logind: introduce CanReboot/CanPowerOff bus calls

7 files changed, 125 insertions, 36 deletions

diff --git a/src/hostname/hostnamed.c b/src/hostname/hostnamed.c
index 1340c29dd5..ad72440845 100644
--- a/src/hostname/hostnamed.c
+++ b/src/hostname/hostnamed.c
@@ -332,7 +332,7 @@ static DBusHandlerResult hostname_message_handler(
                 if (!streq_ptr(name, data[PROP_HOSTNAME])) {
                         char *h;
 
-                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-hostname", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-hostname", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -376,7 +376,7 @@ static DBusHandlerResult hostname_message_handler(
 
                 if (!streq_ptr(name, data[PROP_STATIC_HOSTNAME])) {
 
-                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-static-hostname", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-static-hostname", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -441,7 +441,7 @@ static DBusHandlerResult hostname_message_handler(
 
                         r = verify_polkit(connection, message, k == PROP_PRETTY_HOSTNAME ?
                                           "org.freedesktop.hostname1.set-static-hostname" :
-                                          "org.freedesktop.hostname1.set-machine-info", interactive, &error);
+                                          "org.freedesktop.hostname1.set-machine-info", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
diff --git a/src/locale/localed.c b/src/locale/localed.c
index d46d91e032..e9f9f86878 100644
--- a/src/locale/localed.c
+++ b/src/locale/localed.c
@@ -1100,7 +1100,7 @@ static DBusHandlerResult locale_message_handler(
 
                 if (modified) {
 
-                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-locale", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-locale", interactive, NULL, &error);
                         if (r < 0) {
                                 strv_free(l);
                                 return bus_send_error_reply(connection, message, &error, r);
@@ -1181,7 +1181,7 @@ static DBusHandlerResult locale_message_handler(
                 if (!streq_ptr(keymap, state.vc_keymap) ||
                     !streq_ptr(keymap_toggle, state.vc_keymap_toggle)) {
 
-                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -1251,7 +1251,7 @@ static DBusHandlerResult locale_message_handler(
                     !streq_ptr(variant, state.x11_variant) ||
                     !streq_ptr(options, state.x11_options)) {
 
-                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.locale1.set-keyboard", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index a50db630a0..7794ab917e 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -129,6 +129,12 @@
         "  <method name=\"Reboot\">\n"                                  \
         "   <arg name=\"interactive\" type=\"b\" direction=\"in\"/>\n"  \
         "  </method>\n"                                                 \
+        "  <method name=\"CanPowerOff\">\n"                             \
+        "   <arg name=\"result\" type=\"s\" direction=\"out\"/>\n"      \
+        "  </method>\n"                                                 \
+        "  <method name=\"CanReboot\">\n"                               \
+        "   <arg name=\"result\" type=\"s\" direction=\"out\"/>\n"      \
+        "  </method>\n"                                                 \
         "  <signal name=\"SessionNew\">\n"                              \
         "   <arg name=\"id\" type=\"s\"/>\n"                            \
         "   <arg name=\"path\" type=\"o\"/>\n"                          \
@@ -714,6 +720,37 @@ static int flush_devices(Manager *m) {
         return trigger_device(m, NULL);
 }
 
+static int have_multiple_sessions(
+                DBusConnection *connection,
+                Manager *m,
+                DBusMessage *message,
+                DBusError *error) {
+
+        Session *s;
+
+        assert(m);
+
+        if (hashmap_size(m->sessions) > 1)
+                return true;
+
+        /* Hmm, there's only one session, but let's make sure it
+         * actually belongs to the user who is asking. If not, better
+         * be safe than sorry. */
+
+        s = hashmap_first(m->sessions);
+        if (s) {
+                unsigned long ul;
+
+                ul = dbus_bus_get_unix_user(connection, dbus_message_get_sender(message), error);
+                if (ul == (unsigned long) -1)
+                        return -EIO;
+
+                return s->user->uid != ul;
+        }
+
+        return false;
+}
+
 static const BusProperty bus_login_manager_properties[] = {
         { "ControlGroupHierarchy",  bus_property_append_string,         "s",  offsetof(Manager, cgroup_path),        true },
         { "Controllers",            bus_property_append_strv,           "as", offsetof(Manager, controllers),        true },
@@ -1261,7 +1298,7 @@ static DBusHandlerResult manager_message_handler(
                 if (!pw)
                         return bus_send_error_reply(connection, message, NULL, errno ? -errno : -EINVAL);
 
