From: Joe Perches <joe@perches.com>
Date: Wed, 14 Oct 2015 08:09:40 +0000 (-0700)
Subject: ethtool: Use kcalloc instead of kmalloc for ethtool_get_strings
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=077cb37fcf6f00a45f375161200b5ee0cd4e937b;p=linux-beck.git

ethtool: Use kcalloc instead of kmalloc for ethtool_get_strings

It seems that kernel memory can leak into userspace by a
kmalloc, ethtool_get_strings, then copy_to_user sequence.

Avoid this by using kcalloc to zero fill the copied buffer.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index b495ab1797fa..29edf74846fc 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1284,7 +1284,7 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr)
 
 	gstrings.len = ret;
 
-	data = kmalloc(gstrings.len * ETH_GSTRING_LEN, GFP_USER);
+	data = kcalloc(gstrings.len, ETH_GSTRING_LEN, GFP_USER);
 	if (!data)
 		return -ENOMEM;