From: norly <ny-git@enpas.org>
Date: Tue, 19 Feb 2019 19:19:53 +0000 (+0100)
Subject: Always copy IFNAMSIZ bytes on ioctl(SIOCGIFNAME)
X-Git-Url: https://git.enpas.org/?a=commitdiff_plain;h=7b1cd7413d32e591dac47058721c548080257cfb;p=elmcan.git

Always copy IFNAMSIZ bytes on ioctl(SIOCGIFNAME)

Just in case dev->name is ever not NUL terminated
---

diff --git a/module/elmcan.c b/module/elmcan.c
index abdf8b5..10ca308 100644
--- a/module/elmcan.c
+++ b/module/elmcan.c
@@ -1273,15 +1273,13 @@ static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file,
 			unsigned int cmd, unsigned long arg)
 {
 	struct elmcan *elm = get_elm(tty);
-	unsigned int tmp;
 
 	if (!elm)
 		return -EINVAL;
 
 	switch (cmd) {
 	case SIOCGIFNAME:
-		tmp = strlen(elm->dev->name) + 1;
-		if (copy_to_user((void __user *)arg, elm->dev->name, tmp)) {
+		if (copy_to_user((void __user *)arg, elm->dev->name, IFNAMSIZ)) {
 			put_elm(elm);
 			return -EFAULT;
 		}