Re: [PATCH] leds: do not overflow sysfs buffer in led_trigger_show

[Jacek Anaszewski]

Hi Zach,

On 08/16/2016 12:20 AM, Zach Brown wrote:

From: Nathan Sullivan <nathan.sulli...@ni.com>

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.sulli...@ni.com>
Signed-off-by: Zach Brown <zach.br...@ni.com>
---
  drivers/leds/led-triggers.c | 12 +++++++-----
  1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index c92702a..8668538 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);

Thanks for the patch, applied.

--
Best regards,
Jacek Anaszewski