-                r = verify_polkit(connection, message, "org.freedesktop.login1.set-user-linger", interactive, &error);
+                r = verify_polkit(connection, message, "org.freedesktop.login1.set-user-linger", interactive, NULL, &error);
                 if (r < 0)
                         return bus_send_error_reply(connection, message, &error, r);
 
@@ -1321,7 +1358,7 @@ static DBusHandlerResult manager_message_handler(
                 if (!path_startswith(sysfs, "/sys") || !seat_name_is_valid(seat))
                         return bus_send_error_reply(connection, message, NULL, -EINVAL);
 
-                r = verify_polkit(connection, message, "org.freedesktop.login1.attach-device", interactive, &error);
+                r = verify_polkit(connection, message, "org.freedesktop.login1.attach-device", interactive, NULL, &error);
                 if (r < 0)
                         return bus_send_error_reply(connection, message, &error, r);
 
@@ -1344,7 +1381,7 @@ static DBusHandlerResult manager_message_handler(
                                     DBUS_TYPE_INVALID))
                         return bus_send_error_reply(connection, message, &error, -EINVAL);
 
-                r = verify_polkit(connection, message, "org.freedesktop.login1.flush-devices", interactive, &error);
+                r = verify_polkit(connection, message, "org.freedesktop.login1.flush-devices", interactive, NULL, &error);
                 if (r < 0)
                         return bus_send_error_reply(connection, message, &error, r);
 
@@ -1372,27 +1409,11 @@ static DBusHandlerResult manager_message_handler(
                                     DBUS_TYPE_INVALID))
                         return bus_send_error_reply(connection, message, &error, -EINVAL);
 
-                multiple_sessions = hashmap_size(m->sessions) > 1;
-
-                if (!multiple_sessions) {
-                        Session *s;
-
-                        /* Hmm, there's only one session, but let's
-                         * make sure it actually belongs to the user
-                         * who is asking. If not, better be safe than
-                         * sorry. */
-
-                        s = hashmap_first(m->sessions);
-                        if (s) {
-                                unsigned long ul;
-
-                                ul = dbus_bus_get_unix_user(connection, dbus_message_get_sender(message), &error);
-                                if (ul == (unsigned long) -1)
-                                        return bus_send_error_reply(connection, message, &error, -EIO);
+                r = have_multiple_sessions(connection, m, message, &error);
+                if (r < 0)
+                        return bus_send_error_reply(connection, message, &error, r);
 
-                                multiple_sessions = s->user->uid != ul;
-                        }
-                }
+                multiple_sessions = r > 0;
 
                 if (streq(dbus_message_get_member(message), "PowerOff")) {
                         if (multiple_sessions)
@@ -1410,7 +1431,7 @@ static DBusHandlerResult manager_message_handler(
                         name = SPECIAL_REBOOT_TARGET;
                 }
 
-                r = verify_polkit(connection, message, action, interactive, &error);
+                r = verify_polkit(connection, message, action, interactive, NULL, &error);
                 if (r < 0)
                         return bus_send_error_reply(connection, message, &error, r);
 
@@ -1442,6 +1463,50 @@ static DBusHandlerResult manager_message_handler(
                 if (!reply)
                         goto oom;
 
