rtnl: fix info leak on RTM_GETLINK request for VF devices

[ Upstream commit 84d73cd3fb142bf1298a8c13fd4ca50fd2432372 ]

Initialize the mac address buffer with 0 as the driver specific function
will probably not fill the whole buffer. In fact, all in-kernel drivers
fill only ETH_ALEN of the MAX_ADDR_LEN bytes, i.e. 6 of the 32 possible
bytes. Therefore we currently leak 26 bytes of stack memory to userland
via the netlink interface.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 5229c7f..92f8ed8 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -973,6 +973,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                         * report anything.
                         */
                        ivi.spoofchk = -1;
                         * report anything.
                         */
                        ivi.spoofchk = -1;

+                       memset(ivi.mac, 0, sizeof(ivi.mac));

                        if (dev->netdev_ops->ndo_get_vf_config(dev, i, &ivi))
                                break;
                        vf_mac.vf =
                        if (dev->netdev_ops->ndo_get_vf_config(dev, i, &ivi))
                                break;
                        vf_mac.vf =