Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1844300 Upstream status: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... Build info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=32573686 CVE: CVE-2020-8694

author Len Brown len.brown@intel.com 2020-11-10 13:00:00 -0800 committer Len Brown len.brown@intel.com 2020-11-10 11:40:57 -0500 commit 949dd0104c496fa7c14991a23c03c62e44637e71 (patch) tree a90cbfb8ceb195e7160105a272122f97bab99980 parent 3d7772ea5602b88c7c7f0a50d512171a2eed6659 (diff) download linux-949dd0104c496fa7c14991a23c03c62e44637e71.tar.gz powercap: restrict energy meter to root access 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: Donghai Qiao dqiao@redhat.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 05ddf8be64a..db69be2892a 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; }