Subject: [PATCH 10/11] ethtool: Use kcalloc instead of kmalloc for ethtool_get_strings

From: Joe Perches <[email-masked]>
Date: Wed, 14 Oct 2015 01:09:40 -0700

[ Upstream commit 077cb37fcf6f00a45f375161200b5ee0cd4e937b ]

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 <[email-masked]>
Acked-by: Ben Hutchings <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/core/ethtool.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 06dfb29..14bb158 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1257,7 +1257,7 @@ 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;
 
-- 
1.7.10.4