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>
This commit is contained in:
Daniel P. Berrangé 2018-05-11 12:19:59 +01:00
parent c8c99887d1
commit 55d869846d
7 changed files with 642 additions and 0 deletions

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@ -1,3 +1,4 @@
authz-obj-y += base.o
authz-obj-y += simple.o
authz-obj-y += list.o
authz-obj-y += listfile.o

283
authz/listfile.c Normal file
View File

@ -0,0 +1,283 @@
/*
* QEMU access control list file authorization driver
*
* Copyright (c) 2018 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 "authz/listfile.h"
#include "authz/trace.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/sockets.h"
#include "qemu/filemonitor.h"
#include "qom/object_interfaces.h"
#include "qapi/qapi-visit-authz.h"
#include "qapi/qmp/qjson.h"
#include "qapi/qmp/qobject.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qobject-input-visitor.h"
static bool
qauthz_list_file_is_allowed(QAuthZ *authz,
const char *identity,
Error **errp)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(authz);
if (fauthz->list) {
return qauthz_is_allowed(fauthz->list, identity, errp);
}
return false;
}
static QAuthZ *
qauthz_list_file_load(QAuthZListFile *fauthz, Error **errp)
{
GError *err = NULL;
gchar *content = NULL;
gsize len;
QObject *obj = NULL;
QDict *pdict;
Visitor *v = NULL;
QAuthZ *ret = NULL;
trace_qauthz_list_file_load(fauthz, fauthz->filename);
if (!g_file_get_contents(fauthz->filename, &content, &len, &err)) {
error_setg(errp, "Unable to read '%s': %s",
fauthz->filename, err->message);
goto cleanup;
}
obj = qobject_from_json(content, errp);
if (!obj) {
goto cleanup;
}
pdict = qobject_to(QDict, obj);
if (!pdict) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "obj", "dict");
goto cleanup;
}
v = qobject_input_visitor_new(obj);
ret = (QAuthZ *)user_creatable_add_type(TYPE_QAUTHZ_LIST,
NULL, pdict, v, errp);
cleanup:
visit_free(v);
qobject_unref(obj);
if (err) {
g_error_free(err);
}
g_free(content);
return ret;
}
static void
qauthz_list_file_event(int wd G_GNUC_UNUSED,
QFileMonitorEvent ev G_GNUC_UNUSED,
const char *name G_GNUC_UNUSED,
void *opaque)
{
QAuthZListFile *fauthz = opaque;
Error *err = NULL;
if (ev != QFILE_MONITOR_EVENT_MODIFIED &&
ev != QFILE_MONITOR_EVENT_CREATED) {
return;
}
object_unref(OBJECT(fauthz->list));
fauthz->list = qauthz_list_file_load(fauthz, &err);
trace_qauthz_list_file_refresh(fauthz,
fauthz->filename, fauthz->list ? 1 : 0);
if (!fauthz->list) {
error_report_err(err);
}
}
static void
qauthz_list_file_complete(UserCreatable *uc, Error **errp)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(uc);
gchar *dir = NULL, *file = NULL;
fauthz->list = qauthz_list_file_load(fauthz, errp);
if (!fauthz->refresh) {
return;
}
fauthz->file_monitor = qemu_file_monitor_new(errp);
if (!fauthz->file_monitor) {
return;
}
dir = g_path_get_dirname(fauthz->filename);
if (g_str_equal(dir, ".")) {
error_setg(errp, "Filename must be an absolute path");
goto cleanup;
}
file = g_path_get_basename(fauthz->filename);
if (g_str_equal(file, ".")) {
error_setg(errp, "Path has no trailing filename component");
goto cleanup;
}
fauthz->file_watch = qemu_file_monitor_add_watch(
fauthz->file_monitor, dir, file,
qauthz_list_file_event, fauthz, errp);
if (fauthz->file_watch < 0) {
goto cleanup;
}
cleanup:
g_free(file);
g_free(dir);
}
static void
qauthz_list_file_prop_set_filename(Object *obj,
const char *value,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
g_free(fauthz->filename);
fauthz->filename = g_strdup(value);
}
static char *
qauthz_list_file_prop_get_filename(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
return g_strdup(fauthz->filename);
}
static void
qauthz_list_file_prop_set_refresh(Object *obj,
bool value,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
fauthz->refresh = value;
}
static bool
qauthz_list_file_prop_get_refresh(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
return fauthz->refresh;
}
static void
qauthz_list_file_finalize(Object *obj)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
object_unref(OBJECT(fauthz->list));
g_free(fauthz->filename);
qemu_file_monitor_free(fauthz->file_monitor);
}
static void
qauthz_list_file_class_init(ObjectClass *oc, void *data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
QAuthZClass *authz = QAUTHZ_CLASS(oc);
ucc->complete = qauthz_list_file_complete;
object_class_property_add_str(oc, "filename",
qauthz_list_file_prop_get_filename,
qauthz_list_file_prop_set_filename,
NULL);
object_class_property_add_bool(oc, "refresh",
qauthz_list_file_prop_get_refresh,
qauthz_list_file_prop_set_refresh,
NULL);
authz->is_allowed = qauthz_list_file_is_allowed;
}
static void
qauthz_list_file_init(Object *obj)
{
QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
authz->file_watch = -1;
#ifdef CONFIG_INOTIFY1
authz->refresh = TRUE;
#endif
}
QAuthZListFile *qauthz_list_file_new(const char *id,
const char *filename,
bool refresh,
Error **errp)
{
return QAUTHZ_LIST_FILE(
object_new_with_props(TYPE_QAUTHZ_LIST_FILE,
object_get_objects_root(),
id, errp,
"filename", filename,
"refresh", refresh ? "yes" : "no",
NULL));
}
static const TypeInfo qauthz_list_file_info = {
.parent = TYPE_QAUTHZ,
.name = TYPE_QAUTHZ_LIST_FILE,
.instance_init = qauthz_list_file_init,
.instance_size = sizeof(QAuthZListFile),
.instance_finalize = qauthz_list_file_finalize,
.class_size = sizeof(QAuthZListFileClass),
.class_init = qauthz_list_file_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
static void
qauthz_list_file_register_types(void)
{
type_register_static(&qauthz_list_file_info);
}
type_init(qauthz_list_file_register_types);

