Re: [RFC] add mount options to sysfs

From: Vasiliy Kulikov
Date: Fri May 20 2011 - 06:00:56 EST

On Thu, May 19, 2011 at 10:12 -0700, Greg KH wrote:
> On Thu, May 19, 2011 at 10:26:23AM +0400, Vasiliy Kulikov wrote:
> > On Wed, May 18, 2011 at 12:17 -0700, Greg KH wrote:
> > > Maybe, but fixing the file would be the obvious solution.
> >
> > I mean for a sysadmin, not for a developer.
> And I mean for the developer.
> We have checks in place now to prevent this type of thing from happening
> again in the future. If it does, and it might, we will fix it, it's
> that simple.

Simple indeed. But not as fast as simple:;a=commitdiff;h=49d50fb1c28738ef6bad0c2b87d5355a1653fed5

More than 40 days from the report to the actual commit. Sometimes it
needs some workaround.

> > What do you mean by "breaking system"? Root is able to chmod
> > and chown sysfs files already, he may do "chmod -R" or similar.
> > I suggest sane, race free way to globally restrict permissions *IF* root
> > wants it.
> If root wants it, they can do this today with a simple 1 line bash
> command, so I don't see the issue.

The issue is a race condition between the file creation and chmod'ing.

> > Here you, not aware of usefull
> > applications of world-writable debugfs file, agreeded to statically
> > restrict permissions of all files. I suggest more flexible and
> > configurable in runtime solution. It doesn't break anything - default
> > behaviour doesn't differ from current one. What has changed in your
> > mind since 2/25?
> That's debugfs, not sysfs, which we are talking about here, right?

Correct. So, if I understood you, you are OK with adding mount options
for debugfs, but not sysfs, right? What is the difference between them
in sense of permissions?


Vasiliy Kulikov - bringing security into open computing environments
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at