Re: [PATCH v4] cpuidle: Add a sysfs entry to disable specific C state for debug purpose.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, 16 Mar 2012, Andrew Morton wrote:
> > +#define define_store_state_function(_name) \
> > +static ssize_t store_state_##_name(struct cpuidle_state *state, \
> > +		const char *buf, size_t size) \
> > +{ \
> > +	long value; \
> > +	if (!capable(CAP_SYS_ADMIN)) \
> > +		return -EPERM; \
> 
> Is the capability check required?  The 0644 permissions aren't sufficient?

That depends.  Without capable(), restricted root (one which had its
capabilities dropped) can disable idle states.

If you want to restrict something to "root only", IMHO it should be
using capable(), as restricted root really doesn't qualify for "root
only" things.

If you wanted to restrict it to "owner only" OTOH, then yes, the
capable() check (especially with the very coarse set of capabilities we
currently have) might not be desireable.

However, if we had a power-management capability, it would be best to
use that one instead of CAP_SYS_ADMIN (aka "the new root" as LWN called
it).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/linux-pm


[Index of Archives]     [Linux ACPI]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [CPU Freq]     [Kernel Newbies]     [Fedora Kernel]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux