On Tue, Jan 19, 2016 at 01:55:43PM +0100, Dmitry Vyukov wrote:

quoted

quoted

+static int __init kcov_init(void)
+{
+     if (!debugfs_create_file("kcov", 0666, NULL, NULL, &kcov_fops)) {

Why 0666? May be 0600?.

The idea is that it can be useful to fuzz-test under a normal user as well.
This file is also guarded by debugfs mount permissions. Usually it is mounted
as 0700, so normal users can't get access to it.
However if one wants to fuzz-test under a normal user, he could mount
debugfs as 0777 and get access to this file.

I am not very strong about this, though. If you say, I will change it to 0600.
I open this file as root at the moment. And we can change it back
if/when we better understand a potential use case.

I think it's safer to make it 0600. It's up to system administrator to
change permissions, if he wants give this capability to mortals.

-- 
 Kirill A. Shutemov