authz/pamacct.c

   1 /*
   2  * QEMU PAM authorization driver
   3  *
   4  * Copyright (c) 2018 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "authz/pamacct.h"
  23 #include "trace.h"
  24 #include "qemu/module.h"
  25 #include "qom/object_interfaces.h"
  26
  27 #include <security/pam_appl.h>
  28
  29
  30 static bool qauthz_pam_is_allowed(QAuthZ *authz,
  31                                   const char *identity,
  32                                   Error **errp)
  33 {
  34     QAuthZPAM *pauthz = QAUTHZ_PAM(authz);
  35     const struct pam_conv pam_conversation = { 0 };
  36     pam_handle_t *pamh = NULL;
  37     int ret;
  38
  39     trace_qauthz_pam_check(authz, identity, pauthz->service);
  40     ret = pam_start(pauthz->service,
  41                     identity,
  42                     &pam_conversation,
  43                     &pamh);
  44     if (ret != PAM_SUCCESS) {
  45         error_setg(errp, "Unable to start PAM transaction: %s",
  46                    pam_strerror(NULL, ret));
  47         return false;
  48     }
  49
  50     ret = pam_acct_mgmt(pamh, PAM_SILENT);
  51     pam_end(pamh, ret);
  52     if (ret != PAM_SUCCESS) {
  53         error_setg(errp, "Unable to authorize user '%s': %s",
  54                    identity, pam_strerror(pamh, ret));
  55         return false;
  56     }
  57
  58     return true;
  59 }
  60
  61
  62 static void
  63 qauthz_pam_prop_set_service(Object *obj,
  64                             const char *service,
  65                             Error **errp G_GNUC_UNUSED)
  66 {
  67     QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
  68
  69     g_free(pauthz->service);
  70     pauthz->service = g_strdup(service);
  71 }
  72
  73
  74 static char *
  75 qauthz_pam_prop_get_service(Object *obj,
  76                             Error **errp G_GNUC_UNUSED)
  77 {
  78     QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
  79
  80     return g_strdup(pauthz->service);
  81 }
  82
  83
  84 static void
  85 qauthz_pam_complete(UserCreatable *uc, Error **errp)
  86 {
  87     QAuthZPAM *pauthz = QAUTHZ_PAM(uc);
  88
  89     if (!pauthz->service) {
  90         error_setg(errp, "The 'service' property must be set");
  91         return;
  92     }
  93 }
  94
  95
  96 static void
  97 qauthz_pam_finalize(Object *obj)
  98 {
  99     QAuthZPAM *pauthz = QAUTHZ_PAM(obj);
 100
 101     g_free(pauthz->service);
 102 }
 103
 104
 105 static void
 106 qauthz_pam_class_init(ObjectClass *oc, void *data)
 107 {
 108     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 109     QAuthZClass *authz = QAUTHZ_CLASS(oc);
 110
 111     ucc->complete = qauthz_pam_complete;
 112     authz->is_allowed = qauthz_pam_is_allowed;
 113
 114     object_class_property_add_str(oc, "service",
 115                                   qauthz_pam_prop_get_service,
 116                                   qauthz_pam_prop_set_service);
 117 }
 118
 119
 120 QAuthZPAM *qauthz_pam_new(const char *id,
 121                           const char *service,
 122                           Error **errp)
 123 {
 124     return QAUTHZ_PAM(
 125         object_new_with_props(TYPE_QAUTHZ_PAM,
 126                               object_get_objects_root(),
 127                               id, errp,
 128                               "service", service,
 129                               NULL));
 130 }
 131
 132
 133 static const TypeInfo qauthz_pam_info = {
 134     .parent = TYPE_QAUTHZ,
 135     .name = TYPE_QAUTHZ_PAM,
 136     .instance_size = sizeof(QAuthZPAM),
 137     .instance_finalize = qauthz_pam_finalize,
 138     .class_init = qauthz_pam_class_init,
 139     .interfaces = (InterfaceInfo[]) {
 140         { TYPE_USER_CREATABLE },
 141         { }
 142     }
 143 };
 144
 145
 146 static void
 147 qauthz_pam_register_types(void)
 148 {
 149     type_register_static(&qauthz_pam_info);
 150 }
 151
 152
 153 type_init(qauthz_pam_register_types);