From: Nathan Sullivan <nathan.sullivan@ni.com>
Date: Mon, 15 Aug 2016 22:20:14 +0000 (-0500)
Subject: leds: do not overflow sysfs buffer in led_trigger_show
X-Git-Tag: v4.4.121~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dff485e36287be123a844dc9164ba0417cd34552;p=thirdparty%2Fkernel%2Fstable.git

leds: do not overflow sysfs buffer in led_trigger_show

commit 3b9b95363c45365d606ad4bbba16acca75fdf6d3 upstream.

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>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index e8b1120f486d6..eef3e64ca0a87 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -88,21 +88,23 @@ 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);