View File

@ -9,3 +9,7 @@ qauthz_simple_is_allowed(void *authz, const char *wantidentity, const char *goti
# auth/list.c
qauthz_list_check_rule(void *authz, const char *identity, const char *rule, int format, int policy) "AuthZ list %p check rule=%s identity=%s format=%d policy=%d"
qauthz_list_default_policy(void *authz, const char *identity, int policy) "AuthZ list %p default identity=%s policy=%d"
# auth/listfile.c
qauthz_list_file_load(void *authz, const char *filename) "AuthZ file %p load filename=%s"
qauthz_list_file_refresh(void *authz, const char *filename, int success) "AuthZ file %p load filename=%s success=%d"

111
include/authz/listfile.h Normal file
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@ -0,0 +1,111 @@
/*
* QEMU list file authorization driver
*
* Copyright (c) 2018 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_LIST_FILE_H__
#define QAUTHZ_LIST_FILE_H__
#include "authz/list.h"
#include "qapi/qapi-types-authz.h"
#include "qemu/filemonitor.h"
#define TYPE_QAUTHZ_LIST_FILE "authz-list-file"
#define QAUTHZ_LIST_FILE_CLASS(klass) \
OBJECT_CLASS_CHECK(QAuthZListFileClass, (klass), \
TYPE_QAUTHZ_LIST_FILE)
#define QAUTHZ_LIST_FILE_GET_CLASS(obj) \
OBJECT_GET_CLASS(QAuthZListFileClass, (obj), \
TYPE_QAUTHZ_LIST_FILE)
#define QAUTHZ_LIST_FILE(obj) \
INTERFACE_CHECK(QAuthZListFile, (obj), \
TYPE_QAUTHZ_LIST_FILE)
typedef struct QAuthZListFile QAuthZListFile;
typedef struct QAuthZListFileClass QAuthZListFileClass;
/**
* QAuthZListFile:
*
* This authorization driver provides a file mechanism
* for granting access by matching user names against a
* file of globs. Each match rule has an associated policy
* and a catch all policy applies if no rule matches
*
* To create an instance of this class via QMP:
*
* {
* "execute": "object-add",
* "arguments": {
* "qom-type": "authz-list-file",
* "id": "authz0",
* "props": {
* "filename": "/etc/qemu/myvm-vnc.acl",
* "refresh": true
* }
* }
* }
*
* If 'refresh' is 'yes', inotify is used to monitor for changes
* to the file and auto-reload the rules.
*
* The myvm-vnc.acl file should contain the parameters for
* the QAuthZList object in JSON format:
*
* {
* "rules": [
* { "match": "fred", "policy": "allow", "format": "exact" },
* { "match": "bob", "policy": "allow", "format": "exact" },
* { "match": "danb", "policy": "deny", "format": "exact" },
* { "match": "dan*", "policy": "allow", "format": "glob" }
* ],
* "policy": "deny"
* }
*
* The object can be created on the command line using
*
* -object authz-list-file,id=authz0,\
* filename=/etc/qemu/myvm-vnc.acl,refresh=yes
*
*/
struct QAuthZListFile {
QAuthZ parent_obj;
QAuthZ *list;
char *filename;
bool refresh;
QFileMonitor *file_monitor;
int file_watch;
};
struct QAuthZListFileClass {
QAuthZClass parent_class;
};
QAuthZListFile *qauthz_list_file_new(const char *id,
const char *filename,
bool refresh,
Error **errp);
#endif /* QAUTHZ_LIST_FILE_H__ */

