Re: post-OLS pending cpufreq patches

[Dominik Brodowski <linux@dominikbrodowski.de>]

On Wed, Jul 28, 2004 at 02:59:16PM +0100, Dave Jones wrote:
> On Tue, Jul 27, 2004 at 10:51:26PM +0200, Dominik Brodowski wrote:
> 
>  > As KS and OLS are over, here's a status update on what patches and/or what
>  > issues (in the world outside of KS and OLS) are at what state at the moment.
>  > Also, I'm looking forward to read Paul's paper in the OLS proceedings, and
>  > to see what Dave has added to his TODO list :)
> 
> I fly back today (should have been last night, but thats a long
> story for another time), and expect to spend a few days doing
> nothing work related at all when I get back 8-)

Enjoy that time!

> Notes I scribbled in my TODO during OLS include..
> - check permissons on cpufreq sysfs files
> Someone mentioned that have these root r-- is a bit
> pointless as they aren't really security sensitive.

-r--------  1 root root 4096 28. Jul 18:43 cpuinfo_cur_freq
-r--r--r--  1 root root 4096 28. Jul 18:43 cpuinfo_max_freq
-r--r--r--  1 root root 4096 28. Jul 18:43 cpuinfo_min_freq
-r--r--r--  1 root root 4096 28. Jul 18:43 scaling_available_frequencies
-r--r--r--  1 root root 4096 28. Jul 18:43 scaling_available_governors
-r--r--r--  1 root root 4096 28. Jul 18:43 scaling_cur_freq
-r--r--r--  1 root root 4096 28. Jul 18:43 scaling_driver
-rw-r--r--  1 root root 4096 28. Jul 18:43 scaling_governor
-rw-r--r--  1 root root 4096 28. Jul 18:43 scaling_max_freq
-rw-r--r--  1 root root 4096 28. Jul 18:43 scaling_min_freq
-rw-r--r--  1 root root 4096 28. Jul 18:43 scaling_setspeed

The only file r-- is "cpuinfo_cur_freq", and that may involve calls to
hardware which may take a bit of time... so it's less a security issue, but
a "local DoS" issue because the system might get unresponsive [though I'd
doubt any current cpufreq driver actually might be "exploitable" this
way...]

> Thanks for scooping up the patches, I'll take a look at merging
> them a few days after I get back, possibly the weekend, Monday
> at the latest.

Thanks,
	Dominik