Commit 2a96243e authored by Zhang Rui's avatar Zhang Rui Committed by Rafael J. Wysocki
Browse files

thermal: intel: x86_pkg_temp_thermal: Add lower bound check for sysfs input 



When setting a trip point temperature from sysfs, there is an upper
bound check on the user input, but no lower bound check.

As hardware register has 7 bits for a trip point temperature, the offset
to tj_max of the input temperature must be equal to/less than 0x7f.
Or else,
 1. bogus temperature is updated into the trip temperature bits.
 2. the upper bits of the register can be polluted.

For example,
$ rdmsr 0x1b2
2000003
$ echo -180000 > /sys/class/thermal/thermal_zone1/trip_point_1_temp
$ rdmsr 0x1b2
3980003

Not only the trip point temp is set to 76C on this platform (tj_max is
100), the Power Notification (Bit 24) is also enabled erronously.

Fix the problem by adding lower bound check for sysfs input.

Reported-by: default avatarDan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/all/add7a378-4d50-4ba1-81d3-a0c17db25a0b@kili.mountain/


Signed-off-by: default avatarZhang Rui <rui.zhang@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent eeac8ede

drivers/thermal/intel/x86_pkg_temp_thermal.c

+5 −3
Original line number Diff line number Diff line
@@ -124,14 +124,16 @@ sys_set_trip_temp(struct thermal_zone_device *tzd, int trip, int temp) 
{

	struct zone_device *zonedev = tzd->devdata;

	u32 l, h, mask, shift, intr;

	int tj_max, ret;

	int tj_max, val, ret;



	tj_max = intel_tcc_get_tjmax(zonedev->cpu);

	if (tj_max < 0)

		return tj_max;

	tj_max *= 1000;



	if (trip >= MAX_NUMBER_OF_TRIPS || temp >= tj_max)

	val = (tj_max - temp)/1000;



	if (trip >= MAX_NUMBER_OF_TRIPS || val < 0 || val > 0x7f)

		return -EINVAL;



	ret = rdmsr_on_cpu(zonedev->cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT,
@@ -156,7 +158,7 @@ sys_set_trip_temp(struct thermal_zone_device *tzd, int trip, int temp) 
	if (!temp) {

		l &= ~intr;

	} else {

		l |= (tj_max - temp)/1000 << shift;

		l |= val << shift;

		l |= intr;

	}