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powercap: restrict energy meter to root access

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Remove non-privileged user access to power data contained in
/sys/class/powercap/intel-rapl*/*/energy_uj

Non-privileged users currently have read access to power data and can
use this data to form a security attack. Some privileged
drivers/applications need read access to this data, but don't expose it
to non-privileged users.

For example, thermald uses this data to ensure that power management
works correctly. Thus removing non-privileged access is preferred over
completely disabling this power reporting capability with
CONFIG_INTEL_RAPL=n.

Fixes: 95677a9a38 ("PowerCap: Fix mode for energy counter")

Signed-off-by: Len Brown <len.brown@intel.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Len Brown 2020-11-10 13:00:00 -08:00
parent 3d7772ea56
commit 949dd0104c
1 changed files with 2 additions and 2 deletions
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4
drivers/powercap/powercap_sys.c
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@ -367,9 +367,9 @@ static void create_power_zone_common_attributes(
&dev_attr_max_energy_range_uj.attr;
if (power_zone->ops->get_energy_uj) {
if (power_zone->ops->reset_energy_uj)
dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUGO;
dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUSR;
else
dev_attr_energy_uj.attr.mode = S_IRUGO;
dev_attr_energy_uj.attr.mode = S_IRUSR;
power_zone->zone_dev_attrs[count++] =
&dev_attr_energy_uj.attr;
}