Re: [PATCH] debugfs: Make debugfs_allow RO after init

[Peter.Enderborg]

On 4/5/21 11:39 PM, Kees Cook wrote:
> 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

Tnx. Looks good to me.

You can add:

Reviewed-by: Peter Enderborg <peter.enderborg@xxxxxxxx>