Raffle 0

From: Pawan Gupta <[email protected]>
Subject: [PATCH] powercap: restrict energy meter to root access

From: Len Brown <[email protected]>

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.

---
 drivers/powercap/powercap_sys.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index f808c5fa9838..3f0b8e2ef3d4 100644
@@ -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;
 	}

2.21.3