thermal: fix potential out-of-bounds memory access

temp_crit.name and temp_input.name have a length of 16 bytes.  Using
THERMAL_NAME_LENGTH (20) as length parameter for snprintf() may result in
out-of-bounds memory accesses.  Replace it with sizeof().

Addresses Coverity #115679

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: Len Brown <lenb@kernel.org>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 5be8728..36e6f4d 100644 (file)
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -598,7 +598,7 @@ thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
        temp->tz = tz;
        hwmon->count++;
 
-       snprintf(temp->temp_input.name, THERMAL_NAME_LENGTH,
+       snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
                 "temp%d_input", hwmon->count);
        temp->temp_input.attr.attr.name = temp->temp_input.name;
        temp->temp_input.attr.attr.mode = 0444;
@@ -611,7 +611,8 @@ thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
        if (tz->ops->get_crit_temp) {
                unsigned long temperature;
                if (!tz->ops->get_crit_temp(tz, &temperature)) {
-                       snprintf(temp->temp_crit.name, THERMAL_NAME_LENGTH,
+                       snprintf(temp->temp_crit.name,
+                                sizeof(temp->temp_crit.name),
                                "temp%d_crit", hwmon->count);
                        temp->temp_crit.attr.attr.name = temp->temp_crit.name;
                        temp->temp_crit.attr.attr.mode = 0444;