powercap: restrict energy meter to root access
commit 949dd0104c496fa7c14991a23c03c62e44637e71 upstream.
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: 95677a9a3847 ("PowerCap: Fix mode for energy counter")
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c
index f808c5f..3f0b8e2 100644
--- a/drivers/powercap/powercap_sys.c
+++ b/drivers/powercap/powercap_sys.c
@@ -367,9 +367,9 @@
&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;
}
