Re: [patch v2] fbdev: fix snprintf() limit in show_bl_curve()

From: Tomi Valkeinen <hidden>
Date: 2015-09-01 10:35:57
Also in: kernel-janitors


On 24/08/15 22:54, Dan Carpenter wrote:
quoted hunk
The limit should be "PAGE_SIZE - len" instead of PAGE_SIZE.  Also let's
use scnprintf() because snprintf() returns the number of bytes which
would have been printed if there were space and scnprintf() returns the
number of bytes actually printed.

I don't think we are ever going to actually hit this limit in real life.

Signed-off-by: Dan Carpenter <redacted>
diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
index 60c3f0a..15755ce 100644
--- a/drivers/video/fbdev/core/fbsysfs.c
+++ b/drivers/video/fbdev/core/fbsysfs.c
@@ -485,7 +485,7 @@ static ssize_t show_bl_curve(struct device *device,
 
 	mutex_lock(&fb_info->bl_curve_mutex);
 	for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
-		len += snprintf(&buf[len], PAGE_SIZE, "%8ph\n",
+		len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n",
 				fb_info->bl_curve + i);
 	mutex_unlock(&fb_info->bl_curve_mutex);
Thanks, queued for 4.3.

 Tomi

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