Messages in this thread | | | Date | Tue, 22 Feb 2011 10:47:26 -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 10:32:19AM -0800, David Daney wrote: > On 02/22/2011 10:16 AM, Kees Cook wrote: > >Har har, I forgot --compose to "git send-email". > > > >Anyway, with the continuing deluge of bugs in the "debug" filesystem, I > >would like to make that filesystem's root directory mode 0700 by default > >since it's filled with crazy stuff that regular users do not need to see. > > > >Better to try to just close the door completely on all the stuff in there. > >It is, after all, supposed to only be used for debugging, right? > > > > It depends if you consider use of ftrace and kprobes 'debugging'. > In any event, you really have to be root to be able to manipulate > them. > > I can currently do 'cat /sys/kernel/debug/tracing/trace' as a normal > user. With your change I don't think it would be possible. This is > not something I often (ever) do, but it is a change.
Right, my thinking is that all the manipulations on this tree should be root-only (non-root stuff shouldn't live in something named "debug"), so we might as well lock it down a bit more so we can avoid all the CVEs[1] being assigned for glitches in this tree.
-Kees
[1] http://seclists.org/oss-sec/2011/q1/229 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-4347 etc
-- Kees Cook Ubuntu Security Team
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