user: ldap
+
+    - name: copy spn helper script
+      copy:
+        dest: /usr/local/sbin/ldapspn
+        src: ldapspn.py
+        mode: 0755
+        owner: root
+        group: "{{ ansible_wheel }}"
   when: ldap_master is defined
 
 - name: remove nss cert databases