[PATCH 3.2 45/46] net: fix infoleak in rtnetlink

[Ben Hutchings <ben@decadent.org.uk>]

3.2.81-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Kangjie Lu <kangjielu@gmail.com>

commit 5f8e44741f9f216e33736ea4ec65ca9ac03036e6 upstream.

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>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/core/rtnetlink.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -920,14 +920,16 @@ static int rtnl_fill_ifinfo(struct sk_bu
 		NLA_PUT_STRING(skb, IFLA_IFALIAS, dev->ifalias);
 
 	if (1) {
-		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;
+
 		NLA_PUT(skb, IFLA_MAP, sizeof(map), &map);
 	}