[v6,5/7] util: 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.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 MAINTAINERS          |  7 +++++
 Makefile             |  1 +
 Makefile.objs        |  2 ++
 Makefile.target      |  2 ++
 include/qemu/authz.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 util/Makefile.objs   |  2 ++
 util/authz.c         | 46 +++++++++++++++++++++++++++
 7 files changed, 149 insertions(+)
 create mode 100644 include/qemu/authz.h
 create mode 100644 util/authz.c

Hi

On Tue, Jun 14, 2016 at 6:07 PM, Daniel P. Berrange <berrange@redhat.com> wrote:
> 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.
>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  MAINTAINERS          |  7 +++++
>  Makefile             |  1 +
>  Makefile.objs        |  2 ++
>  Makefile.target      |  2 ++
>  include/qemu/authz.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  util/Makefile.objs   |  2 ++
>  util/authz.c         | 46 +++++++++++++++++++++++++++
>  7 files changed, 149 insertions(+)
>  create mode 100644 include/qemu/authz.h
>  create mode 100644 util/authz.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index df990a8..f8fa73a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1324,6 +1324,13 @@ F: include/qemu/throttle.h
>  F: util/throttle.c
>  L: qemu-block@nongnu.org
>
> +Authorization
> +M: Daniel P. Berrange <berrange@redhat.com>
> +S: Maintained
> +F: util/authz*
> +F: include/qemu/authz*
> +F: tests/test-authz-*
> +
>  Usermode Emulation
>  ------------------
>  Overall
> diff --git a/Makefile b/Makefile
> index ed4032a..421c390 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -148,6 +148,7 @@ endif
>  dummy := $(call unnest-vars,, \
>                  stub-obj-y \
>                  util-obj-y \
> +                util-qom-obj-y \
>                  qga-obj-y \
>                  ivshmem-client-obj-y \
>                  ivshmem-server-obj-y \
> diff --git a/Makefile.objs b/Makefile.objs
> index da49b71..24db7f7 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -4,6 +4,8 @@ stub-obj-y = stubs/ crypto/
>  util-obj-y = util/ qobject/ qapi/
>  util-obj-y += qmp-introspect.o qapi-types.o qapi-visit.o qapi-event.o
>
> +util-qom-obj-y += util/
> +
>  #######################################################################
>  # block-obj-y is code used by both qemu system emulation and qemu-img
>
> diff --git a/Makefile.target b/Makefile.target
> index 495b474..e79d942 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -176,6 +176,7 @@ include $(SRC_PATH)/Makefile.objs
>  dummy := $(call unnest-vars,,target-obj-y)
>  target-obj-y-save := $(target-obj-y)
>  dummy := $(call unnest-vars,.., \
> +               util-qom-obj-y \
>                 block-obj-y \
>                 block-obj-m \
>                 crypto-obj-y \
> @@ -188,6 +189,7 @@ target-obj-y := $(target-obj-y-save)
>  all-obj-y += $(common-obj-y)
>  all-obj-y += $(target-obj-y)
>  all-obj-y += $(qom-obj-y)
> +all-obj-y += $(util-qom-obj-y)
>  all-obj-$(CONFIG_SOFTMMU) += $(block-obj-y)
>  all-obj-$(CONFIG_USER_ONLY) += $(crypto-aes-obj-y)
>  all-obj-$(CONFIG_SOFTMMU) += $(crypto-obj-y)
> diff --git a/include/qemu/authz.h b/include/qemu/authz.h
> new file mode 100644
> index 0000000..6a73063
> --- /dev/null
> +++ b/include/qemu/authz.h
> @@ -0,0 +1,89 @@
> +/*
> + * QEMU authorization framework
> + *
> + * Copyright (c) 2016 Red Hat, Inc.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#ifndef QAUTHZ_H__
> +#define QAUTHZ_H__
> +
> +#include "qemu-common.h"
> +#include "qapi/error.h"
> +#include "qom/object.h"
> +
> +
> +#define TYPE_QAUTHZ "authz"
> +
> +#define QAUTHZ_CLASS(klass) \
> +     OBJECT_CLASS_CHECK(QAuthZClass, (klass), \
> +                        TYPE_QAUTHZ)
> +#define QAUTHZ_GET_CLASS(obj) \
> +     OBJECT_GET_CLASS(QAuthZClass, (obj), \
> +                      TYPE_QAUTHZ)
> +#define QAUTHZ(obj) \
> +     INTERFACE_CHECK(QAuthZ, (obj), \
> +                     TYPE_QAUTHZ)
> +
> +typedef struct QAuthZ QAuthZ;
> +typedef struct QAuthZClass QAuthZClass;
> +
> +/**
> + * QAuthZ:
> + *
> + * The QAuthZ class defines an API contract to be used
> + * for providing an authorization driver for services
> + * with user identities.
> + */
> +
> +struct QAuthZ {
> +    Object parent_obj;
> +};
> +
> +
> +struct QAuthZClass {
> +    ObjectClass parent_class;
> +
> +    bool (*is_allowed)(QAuthZ *authz,
> +                       const char *identity,
> +                       Error **errp);
> +};
> +
> +
> +/**
> + * qauthz_is_allowed:
> + * @authz: the authorization object
> + * @identity: the user identity to authorize
> + * @errp: pointer to a NULL initialized error object
> + *
> + * Check if a user @identity is authorized. If an error
> + * occurrs this method will return false to indicate