View File

@ -4389,6 +4389,52 @@ would look like:
Note the use of quotes due to the x509 distinguished name containing
whitespace, and escaping of ','.
@item -object authz-listfile,id=@var{id},filename=@var{path},refresh=@var{yes|no}
Create an authorization object that will control access to network services.
The @option{filename} parameter is the fully qualified path to a file
containing the access control list rules in JSON format.
An example set of rules that match against SASL usernames might look
like:
@example
@{
"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"
@}
@end example
When checking access the object will iterate over all the rules and
the first rule to match will have its @option{policy} value returned
as the result. If no rules match, then the default @option{policy}
value is returned.
The rules can either be an exact string match, or they can use the
simple UNIX glob pattern matching to allow wildcards to be used.
If @option{refresh} is set to true the file will be monitored
and automatically reloaded whenever its content changes.
As with the @code{authz-simple} object, the format of the identity
strings being matched depends on the network service, but is usually
a TLS x509 distinguished name, or a SASL username.
An example authorization object to validate a SASL username
would look like:
@example
# $QEMU \
...
-object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes
...
@end example
@end table
ETEXI

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@ -118,6 +118,7 @@ check-unit-$(CONFIG_INOTIFY1) += tests/test-util-filemonitor$(EXESUF)
check-unit-y += tests/test-util-sockets$(EXESUF)
check-unit-y += tests/test-authz-simple$(EXESUF)
check-unit-y += tests/test-authz-list$(EXESUF)
check-unit-y += tests/test-authz-listfile$(EXESUF)
check-unit-y += tests/test-io-task$(EXESUF)
check-unit-y += tests/test-io-channel-socket$(EXESUF)
check-unit-y += tests/test-io-channel-file$(EXESUF)
@ -667,6 +668,7 @@ tests/test-util-sockets$(EXESUF): tests/test-util-sockets.o \
tests/socket-helpers.o $(test-util-obj-y)
tests/test-authz-simple$(EXESUF): tests/test-authz-simple.o $(test-authz-obj-y)
tests/test-authz-list$(EXESUF): tests/test-authz-list.o $(test-authz-obj-y)
tests/test-authz-listfile$(EXESUF): tests/test-authz-listfile.o $(test-authz-obj-y)
tests/test-io-task$(EXESUF): tests/test-io-task.o $(test-io-obj-y)
tests/test-io-channel-socket$(EXESUF): tests/test-io-channel-socket.o \
tests/io-channel-helpers.o tests/socket-helpers.o $(test-io-obj-y)