+        } else if (dbus_message_is_method_call(message, "org.freedesktop.login1.Manager", "CanPowerOff") ||
+                   dbus_message_is_method_call(message, "org.freedesktop.login1.Manager", "CanReboot")) {
+
+                bool multiple_sessions, challenge, b;
+                const char *t, *action;
+
+                r = have_multiple_sessions(connection, m, message, &error);
+                if (r < 0)
+                        return bus_send_error_reply(connection, message, &error, r);
+
+                multiple_sessions = r > 0;
+
+                if (streq(dbus_message_get_member(message), "CanPowerOff")) {
+                        if (multiple_sessions)
+                                action = "org.freedesktop.login1.power-off-multiple-sessions";
+                        else
+                                action = "org.freedesktop.login1.power-off";
+
+                } else {
+                        if (multiple_sessions)
+                                action = "org.freedesktop.login1.reboot-multiple-sessions";
+                        else
+                                action = "org.freedesktop.login1.reboot";
+                }
+
+                r = verify_polkit(connection, message, action, false, &challenge, &error);
+                if (r < 0)
+                        return bus_send_error_reply(connection, message, &error, r);
+
+                reply = dbus_message_new_method_return(message);
+                if (!reply)
+                        goto oom;
+
+                t =     r > 0 ?     "yes" :
+                        challenge ? "challenge" :
+                                    "no";
+
+                b = dbus_message_append_args(
+                                reply,
+                                DBUS_TYPE_STRING, &t,
+                                DBUS_TYPE_INVALID);
+                if (!b)
+                        goto oom;
+
         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Introspectable", "Introspect")) {
                 char *introspection = NULL;
                 FILE *f;
diff --git a/src/login/org.freedesktop.login1.conf b/src/login/org.freedesktop.login1.conf
index 5ae143694d..9ef852bb73 100644
--- a/src/login/org.freedesktop.login1.conf
+++ b/src/login/org.freedesktop.login1.conf
@@ -86,6 +86,14 @@
 
                 <allow send_destination="org.freedesktop.login1"
                        send_interface="org.freedesktop.login1.Manager"
+                       send_member="CanPowerOff"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Manager"
+                       send_member="CanReboot"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Manager"
                        send_member="AttachDevice"/>
 
                 <allow send_destination="org.freedesktop.login1"
diff --git a/src/polkit.c b/src/polkit.c
index 5b67480fe5..3acbdc6135 100644
--- a/src/polkit.c
+++ b/src/polkit.c
@@ -82,6 +82,7 @@ int verify_polkit(
                 DBusMessage *request,
                 const char *action,
                 bool interactive,
+                bool *_challenge,
                 DBusError *error) {
 
         DBusMessage *m = NULL, *reply = NULL;
@@ -94,7 +95,7 @@ int verify_polkit(
         uint64_t starttime_u64;
         DBusMessageIter iter_msg, iter_struct, iter_array, iter_dict, iter_variant;
         int r;
-        dbus_bool_t authorized = FALSE;
+        dbus_bool_t authorized = FALSE, challenge = FALSE;
 
         assert(c);
         assert(request);
@@ -176,7 +177,21 @@ int verify_polkit(
 
         dbus_message_iter_get_basic(&iter_struct, &authorized);
 
-        r = authorized ? 0 : -EPERM;
+        if (!dbus_message_iter_next(&iter_struct) ||
+            dbus_message_iter_get_arg_type(&iter_struct) != DBUS_TYPE_BOOLEAN) {
+                r = -EIO;
+                goto finish;
+        }
+
+        dbus_message_iter_get_basic(&iter_struct, &challenge);
+
+        if (authorized)
+                r = 1;
+        else if (_challenge) {
+                *_challenge = !!challenge;
+                r = 0;
+        } else
+                r = -EPERM;
 
 finish:
 
diff --git a/src/polkit.h b/src/polkit.h
index fc4e77118f..0d08194b26 100644
--- a/src/polkit.h
+++ b/src/polkit.h
@@ -30,6 +30,7 @@ int verify_polkit(
                 DBusMessage *request,
                 const char *action,
                 bool interactive,
+                bool *challenge,
                 DBusError *error);
 
 #endif
diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
index 97306e9a32..792c61a7d7 100644
--- a/src/timedate/timedated.c
+++ b/src/timedate/timedated.c
@@ -553,7 +553,7 @@ static DBusHandlerResult timedate_message_handler(
                 if (!streq_ptr(z, tz.zone)) {
                         char *t;
 
-                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-timezone", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-timezone", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -611,7 +611,7 @@ static DBusHandlerResult timedate_message_handler(
                 if (lrtc != tz.local_rtc) {
                         struct timespec ts;
 
-                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-local-rtc", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-local-rtc", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -702,7 +702,7 @@ static DBusHandlerResult timedate_message_handler(
                         struct timespec ts;
                         struct tm* tm;
 
-                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-time", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-time", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);
 
@@ -741,7 +741,7 @@ static DBusHandlerResult timedate_message_handler(
 
                 if (ntp != !!tz.use_ntp) {
 
-                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-ntp", interactive, &error);
+                        r = verify_polkit(connection, message, "org.freedesktop.timedate1.set-ntp", interactive, NULL, &error);
                         if (r < 0)
                                 return bus_send_error_reply(connection, message, &error, r);