qemu/authz/pamacct.c
Markus Armbruster d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00

149 lines
3.7 KiB
C

/*
* QEMU PAM 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/pamacct.h"
#include "trace.h"
#include "qemu/module.h"
#include "qom/object_interfaces.h"
#include <security/pam_appl.h>
static bool qauthz_pam_is_allowed(QAuthZ *authz,
const char *identity,
Error **errp)
{
QAuthZPAM *pauthz = QAUTHZ_PAM(authz);
const struct pam_conv pam_conversation = { 0 };
pam_handle_t *pamh = NULL;
int ret;
trace_qauthz_pam_check(authz, identity, pauthz->service);
ret = pam_start(pauthz->service,
identity,
&pam_conversation,
&pamh);
if (ret != PAM_SUCCESS) {
error_setg(errp, "Unable to start PAM transaction: %s",
pam_strerror(NULL, ret));
return false;
}
ret = pam_acct_mgmt(pamh, PAM_SILENT);
pam_end(pamh, ret);
if (ret != PAM_SUCCESS) {
error_setg(errp, "Unable to authorize user '%s': %s",
identity, pam_strerror(pamh, ret));
return false;
}
return true;
}
static void
qauthz_pam_prop_set_service(Object *obj,
const char *service,
Error **errp G_GNUC_UNUSED)
{
QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
g_free(pauthz->service);
pauthz->service = g_strdup(service);
}
static char *
qauthz_pam_prop_get_service(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
return g_strdup(pauthz->service);
}
static void
qauthz_pam_complete(UserCreatable *uc, Error **errp)
{
}
static void
qauthz_pam_finalize(Object *obj)
{
QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
g_free(pauthz->service);
}
static void
qauthz_pam_class_init(ObjectClass *oc, void *data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
QAuthZClass *authz = QAUTHZ_CLASS(oc);
ucc->complete = qauthz_pam_complete;
authz->is_allowed = qauthz_pam_is_allowed;
object_class_property_add_str(oc, "service",
qauthz_pam_prop_get_service,
qauthz_pam_prop_set_service);
}
QAuthZPAM *qauthz_pam_new(const char *id,
const char *service,
Error **errp)
{
return QAUTHZ_PAM(
object_new_with_props(TYPE_QAUTHZ_PAM,
object_get_objects_root(),
id, errp,
"service", service,
NULL));
}
static const TypeInfo qauthz_pam_info = {
.parent = TYPE_QAUTHZ,
.name = TYPE_QAUTHZ_PAM,
.instance_size = sizeof(QAuthZPAM),
.instance_finalize = qauthz_pam_finalize,
.class_size = sizeof(QAuthZPAMClass),
.class_init = qauthz_pam_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
static void
qauthz_pam_register_types(void)
{
type_register_static(&qauthz_pam_info);
}
type_init(qauthz_pam_register_types);