Check that a user-provided thermal state is within the maximum thermal states supported by a given driver before attempting to apply it. This prevents a subsequent OOB access in thermal_cooling_device_stats_update() while performing state-transition accounting on drivers that do not have this check in their set_cur_state() handle.
Signed-off-by: Varad Gautam varadgautam@google.com Cc: stable@vger.kernel.org --- drivers/thermal/thermal_sysfs.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 1c4aac8464a7..0c6b0223b133 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -607,7 +607,7 @@ cur_state_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct thermal_cooling_device *cdev = to_cooling_device(dev); - unsigned long state; + unsigned long state, max_state; int result;
if (sscanf(buf, "%ld\n", &state) != 1) @@ -618,10 +618,20 @@ cur_state_store(struct device *dev, struct device_attribute *attr,
mutex_lock(&cdev->lock);
+ result = cdev->ops->get_max_state(cdev, &max_state); + if (result) + goto unlock; + + if (state > max_state) { + result = -EINVAL; + goto unlock; + } + result = cdev->ops->set_cur_state(cdev, state); if (!result) thermal_cooling_device_stats_update(cdev, state);
+unlock: mutex_unlock(&cdev->lock); return result ? result : count; }