From: Len Brown len.brown@intel.com

stable inclusion from linux-4.19.157 commit 900281e167f45e0c0e5df6e59fa00334b5e38133 CVE: CVE-2020-8694

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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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/powercap/powercap_sys.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c index 9e2f274bd44f..60c8375c3c81 100644 --- a/drivers/powercap/powercap_sys.c +++ b/drivers/powercap/powercap_sys.c @@ -379,9 +379,9 @@ 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; }