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 b495ab1797fae303d12a3251f09b141052c1ff55..29edf74846fc9cfef49f3fc35b4ba41de6c254af 100644 (file)
--- 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;