[PATCH] debugfs: Make debugfs_allow RO after init

From: Kees Cook
Date: Mon Apr 05 2021 - 17:40:16 EST


Since debugfs_allow is only set at boot time during __init, make it
read-only after being set.

Cc: Peter Enderborg <peter.enderborg@xxxxxxxx>
Fixes: a24c6f7bc923 ("debugfs: Add access restriction option")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/debugfs/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 22e86ae4dd5a..1d252164d97b 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -35,7 +35,7 @@
static struct vfsmount *debugfs_mount;
static int debugfs_mount_count;
static bool debugfs_registered;
-static unsigned int debugfs_allow = DEFAULT_DEBUGFS_ALLOW_BITS;
+static unsigned int debugfs_allow __ro_after_init = DEFAULT_DEBUGFS_ALLOW_BITS;

/*
* Don't allow access attributes to be changed whilst the kernel is locked down
--
2.25.1