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leds: do not overflow sysfs buffer in led_trigger_show

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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>
This commit is contained in:
Nathan Sullivan 2016-08-15 17:20:14 -05:00 committed by Jacek Anaszewski
parent 50237863c4
commit 3b9b95363c
1 changed files with 7 additions and 5 deletions
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12
drivers/leds/led-triggers.c
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@ -81,21 +81,23 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
down_read(&led_cdev->trigger_lock); down_read(&led_cdev->trigger_lock);
if (!led_cdev->trigger) if (!led_cdev->trigger)
len += sprintf(buf+len, "[none] "); len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
else else
len += sprintf(buf+len, "none "); len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
list_for_each_entry(trig, &trigger_list, next_trig) { list_for_each_entry(trig, &trigger_list, next_trig) {
if (led_cdev->trigger && !strcmp(led_cdev->trigger->name, if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
trig->name)) trig->name))
len += sprintf(buf+len, "[%s] ", trig->name); len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
trig->name);
else 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(&led_cdev->trigger_lock);
up_read(&triggers_list_lock); up_read(&triggers_list_lock);
len += sprintf(len+buf, "\n"); len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
return len; return len;
} }
EXPORT_SYMBOL_GPL(led_trigger_show); EXPORT_SYMBOL_GPL(led_trigger_show);