net: fix infoleak in rtnetlink

The stack object “map” has a total size of 32 bytes. Its last 4
bytes are padding generated by compiler. These padding bytes are
not initialized and sent out via “nla_put”.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a75f7e94b4456eed264a8d52c460f0b6bbf72569..65763c29f84549583cf55546ff9a45bbe921a598 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1180,14 +1180,16 @@ static noinline_for_stack int rtnl_fill_vfinfo(struct sk_buff *skb,
 
 static int rtnl_fill_link_ifmap(struct sk_buff *skb, struct net_device *dev)
 {
-       struct rtnl_link_ifmap map = {
-               .mem_start   = dev->mem_start,
-               .mem_end     = dev->mem_end,
-               .base_addr   = dev->base_addr,
-               .irq         = dev->irq,
-               .dma         = dev->dma,
-               .port        = dev->if_port,
-       };
+       struct rtnl_link_ifmap map;
+
+       memset(&map, 0, sizeof(map));
+       map.mem_start   = dev->mem_start;
+       map.mem_end     = dev->mem_end;
+       map.base_addr   = dev->base_addr;
+       map.irq         = dev->irq;
+       map.dma         = dev->dma;
+       map.port        = dev->if_port;
+
        if (nla_put(skb, IFLA_MAP, sizeof(map), &map))
                return -EMSGSIZE;