tracefs: Add missing lockdown check to tracefs_create_dir()

commit 51aab5ffceb43e05119eb059048fd75765d2bc21 upstream.

The function tracefs_create_dir() was missing a lockdown check and was
called by the RV code. This gave an inconsistent behavior of this function
returning success while other tracefs functions failed. This caused the
inode being freed by the wrong kmem_cache.

Link: https://lkml.kernel.org/r/20230905182711.692687042@goodmis.org
Link: https://lore.kernel.org/all/202309050916.58201dc6-oliver.sang@intel.com/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Ching-lin Yu <chinglinyu@google.com>
Fixes: bf8e602186ec4 ("tracing: Do not create tracefs files if tracefs lockdown is in effect")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index da85b3979195747d09b788ca7884f7575bf3ff15..6541d917e15e10ee9b946b5ed1805bb084d8203c 100644 (file)
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -556,6 +556,9 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent,
  */
 struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
 {
+       if (security_locked_down(LOCKDOWN_TRACEFS))
+               return NULL;
+
        return __create_dir(name, parent, &simple_dir_inode_operations);
 }