ethtool: Use kcalloc instead of kmalloc for ethtool_get_strings

commit 077cb37fcf6f00a45f375161200b5ee0cd4e937b upstream.

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>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 17cb912793fa5ef0d221abda0dfb447b216b4268..e264527e41f8796035220b004c1f1f6d01cb1fba 100644 (file)
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1255,7 +1255,7 @@ 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;