leds: do not overflow sysfs buffer in led_trigger_show

Per the documentation, use scnprintf instead of sprintf to ensure there
is never more than PAGE_SIZE bytes of trigger names put into the
buffer.

Signed-off-by: Nathan Sullivan <nathan.sullivan@ni.com>
Signed-off-by: Zach Brown <zach.brown@ni.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index f0b3d101994b..59d6a3e58a3d 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -81,21 +81,23 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
         down_read(&led_cdev->trigger_lock);
 
         if (!led_cdev->trigger)
-                len += sprintf(buf+len, "[none] ");
+                len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
         else
-                len += sprintf(buf+len, "none ");
+                len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
 
         list_for_each_entry(trig, &trigger_list, next_trig) {
                 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
                                                         trig->name))
-                        len += sprintf(buf+len, "[%s] ", trig->name);
+                        len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
+                                         trig->name);
                 else
-                        len += sprintf(buf+len, "%s ", trig->name);
+                        len += scnprintf(buf+len, PAGE_SIZE - len, "%s ",
+                                         trig->name);
         }
         up_read(&led_cdev->trigger_lock);
         up_read(&triggers_list_lock);
 
-        len += sprintf(len+buf, "\n");
+        len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
         return len;
 }
 EXPORT_SYMBOL_GPL(led_trigger_show);