capng: Drop supplemental groups when switching to daemon user

This patch ensures the daemon process doesn't inherit any supplemental
groups for the root user from an administrator login via an init
script.

This is only an issue for pre-systemd systems.

https://bugzilla.redhat.com/show_bug.cgi?id=726953

diff --git a/bus/selinux.c b/bus/selinux.c
index e94d8a8..36287e9 100644 (file)
--- a/bus/selinux.c
+++ b/bus/selinux.c
@@ -1055,7 +1055,7 @@ _dbus_change_to_daemon_user  (const char    *user,
       capng_clear (CAPNG_SELECT_BOTH);
       capng_update (CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
                     CAP_AUDIT_WRITE);
-      rc = capng_change_id (uid, gid, 0);
+      rc = capng_change_id (uid, gid, CAPNG_DROP_SUPP_GRP);
       if (rc)
         {
           switch (rc) {