1 files changed, 83 insertions, 0 deletions
diff --git a/src/dbus-common.c b/src/dbus-common.c
new file mode 100644
index 000000000..504eefbbb
--- /dev/null
+++ b/src/dbus-common.c
@@ -0,0 +1,83 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <unistd.h>
+#include <dbus/dbus.h>
+
+#include "log.h"
+#include "dbus-common.h"
+
+int bus_check_peercred(DBusConnection *c) {
+        int fd;
+        struct ucred ucred;
+        socklen_t l;
+
+        assert(c);
+
+        assert_se(dbus_connection_get_unix_fd(c, &fd));
+
+        l = sizeof(struct ucred);
+        if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0) {
+                log_error("SO_PEERCRED failed: %m");
+                return -errno;
+        }
+
+        if (l != sizeof(struct ucred)) {
+                log_error("SO_PEERCRED returned wrong size.");
+                return -E2BIG;
+        }
+
+        if (ucred.uid != 0)
+                return -EPERM;
+
+        return 1;
+}
+
+int bus_connect(DBusBusType t, DBusConnection **_bus, DBusError *error) {
+        DBusConnection *bus;
+
+        assert(_bus);
+
+        /* If we are root, then let's not go via the bus */
+        if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
+
+                if (!(bus = dbus_connection_open("unix:abstract=/org/freedesktop/systemd1/private", error)))
+                        return -EIO;
+
+                if (bus_check_peercred(bus) < 0) {
+                        dbus_connection_unref(bus);
+
+                        dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
+                        return -EACCES;
+                }
+        } else {
+                if (!(bus = dbus_bus_get(t, error)))
+                        return -EIO;
+        }
+
+        dbus_connection_set_exit_on_disconnect(bus, FALSE);
+
+        *_bus = bus;
+        return 0;
+}