Commit Graph

4 Commits

Author SHA1 Message Date
Daniel P. Berrangé 55d869846d authz: add QAuthZListFile object type for a file access control list
Add a QAuthZListFile object type that implements the QAuthZ interface. This
built-in implementation is a proxy around the QAuthZList object type,
initializing it from an external file, and optionally, automatically
reloading it whenever it changes.

To create an instance of this object via the QMP monitor, the syntax
used would be:

      {
        "execute": "object-add",
        "arguments": {
          "qom-type": "authz-list-file",
          "id": "authz0",
          "props": {
            "filename": "/etc/qemu/vnc.acl",
	    "refresh": true
          }
        }
      }

If "refresh" is "yes", inotify is used to monitor the file,
automatically reloading changes. If an error occurs during reloading,
all authorizations will fail until the file is next successfully
loaded.

The /etc/qemu/vnc.acl file would contain a JSON representation of a
QAuthZList object

    {
      "rules": [
         { "match": "fred", "policy": "allow", "format": "exact" },
         { "match": "bob", "policy": "allow", "format": "exact" },
         { "match": "danb", "policy": "deny", "format": "glob" },
         { "match": "dan*", "policy": "allow", "format": "exact" },
      ],
      "policy": "deny"
    }

This sets up an authorization rule that allows 'fred', 'bob' and anyone
whose name starts with 'dan', except for 'danb'. Everyone unmatched is
denied.

The object can be loaded on the comand line using

   -object authz-list-file,id=authz0,filename=/etc/qemu/vnc.acl,refresh=yes

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-26 15:32:18 +00:00
Daniel P. Berrange c8c99887d1 authz: add QAuthZList object type for an access control list
Add a QAuthZList object type that implements the QAuthZ interface. This
built-in implementation maintains a trivial access control list with a
sequence of match rules and a final default policy. This replicates the
functionality currently provided by the qemu_acl module.

To create an instance of this object via the QMP monitor, the syntax
used would be:

  {
    "execute": "object-add",
    "arguments": {
      "qom-type": "authz-list",
      "id": "authz0",
      "props": {
        "rules": [
           { "match": "fred", "policy": "allow", "format": "exact" },
           { "match": "bob", "policy": "allow", "format": "exact" },
           { "match": "danb", "policy": "deny", "format": "glob" },
           { "match": "dan*", "policy": "allow", "format": "exact" },
        ],
        "policy": "deny"
      }
    }
  }

This sets up an authorization rule that allows 'fred', 'bob' and anyone
whose name starts with 'dan', except for 'danb'. Everyone unmatched is
denied.

It is not currently possible to create this via -object, since there is
no syntax supported to specify non-scalar properties for objects. This
is likely to be addressed by later support for using JSON with -object,
or an equivalent approach.

In any case the future "authz-listfile" object can be used from the
CLI and is likely a better choice, as it allows the ACL to be refreshed
automatically on change.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:32:18 +00:00
Daniel P. Berrangé fb5c4ebc08 authz: add QAuthZSimple object type for easy whitelist auth checks
In many cases a single VM will just need to whitelist a single identity
as the allowed user of network services. This is especially the case for
TLS live migration (optionally with NBD storage) where we just need to
whitelist the x509 certificate distinguished name of the source QEMU
host.

Via QMP this can be configured with:

  {
    "execute": "object-add",
    "arguments": {
      "qom-type": "authz-simple",
      "id": "authz0",
      "props": {
        "identity": "fred"
      }
    }
  }

Or via the command line

  -object authz-simple,id=authz0,identity=fred

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:25:58 +00:00
Daniel P. Berrange 5b76dd132c authz: add QAuthZ object as an authorization base class
The current qemu_acl module provides a simple access control list
facility inside QEMU, which is used via a set of monitor commands
acl_show, acl_policy, acl_add, acl_remove & acl_reset.

Note there is no ability to create ACLs - the network services (eg VNC
server) were expected to create ACLs that they want to check.

There is also no way to define ACLs on the command line, nor potentially
integrate with external authorization systems like polkit, pam, ldap
lookup, etc.

The QAuthZ object defines a minimal abstract QOM class that can be
subclassed for creating different authorization providers.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:25:58 +00:00