195
tests/test-authz-listfile.c Normal file
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@ -0,0 +1,195 @@
/*
* QEMU list authorization object tests
*
* Copyright (c) 2018 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/main-loop.h"
#include "authz/listfile.h"
static char *workdir;
static gchar *qemu_authz_listfile_test_save(const gchar *name,
const gchar *cfg)
{
gchar *path = g_strdup_printf("%s/default-deny.cfg", workdir);
GError *gerr = NULL;
if (!g_file_set_contents(path, cfg, -1, &gerr)) {
g_printerr("Unable to save config %s: %s\n",
path, gerr->message);
g_error_free(gerr);
g_free(path);
rmdir(workdir);
abort();
}
return path;
}
static void test_authz_default_deny(void)
{
gchar *file = qemu_authz_listfile_test_save(
"default-deny.cfg",
"{ \"policy\": \"deny\" }");
Error *local_err = NULL;
QAuthZListFile *auth = qauthz_list_file_new("auth0",
file, false,
&local_err);
unlink(file);
g_free(file);
g_assert(local_err == NULL);
g_assert(!qauthz_is_allowed(QAUTHZ(auth), "fred", &error_abort));
object_unparent(OBJECT(auth));
}
static void test_authz_default_allow(void)
{
gchar *file = qemu_authz_listfile_test_save(
"default-allow.cfg",
"{ \"policy\": \"allow\" }");
Error *local_err = NULL;
QAuthZListFile *auth = qauthz_list_file_new("auth0",
file, false,
&local_err);
unlink(file);
g_free(file);
g_assert(local_err == NULL);
g_assert(qauthz_is_allowed(QAUTHZ(auth), "fred", &error_abort));
object_unparent(OBJECT(auth));
}
static void test_authz_explicit_deny(void)
{
gchar *file = qemu_authz_listfile_test_save(
"explicit-deny.cfg",
"{ \"rules\": [ "
" { \"match\": \"fred\","
" \"policy\": \"deny\","
" \"format\": \"exact\" } ],"
" \"policy\": \"allow\" }");
Error *local_err = NULL;
QAuthZListFile *auth = qauthz_list_file_new("auth0",
file, false,
&local_err);
unlink(file);
g_free(file);
g_assert(local_err == NULL);
g_assert(!qauthz_is_allowed(QAUTHZ(auth), "fred", &error_abort));
object_unparent(OBJECT(auth));
}
static void test_authz_explicit_allow(void)
{
gchar *file = qemu_authz_listfile_test_save(
"explicit-allow.cfg",
"{ \"rules\": [ "
" { \"match\": \"fred\","
" \"policy\": \"allow\","
" \"format\": \"exact\" } ],"
" \"policy\": \"deny\" }");
Error *local_err = NULL;
QAuthZListFile *auth = qauthz_list_file_new("auth0",
file, false,
&local_err);
unlink(file);
g_free(file);
g_assert(local_err == NULL);
g_assert(qauthz_is_allowed(QAUTHZ(auth), "fred", &error_abort));
object_unparent(OBJECT(auth));
}
static void test_authz_complex(void)
{
gchar *file = qemu_authz_listfile_test_save(
"complex.cfg",
"{ \"rules\": [ "
" { \"match\": \"fred\","
" \"policy\": \"allow\","
" \"format\": \"exact\" },"
" { \"match\": \"bob\","
" \"policy\": \"allow\","
" \"format\": \"exact\" },"
" { \"match\": \"dan\","
" \"policy\": \"deny\","
" \"format\": \"exact\" },"
" { \"match\": \"dan*\","
" \"policy\": \"allow\","
" \"format\": \"glob\" } ],"
" \"policy\": \"deny\" }");
Error *local_err = NULL;
QAuthZListFile *auth = qauthz_list_file_new("auth0",
file, false,
&local_err);
unlink(file);
g_free(file);
g_assert(local_err == NULL);
g_assert(qauthz_is_allowed(QAUTHZ(auth), "fred", &error_abort));
g_assert(qauthz_is_allowed(QAUTHZ(auth), "bob", &error_abort));
g_assert(!qauthz_is_allowed(QAUTHZ(auth), "dan", &error_abort));
g_assert(qauthz_is_allowed(QAUTHZ(auth), "danb", &error_abort));
object_unparent(OBJECT(auth));
}
int main(int argc, char **argv)
{
int ret;
GError *gerr = NULL;
g_test_init(&argc, &argv, NULL);
module_call_init(MODULE_INIT_QOM);
workdir = g_dir_make_tmp("qemu-test-authz-listfile-XXXXXX",
&gerr);
if (!workdir) {
g_printerr("Unable to create temporary dir: %s\n",
gerr->message);
g_error_free(gerr);
abort();
}
g_test_add_func("/auth/list/default/deny", test_authz_default_deny);
g_test_add_func("/auth/list/default/allow", test_authz_default_allow);
g_test_add_func("/auth/list/explicit/deny", test_authz_explicit_deny);
g_test_add_func("/auth/list/explicit/allow", test_authz_explicit_allow);
g_test_add_func("/auth/list/complex", test_authz_complex);
ret = g_test_run();
rmdir(workdir);
g_free(workdir);
return ret;
}