occurs

> + * denial, as well as setting @errp to contain the details.
> + * Callers are recommended to treat the denial and error
> + * scenarios identically. Specifically the error info in
> + * @errp should never be fed back to the user being
> + * authorized, it is merely for benefit of administrator
> + * debugging.
> + *
> + * Returns: true if @identity is authorized, false if denied or if
> + * an error occurred.
> + */
> +bool qauthz_is_allowed(QAuthZ *authz,
> +                       const char *identity,
> +                       Error **errp);
> +
> +#endif /* QAUTHZ_H__ */
> +
> diff --git a/util/Makefile.objs b/util/Makefile.objs
> index 45f8794..0d83583 100644
> --- a/util/Makefile.objs
> +++ b/util/Makefile.objs
> @@ -34,3 +34,5 @@ util-obj-y += base64.o
>  util-obj-y += log.o
>  util-obj-y += qdist.o
>  util-obj-y += qht.o
> +
> +util-qom-obj-y += authz.o
> diff --git a/util/authz.c b/util/authz.c
> new file mode 100644
> index 0000000..fd9f84e
> --- /dev/null
> +++ b/util/authz.c
> @@ -0,0 +1,46 @@
> +/*
> + * QEMU authorization framework
> + *
> + * Copyright (c) 2016 Red Hat, Inc.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/authz.h"
> +
> +bool qauthz_is_allowed(QAuthZ *authz,
> +                       const char *identity,
> +                       Error **errp)
> +{
> +    QAuthZClass *cls = QAUTHZ_GET_CLASS(authz);
> +
> +    return cls->is_allowed(authz, identity, errp);
> +}
> +
> +static const TypeInfo authz_info = {
> +    .parent = TYPE_OBJECT,
> +    .name = TYPE_QAUTHZ,
> +    .instance_size = sizeof(QAuthZ),
> +    .class_size = sizeof(QAuthZClass),

.abstract = true? (perhaps it's not necessary, but that would be more clear)

> +};
> +
> +static void qauthz_register_types(void)
> +{
> +    type_register_static(&authz_info);
> +}
> +
> +type_init(qauthz_register_types)
> +
> --
> 2.5.5
>
>

On Tue, Jun 28, 2016 at 06:22:10PM +0200, Marc-André Lureau wrote:

> > +
> > +static const TypeInfo authz_info = {
> > +    .parent = TYPE_OBJECT,
> > +    .name = TYPE_QAUTHZ,
> > +    .instance_size = sizeof(QAuthZ),
> > +    .class_size = sizeof(QAuthZClass),
> 
> .abstract = true? (perhaps it's not necessary, but that would be more clear)

Yes, makes sense to add that since you can't instantiate this class
and do anything useful with it.


Regards,
Daniel