Messages in this thread | | | Date | Tue, 22 Feb 2011 11:50:18 -0800 | From | Kees Cook <> | Subject | Re: [PATCH 2/2] debugfs: only allow root access to debugging interfaces |
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On Tue, Feb 22, 2011 at 07:34:18PM +0000, Alan Cox wrote: > > What system do you proposed to keep these "stupid mistakes" from > > continuing to happen? If debugfs had already been mode 0700, we could have > > avoided all of these CVEs, including the full-blown local root escalation. > > And all sorts of features would have put themselves in sysfs instead and > broken no doubt. > > > The "no rules" approach to debugfs is not a good idea, IMO. > > It's a debugging fs, it needs to be "no rules" other than the obvious > "don't mount it on production systems"
Okay, so the debugfs is not supposed to be mounted on a production system. This seems to be news to a lot of developers trying to use the interfaces exposed there. It would be nice to say this more loudly. Basically, a normal system should not depend on anything in the debugfs. I can get behind that.
> Or of course you could just chmod it 0700 in the distro !
I'm trying to, but that involves a race condition since I can't control it during the mount (nor set the default mode like I was trying to with the patchset). tmpfs allows "mode=", but debugfs does not...
-Kees
-- Kees Cook Ubuntu Security Team
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