debugfs: Make debugfs_allow RO after init

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

Fixes: a24c6f7bc9 ("debugfs: Add access restriction option")
Cc: Peter Enderborg <peter.enderborg@sony.com>
Reviewed-by: Peter Enderborg <peter.enderborg@sony.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210405213959.3079432-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kees Cook 2021-04-05 14:39:59 -07:00 committed by Greg Kroah-Hartman
parent c2f3f755f5
commit 312723a0b3

View File

@ -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